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Pluske, J. R., D. K. Kerton, P. D. Cranwell, R. G. Campbell, B. P. Mullan, R. H. King, G. N. Power i in. "Age, sex, and weight at weaning influence organ weight and gastrointestinal development of weanling pigs". Australian Journal of Agricultural Research 54, nr 5 (2003): 515. http://dx.doi.org/10.1071/ar02156.
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The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on aspects of physiological and gastrointestinal development in pigs. Forty-eight Large White × Landrace pigs were used in a factorial arrangement with the respective factors being: age at weaning (14 or 28 days), weight at weaning (heavy or light), sex (boar or gilt), and time after weaning (1, 7, and 14 days). At weaning, 48 pigs were removed from the sow: 16 pigs were then fasted for 24 h before euthanasia for determination of organ weights, gut histology, and enzymology, and 32 pigs were offered a high quality pelleted weaner diet ad libitum for subsequent assessment of organ weights, histology, and enzymology at 7 and 14 d after weaning. On Day 6 and 13 after weaning, 2 pigs from each group had their feed removed, and 24 h later were euthanased and similar measurements were taken. In general, the data highlighted the overall gastrointestinal underdevelopment of pigs weaned at 2 weeks of age and of pigs weaned light-for-age at either 2 or 4 weeks. Heavier body organs, gastrointestinal organs, and accessory digestive organs observed after weaning, except for the spleen, presumably reflected the increase in substrates available for cellular growth as feed intake increased after weaning, and the development of organs required to process this feed. Interestingly, the relative weights (% of liveweight) of the stomach and small intestine and, to a lesser extent, the caecum and colon, were greater in the light, 14-day-old weaned pigs, but these differences diminished with increasing time after weaning. Consistent effects due to age, weight, and sex were not observed for villous height and crypt depth, or for the specific activities of the brush-border and pancreatic enzymes measured. However, increases (P < 0.001) in the activities of maltase (P�<�0.001), glucoamylase (P < 0.001), and sucrase (P = 0.020) (all expressed per gram of mucosa), and that of trypsin (per gram of pancreas), occurred by 14 days after weaning. This most likely reflected the inducible nature of these enzymes in response to the increasing intake of substrates provided in the diet. In contrast, the specific activity of lactase declined (P = 0.012) in the first 14 days after weaning. These data suggest that pigs weaned at 2 weeks of age and pigs weaned light-for-age at either 2 or 4 weeks have a less developed gastrointestinal tract, and that its development after weaning might proceed differently to that of pigs weaned older and heavier.
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Kutluca Korkmaz, Müzeyyen, i Ebru Emsen. "Farklı Yaşlarda Sütten Kesimin Prolifik ve Terminal Irk Melez Kuzuların Büyüme Özellikleri ve Yaşama Güçleri Üzerine Etkisi". Turkish Journal of Agriculture - Food Science and Technology 8, nr 11 (24.11.2020): 2255–60. http://dx.doi.org/10.24925/turjaf.v8i11.2255-2260.2468.
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In this study, we compared the growth and survival characteristics of Romanov × Morkaraman (F1 Rom), Romanov × F1 Romanov (G1 Rom) and Charollais × F1 Romanov (Charom) crossbreed lambs weaning weight at different ages. After birth, from three genotypes lambs were weaned at two different ages of 50 and 75 days and growth performance after weaning was examined at 120 days of age. The effect of three different genotypes and birth type on birth weight was very important, and sex effect was insignificant. In weaning weight, only the effect of birth type was found to be significant. Lamb birth and weaning weights were in Charom, F1 Rom, G1 Rom lambs, 3.38-15.28; 3.98-15.04; 3.21-15.55 kg, respectively. The type of birth showed variation in the birth weight of the lamb and the decrease in lamb birth weights (Single: 4.19 kg: Twin: 3.42 kg; Triplet: 3.15 kg and Quadrature: 2.88 kg) was observed as the number of offspring increased. The effect of the birth type on weaning weights was similar in single and triplet. Single-born lambs have higher weaning weights than those of twins and quadruplets. Average daily live weight gain (ADG) from weaning in single lambs, 247.37 g were found higher than twin (190.67 g), triplets (201.44 g) and quadruplets (178.57 g). The effect of weaning age was insignificant on weaning weights. The first month weight after weaning, effect of the genotype of the lamb, the birth type and the sex were insignificant; but effect of weaning age was significant weaning weights and first month after weaning weights the ADG. The late weaned lambs had higher next first month live weight (18.62-17.89 kg) and ADG (179.45-81.32 g). The live weights of the lambs on the 120 days were similar and none of the factors investigated were found to be effective.
