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Ruoss, Chantelle, Amanda Tadros, Tim O'Shea, Jim McFarlane y Ghanim Almahbobi. "Ovarian follicle development in Booroola sheep exhibiting impaired bone morphogenetic protein signalling pathway". REPRODUCTION 138, n.º 4 (octubre de 2009): 689–96. http://dx.doi.org/10.1530/rep-09-0190.
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The role of bone morphogenetic proteins (BMPs) in the regulation of ovarian function has been extensively investigated but the mechanism of regulation is not well understood. The aim of this study was to investigate the effect of mutation in the BMP receptor in Booroola sheep on the number of primordial follicles and rate of follicle recruitment in comparison with that in normal merino sheep in vivo. Whole sheep ovaries at the time of birth, 1.5 and 5 years old were collected and processed for the follicle quantification, using computerised stereological methods and statistical analyses. At birth, the total number of primordial follicles in Booroola sheep was significantly lower than in merino sheep. At 1.5 and 5 years, a reversed pattern in favour of Booroola ewes was seen with significantly more primordial follicles than merino. In parallel, the rate of primordial follicle recruitment to developing cohort was substantially lower in Booroola ewes with only 51 and 66% of primordial follicle consumption at 1.5 and 5 years respectively compared to 92 and 97% in merino ewes. On other hand, the mean numbers of developing primary follicles were smaller in Booroola sheep at the time of birth, yet, Booroola ewes possess more primary follicles than merino at 1.5 years. These findings suggest that attenuation of the intraovarian signalling pathway of BMPs may in fact be a successful means of rationalising follicle consumption, preventing unnecessary loss of follicles from the initial primordial follicle pool, hence increasing reproductive longevity and fertility.
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Torekhanov, A. A. y N. K. Zhumadillayev. "ETTI MERINOS – KAZAKHSTANI EXPORT-ORIENTED MEAT BREAD". REPORTS 335, n.º 1 (12 de febrero de 2021): 146–51. http://dx.doi.org/10.32014/2021.2518-1483.21.
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Sheep breeding in Kazakhstan is a traditional branch of animal husbandry. The development of the industry is facilitated by the presence of large areas of pasture lands, as well as the existing valuable gene pool of breed resources, created by national selection and long-term work of scientists-breeders. The republic has great potential for the further development of sheep breeding industry and is able not only to meet the population's need for mutton, but also to become a major exporter. The restoration and further development of domestic sheep breeding should be based on rational use of genetic potential of animals and natural pastures of the country for the cost-effective production of high quality sheep products that meet international standards. The article deals with the development of fine-wool sheep breeding in Almaty, Zhambyl and South Kazakhstan regions, improvement of meat characteristics of the South Kazakh merino. The experience of using "etti merino" rams-producers in farms of Turkestan region showed that meat merino rams have a positive effect on meat productivity of the South Kazakh merino, and at the same time do not worsen their wool characteristics. The information on the population number of sheep of "Etti Merino" breed for 2020, the class composition of the ewes on farms, productivity of rams-producers in a number of generations, assessment of the quality of the offspring of 6-7 month old rams, wool productivity of the breeding groups of female sheep are presented.
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Bell, Stephen. "Aimé Bonpland and Merinomania in Southern South America". Americas 51, n.º 3 (enero de 1995): 301–23. http://dx.doi.org/10.2307/1008225.
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As an integrating theme in the biological or ecological expansion of Europe, merino sheep were so important that one authority on their dispersal sees the nineteenth century standing as “the century of the Merino.” Merinos produce a wool of distinctive quality, one long appreciated for providing warmth without excessive weight. Guarded for centuries by Spanish monopoly, the breed's status as something of a prize outside Spain began to change in 1808 with the Napoleonic invasion of the Iberian peninsula. By around 1820, a major new phase in merino dispersal was underway with its adaptation to some of the vast grassland ecosystems in the Europeanizing peripheries. The breed was of critical importance to the settlement and development of Australia. It was also highly important in other parts of the southern hemisphere, including in the transformation of existing cattle cultures on the great grassland regions of the Río de la Plata. Here the merino formed the leading edge of rural modernization, offering real potential for ground-up development.
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Szabó, Mária, Szilvia Kusza, István Csízi y István Monori. "The status of the Hungarian Merino sheep breed compared to the other merino breeds". Acta Agraria Debreceniensis, n.º 69 (23 de marzo de 2016): 151–56. http://dx.doi.org/10.34101/actaagrar/69/1804.
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Merino and Merino-derived sheep breeds have been widely known and distributed across the world, both as purebred and admixed populations. They represent a diverse genetic resource which over time has been used as the basis for the development of new breeds. In spite of this, their gene-pool potential is still unexplored. The Merino sheep represent the most important sheep resource of the Hungarian husbandry. It has the largest amount of individuals between both of the stock and commercial flocks. But in Europe the Merino stocks went through a drastic reduction in number. Thus these breeds became endangered in several countries as well as in Hungary. In this study we would like to present the recent status of different Merino breeds of the world to ground our further phylogenetic research with the Hungarian Merino breed.
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Wilkes, M. J., P. I. Hynd y W. S. Pitchford. "Damara sheep have higher digestible energy intake than Merino sheep when fed low-quality or high-quality feed". Animal Production Science 52, n.º 1 (2012): 30. http://dx.doi.org/10.1071/an11033.
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The use of animals that are resilient to challenging environments is becoming of increasing importance in animal production systems. Interest in breeds of sheep such as the Damara for sheep meat production is increasing in Australia. Anecdotally this breed outperforms the traditionally grazed Merino in the harsh rangeland environments encountered in the Pastoral Zone of Australia, but little evidence is available to support this claim. A trial was conducted to quantify differences in the efficiency of feed utilisation and growth performance of Damara and Merino sheep under two contrasting dietary regimes. Eighteen castrate males of each breed were offered a ‘low-quality’ diet (L) (7 MJ/kg ME; 8% crude protein, as per manufacturer’s analysis) followed by a ‘high-quality’ diet (H) (11 MJ/kg dry matter and 16% crude protein, as per manufacturer’s analysis). On the L diet, Damaras had similar ad libitum feed intake as Merinos, but the digestibility of feed dry matter and energy was ~10% higher in Damaras than Merinos. Damaras also gained weight (38 g/day) on the L diet, while Merinos lost weight (28 g/day) (P < 0.002). On the H diet the Damaras consumed 14% more feed (P < 0.053) and grew 30% faster than Merinos (P < 0.002), but there was no difference in the apparent dry matter or energy digestibility of the feed. At the conclusion of the trial the Damara carcasses were 22% heavier (28.1 versus 23.1 kg), and had higher dressing percentages (53.2 versus 41.5%) than Merinos, but the proportions of carcass components did not differ. The Damaras achieved higher total digestible energy intakes than the Merinos on both diets. On the low-quality feed this was achieved through higher feed digestibility and on the high-quality feed through greater voluntary feed intake. We speculate that this arises from variation between the breeds in rumen volume, particle flow and the site of digestion, but further studies are required to confirm this contention. The ability of Damara sheep to obtain more nutrients from widely differing feed bases makes them an attractive alternative sheep breed for sheep meat production. Furthermore, the presence of such variation between genotypes offers potential for selective breeding and development of commercial lines of sheep.
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Edwards, J. E. Hocking, M. J. Birtles, P. M. Harris, A. L. Parry, E. Paterson, G. A. Wickham y S. N. McCutcheon. "Pre- and post-natal wool follicle development and density in sheep of five genotypes". Journal of Agricultural Science 126, n.º 3 (mayo de 1996): 363–70. http://dx.doi.org/10.1017/s002185960007492x.
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SUMMARYThe pre-natal and post-natal development of wool follicles in sheep of five genotypes with contrasting wool types was examined to provide data on which to base studies of physiological factors affecting wool type via follicle development. This study was conducted following Autumn mating in 1992 at Palmerston North, New Zealand (40° S, 176° E). The rate and timing of follicle development in midside skin samples from Romney, Merino, Merino × Romney (M × R), Drysdale and Wiltshire foetuses and lambs collected at weekly intervals from days 76 to 143 of gestation and 1, 3, 7, 12 and 32 weeks after birth were examined.Primary (P) follicle density had a similar pattern of development in each of the genotypes, although the Merino had a significantly greater density of P follicles than the other genotypes. There was a difference in the rate of P follicle maturation between genotypes with the Drysdale, Wiltshire and M × R completing P follicle maturation before the other two genotypes. However, the majority of P follicles in all genotypes were producing fibres by 111 days of gestation. It was concluded that the small differences in the density and time of development of the P follicles could not cause the differences in wool type between genotypes.The pattern of development of the secondary (S) follicle population was examined by comparing S: P ratios. The initiation of S follicles began at similar ages in the five genotypes, but initiation was completed earlier in the Romney, Drysdale and Wiltshire than in the Merino and M × R, as indicated by a significant genotype by age interaction (P < 0·001). There was no difference between genotypes in S:P ratio from 90 to 104 days of gestation. The S:P ratio of the Romney, Drysdale and Wiltshire did not change significantly from 104 days of gestation until the end of the study, indicating that few S follicles were initiated in these genotypes after 104 days of gestation. The M × R data showed a significant increase in S:P ratio until 119 days of gestation and the Merino S:P ratio increased until 126 days of gestation.The period between days 90 and 125 of gestation was identified as being the critical period for the development of different follicle populations in Merino and non-Merino genotypes and it is this period which should be the focus for studies to determine physiological factors controlling secondary follicle development.
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Khasanah, Himmatul, Gayuh Syaikhullah y Muhammad Adhyatma. "The Carcass and Nutritional Meat Characteristics of Sapudi and Cross Merino Sheep". Buletin Peternakan 46, n.º 3 (31 de agosto de 2022): 184. http://dx.doi.org/10.21059/buletinpeternak.v46i3.74048.
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Sheep meat plays an important role in accomplishing balanced and healthy nutrition as a source of protein, fat, and essential micronutrients such as zinc, iron, and vitamin B12. The amino and fatty acid composition of meat in different breeds need to be assessed to characterize and determine the development prospects of sheep that produce healthy and good quality meat. Therefore, this study aimed to investigate the phenotypic characteristics of the Sapudi and Cross Merino meat sheep including the carcass performance and meat qualities. We reared four Sapudi and four Cross Merino ewes in the same feed and environmental management for two months then slaughtered and analysed the carcass, non-carcasses and chemical meat properties. We used Bicep femoris muscle to perform proximate, amino acid, and fatty acid contents. An independent t-test was conducted to compared obtained data. Heart weight and protein content were higher in Sapudi sheep. Of the 51 fatty acids observed, we found 11 and 10 types of fatty acid in the Sapudi and Cross Merino meat, respectively. The fatty acid percentage of Sapudi meat tended to have higher value compared to Cross Merino. We also found that the two breeds have the same amino and fatty acid compositions. The levels of glycine, arginine, serine, tyrosine, phenylalanine, lysine and threonine were statistically higher in Cross Merino than Sapudi. In conclusion, the non-carcass, crude protein, amino acid and fatty acid level were significantly different between Sapudi and Cross Merino
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MUSALAYEV, KH KH, R. A. ABDULLABEKOV y P. M. MAGOMEDOVA. "MERINO SHEEP BREED RAISED UNDER MOUNTAIN BREEDING SYSTEM". Izvestiâ Timirâzevskoj selʹskohozâjstvennoj akademii, n.º 3 (2020): 81–93. http://dx.doi.org/10.26897/0021-342x-2020-3-81-93.
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Dagestan is the leading Republic of Russia in terms of the number of sheep and sheep breeding products. The zoned target sheep breed in Dagestan is the Dagestan mountain breed. However, this breed produces thin but non-merino wool. Developing the Merino sheep breed suitable for mountain breeding is an urgent problem. The new Merino sheep breed was developed for the foothill zone of Dagestan, where summer Alpine and winter low-lying pastures are located at a distance of no more than 150 km from each other, and summer Alpine pastures are located at an altitude of up to 3000 meters above sea level. The research and stock breeding work was carried out at the farm production enterprise “Krasniy Oktyabr’”, the Kazbek district, in the period between 2005 and 2019. The work resulted in the development of the Arthlukh Merino sheep breed. (Patent for selection achievement No. 10112 “State Commission of the Russian Federation for Selection Achievement Tests and Protection”). The breed was developed by crossing the Stavropol sheep rams with the Dagestan mountain sheep, with the subsequent improvement of crossbreeds by the Manych Merino breed. A distinctive feature of the new Merino breed from the basic herdmates of the Dagestan Mountain breed is the high live weight, which is 15.3–16.5% higher in different sex and age groups. Besides, the amount of washed wool shorn is 16.2–26.0% higher. The ewes’ wool fineness is 22.9 microns (19.4–23.0) – 64 qualities. That of adult rams amounts to 23.3 microns (19.9–23.3) and has 60 qualities. The difference of the wool fineness on the side and thigh does not exceed one quality. The coat length on the side of ewes is not less than 9.0 cm, rams – 9.5 cm, gimmers (young ewes) – 9.5 cm and replacement rams – 10.0 cm. The wool strength is 7.0 cN/Tex. The belly wool cover is good. The suint is stable, of a white and light cream color. The average yield of washed wool excluding the lowest grades is 64%. The fertility of ewes ranged from 125% to 135%.
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Lakota, E. А. "PRESERVATION OF GENETIC POTENTIAL OF STAVROPOL SHEEP BREED FOR POVOLZHYE DREY STEPPE ZONE". Vestnik of Ulyanovsk state agricultural academy, n.º 3(50) (8 de septiembre de 2020): 179–84. http://dx.doi.org/10.18286/1816-4501-2020-3-179-184.
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In conditions of Povolzhye steppe zone development of productive qualities of Stavropol breed sheep was conducted by meat merino sheep. Experimental research was carried out in ZAO «Novaya Zhizn» in Novouzensky district of Saratov region, located in semi desert zone, bordering upon South-West Khazakhstan. The research aim was the increase and maintenance of genetic potential of Stavropol breed sheep of Povolzhye population. Working procedure is based on guidelines of the All-Union Academy of Agricultural sciences, All Union research institute of sheep and goat breeding. The study materials were Stavropol pure breed sheep and 1/8 –thoroughbred cross breed with Australian meat merino herdmates. As the result of stepped breeding of local Stavropol ewe with half bred by Australian meat merino ram- breeder of Stavropol breed animals of 1/2 ,1/4, 1/8 –blood were obtained, which then one- shear tupped by breeding «inter se». It is proved that in applying such selective method 1/8-blood by Australian meat merino sheep were characterized with higher body weight, better wool quality in contrast to Stavropol pure –breed herdmates. So, in 1/8-blood by Australian meat merino of hybrid ewe during breeding «inter se» live body at birth was higher than at pure breed herdmates for 5,56 %, during ablactation –at the age of 4 months - for 6,38 % (difference isn’t accurate). According to sharing of wool in grease, superiority of ewe of hybrid origin over pure breed was 5,6 % (Р≥0,99), but in terms of washed fiber it increases to 8,3 % (Р≥0,999). So, in dry steppe zone of Povolzhye new improved, according to its productive qualities, genotype of Stavropol breed sheep is created with retention of genetic resource that is essential economic factor for the modern maintenance of fine-wool sheep breeding field.
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Forrest, JW y MR Fleet. "Pigmented Spots in the WoolBearing Skin of White Merino Sheep Induced by Ultraviolet Light". Australian Journal of Biological Sciences 39, n.º 2 (1986): 125. http://dx.doi.org/10.1071/bi9860125.
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Black-grey pigmented skin spots, some of which contained pigmented wool fibres, were observed in a flock of 8� 5-year-old white Merino ewes. The spots were concentrated along the backline and increased in number following shearing, suggesting exposure to sunlight to be of importance in the development of these non-congenital pigmented skin spots in genetically white Merino sheep. To test the effect of ultraviolet light, white Merino sheep, ranging in age from 3 to 8 years, had a closely clipped mid side area of wool-bearing skin irradiated on each of 28 consecutive days. Pigmented skin spots developed in 6 of the 16 white Merino sheep irradiated. Spots first appeared after 10 days of irradiation, the number subsequently increasing with time, and two skin spots were found to contain sparse numbers of blackgrey pigmented wool fibres. Histological examination showed both the naturally occurring and irradiationinduced pigmented skin spots resulted from an increase in both number and activity of melanocytes localized along the epidermal-dermal border of the epidermis. With time, the melanocytes were observed to have entered, to varying depths, the outer-root sheath of follicles still producing white wool fibres. These ultraviolet-light-induced changes to epidermal melanocytes in white Merino sheep presumably occur due to alterations within the local tissue environment in which the melanocytes lie.
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Ponnampalam, E. N., D. L. Hopkins, K. L. Butler, F. R. Dunshea y R. D. Warner. "Genotype and age effects on sheep meat production. 2. Carcass quality traits". Australian Journal of Experimental Agriculture 47, n.º 10 (2007): 1147. http://dx.doi.org/10.1071/ea07001.
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The present study examines carcass quality traits in different genotypes of Australian sheep slaughtered at 4, 8, 14 and 22 months of age. Poll Dorsetgrowth × Border Leicester Merino (PDg × BLM), Poll Dorsetgrowth × Merino (PDg × M), Poll Dorsetmuscling × Merino (PDm × M), Merino × Merino (M × M) and Border Leicester × Merino (BL × M) genotypes were compared. Sires were selected on the basis of growth (PDg, M and BL) and muscle (PDm) using estimated breeding values (EBVs). Approximately 150 mixed sex animals were slaughtered at each age (595 in total for the four slaughters) and carcass quality traits, including hot carcass weight, loin and semitendinosus (ST) muscle weights, GR fat, fat C, rump fat depth and eye muscle area (EMA), were determined at 45 min to 3 days postslaughter. With age, all carcass quality traits increased in magnitude. Merinos produced the lightest and leanest carcasses (P < 0.01) with lowest values in nearly all the carcass quality traits. At 4 and 8 months of age carcass and loin weights, EMA and GR fat measures were greater (P < 0.01) in second-cross PDg × BLM sheep than all other genotypes. However, traits related to muscle content were similar between first- and second-cross Poll Dorset genotypes at 14 and 22 months of age. The BL × M genotype had lower values than the PD × M genotypes for these traits, at all ages. Traits related to carcass fatness showed that sheep with Border Leicester genetics tend to deposit more fat (P < 0.001) in the carcass than those with Merino or Poll Dorset genetics from 14 months of age onwards. Most carcass quality traits did not differ (P > 0.05) between first-cross Poll Dorset genotypes selected for growth or muscling (PDg × M v. PDm × M). Sires with high muscling EBVs are associated more with shorter carcass length than low muscling EBVs. From ~8 months of age, wethers had greater values (P < 0.05) than ewes of the same age for most carcass quality traits related to size and muscle development, but no effect was present for carcass quality traits that were related to fat deposition. It was clear that the carcass weight of M × M at 8 and 14 months were similar to that observed in PDg × BLM at 4 and 8 months, respectively. Loin weights of M × M and BL × M at 13 and 8 months were similar to that weights observed in PDg × BLM at 8 and 4 months of age, respectively. Animals slaughtered to a muscle weight specification will reach the target at a younger age when they have more Poll Dorset than Border Leicester background genetics. Alternatively animals slaughtered at a specified fat score (using fat C or rump fat depth) will reach the specification at a younger age when they have more Border Leicester than Poll Dorset genetics.
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Tuncer, Selçuk Seçkin, Sedat Behrem, Yunus Arzık y Mehmet Kızılaslan. "Some Morphologic Characteristics of Central Anatolian Merino Sheep". Turkish Journal of Agriculture - Food Science and Technology 10, n.º 12 (20 de diciembre de 2022): 2410–14. http://dx.doi.org/10.24925/turjaf.v10i12.2410-2414.5293.