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Meyer, K. "Estimates of covariance components for growth traits of Australian Charolais cattle". Australian Journal of Agricultural Research 44, nr 7 (1993): 1501. http://dx.doi.org/10.1071/ar9931501.
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Restricted maximum likelihood estimates of covariance components and the resulting genetic parameters were obtained for birth, weaning, yearling and final weights and postweaning gain of Australian Charolais cattle fitting an animal model including genetic or permanent environmental maternal effects. No 'carry-over' of maternal effects till weaning on postweaning weights was found. Direct heritability estimates were 34, 41 and 22% for yearling weight, final weight and postweaning gain respectively. Maternal genetic effects were not important for birth weight and were small for weaning weight. Permanent environmental maternal effects affected birth weight to a moderate extent, but were the main factor determining weaning weight, explaining 4% and 21% of the respective phenotypic variance while direct heritabilities were 21% (birth) and 12% (weaning). Direct genetic correlations between birth and the other weights were medium, ranging from 0.44 to 0.67, while estimates between weaning, yearling and final weight were close to unity.
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Anous, M. R. "Selection indexes for improved weaning and marketing body weights of the Burundi local rabbits". Archives Animal Breeding 44, nr 5 (10.10.2001): 561–68. http://dx.doi.org/10.5194/aab-44-561-2001.
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Abstract. Estimates of genetic and phenotypic parameters for growth-related traits involving body weights at 4, 6 (weaning), 8 and 10 (marketing) weeks of age and average daily gains from 4- to 6- and 6- to 10-weeks of age (postweaning daily gain) were computed on 193 males of the Burundian local rabbits . Estimates were then used for constructing thirteen selection indexes, involved body weights at 4, 6 and 10 weeks of age and daily gains, to improve body weights of rabbits at weaning and marketing. The use of weaning weight in an index combined with body weight at 4 weeks of age (W4) and posuveaning average daily gain (index12) or postweaning daily gain solely (index2) resulted in a relative efficiency of about 100 % as using weaning weight combined with body weights at 4 and 10 weeks of age (index,) or with marketing body weight (index2) or W4 (index3). The accuracy of selection (rTI) using these indexes ranged between 0.890 and 0.906. They lead to a progress in weaning weight from 77–79 g and in marketing weight from 54–56 g. However, from a practical stand point, selection on index 3, including W4 and weaning weight, or on index 5, including weaning weight alone, could be recommended for improving both weaning and marketing weights of Burundian local rabbits.
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Adedibu, I. I., F. E. Sola- Ojo i M. Lawal. "Sokoto Red and Sahelian goats: The untapped potential for improving meat production in the developing economy of Nigeria". Nigerian Journal of Animal Production 44, nr 4 (27.12.2020): 325–32. http://dx.doi.org/10.51791/njap.v44i4.494.
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A study was conducted on indigenous unselected Sokoto Red (SR) and Sahel (SH) goats in National Animal Production Research Institute, (NAPRI), Ahmadu Bello University, Shika- Zaria, Kaduna State, Nigeria. The study was carried out to understand how birth, pre- weaning and post-weaning weights in the SR and SH goats can be used to improve their productivity. Thirty kids (10 males and 20 females) of SR and thirty kids (10 males and 20 females) of SH breeds of goat were utilised for this study. Results obtained showed that the coefficient of variation (CV) was very low. There were no significant differences (P>0.05) among mean bodyweight at birth, 30 days pre-weaning, 60 days pre-weaning, 90 days post- weaning and 120 days post-weaning weights of SR and SH goats except at 150 days post- weaning weight. Highly positive phenotypic correlations existed in the SR goats between 90- day weaning weight and 120-day post weaning; 90-day weaning weight and 150-day post weaning.120-day post weaning weight and 150-day post weaning.The birth weight of the SH goats were highly significant (P<0.05) and positively correlated with body weight at 30, 60, 90, 120 and 150 days old. It was observed that the sampled population was homogeneous for all traits. The 90-day weight of the SR can be utilised to improve for body weight at 30-, 120- and 150- days of age while in the SH goat, selection for high birth weight would enhance improvement for high body weight at later stages of growth.