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This study aimed to investigate the body weight and some body measurements in Central Anatolian Merino sheep regarding ages and to carry out a comparative analysis between them. The study included a total of 60 animals aged 2, 3 and 4 years. The sheep were fed daily with hay, vetch, alfalfa and limited amount of concentrated feed (400 g head-1) until the pasture period, and pasture grass and mixed grass-clover hay during the pasture period. The live weights of the sheep of different ages in the farms were measured with a digital scale, and some body size were measured using a measuring tape and a measuring stick. When the live weight and chest circumference values of the 4-year-old sheep were compared with the data obtained in the other age groups (2 and 3 years old), and it was statistically significant, chest width and rump height values were found to be similar to those in the 3-age group. There were significant correlations between live weight and chest circumference, between withers height and rump height and significant correlations between live weight and chest width, body length with rump height, chest width with chest depth. In addition, significant correlations were found between live weight and chest depth, and between withers height, body length, and chest depth. Present findings revealed that the Central Anatolian Merino sheep can be beneficial in the development of meat-type sheep breeding.
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Dimitrova, Ivona, Milena Bozhilova-Sakova, Margarit Iliev y Atanaska Teneva. "Genetic variation of CAST gene in Local Karnobat and Karnobat merino sheep breeds". BIO Web of Conferences 42 (2022): 01029. http://dx.doi.org/10.1051/bioconf/20224201029.
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Karnobat sheep plays an important role in the development of sheep breeding in Southeastern region of Bulgaria. They are valuable source of genetic material. The aim of present experiment was to determine the allele variation of CAST gene in Local Karnobat and Karnobat Merino sheep breeds. A total of 60 blood samples were collected – 30 per breed. DNA was extracted and genotypes of all animals were identified by means of PCR-RFLP technique. The restriction reactions were accomplished by specific enzyme MspI. As expected both breeds were characterized with low level of genetic diversity due to the fact that mostly maintaining selection has been implemented. In Local Karnobat sheep breed was identified only one heterozygous individual from all 30. In Karnobat merino were identified allele M with frequency 0,97 and allele N with frequency 0,03. Genotypes MM and MN were revealed with frequencies 0,93 and 0,07, respectively. According to the statistical analysis both breeds were in HWE equilibrium.
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Santiago, L. Lomas, D. Blache, M. A. Blackberry, G. B. Martin y A. B. Mâncio. "309. Nutrition, insulin, leptin and puberty in Merino ram lambs". Reproduction, Fertility and Development 17, n.º 9 (2005): 132. http://dx.doi.org/10.1071/srb05abs309.
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Merino sheep developed in Mediterranean regions so are well adapted to acute changes in food availability. However, restricted intake during pregnancy, especially in animals that are pregnant over the dry summer, could limit the positive effects of a winter rainy season on fetal development. In this study, we tested whether the level of nutrition during pregnancy and during pre-pubertal development affected blood concentrations of insulin and leptin, scrotal circumference and age of puberty in male Merino lambs fed with pasture. During dry weather, pregnant sheep were supplemented ad libitum with hay and lupin grain (Lupinus angustifolius) to compensate for decreases in pasture supply. Puberty was detected using a standardised behavioural test with oestrous ewes. Lambs were considered pubertal if they displayed mounting in two successive weekly tests. There were no differences in plasma concentrations of insulin or leptin. The values for both hormones simply displayed the same pattern, with a rise after feeding and a fall during non-feeding periods. There was no difference among treatments in either scrotal growth or age to puberty (Table 1). This might be because the dietary treatments, being administered by food restriction under field conditions, would not have the same effects as severe undernutrition that has been used in laboratory studies. Alternatively, Merino sheep may have a greater capacity to cope with mild nutritional stress.
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Norris, B. J., N. I. Bower, W. J. M. Smith, G. R. Cam y A. Reverter. "Gene expression profiling of ovine skin and wool follicle development using a combined ovine - bovine skin cDNA microarray". Australian Journal of Experimental Agriculture 45, n.º 8 (2005): 867. http://dx.doi.org/10.1071/ea05050.
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Low fibre diameter and high fleece weight are important determinants of the economic value of the Merino fleece. The combination of these traits is found in Merino sheep with high follicle densities resulting from a high secondary to primary follicle ratio. Morphological stages in the development of primary and secondary follicles of fetal sheep skin have been well described. We have used gene expression profiling of fetal skin to identify genes that may be important in controlling these follicle developmental processes. A combined ovine (2.3 K) and bovine (6.14 K) cDNA microarray of 2 fetal and 1 adult stage skin tissues was constructed to compare gene expression levels between fetal day 82, day 105, day 120 and adult sheep skin developmental stages. The transcript profile resulted in 238 differentially expressed array elements relative to the adult expression, which represented 132 unique genes. These clustered into 50 up- and 82 down-regulated genes and distinct gene ontologies including structural constituents, phosphate transport, signal transduction and organogenesis. Northern blot analysis of 2 selected genes, S100A7LI and TAGLN, validated the microarray results. This list of genes contains candidates of interest for further investigation into the molecular control of wool follicle development.
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Z, Hernández-Russo. "Effect of Gastrointestinal Nematodes on Reproduction and Lamb Growth in Australian Merino Sheep". Open Access Journal of Veterinary Science & Research 5, n.º 2 (2020): 1–5. http://dx.doi.org/10.23880/oajvsr-16000204.
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Environmental conditions in Uruguay favour the development of gastrointestinal nematodes (GIN) throughout the year, with clinical or subclinical manifestations that cause significant economic losses. The aim of this study was to evaluate the effect of the GIN on fertility, fecundity, reproductive rate and lamb growth in Australian Merino sheep grazing on basalt fields. The study was carried out in a farm located in north of Uruguay. Sixty-eight Merino ewes facing a natural parasite challenge were divided into two groups. Control group was doused with active anthelmintic that have proven efficacy to minimize the effects of parasitic and the parasitized group that did not receive anthelmintic, except rescue dosages. Stool sample of each sheep was collected monthly for egg counts (EPG) of GIN using McMaster technique and nematode genders were identified from infective larvae obtained in cultures by Roberts O’ Sullivan technique. Artificial insemination and ewes were mated for new service, and pregnancy condition was diagnosed by ultrasound. Lambing control was made and lambs were weighed at birth and marking. The evolution of EPG values showed significant differences between groups at the end of gestation and lactation. Haemonchus spp. was the main gender of nematodes found, followed by Trichostrongylus spp. Fertility was 95 % versus 90 %; fecundity 87 % versus 63 % and reproductive rate 73 % versus 47 % for the control group and the parasitized one respectively. No significant differences were recorded in birth-weight. However market-weight and lamb daily gain were lower in the parasitized group. The effect of natural infection GIN was evident in lower reproductive performance of Australian Merino sheep.
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Raadsma, HW, AR Gilmour y WJ Paxton. "Fleece rot and body strike in Merino sheep. I. Evaluation of liability to fleece rot and body strike under experimental conditions". Australian Journal of Agricultural Research 39, n.º 5 (1988): 917. http://dx.doi.org/10.1071/ar9880917.
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The conceptual model that variation in resistance of Merino sheep to fleece rot and body strike could be attributed to an underlying variable with a continuous normal distribution, termed 'liability', was examined in four experiments. A total of 640 young Merino sheep were exposed from 0 to 13 days to a simulated rainfall treatment to allow the development of fleece rot. The incidence of fleece rot ranged from 0% of sheep affected in unwetted control groups and increased up to 100% affected with increased exposure to wetting. Assuming binomial variation, the response in fleece rot and flystrike incidence was fitted on an underlying scale using generalized linear models. In the case of fleece rot severity, grades of exudative fleece rot were shown to fit an ordered categorical response model. The assessment, induction and liability of sheep to fleece rot were found to be highly repeatable in all three cases, indicating that liability to fleece rot could be accurately screened for using experimental induction. Fleece rot severity was found to be an accurate indicator of liability to body strike but not of other forms of flystrike. The possible mechanisms and factors contributing to the liability of sheep to fleece rot and body strike have been discussed, and moisture status of the fleece during the development of the two diseases was indicated as an essential common denominator.
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Krivoruchko, A. y O. Yacyk. "New parameters of lifetime assessment of meat productivity of Dzhalginskiy merino sheep". Agrarian Bulletin of the 207, n.º 04 (6 de junio de 2021): 74–84. http://dx.doi.org/10.32417/1997-4868-2021-207-04-74-84.
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Abstract. For breeding work in order to increase productivity indicators in sheep, it is necessary to use the most informative exterior parameters. This dictates the need to develop new approaches to assessing phenotypic parameters. Purpose. Development of new parameters for live assessment of meat productivity of sheep of the Dzhalginskiy merino breed and study of their significance using the method of principal components. Scientific novelty. We have proposed several new parameters for the lifetime assessment of the parameters of meat productivity and studied the possibility of their use in sheep of the Dzhalginskiy merino breed. Methods. The possibility was studied for life determination of the size of individual muscle groups using such parameters as the girth of the shoulder, forearm and thigh by instrumental methods, as well as measuring the parameters of the muscle eye, the thickness of the femoral muscle and fat using ultrasound. To assess the significance of the proposed parameters, in comparison with those used in existing practice, we applied the principal component method and correlation analysis. Results. Five main components have been established, which determine 70, 3% of the total phenotypic variability in sheep of the Dzhalginskiy merino breed. They characterize the size of the forelimbs, the size of the chest, the parameters of the muscular eye, the size of the hind limbs and the thickness of fat in the lumbar region. The parameters of the shoulder, forearm and hip girth we proposed showed high significance in the calculation of the components. The thickness of the femoral muscle was found to be of little significance. It was also found that most of the measurements used do not reliably correlate with each other. High positive significant correlations were found only between body weight and average daily weight gain, thickness and width of the muscle eye, shoulder girth and height at the sacrum. Thus, we have found that for the phenotypic assessment of the Dzhalginskiy merino sheep, it is advisable to use the girth of the shoulder, forearm and thigh as additional parameters.
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McDowall, M. L., N. S. Watson-Haigh, N. M. Edwards, H. N. Kadarmideen, G. S. Nattrass, H. A. McGrice y P. I. Hynd. "Transient treatment of pregnant Merino ewes with modulators of cortisol biosynthesis coinciding with primary wool follicle initiation alters lifetime wool growth". Animal Production Science 53, n.º 10 (2013): 1101. http://dx.doi.org/10.1071/an12193.