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Caro-Petrovic, Violeta, Milan Petrovic, Dragana Ruzic-Muslic, Nevena Maksimovic, Irina Sycheva, Bogdan Cekic i Ivan Cosic. "Interrelation between body weights of sire, dam and their lambs at early stage of growth". Biotehnologija u stocarstvu 36, nr 2 (2020): 205–14. http://dx.doi.org/10.2298/bah2002205c.
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Records of female lambs and their parents of the Mis sheep breed have used. All animals are approximately have weaned at 90 days of age. Descriptive statistics, paired sample test, paired differences, measures of association, correlations and regression of body weights between female lambs and their parents have done. A complementary least body weights at 30 days and weaning between dams and lambs but utmost weight at 30 days, the lambs were higher while at weaning, the dams had higher weight. It can observe that the averages on body weights the rams were the highest, followed by lambs and the lowest the dams? body weights. The coefficient of determination of R2 varies from low to high, indicating that the lamb's body weight has more influenced by other factors that we have not considered. There were significant correlations between lamb body weight at birth and sire/dam body weight at birth. The results showed highly significant correlations of lamb's body weight at 30 days with dams but with sires, positive and very low. There had positive but no significant correlation between lamb body weight at weaning and sire body weight at weaning. Lamb body weight at weaning and dam body weight at weaning are highly correlated.
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Lee, G. J., i C. S. Haley. "Comparative farrowing to weaning performance in Meishan and Large White pigs and their crosses". Animal Science 60, nr 2 (kwiecień 1995): 269–80. http://dx.doi.org/10.1017/s1357729800008432.
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AbstractGrowth and survival from birth to weaning were monitored during three generations of crossbreeding between British Large White (LW) and Chinese Meishan (MS) pigs. The design allowed comparisons between sow genotypes ranging from zero to all MS genes, which were mated toLWor MS boars, to produce progeny with proportions of 0·0 to 0·5 or 0·5 to 1·0 MS genes, respectively. Crossbreeding parameters of both maternal and direct piglet performance were estimated for the first two parities using restricted maximum likelihood (REML) methods for litter traits (litter weight at birth, litter mean and within litter standard deviation of piglet weight at birth, proportion surviving to weaning, litter size and weight at weaning and litter mean piglet weight at weaning) and for traits of the piglet (birth weight, probability of survival and weaning weight). For litter traits, the estimated contribution of the additive maternal effect to the breed differences (MS-LW) was significant for litter mean piglet birth weight (–0·46 (s.e. 0·04) kg), survival to weaning (0·15 (s.e. 0·02)), litter size at weaning (1·6 (s.e. 0·16) piglets), litter weaning weight (–11·2 (s.e. 3·8) kg) and litter mean piglet weaning weight (2·54 (s.e. 0·24) kg). Adding litter size and litter mean piglet birth weight to the model removed the additive maternal contribution to the breed differences in survival, and litter size and reduced that for litter mean piglet weaning weight. The contribution of the direct additive effect to the breed difference (MS-LW) was significant for the within litter standard deviation in birth weight (0·018 (s.e. 0·006)), survival to weaning (0·12 (s.e. 0·02)) and litter size (1·12 (s.e. 0·64)) and weight (11·6 (s.e. 4·0) kg) at weaning, but not for piglet weight at birth or weaning. Fitting litter size and litter mean birth weight had comparatively little impact on the direct additive effects. There were significant maternal heterosis effects for litter weight at birth and litter size and weight at weaning, the estimated deviation of the F1 from the midpoint of the two purebreds 3·22 (s.e. 0·55) kg, 2·20 (s.e. 0·47) piglets, and 20·1 (s.e. 3·3) kg respectively, but none for survival or piglet weights. There were direct heterosis effects for litter weight and litter mean piglet weights, the estimated deviation of the Fjfrom the mid point of the two purebreds being 1·16 (s.e. 0·41) kg and 0·14 (s.e. 0·02) kg, for survival to weaning (0·04 (s.e. 0·02)) and for litter weight (11·2 (s.e. 2·5) kg) and litter mean piglet weight (0·96 (s.e. 0·17) kg) at weaning. Fitting litter size and litter mean piglet birth weight removed or reduced both maternal and direct heterosis effects. Individual piglet analyses gave similar results to analyses of the equivalent sow trait. It was concluded that in litters born to MS cows, the lower piglet survival and lower weaning weights were related to the larger litter sizes and lower piglet birth weights. For their birth weight, however, MS piglets have a greater ability to survive and thrive. The large direct and maternal heterosis effects observed for litter and mean piglet weight at weaning werepartly associated with the heavier birth weight of the crossbred piglet.