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The economically important characteristics of the adult fleece of Merino sheep, such as increases in clean fleece weight, fibre length, fibre diameter and crimp characteristics are determined during critical phases of fetal development of the skin and its appendages. Genetics plays a major role in the development of traits, but the maternal uterine environment could also influence development. Treatment of pregnant ewes with cortisol and its analogues has previously been shown to produce changes in wool follicle morphology. The aim of this study was to determine the effect of transient manipulation of maternal cortisol status during critical phases of wool follicle initiation and development in utero. From Days 55–65 post-conception, singleton-bearing Merino ewes were treated with metyrapone (cortisol inhibitor) or betamethasone (cortisol analogue). Lambs exposed to metyrapone in utero were born with hairier birthcoats than the control or betamethasone treatment groups (P < 0.05), displayed a 10% increase in staple length and a reduction in crimp frequency for the first three shearings (P < 0.05). Co-expression network analysis of microarray data revealed up-regulation of members of the transforming growth factor-β and chemokine receptor superfamilies, gene families known to influence hair and skin development. These experiments demonstrate that presumptive transient manipulation of maternal cortisol status coinciding with the initiation of fetal wool follicle development results in long-term alteration in fleece characteristics, namely fibre length and fibre crimp frequency. These results indicate it is possible to alter the lifetime wool production of Merino sheep with therapeutics targeted to gene expression during key windows of development in utero.
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Brown, D. J. y N. M. Fogarty. "Genetic relationships between internal parasite resistance and production traits in Merino sheep". Animal Production Science 57, n.º 2 (2017): 209. http://dx.doi.org/10.1071/an15469.
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Breeding Merino sheep that are resistant to internal parasites alleviates the high costs associated with treatment of worm infestation and loss of production, as well as mitigating the development of anthelmintic resistance among the major worm species. Faecal worm egg count ((cube root transformation), wec) can be used in sheep as a measure of internal parasite resistance. Accurate estimates of genetic parameters for wec are required for calculation of Australian Sheep Breeding Values and inclusion of worm resistance in sheep breeding programs. This study provides updated estimates of heritability for wec and its genetic correlations with production traits. Data were analysed from a wide range of Australian and New Zealand Merino sheep in the MERINOSELECT database, which included 141 flocks with 801 flock years and up to 217 137 animals with wec recorded in at least one of four ages (W = weaning, P = post weaning, Y = yearling, H = hogget). The heritability estimates ranged from 0.16 ± 0.01 for Ywec to 0.29 ± 0.01 for Wwec, with generally high genetic correlations between the ages. Bivariate analyses estimated genetic correlations between wec at the various ages and growth, carcass quality, reproduction and wool production traits at various ages. These genetic correlations were generally small or close to zero, albeit with some significantly different from zero. The moderate heritability for wec (0.2–0.3) and its high phenotypic variation (coefficient of variation >30%) shows that relatively rapid selection response for worm resistance could be achieved. Inclusion of wec in sheep breeding programs to increase worm resistance would be expected to have little if any impact on other important production traits. These genetic parameters have been incorporated into MERINOSELECT by Sheep Genetics to provide Australian Sheep Breeding Values for wec and appropriate indices for wool and meat production. There is evidence that genotype × environment interactions may be important in some environments by reducing the accuracy of Australian Sheep Breeding Values for wec. Hence it may be prudent for breeders to implement strategies that manage the risk of any impact of genotype × environment on their breeding program.
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Lv, Xuefeng, Lei Chen, Sangang He, Chenxi Liu, Bin Han, Zhilong Liu, Mayila Yusupu et al. "Effect of Nutritional Restriction on the Hair Follicles Development and Skin Transcriptome of Chinese Merino Sheep". Animals 10, n.º 6 (19 de junio de 2020): 1058. http://dx.doi.org/10.3390/ani10061058.
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The high concentration of secondary branched wool follicles is a distinctive feature of the Merino sheep. At present, the molecular control of the development and branching of secondary wool follicles (SF) remains elusive. To reveal the potential genes associated with the development of hair follicles, we investigated the characteristics of prenatal and postnatal development of wool follicles, and the transcriptional expression profile in fetuses/lambs from dams under either maternal maintenance or sub-maintenance (75% maintenance) nutrition. The density of SF and the ratio of SF to primary wool follicles (PF) were reduced (p < 0.05) in fetuses from day 105 to 135 of gestation under sub-maintenance nutrition. Differentially expressed genes were enriched in the binding, single-organism process, cellular process, cell and cell part Gene Ontology (GO) functional categories and metabolism, apoptosis, and ribosome pathways. Four candidate genes, SFRP4, PITX1, BAMBI, and KRT16, which were involved in secondary wool follicles branching and development, were identified. Our results indicate that nutritional intervention imposed on pregnant ewes by short-term sub-maintenance nutrition could provide a strategy for the study of wool follicle development. Overall insight into the global gene expression associated with SF development can be used to investigate the underlying mechanisms of SF branching in Merino sheep.
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Chao, Tianle, Zhibin Ji, Lei Hou, Jin Wang, Chunlan Zhang, Guizhi Wang y Jianmin Wang. "Sheep skeletal muscle transcriptome analysis reveals muscle growth regulatory lncRNAs". PeerJ 6 (11 de abril de 2018): e4619. http://dx.doi.org/10.7717/peerj.4619.
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As widely distributed domestic animals, sheep are an important species and the source of mutton. In this study, we aimed to evaluate the regulatory lncRNAs associated with muscle growth and development between high production mutton sheep (Dorper sheep and Qianhua Mutton Merino sheep) and low production mutton sheep (Small-tailed Han sheep). In total, 39 lncRNAs were found to be differentially expressed. Using co-expression analysis and functional annotation, 1,206 co-expression interactions were found between 32 lncRNAs and 369 genes, and 29 of these lncRNAs were found to be associated with muscle development, metabolism, cell proliferation and apoptosis. lncRNA–mRNA interactions revealed 6 lncRNAs as hub lncRNAs. Moreover, three lncRNAs and their associated co-expressed genes were demonstrated by cis-regulatory gene analyses, and we also found a potential regulatory relationship between the pseudogene lncRNA LOC101121401 and its parent gene FTH1. This study provides a genome-wide resolution of lncRNA and mRNA regulation in muscles from mutton sheep.
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Fleet, M. R. "Development of black pigmented skin spots and pigmented wool fibres in a Merino flock—causes, field observations, and wool measurement". Australian Journal of Agricultural Research 57, n.º 7 (2006): 751. http://dx.doi.org/10.1071/ar05032.
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The development of black-grey pigmented skin spots and pigmented wool fibres on adult Merino sheep over a 3-year period was assessed. Effects of long-term grazing of oestrogenic pasture and multiple shearing were studied. The number of affected sheep and number of pigmented spots on affected sheep increased with age, with the greatest increase at 8.5 years age. Grazing of oestrogenic pastures had no effect but twice yearly shearing increased the development of pigmented spots after 2 years of treatment. Measurements on fleeces and top from sheep with no apparent pigmented spots showed that this wool was generally free of pigmented fibres. In contrast, wool from affected individuals generally had high concentrations of pigmented wool fibres, with substantial pigmented lengths (means 20–40 mm) and intensely darkened, which related to the field records of black-grey pigmented skin spots. The amounts of dark pigmented fibres found in the processed top from affected fleeces ranged between 262 and 1293/kg. Based on these findings, sheep age is an important factor for inclusion in decision systems alerting wool buyers to the risk of hidden dark fibres. However, if adequate inspection of sheep during shearing is practical to isolate fleeces from sheep with black-grey pigmented skin spots in the fleece areas, then the risk level applied could be lowered or removed for the wool from the unaffected sheep.
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Murray, JD, CD Nancarrow, RJ Scaramuzzi y Y. Cognie. "Polyploid Abnormalities in Day 3 and Day 5 Merino Sheep Embryos". Australian Journal of Biological Sciences 41, n.º 2 (1988): 157. http://dx.doi.org/10.1071/bi9880157.
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The chromosome complement was assessed in Merino sheep embryos collected at 3 and 5 days after the onset of oestrus. Donor ewe treatments were: untreated, or immunized against androstenedione (day 3); and untreated, or treated with follicle-stimulating hormone (FSH), or treated with FSH plus immunization against androstenedione (day 5). No significant differences in the frequency of chromosomally abnormal embryos between treatment groups within each age group were observed, so the data have been combined. Euploid abnormalities were observed in 10�8070 of the day-3 embryos (4/37), with the abnormalities being one In, one 3n and two 5n. Embryos with euploidy (10%) were also observed at day 5, with three 1n12n mosaics and a 3n embryo present in a sample of 40. These data suggest that chromosomally aberrant embryos are not lost before day 5 of development.
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Moore, GPM, N. Jackson, K. Isaacs y G. Brown. "Development and density of wool follicles in Merino sheep selected for single fibre characteristics". Australian Journal of Agricultural Research 47, n.º 8 (1996): 1195. http://dx.doi.org/10.1071/ar9961195.
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Wool follicles are classified into 3 major types: primary (P), original secondary (SO), and derived secondary (SD). They are formed during fetal life as successive waves of initiation pass through the skin. P follicles are the first to be initiated. SO follicles develop between the primaries and are separated from them at non-randomly distributed sites. SD follicles are the last to be initiated and branch from SO and other SD follicles. We have measured the densities of these follicles in 4 lines of sheep selected for different fleece characters. Primary follicle and total follicle densities (NP and NP + NS) were estimated by conventional procedures. The densities of pilary canals were also obtained to provide a measure of Np + NSO. Follicle counts in both adult and fetal animals showed that NP and NP + NSO were relatively constant across the lines. Predominantly, density differences were due to variations in the numbers of follicles initiated during the last wave, forming the derived secondary population. Changes in follicle densities were therefore effected by developmental mechanisms that increase or decrease the extent of branching rather than by altering the numbers of P and SO follicles. The results suggest firstly that the numbers of initiation sites for P or SO follicle formation in the fetus, corresponding to the pilary canals of adult skin, are limited. Secondly, the skin has the capacity to continue to initiate follicles after most or all of the sites have been occupied. It is concluded that the mechanisms controlling follicle initiation site densities and total follicle densities are independently regulated in the sheep. The observations are discussed in relation to factors that influence the densities of the different follicle types. The results have practical implications for changing fleece weight and fibre diameter through selective breeding.