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Yaylak, Erdal, Hikmet Orhan i Alim Daşkaya. "Some Environmental Factors Affecting Birth Weight, Weaning Weight and Daily Live Weight Gain of Holstein Calves". Turkish Journal of Agriculture - Food Science and Technology 3, nr 7 (11.07.2015): 617. http://dx.doi.org/10.24925/turjaf.v3i7.617-622.392.
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The present study was conducted to determine some environmental factors affecting birth weight, weaning weight and daily live weight gain of Holstein calves of a livestock facility in Izmir, Turkey. The data on 2091 calves born between the years 2005-2010 were used to assess the relevant parameters. Effects of calving year, calving month, calf gender and the interaction between calving year and calving month on calves’ birth weights were highly significant. The overall mean of birth weights was 39.6±0.15 kg. In addition, effects of calving year, calving month, gender, birth weight, weaning age, calving year x calving month, calving year x gender and calving year x calving month x gender interactions on weaning weight (WW) and daily live weight gain (DLWG) were highly significant. The overall means of WW and DLWG were respectively found to be 79.7±0.20 kg and 525±2.5 g. A one kilogram increase in birth weight resulted in an increase of 0.89 kg in weaning weight and a decrease of 1.26 g in daily live weight gain. Prenatal temperature-humidity index (THI) affected birth weight of calves (R2=0.67). Increasing THI from 50 to 80 resulted in 3.8 kg decrease in birth weight.
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Koketsu, Y., i G. D. Dial. "Factors associated with average pig weight at weaning on farms using early weaning". Animal Science 66, nr 1 (luty 1998): 247–53. http://dx.doi.org/10.1017/s1357729800009024.
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AbstractThe objective of this study was to investigate the effect of various factors on average pig weight at weaning on farms using early weaning. Farms were selected based on average weaning age and whether they recorded lactation food intake and litter weights at weaning. The database contained 9834 litter weights and 8903 food intake records. Average pig weight at weaning, litter size at weaning, weaning age, and average daily food intake during lactation (ADFl) were 4·9 (s.d. 1·0) kg, 9·3 (s.d. 1·6) pigs, 16·8 (s.d. 2·8) days, and 4·9 (s.d. 1·1) kg, respectively. Litter size, weaning age, parity, farrowing season, and ADFl groups influenced average pig weight at weaning (P < 0·01). Three two-way interactions between parity and season, weaning age and farrowing season, and weaning age and ADFl groups were found fP < 0·01). Average pig weights for litter sizes between six and 10 were higher than those between litter sizes one and four, and 11 and 22. Parity 1 sows produced lighter pig weights than any other parity group during any other season (P < 0·01). Average weights of weaned pigs farrowed during the summer in all parities groups were lighter (P < 0·01) than those during the autumn. Pig weights for weaning ages between 22 and 21 days during the summer tended to be lighter than those during the autumn. Pigs weaned between days 16 and 22 of age in the high ADFI group (>5·6 kg) were heavier (P < 0·01) than those in the low ADFl (> 4·2 kg) group.
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Glaze, J. B. Jr, i R. R. Schalles. "Relationships between weaning weight, maternal weaning weight, and milk production in polled Hereford cattle". Kansas Agricultural Experiment Station Research Reports, nr 1 (1.01.1995): 89–90. http://dx.doi.org/10.4148/2378-5977.2042.
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Mavrogenis, A. P., i A. Constantinou. "Relationships between pre-weaning growth, post-weaning growth and mature body size in Chios sheep". Animal Science 50, nr 2 (kwiecień 1990): 271–75. http://dx.doi.org/10.1017/s0003356100004724.