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Franco, Antonio, Javier Masot y Eloy Redondo. "Comparative analysis of the merino sheep and Iberian red deer abomasum during prenatal development". Animal Science Journal 88, n.º 10 (19 de abril de 2017): 1575–87. http://dx.doi.org/10.1111/asj.12783.
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Morcombe, PW, KP Croker y JG Allen. "Liver damage and the liveweight changes in Merino wether weaners grazing mixed crops of oats and sweet narrow-leafed lupins". Australian Journal of Experimental Agriculture 27, n.º 1 (1987): 19. http://dx.doi.org/10.1071/ea9870019.
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Merino wether weaners were grazed on mixed crops of oats and sweet lupins at 3 stocking rates (15, 30 and 60 sheep/ha), pure lupins (60 sheep/ha) or pastures (7.5 sheep/ha) with and without an ad libitum ration of an oat-lupin grain mix in 2 experiments. Changes in liveweights and liver damage due to lupinosis were measured. In experiment 1, when grazing commenced in late January 1982, the weaners grazed on the mixed crops at 15, 30 and 60 sheep/ha gained 4.8 kg over 91 days, 2.9 kg over 43 days and 1.2 kg over 43 days, respectively, while those on the pure lupins gained 0.7 kg over 14 days. These liveweight gains were all less (P<0.05) than the 10 kg increase over 70 days by the weaners on pasture which received the ad libitum supplement of oat-lupin grain (about 2.2% N). Liver damage developed at a slower rate in the sheep on the mixed crops. In experiment 2, when grazing commenced in late November 1983, the weaners grazed on the mixed crops at 15,30 and 60 sheep/ha gained 1 1.3 kg over 70 days, 6.2 kg over 42 days and 3.5 kg over 28 days, respectively, while those on the pure lupins gained 3.4 kg over 28 days. These liveweight gains compared with a 12.5 kg gain over 84 days by the weaners on pasture which received the ad libitum supplement of oat-lupin grain (about 2.60%N). There was less Phomopsis leptostromiformis on the lupin stems in this experiment and the sheep livers were not as badly damaged as in the previous experiment. The development of liver damage was again delayed in the weaners grazed on the mixed crops. It was concluded that Merino wether weaners can increase liveweights when grazed on mixed crops of oats and sweet lupins. The amount of increase depends on the grain available to the sheep and the degree of lupinosis-associated liver damage suffered by the sheep. Grazing mixed crops reduces the development of lupinosis.
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Tatara, MR, A. Brodzki, K. Pasternak, M. Szpetnar, P. Rosenbeiger, B. Tymczyna y D. Niedziela. "Changes of amino acid concentrations in Polish Merino sheep between 21 and 150 days of life". Veterinární Medicína 59, No. 2 (27 de marzo de 2014): 68–75. http://dx.doi.org/10.17221/7315-vetmed.
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The aim of this study was to evaluate plasma amino acid profiles and their interrelationships in male Polish Merino sheep at two different stages of their systemic development – at the neonatal monogastric stage and as a fully grown ruminant. Male lambs (n = 12, singles) were kept indoors in pens under standard rearing conditions and weaned at the age of 10 weeks of life. Blood samples were collected on day 21 and 150 of life. Free amino acids were determined in plasma using ion-exchange chromatography. There was a significant reduction in plasma amino acid concentrations between neonatal and functioning ruminants for threonine, serine, glutamate, proline, citrulline, tyrosine, tryptophan, lysine, histidine and arginine. Significant increases in the plasma concentrations of alpha-amino-butyrate and isoleucine were observed in 150 day old lambs. Except for glutamine in 21 day old sheep which was significantly negatively correlated with serine, glutamate, proline and tyrosine concentrations in plasma, the obtained results in younger and older groups of lambs showed 47 and 22 significant positive correlations between the evaluated amino acids. This study shows that decreases in plasma amino acid concentrations in 150 day old sheep with physiologically developed forestomachs are dominant in comparison to 21 day-old animals receiving maternal milk as a basic diet. Our results address the possibility of utilising improved amino acid supply for growing lambs with developed forestomachs.
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Regan, Sheena L. P., James R. McFarlane, Tim O'Shea, Nicholas Andronicos, Frank Arfuso, Arun Dharmarajan y Ghanim Almahbobi. "Flow cytometric analysis of FSHR, BMRR1B, LHR and apoptosis in granulosa cells and ovulation rate in merino sheep". REPRODUCTION 150, n.º 2 (agosto de 2015): 151–63. http://dx.doi.org/10.1530/rep-14-0581.
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The aim of the present study was to determine the direct cause of the mutation-induced, increased ovulation rate in Booroola Merino (BB) sheep. Granulosa cells were removed from antral follicles before ovulation and post-ovulation from BB (n=5) and WT (n=12) Merino ewes. Direct immunofluorescence measurement of mature cell surface receptors using flow cytometry demonstrated a significant up-regulation of FSH receptor (FSHR), transforming growth factor beta type 1, bone morphogenetic protein receptor (BMPR1B), and LH receptor (LHR) in BB sheep. The increased density of FSHR and LHR provide novel evidence of a mechanism for increasing the number of follicles that are recruited during dominant follicle selection. The compounding increase in receptors with increasing follicle size maintained the multiple follicles and reduced the apoptosis, which contributed to a high ovulation rate in BB sheep. In addition, we report a mutation-independent mechanism of down-regulation to reduce receptor density of the leading dominant follicle in sheep. The suppression of receptor density coincides with the cessation of mitogenic growth and steroidogenic differentiation as part of the luteinization of the follicle. The BB mutation-induced attenuation of BMPR1B signaling led to an increased density of the FSHR and LHR and a concurrent reduction in apoptosis to increase the ovulation rate. The role of BMPs in receptor modulation is implicated in the development of multiple ovulations.
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Steel, J. W. "Effects of protein supplementation of young sheep on resistance development and resilience to parasitic nematodes". Australian Journal of Experimental Agriculture 43, n.º 12 (2003): 1469. http://dx.doi.org/10.1071/ea03004.
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The influence of dietary protein content, particularly the supply of metabolisable protein, on immunocompetence and on resilience to pathogenic effects during continuous exposure of young sheep to infective larvae is reviewed for the most important abomasal and small intestinal nematodes infecting young sheep in Australian grazing systems. In lambs infected with Haemonchus contortus supplementary protein improves both development of immunity and resilience in breeds of sheep that are susceptible to haemonchosis, but in relatively resistant breeds dietary supplementation appears unnecessary. Recent studies indicate that the increased protein requirements of Merino weaners parasitised by H. contortus would be met by diets containing about 190 g crude protein/kg dry matter, depending on the rumen degradability of the dietary protein source and level of feed intake. Some evidence exists for an enhanced immune response to Teladorsagia circumcincta in lambs receiving an increased supply of protein at the intestines.Response to protein supplementation of lambs infected with Trichostrongylus colubriformis depends on the metabolisable protein content of the basal diet and on the period of exposure to incoming larvae. Where the basal diet only meets requirements for maintenance or low growth rates, increased supply of rumen undegradable protein enhances immune expression in terms of reducing faecal egg count and expelling adult worms, but does not appear to limit the initial establishment of incoming larvae. Effects on growth rate and wool production are most pronounced during the period of worm expulsion, indicating that this phase of the immune response competes with production when nutrient resources, and particularly protein, are limited.Field trials in the Armidale region have shown that supplementation with protein meals of Merino weaners, exposed to natural infection from pasture, can reduce faecal egg count and improve resilience in terms of both growth rate and wool production. These effects may persist for some time after supplementation ceases. Further work is needed to determine the generality of these responses in other sheep-producing regions and genotypes and to establish cost-effective supplementation strategies.
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Pannier, L., G. E. Gardner y D. W. Pethick. "Effect of Merino sheep age on consumer sensory scores, carcass and instrumental meat quality measurements". Animal Production Science 59, n.º 7 (2019): 1349. http://dx.doi.org/10.1071/an17337.
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Slower growing Merino sheep often miss the lamb category and become yearlings. Yet, they may still produce meat of acceptable eating quality, thus opening the opportunity to develop high quality yearling products. Consumer sensory differences (tenderness, overall liking, juiciness, liking of flavour and liking of odour) of grilled wet-aged (5 days) steaks from the M. longissimus lumborum (LL) and M. semimembranosus (SM) derived from wether lamb (n = 185; average age 355 days) and wether yearling (n = 206; average age 685 days) Merinos were tested. Additionally, the age effect on carcass and instrumental meat quality traits was analysed. Lambs were born in 2009 and 2010 at two research sites (Kirby, Katanning), and yearlings were born in 2009 at five research sites (Kirby, Cowra, Rutherglen, Struan, Katanning). On average within each muscle, yearlings had lower scores for all sensory attributes (P < 0.01) compared to lambs. Lambs versus yearlings born in the same year and reared at the same research site had greater sensory differences within the SM (P < 0.01), up to 10.0 eating quality scores more for tenderness. In contrast, the LL samples had almost no significant differences between the two age groups. A portion of the differences in overall liking and liking of flavour scores was explained by intramuscular fat. Yearlings were slightly heavier (P < 0.01) but leaner (P < 0.01), compared to lambs, and yearling meat colour was darker (P < 0.01). While the results generally supported the better eating quality of lamb, they demonstrated a very acceptable yearling LL eating quality, and showed the smaller impact of age on the LL muscle in Merinos. Hence, the development of a high quality yearling product for the LL muscle is possible.
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Adams, N. R. y P. B. Cronjé. "A review of the biology linking fibre diameter with fleece weight, liveweight, and reproduction in Merino sheep". Australian Journal of Agricultural Research 54, n.º 1 (2003): 1. http://dx.doi.org/10.1071/ar02059.