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ABSTRACTThe study examined early measures of growth and their relationships with mature body size. Data on 792 purebred females of the Chios breed, born and reared on two experimental farms between 1978 and 1986, were analysed. Pedigree information and records on live weight at birth, at weaning, 105 days of age and at first and subsequent matings was recorded. There were flock-year differences for all traits studied (P < 0·01) and birth type was important for all traits except post-weaning growth rate. Dam lactation number had no significant effect on birth weight and pre-weaning growth rate, but it significantly affected all subsequent weights and post-weaning growth rate. Estimated heritabilities increased with age and ranged from 0·13 (s.e. 0·14) (birth weight) to 0·30 (s.e. 0·15) (mature weight). Genetic correlations were generally positive between weights and growth traits. Phenotypic correlations were positive and followed the pattern of the genetic correlations. The results suggest that selection for 105-day weight will result in increased mature weight.
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Vaz, Ricardo Zambarda, i José Fernando Piva Lobato. "Effects of the weaning age of calves on somatic development and on reproductive performance of beef cows". Revista Brasileira de Zootecnia 39, nr 5 (maj 2010): 1058–67. http://dx.doi.org/10.1590/s1516-35982010000500016.
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This study evaluated body development and reproductive performance of beef cows whose calves were submitted to early weaning (76 days of age), or conventional weaning (148 days of age). It was used 141 Braford cows that calved in 2004, 2005, and 2006 to evaluate weight at calving at 76 days, weight at calving at 148 days, weight at the beginning and end of the breeding season, variation of the average daily weight, body condition, pregnancy rate, and calving interval. Dams of calves weaned at 148 days of age showed daily weight gain higher body weight and better body condition at 148 days of age. The weights at the end of breeding season and average weight gain during the breeding season were higher in early weaning cows than in conventional cows. Pregnancy rate of early weaning cows (86.34%) was higher than those submitted to weaning at conventional age (55.45%). Pasture interval was similar among early weaning cows and conventional weaning cows. The best benefit on reducing weaning age in pregnancy rate was in primiparous cows. There was significant interaction between weaning age and the year for calving interval and milk production. The early weaning of calves carried out at 76 days of age allows cows to better weight recovery in the post-weaning and breeding periods, improving their body condition and consequently increasing pregnancy rate regarding to cows whose calves suckled until 148 days of age.
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Vera, R. R. "Growth and conception in continuously underfed Brahman heifers". Animal Science 53, nr 1 (sierpień 1991): 45–50. http://dx.doi.org/10.1017/s0003356100005961.
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ABSTRACTThe objective of the experiment was to determine the effects of different, sustained levels of undernutrition on the reproductive performance of Brahman heifers, and on their subsequent growth to adulthood, when reared exclusively on a low-quality tropical pasture.Irrespective of the live-weight gains realized between weaning and the target weight of 270 kg, heifers on all treatments conceived at a similar mean weight of 290 kg. Nevertheless, heifers on the low weight-gain treatment had a significantly different relationship of cumulative conceptions to weight, which was confirmed when Cox's proportional hazard model was fitted to the data, using a dummy variable to represent treatment effect.A Gompertz growth model was fitted to the live weight of each individual animal. A significantly larger mean asymptotic weight was observed for the low weight-gain treatment, which was unrelated to the number of calvings or weanings, or to the total weight of calves weaned per animal. Asymptotic weights were positively correlated with first conception weight and age, both within and across treatments.The implications of drastic post-weaning undernutrition and continued suboptimal feeding are discussed briefly.
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Schreurs, N. M., P. R. Kenyon, F. J. Mulvaney, P. C. H. Morel, D. M. West i S. T. Morris. "Response of additional ewe lamb liveweight during gestation on birth and weaning weight of offspring and liveweight of the ewe lamb at weaning". Animal Production Science 50, nr 6 (2010): 528. http://dx.doi.org/10.1071/an09185.
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Increasing the liveweight of ewe lambs during gestation may have positive effects on lamb birthweight and weaning weight and also on ewe lamb liveweight at weaning. Specific times during the gestation period of the ewe lamb may be more responsive to improved nutrition and increases in liveweight. The objective of this work was to use a meta-analytic approach to investigate the effects of ewe lamb liveweight at mating and during pregnancy on lamb birth and weaning weights, and the ewe lamb’s liveweight at weaning. Increasing ewe lamb liveweight in early gestation and in particular before mating gave the greatest increases in the birth and weaning weight of the lambs, and also of the ewe lamb’s liveweight at weaning compared with increasing liveweight in the second and third trimester of gestation. This indicates that management practices for ewe lambs that generate higher liveweight at mating are likely to result in increased lamb survival, higher weaning percentages, greater lamb weaning weights and create rising 2-year-old ewes with better liveweight for mating in the subsequent season. Compared with ewe lambs that gave birth and reared singletons to weaning, those ewe lambs that gave birth to twins and reared twins had greater increases in lamb birthweights, lamb weaning weights and ewe lamb weights at weaning for each extra kilogram of ewe lamb liveweight during gestation. For ewe lambs, especially those that birth and rear twins, management options that increase the pre-mating weights will have the greatest response in lamb birthweight, weaning weight and liveweight of the ewe lamb itself at weaning.