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There is increasing economic pressure on the Merino industry to grow finer wool and at the same time to turn off more sheep meat. Fleece weight generally decreases with finer fibre diameters, so theoretically, finer wool sheep should be able to partition more nutrients to reproduction and muscle growth. However, complex and often indirect mechanisms appear to prevent this in practice. This review summarises the available data on genetic and phenotypic relationships between wool fibre diameter and fleece weight, liveweight, fatness, and reproductive performance, and develops mechanistic hypotheses for these relationships that could be tested experimentally.Selection for reduced fibre diameter may decrease liveweight, fatness, and reproductive performance. These characteristics are also affected by the availability of nutrients, and finer fibre diameter may affect nutrient metabolism through 2 adaptations that tend to maintain fleece weight: an increase in follicle density and/or an increase in relative fibre length. These act in different ways. Follicle density may affect final body size through linkages established during fetal development. Increased fibre growth rate requires an increase in protein synthesis rate in the skin, which in turn may affect whole-body protein turnover rate and the sensitivity of tissues to insulin. Other pathways potentially affected by fibre diameter include the control of feed intake, prenatal programming of insulin sensitivity, and a reduced responsiveness of tissues to nutrient supply. However, none of these mechanisms accounts for the reports of an increased proportion of dry ewes in fine wool sheep, particularly if run in environments that experience periods of low quality pasture.Although associations between fibre diameter and growth rate, fatness, and reproduction rate are repeatable, there are not yet enough data for such associations to be realistically accounted for in breeding goals. More experimentation and a better knowledge of the causative relationships will facilitate development of finer wool sheep for environments where sheep turnoff normally provides a significant proportion of income from the sheep enterprise. Such mechanistic understanding will facilitate the development of molecular techniques for targetted selection, and the identification of more useful attributes for a quantitative genetics approach to improving simultaneously the profitability from both wool and meat.
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TRUKHACHEV, V., G. DZHAILIDY, V. SKRIPKIN, A. KULICHENKO, D. KOVALEV, M. SELIONOVA, M. AYBAZOV, E. TELEGINA, O. YATSYK y A. KRIVORUCHKO. "The polymorphisms of MyoD1 gene in Manych Merino sheep and its influence on body conformation traits". Journal of the Hellenic Veterinary Medical Society 68, n.º 3 (29 de enero de 2018): 319. http://dx.doi.org/10.12681/jhvms.15476.
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Candidate genes associated with meat productivity often affect the performance of myostatin and muscle development in general. The MyoD1 gene is a member of the myogenic regulatory factor (MRF) family and plays a key role in the differentiation of skeletal muscle cells in vertebrates. We investigated the structure of the MyoD1 gene. The effect of polymorphisms on meat production was studied in the Russian sheep breed Manych Merino. To detect alleles, we used NimbleGen sequencing technology (Roche, USA). In the Manych Merino breed, we found 14 single nucleotide polymorphisms (SNPs) associated with substitutions, all in the second exon, namely, c.244C>T, c.246G>T, c.253G>T, c.259G>C, c.261C>T, c.269C>G, c.274C>A, c.276C>G, c.277C>A, c.279C>T, c.281C>A, c.287C>A, c.325T>C, and c.483C>T. All of these SNPs, except from c.325T>C, were detected here for the first time. The Manych Merino breed had 13 substitutions that were present as homozygous type. Only SNP c.325T>C occurred as the wild type of homozygotes and heterozygotes in the ratio 2:1. We found that SNP c.325T>C was associated with some vital body parameters, including parameters of height and croup measurement. Thus, the determination of allelic variants of the MyoD1 gene may be used in marker assisted genetic selection schemes.
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Wang, Xinyue, Jingjing Bao, Yazhen Bi, Wenping Hu y Li Zhang. "Polymorphism, Expression, and Structure Analysis of a Key Gene ARNT in Sheep (Ovis aries)". Biology 11, n.º 12 (10 de diciembre de 2022): 1795. http://dx.doi.org/10.3390/biology11121795.
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Growth traits are influential factors that significantly affects the development of the sheep industry. A previous TMT proteomic analysis found that a key protein in the HIF signaling pathway, ARNT, may influence embryonic skeletal muscle growth and development in sheep. The purpose of this study was to better understand the association between the polymorphisms of ARNT and growth traits of sheep, and the potential function of ARNT. Real-time qPCR (qRT-PCR) of ARNT was carried out to compare its expression in different developmental stages of the muscle tissues and primary myoblasts in the Hu, Chinese merino, and Gangba sheep. The genetic variance of ARNT was detected using the Illumina Ovine SNP 50 K and 600 K BeadChip in the Hu and Ujimqin sheep populations, respectively. The CDS sequence of the ARNT gene was cloned in the Hu sheep using PCR technology. Finally, bioinformatic analytical methods were applied to characterize the genes and their hypothetical protein products. The qRT-PCR results showed that the ARNT gene was expressed significantly in the Chinese merino embryo after 85 gestation days (D85) (p < 0.05). Additionally, after the sheep were born, the expression of ARNT was significant at the weaning stage of the Hu sheep (p < 0.01). However, there was no difference in the Gangba sheep.In addition, six SNP loci were screened using 50 K and 600 K BeadChip. We found a significant association between rs413597480 A > G and the Hu sheep weight at weaning and backfat thickness in the 5-month-old sheep (p < 0.05), and four SNP loci (rs162298018 G > C, rs159644025 G > A, rs421351865 G > A, and rs401758103 A > G) were also associated with growth traits in the Ujimqin sheep (p < 0.05). Interestingly, we found that a G > C mutation at 1948 bp in the cloned ARNT CDS sequence of the Hu sheep was the same locus mutation as rs162298018 G > C identified using the 600 K BeadChip, which resulted in a nonconservative missense point mutation, leading to a change from proline to alanine and altering the number of DNA, protein-binding sites, and the α-helix of the ARNT protein. There was a strong linkage disequilibrium between rs162298018 G > C and rs159644025 G > A, and the ARNT protein was conserved among the goat, Hu sheep, and Texel sheep. And, we propose that a putative molecular marker for growth and development in sheep may be the G > C mutation at 1948 bp in the CDS region of the ARNT gene. Our study systematically analyzed the expression, structure, and function of the ARNT gene and its encoded proteins in sheep. This provides a basis for future studies of the regulatory mechanisms of the ARNT gene.
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Raadsma, HW. "Fleece rot and body strike in Merino sheep. III. Significance of fleece moisture following experimental induction of fleece rot". Australian Journal of Agricultural Research 40, n.º 4 (1989): 897. http://dx.doi.org/10.1071/ar9890897.
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The relationship between fleece wetting and drying characteristics and liability of sheep to fleece rot and body strike was examined following experimental wetting. The liability of sheep to fleece rot was reflected by both wetting and drying characteristics. Wetness of the fleece was estimated gravimetrically and was found to be a simple, fast and relatively robust technique. Moisture increased from 13% in the dry fleece up to 123% at skin level in sheep exposed from 0 to 10 days' wetting. Consistent differences were reported in proximal and full staple moisture levels between sheep affected and unaffected with fleece rot or body strike. Drying characteristics of individual sheep were recorded by means of an electronic hygrometer in sheep up to 5 days after wetting. A lag phase in the drying of sheep susceptible to fleece rot or bodystrike was recorded, compared with resistant sheep. The most resistant sheep showed a slightly concave drying curve (-12.4% R.H. day-1 + 0.06% R.H. day-2) after wetting, whereas the most susceptible sheep showed a slightly convex drying curve (- 11.4% R.H. day-1 0.05% R.H. day-2). The maximum difference in fleece relative humidity between the two groups of sheep occurred between 1 and 3 days after wetting. Measurement of fleece relative humidity before wetting in the dry fleece, did not predict the liability of sheep to fleece rot and body strike.Moisture levels in the fleece during and immediately following wetting accounted for differences in fleece rot due to experimental treatments and genetic flock differences. Based on a single full-staple moisture measurement of 945 sheep, representing the progeny of 134 sires, the heritability of fleece moisture was 0.28 � 0.12 and had a genetic correlation with fleece rot incidence and severity of 0.74 � 0.24 and 0.79 � 0.19 respectively. Further work should identify fleece components which affect the wetting and drying characteristics of the fleece during the development of fleece rot.
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Thompson, A. C. Toland, M. L. Hebart, N. M. Penno y P. I. Hynd. "Perinatal wool follicle attrition coincides with elevated perinatal circulating cortisol concentration in Merino sheep". Australian Journal of Agricultural Research 58, n.º 7 (2007): 748. http://dx.doi.org/10.1071/ar06327.
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The development of the follicle population in Merino sheep skin was studied from 30 days pre-partum to 112 days post-partum in single- and twin-born Merino lambs. The total number of primary follicles estimated from primary follicle density and skin surface area did not change over this period, while secondary follicle number increased to Day 28 post-partum in singles and Day 56 post-partum in twins. Twins had 14% fewer total follicles than singletons (P < 0.001), largely reflecting a bodyweight (hence estimated skin surface area) difference of 10%, with little difference in total follicle density (P > 0.05). Immediately post-partum there was a 36% decrease (P < 0.0001) in the secondary to primary follicle ratio (S/P) of the twin lambs, while a small non-significant decrease (7%; P > 0.05) occurred in the single lambs. This attrition coincided with a surge in plasma cortisol concentration that commenced ~12 days before birth and persisted for 6–12 days post-partum. The surge in plasma cortisol concentration occurred in both single and twin lambs, commencing on Day 138 of gestation; however, the peak cortisol concentration and the period over which cortisol remained elevated was greater in twin lambs than in singletons (P < 0.001). This study confirms a previous finding of a perinatal reduction in S/P ratio in Merino sheep. The reduction was greater in twin lambs than in singletons but the follicles of twins recovered rapidly so that there was little difference in final S/P ratio between birth types after Day 30 post-partum. The postnatal follicle reduction followed the perinatal surge in plasma cortisol concentration and appeared to reflect the magnitude of the cortisol surge in that twins, which displayed a higher peak cortisol concentration, had a greater reduction in active follicles than singletons.
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Vasseur, S., D. R. Paull, S. J. Atkinson, I. G. Colditz y A. D. Fisher. "Effects of dietary fibre and feeding frequency on wool biting and aggressive behaviours in housed Merino sheep". Australian Journal of Experimental Agriculture 46, n.º 7 (2006): 777. http://dx.doi.org/10.1071/ea05320.