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Hamdani, Muhammad Dima Iqbal, Kusuma Adhianto, Sumarni Sumarni i Sulastri Sulastri. "Estimasi Korelasi Genetik antara Bobot Lahir dengan Bobot Sapih pada Kambing Saburai di Sentra Pembibitan Kabupaten Tanggamus Provinsi Lampung". Jurnal Ilmu dan Teknologi Peternakan Tropis 7, nr 3 (30.09.2020): 247. http://dx.doi.org/10.33772/jitro.v7i2.5628.
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ABSTRAKPenelitian ini bertujuan untuk mengetahui estimasi nilai korelasi genetik antara berat lahir dan berat sapih pada kambing saburai di Kabupaten Tanggamus. Penelitian dilakukan pada bulan Juli-Agustus 2018, berlokasi di Sentra pembibitan kambing saburai di Kabupaten Tanggamus. Materi penelitian ini sebanyak data 136 indukan dan data 150 anakan kambing saburai. Metode penelitian yaitu survei menggunakan data recording dan kuesioner. Variabel yang diamati adalah berat lahir dan berat sapih induk, berat lahir dan berat sapih cempe, umur sapih, umur induk saat melahirkan, tipe kelahiran cempe, dan jenis kelamin cempe. Hasil penelitian menunjukkan bahwa berat lahir dan berat sapih induk masing-masing adalah 3,10±0,47 dan 12,15± 2,29; berat lahir dan berat sapih cempe masing-masing adalah 3,25±0,48 dan 12,60± 2,77. Korelasi genetik berat lahir dan berat sapih di Sentra Pembibitan Kabupaten Tanggamus adalah 0,37. Kesimpulan dari penelitian ini adalah seleksi peningkatan bobot lahir akan meningkatkan bobot sapih kambing saburai.Kata kunci: bobot lahir, bobot sapih, kambing saburai, korelasi genetikABSTRACTThis study aims to determine the estimation of genetic correlation values of birth weights and weaning weights in Saburai goats in Tanggamus regency. The study was conducted in July-August 2018, located in the breeding area, Tanggamus Regency. The materials of research were data from 136 doe and 150 kids. The research was conducted by survey method using the recording data and questionnaire. The variables observed were birth weight and weaning weight of doe, birth weight and weaning weight of the kid, weaning age, doe’s age at parturition, birth type of kid, and sex of kid. The results of this study indicate that the average birth weight of doe was 3.10±0.47, the weaning weight of doe was 12.15±2.29, the birth weight of kid was 3.25±0.48, and weaning weight of kid was 12.60±2.77. It can be concluded that the estimation of genetic correlation between birth weight and weaning weight of saburai goat was high with score of 0.37. Selection on birth weight can increase weaning weight in saburai goat. Keywords: birth weight, weaning weight, saburai goat, genetic correlation
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Selaive -Villarroel, Arturo Bernardo, Marcus Brocardo Maciel i Nelson Manzoni de Oliveira. "Effects of weaning age and weight on lamb growth rate of Morada Nova breed raised in a tropical extensive production system". Ciência Rural 38, nr 3 (czerwiec 2008): 784–88. http://dx.doi.org/10.1590/s0103-84782008000300030.
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The aim of this research were to study the effect of weaning age and weight on post-growing rate (PWG) and to estimate the optimal weaning age (WA) and weight (WW) of Morada Nova-white variety breed lambs raised under extensive system conditions. A total of 31 male and female lambs were evaluated, being 19 lambs born in April/May 2001 and 12 lambs born in February/March 2002. Lambs were distributed in the following treatments at weaning: 1) weaning age = T1: weaned at 60 days; T2: weaned at 75 days; T3: weaned at 90 days, and 2) weaning weight = T1: weaned with 9 to 10.4kg weigth; T2: weaned with 10.5 to 12.4kg weight and T3: weaned with above 12.5kg weight. The PWG was recorded through successive weightings done every fourteen days from weaning to 180 days of age. Data were analysed through a statistical model that included age and weight at weaning, sex and year of birth as fixed effects. Lambs weaned with 60, 75 and 90 days of age showed non-significant differences (P>0.05) on PWG. However, WW had a significant influence (P<0.05) on lamb weight. The group weaned with 9-10.4kg had smaller live weight than those weaned with 10.5-12.4kg or above 12.5kg. No differences were found between these last two groups. Also, sex had significant effect (P<0.05) on lamb growing with males being heavier than females (20.7kg and 17.6kg, respectively). Year of birth did not affect PWG. It was concluded that weight at weaning is more important than age at weaning on post-weaning growing of lambs. The most efficient live weaning weight on white Morada Nova lambs raised in extensive system production is over 10.5kg.
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Kramarenko, A. S., S. S. Kramarenko, S. I. Lugovoy i O. I. Yulevich. "Analysis of the influence of genetic and non-genetic factors on the birth weight and weaning weight of lambs". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 22, nr 93 (21.09.2020): 14–21. http://dx.doi.org/10.32718/nvlvet-a9303.
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The main aim of this paper is to analyze the influence of genetic and non-genetic factors on the birth weight and weaning weight of lambs. The study was carried out on the basis of the Institute of Animal Husbandry of Steppe Regions named by M. F. Ivanov “Askania-Nova” – the National Scientific Agricultural Center in Sheep Breeding of NAAS. Birth and weaning weights data collected during a 5-vear period from 3961 lambs were used. The reproductive traits of the Ascanian fine-fleece (AC) ewes were evaluated in combination with the rams of different genotypes: Ascanian fine-fleece, Australian merino (AM) and half-bred animals (1/2AC+1/2AM). The main effect of the ram genotype and the year of lambing, the age of the ewes, the litter size, the sex of lamb and the sex ratio in twins on the birth weight and weaning weight of lambs was analysed using one-way ANOVA. Differences between years of the 5-year period were highly significantly (P < 0.001) for all lamb traits studied. The effects of the environmental factor (year of lambing) on the birth weight and weaning weight of lambs represented 27.2 and 15.2 per cent of the total variance, respectively. The ram-group effects, which are mainly genetic differences, were highly significant (P < 0.001) in all traits. Age of dam had significant effect on the birth weight of lambs (P = 0.048) and was relatively unimportant as a source of variation. Two-year-old ewes bore lighter lambs than older ewes. There were no significant differences in the weaning weight of lambs from the ewes of different age classes. Survival rate was related to birth weight of lambs. Lamb survival increased up to a birth weight of 4.0 kg and only declined when they weighed more than 5.0 kg at birth. Our results showed that singles were 0.61 kg heavier than twins at birth and were 2.42 kg heavier than twins at weaning. Litter size (type of birth) was responsible for 42.5 and 10.0 % of total variability in birth and weaning weights of lambs, respectively (in both cases: P < 0.001). Average birth and weaning weights of male lambs were higher than the females (in both cases: P < 0.001).
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Wolter, B. F., i M. Ellis. "The effects of weaning weight and rate of growth immediately after weaning on subsequent pig growth performance and carcass characteristics". Canadian Journal of Animal Science 81, nr 3 (1.09.2001): 363–69. http://dx.doi.org/10.4141/a00-100.