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Wool biting is a behaviour that can develop in housed sheep, in which sheep start to bite and eat the wool of others. The aim of this study was to determine whether (i) supplementing the diet of housed sheep with fibre and (ii) increasing feeding frequency would help to reduce wool biting, aggressive behaviours and wool damage. In a 2 × 2 factorial experiment, 40 Merino wethers were either fed with lucerne-based pellets only, or with pellets supplemented with barley straw. They received their pellets either on a low feeding frequency basis (once a day Monday to Friday mornings, double ration on Friday afternoon, nothing Saturdays and Sundays), or on a high feeding frequency basis (twice a day, every day). The sheep were housed in 4 treatment pens, each with 10 animals. Wool biting and aggressive behaviours were recorded through direct observation and the sheep were scored for wool damage twice a week during the 15-week study. The provision of fibre had a significant effect on reducing wool biting (P<0.001) and wool damage score (P<0.001). There was no consistent effect of feeding frequency on wool biting or wool damage, and no fibre × feeding frequency interactions. Whereas wool biting in general increased with time during the study (P<0.001), levels of aggressive behaviour showed no consistent time trend, and there were no effects of fibre or feeding frequency treatments. It is concluded that wool biting is largely a redirected behaviour in concentrate-fed housed sheep deprived of adequate levels of activity or oral stimulus, and that the provision of roughage will reduce the development of wool biting and improve animal welfare in housed experimental sheep.
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Lee, Caroline, Steve Colegate y Andrew D. Fisher. "Development of a maze test and its application to assess spatial learning and memory in Merino sheep". Applied Animal Behaviour Science 96, n.º 1-2 (enero de 2006): 43–51. http://dx.doi.org/10.1016/j.applanim.2005.06.001.
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Potter, B. J., G. H. McIntosh, M. T. Mano, P. A. Baghurst, J. Chavadej, C. H. Hua, B. G. Cragg y B. S. Hetzel. "The effect of maternal thyroidectomy prior to conception on foetal brain development in sheep". Acta Endocrinologica 112, n.º 1 (mayo de 1986): 93–99. http://dx.doi.org/10.1530/acta.0.1120093.
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Abstract. Merino ewes were surgically thyroidectomized, and mated 6 weeks later when their plasma thyroxine (T4) levels were negligible. Their foetuses were delivered by hysterotomy at 52, 71, 84, 98, 125, 140 days gestation or at term (150 days). Despite the very low levels of T4 in maternal plasma, the concentrations of T4 in foetal plasma were not significantly different after 71 days gestation from those of foetuses of sham-operated (control) ewes. Foetal brain and body weights, however, were reduced from 71 days compared to those of foetuses of sham-operated ewes. The foetal brain weights but not the body weights were restored to normal from 125 days to term. In additon to the weights, cell number (DNA) and cell size (protein:DNA ratio) appeared to be normal in the neonatal brain at parturition and this was confirmed by histological examination of the brains. Thus lack of maternal thyroid hormones in early pregnancy may cause a reduction in brain and body growth in the foetus which, in the case of the brain, appears to be restored to normal after the onset of foetal thyroid function.
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Thomas, Dean T., Matt G. Wilmot, Mark Alchin y David G. Masters. "Preliminary indications that Merino sheep graze different areas on cooler days in the Southern Rangelands of Western Australia". Australian Journal of Experimental Agriculture 48, n.º 7 (2008): 889. http://dx.doi.org/10.1071/ea08061.
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High ambient temperature can decrease weight gain in livestock, but domestic livestock in extensive grazing systems may have some capacity to adjust their behaviour to reduce the impact of periods of high temperature. We hypothesised that sheep grazing in the semiarid Southern Rangelands of Western Australia would reduce distance travelled on days with high mean daily temperature. Eight Merino ewes were fitted with GPS collars for 3 weeks in a 5575-ha paddock on Carlaminda station (28°20′S, 116°41′E). Mean daily temperature was used to separate the 18 days of the study into three temperature classes, cool (≤23.2°C), warm (23.3 to 25.9°C) and hot (≥26.0°C). Sheep travelled more quickly (P < 0.05) and further from water on cool days, compared with warm and hot days (3.74 v. 2.93 and 2.73 km from water, respectively; P < 0.001). On cool days, sheep spent most of their time grazing in the western area of the paddock. This area was rarely visited on warm or hot days. Mapping livestock distribution may assist in strategic relocation of existing water points and/or justify the development of additional watering points. However, our results suggest that sheep adjust their behaviour during hot weather, which may be a strategy to conserve energy, manage higher water requirements and/or reduce thermal load. Although grazing range decreases with higher temperatures, overall utilisation of a paddock may not be severely affected unless cooler days were too infrequent to facilitate regular access to these areas.
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Conz, Christopher R. "Sheep, Scab Mites, and Society: The Process and Politics of Veterinary Knowledge in Lesotho, Southern Africa, c. 1900-1933". Environment and History 26, n.º 3 (1 de agosto de 2020): 383–412. http://dx.doi.org/10.3197/096734018x15440029363690.
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This paper reconstructs a sheep-dipping campaign in Lesotho, southern Africa to explore the historical dynamics between local social and political circumstances, ecological change and veterinary knowledge. African livestock owners and the British colonial government accelerated a biological transition from local breeds to non-native merino sheep in the early 1900s to produce wool. Wool-bearing sheep ushered in Psoroptes ovis, a parasitic mite that caused the skin condition called scab. Examining colonial Lesotho's anti-scab campaign from 1903 to 1933, its politics, ideas and procedures, improves our understanding of the past and present interplay between transnational science, farmers, governments and the non-human world. This case study of sheep-dipping and the wool industry that it bolstered shows, too, how people from across the social spectrum interacted within new regulatory communities under a colonial state. These communities, fraught with social cleavages of race and class, and geared towards capitalist production, coalesced during the anti-scab campaigns and formed the political, technical and ideological foundation on which subsequent development schemes were built. Chiefs, stockowners, herders, labourers and European veterinarians too participated in various ways in this process of producing and circulating knowledge, and transforming livestock practices and policies.
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Zhai, Bo, Lichun Zhang, Chunxin Wang, Zhuo Zhao, Mingxin Zhang y Xu Li. "Identification of microRNA-21 target genes associated with hair follicle development in sheep". PeerJ 7 (27 de junio de 2019): e7167. http://dx.doi.org/10.7717/peerj.7167.
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Aim The target molecule regulatory function of microRNA-21 (miR-21) in multiple signalling pathways has become a main focus of genetic and pharmacological regulatory studies of various diseases. The identification of target genes for miRNA-21 in the development of hair follicles can provide new research pathways for the regulation of cell development. Methods In the present study, eight six-month-old ewes from Super Merino (SM) and Small Tailed Han (STH) sheep breeds were selected. Target prediction and dual-luciferase wild-type and mutant vectors were used to identify the target genes of miR-21. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and bioinformatics analysis were conducted to analyze the effects of miR-21. Results The results show that the expressions of CNKSR2, KLF3 and TNPO1 were downregulated by miRNA-21 at rates of 36%, 26% and 48%, respectively. Moreover, there was a significant negative correlation between the expression of miR-21 and the three target genes in sheep with two extreme phenotypes. The expression of microRNA-21in October was significantly lower than that in January and February; while the expression of CNKSR2, KLF3 and TNPO1 in October was higher than that in January and February. Conclusions: These results suggest that CNKSR2, KLF3 and TNPO1 are three newly discovered target genes of miR-21 and might be involved in the effects of miR-21 on hair follicle development.
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White, CL, DG Masters, DI Paynter, JMC Howell, SP Roe, MJ Barnes y JG Allen. "The effects of supplementary copper and a mineral mix on the development of lupinosis in sheep". Australian Journal of Agricultural Research 45, n.º 2 (1994): 279. http://dx.doi.org/10.1071/ar9940279.
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Lupinosis in grazing sheep is often associated with a potentially deleterious increase in the concentration of copper in the liver. Siromin�, a mineral mix developed by CSIRO for sheep on dry herbage and containing Cu at 116 mg/kg, was tested for its suitability for use with sheep consuming toxic lupin stubble, taking particular regard for dangers of Cu toxicity. There were three dietary treatments applied at two levels (either present or absent) to 40 Merino wethers for 8 weeks. Treatments consisted of adding Cu (10 mg Cu as CuS04/kg), minerals (25 g/kg as Siromin�) and toxic lupin stubble (50 g/kg) to a basal diet consisting of oaten hay and lupin seed and containing 3 mg/kg of Cu. Toxic lupin stubble decreased feed intake and growth, increased plasma activities of liver enzymes and increased plasma concentrations of protein, globulin, bilirubin, Cu and Zn. It also decreased concentrations of Zn and Fe in liver, but had no effect on Cu. The mineral mix had no adverse effects on any signs of lupinosis, and it did not increase liver Cu concentration at either level of dietary Cu. The mineral mix prevented the inappetence caused by lupinosis in sheep fed the low Cu basal diet. Cu treatment resulted in increased concentrations of Cu and Fe in liver, and exacerbated some signs of lupinosis. The results show that the mineral mix is safe to feed to sheep grazing toxic lupin stubble, and it may provide a practical means of supplying additional Zn. The exacerbation of signs of lupinosis by the addition of only 10 mg Cu/kg as CuS04 suggests that under field conditions the supply of Cu in the absence of suitable amounts of molybdenum and sulfur should be kept to a minimum.
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Dixon, T. J., S. I. Mortimer y B. J. Norris. "16S rRNA gene microbial analysis of the skin of fleece rot resistant and susceptible sheep". Australian Journal of Agricultural Research 58, n.º 7 (2007): 739. http://dx.doi.org/10.1071/ar06273.
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Fleece rot is a bacterial dermatitis that follows prolonged wetting of the sheep’s skin, and a major pre-disposing condition to body strike in the Australian Merino. Several studies have examined bacterial load of the fleece in relation to fleece rot using traditional culture-based techniques focussing on only a few bacterial species. We examined the natural bacterial diversity of the healthy sheep skin and changes that occurred in fleece-rot resistant and susceptible animals during fleece rot development. Presented is a preliminary molecular genetic analysis of the bacterial ecology of the sheep skin. Eight 16S rRNA gene libraries were constructed from susceptible and resistant sheep both before and after onset of the disease following induction by simulated rainfall. Approximately 75% of the sequences obtained in this study have not been previously identified in fleece-rot studies. Four operational taxonomic units (OTU; groups of >97% sequence similarity) of major interest were present on susceptible animals and absent from resistant animals. Data on these OTU expand current knowledge of bacteria involved in inflammation and wounding of sheep skin tissue, and provide direction for future research that may lead to new treatment options for fleece rot and body strike.
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Hua, Guoying, Xue Yang, Yuhao Ma, Tun Li, Jiankui Wang y Xuemei Deng. "m6A Methylation Analysis Reveals Networks and Key Genes Underlying the Coarse and Fine Wool Traits in a Full-sib Merino Family". Biology 11, n.º 11 (9 de noviembre de 2022): 1637. http://dx.doi.org/10.3390/biology11111637.
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In our study, a set of lambs with coarse wool type all over their bodies were discovered within a full-sib family during an embryo transfer experiment of merino fine wool sheep. The difference between coarse and fine wool traits were studied from the perspective of RNA modification-N6-methyladenosine. A total of 31,153 peaks were collected, including 15,968 peaks in coarse skin samples and 15,185 peaks in fine skin samples. In addition, 7208 genes were differentially m6A methylated, including 4167 upregulated and 3041 downregulated in coarse skin samples. Four key genes (EDAR, FGF5, TCHH, KRT2) were obtained by comprehensive analysis of the MeRIP-seq and RNA sequence, which are closely related to primary wool follicle morphogenesis and development. The PI3K/AKT pathway was enriched through different m6A-related genes. These results provided new insights to understand the role of epigenetics in wool sheep domestication and breeding.
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Tüfekci, Hacer y Mustafa Olfaz. "Kastamonu İli Küçükbaş Hayvan Yetiştiriciliğinin Sorunları ve Çözüm Önerileri". Turkish Journal of Agriculture - Food Science and Technology 3, n.º 7 (30 de junio de 2015): 577. http://dx.doi.org/10.24925/turjaf.v3i7.577-582.360.
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This study was conducted by using a survey made at 80 enterprises from 63 villages with the aim of determining situations, problems and solution proposals related to the sheep and goat farms in Kastamonu province. The average age of the farmers was 49.3 years. The farmers were 8.75% of primary school graduates, 68.75% of secondary school and also 22.6% of illiterate. The enterprises have raised animals as 31.75% of state + own land and 68.75%’ of private + leased land. Also they are kept the rate of 70% Hair goat, 30% Angora goat and 55% Merino sheep, 42.5% Akkaraman sheep, and 16.25% Turkmen genotype, 7.5% Sakız sheep and 6.25% of Kıvırcık Sheep. The average flock sizes goat and sheep enterprises were 77.3 head goats and 71.7 heads sheep, respectively. Sixty percent of the breeder feed their animals on the pasture for 8-10 months and only 30% the breeders give supplementary feeding before and during mating period. The enterprises have 31.2% parturition chamber and 92.5% lamb growth areas. While all enterprises are routinely used to protective vaccines but only used disinfectant of 73.7% enterprises. The reason of sheep and goat breeders is majority contributions of income and habits. So, flock sizes are small (74.5 heads animal). In conclusion, young people by encouraging small animal farming in the province of Kastamonu, should be given to technical, economic support and educational seminars. In the future, as the sole source of income and a large flock size may lead to a development of sheep and goat breeding in Kastamonu province.
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Szabelska, Anna, Marcin R. Tatara y Witold Krupski. "Morphometric, Densitometric, and Mechanical Properties of Maxillary Teeth in 5-Month-Old Polish Merino Sheep". Cells Tissues Organs 206, n.º 4-5 (2018): 196–207. http://dx.doi.org/10.1159/000499479.
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This study was performed to determine morphological, densitometric, mechanical, and elemental characteristics of maxillary teeth in 5-month-old Polish Merino sheep. The total tooth volume (Tvol) was determined using quantitative computed tomography. Micro-computed tomography was used to determine the total enamel volume (Evol), volumetric enamel mineral density, total dentine volume (Dvol), volumetric dentine mineral density, and total tooth enamel and dentine volume (EDvol). Compression testing was used to determine the ultimate force of teeth. Microhardness of enamel and dentine was evaluated using Vicker’s test. Elemental analysis of enamel and dentine was performed using a scanning electron microscopy technique. Tooth weight, length, Tvol, Evol, Dvol, and EDvol increased consequently from the lowest values for p2, then for p3 and p4, to the highest values obtained for M1 (all p < 0.05). Ultimate force reached the lowest value for p2 compared with the other teeth (p < 0.05). The comparison of left and right teeth did not reveal significant differences for all the evaluated parameters (p > 0.05). Volumetric mineral density, calcium and phosphorus content, and microhardness were higher in enamel than in dentine, while the opposite results were obtained for magnesium and oxygen (all p < 0.05). Significantly higher enamel microhardness was found in mandibular i1 compared with maxillary and mandibular premolars (p < 0.05). The elaborated experimental model of the determination of maxillary deciduous teeth traits may serve for further studies on the effects of physiological, pathological, environmental, nutritional, pharmacological, and toxicological factors affecting tooth development and mineralized tissue properties.
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Han, Jilong, Tingting Guo, Yaojing Yue, Zengkui Lu, Jianbin Liu, Chao Yuan, Chune Niu, Min Yang y Bohui Yang. "Quantitative proteomic analysis identified differentially expressed proteins with tail/rump fat deposition in Chinese thin- and fat-tailed lambs". PLOS ONE 16, n.º 2 (2 de febrero de 2021): e0246279. http://dx.doi.org/10.1371/journal.pone.0246279.
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Tail adipose as one of the important functional tissues can enhance hazardous environments tolerance for sheep. The objective of this study was to gain insight into the underlying development mechanisms of this trait. A quantitative analysis of protein abundance in ovine tail/rump adipose tissue was performed between Chinese local fat- (Kazakh, Hu and Lanzhou) and thin-tailed (Alpine Merino, Tibetan) sheep in the present study by using lable-free approach. Results showed that 3400 proteins were identified in the five breeds, and 804 were differentially expressed proteins, including 638 up regulated proteins and 83 down regulated proteins in the tail adipose tissues between fat- and thin-tailed sheep, and 8 clusters were distinguished for all the DEPs’ expression patterns. The differentially expressed proteins are mainly associated with metabolism pathways and peroxisome proliferator activated receptor signaling pathway. Furthermore, the proteomics results were validated by quantitative real-time PCR and Western Blot. Our research has also suggested that the up-regulated proteins ACSL1, HSD17β4, FABP4 in the tail adipose tissue might contribute to tail fat deposition by facilitating the proliferation of adipocytes and fat accumulation in tail/rump of sheep. Particularly, FABP4 highly expressed in the fat-tail will play an important role for tail fat deposition. Our study might provide a novel view to understanding fat accumulation in special parts of the body in sheep and other animals.
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Koynarski, T. "PrP gene polymorphism and its influence on some productive traits of sheepbreeds reared in Bulgaria". BULGARIAN JOURNAL OF VETERINARY MEDICINE 23, n.º 2 (2020): 170–77. http://dx.doi.org/10.15547//bjvm.2219.
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The rapiddissemination of scrapie over the past few decades led to development of aspecific eradication programme, based on the polymorphisms within the prionprotein gene (PRNP). Current approach encourages the selection ofanimals carrying the resistant ARR/ARR genotype, while other genotypes areconsidered less preferable. Although the strategy seems to be working quitewell, farmers are concerned whether this will affect sheep productivity andsubsequently decrease net profits. The current study was aimed to elucidatethe linkage between the PrP gene polymorphism (based on codons 136,154 and 171) and some productive traits (live weight, reproduction, milk andfleece yield) of three sheep breeds reared in Bulgaria – Assaf, NortheastBulgarian Merino and Blackhead Pleven. The total number of detectedgenotypes was six – ARR/ARR, ARR/ARQ, ARR/ARH, ARQ/ARQ, AHQ/ARQ and ARR/VRQ,with different prevalence within each breed. The observed lack ofsignificant differences in the studied performance traits between the PRNP genotypes suggests that PRNP polymorphisms did not influencethe sheep productive performance. Therefore, selection of animals on theresistant genotype (ARR/ARR) would not worsen their productivity. Theobtained results should help the better understanding of scrapie selectionand the positive effect that it would have to both health care and industry.
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Hodge, Marnie J., Sara de las Heras-Saldana, Sally J. Rindfleish, Cyril P. Stephen y Sameer D. Pant. "Characterization of Breed Specific Differences in Spermatozoal Transcriptomes of Sheep in Australia". Genes 12, n.º 2 (30 de enero de 2021): 203. http://dx.doi.org/10.3390/genes12020203.
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Reduced reproductive efficiency results in economic losses to the Australian sheep industry. Reproductive success, particularly after artificial insemination, is dependent on a number of contributing factors on both ewe and ram sides. Despite considerable emphasis placed on characterising ewe side contributions, little emphasis has been placed on characterising ram side contributions to conception success. Over 14,000 transcripts are in spermatozoa of other species, which are transferred to the ova on fertilisation. These transcripts conceivably influence early embryonic development and whether conception is successful. Semen was collected (n = 45) across three breeds; Merino, Dohne, and Poll Dorset. Following collection, each ejaculate was split in two; an aliquot was assessed utilising Computer Assisted Semen Analysis (CASA) and the remaining was utilised for RNA extraction and subsequent next-generation sequencing. Overall, 754 differentially expressed genes were identified in breed contrasts and contrast between ejaculates of different quality. Downstream analysis indicated that these genes could play significant roles in a broad range of physiological functions, including maintenance of spermatogenesis, fertilisation, conception, embryonic development, and offspring production performance. Overall results provide evidence that the spermatozoal transcriptome could be a crucial contributing factor in improving reproductive performance as well as in the overall productivity and profitability of sheep industries.