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Effect of accelerated weight gain immediately after weaning on subsequent performance was evaluated in pigs with heavy and light weaning weights. The study was carried out as a randomized complete block design with a 2 × 2 × 2 factorial arrangement with the treatments being weaning weight (Heavy vs. Light), post-weaning growth rate (Accelerated vs. Conventional) and sex (Barrow vs. Gilt). Pigs were weaned at 18 to 22 d of age, weighed and classified as either Heavy or Light (5.4 vs. 3.9 kg, SE ± 0.04). During the first 14 d after weaning, pigs on the Accelerated growth treatment were housed in a specialized nursery and provided with liquid milk replacer and a dry diet; pigs on the Conventional treatment were housed in a standard nursery and provided with a dry diet only. Subsequent to the 14 d post-weaning treatment period, pigs from all treatments were housed in standard accommodation and provided the same dietary regimen to slaughter weight (110 kg). Pigs on the Accelerated treatment were heavier (P < 0.01) than pigs on the Conventional treatment at the end of the treatment period (9.2 vs. 8.1 kg, SE ± 0.13) and at 56 d of age (19.6 vs. 18.3 kg, SE ± 0.28). Early growth rate did not affect growth from 35 d of age to slaughter weight, or days to reach slaughter weight. Pigs on the Conventional treatment had greater (15.6 vs. 14.1 mm, SE ± 0.47, P < 0.01) backfat depths at slaughter than those on the Accelerated treatment. Heavy pigs at weaning were heavier (P < 0.001) at birth and 56 d of age than light pigs, and reached slaughter weight 8.6 d earlier (P < 0.001). In summary, weaning weight, but not growth rate in the first 2 wk after weaning, influenced age at slaughter. Key words: Pigs, weaning weight, post-weaning growth rate, weaning management
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Bunok, Debora K. I., M. Th R. Lapian, V. R. W. Rawung i G. D. G. Rembet. "HUBUNGAN BOBOT LAHIR ANAK BABI DENGAN PERTAMBAHAN BOBOT BADAN, BOBOT SAPIH, MORTALITAS, DAN LITTER SIZE SAPIHAN PADA PETERNAKAN PT. KARYA PROSPEK SATWA". ZOOTEC 40, nr 1 (15.01.2020): 260. http://dx.doi.org/10.35792/zot.40.1.2020.27181.
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RELATIONSHIP OF WEIGHT BIRTH PIGLET WITH ADDITION OF AGENCY WEIGHT, WEANING WEIGHT, MORTALITY, AND LITTER SIZE WEANING IN LIVESTOCK PT. KARYA PROSPEK SATWA. This study aims to determine how much the relationship of birth weight with weight gain, weaning weight, mortality, and litter size of weaning in animal husbandry companies owned by Animal Prospects. The material used is 7 pregnant sows from Yorkshire and Landrace, with an average body weight of 140 kg which will be taken by 54 children randomly. Furthermore, this research data obtained from weighing piglets during parturition, weighing weekly during weaning and weighing when weaned and taking data on live and dead piglets during the study. The data is then processed by procentage descriptive method and evaluated by simple correlation (r) and determination (R) tests. The variables measured in the study were body weight gain, weaning weight, mortality, and weaning litter size. Birth weight has a very close relationship with weight gain and weaning weight, but litter size weaning has a very weak relation. While mortality is not related. Key words: Piglets, Birth weight, Weight gain, Weaning weight, Mortality, Litter size weaning.
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Vaez, Torshizi R., FW Nicolas i HW Raadsma. "REML estimates of variance and covariance components for production traits in Australian Merino sheep, using an animal model. 1. Body weight from birth to 22 months". Australian Journal of Agricultural Research 47, nr 8 (1996): 1235. http://dx.doi.org/10.1071/ar9961235.
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Variance components for direct additive genetic, maternal additive genetic, and maternal environmental effects, and the covariance between direct and maternal additive genetic effects, were estimated by restricted maximum likelihood (REML) procedures, using an animal model, for body weight between birth and 22 months of age in Australian Merino sheep. Direct heritability was estimated to be 0.30 for birth weight, 0.28 for weaning weight, 0.24 for body weight at 10 months, 0.34 for body weight at 16 months, and 0.34 for body weight at 22 months. Maternal heritability estimates were 0.29, 0.41, 0.14, 0.07, and 0.07 for the same performances, respectively. Our results suggested that for birth weight and weaning weight, maternal additive genetic effects and the covariance between direct and maternal additive genetic effects were important. Following weaning, maternal additive genetic effects were the only significant maternal effects. Genetic correlations between direct and maternal additive effects were -0.43, -0.59, and -0.29 for birth weight, weaning weight, and body weight at 10 months, respectively. Direct and maternal additive genetic correlations between birth weight and body weight performances at later ages were positive and moderate, ranging from 0.17 to 0.52 and from 0.06 to 0.65, respectively, whereas they were positive and high between weaning weight and later weights, ranging from 0.59 to 0.77 and from 0.61 to 0.85, respectively. A carry-over of maternal influence after weaning was shown. Early (indirect) selection for body weight at weaning or 10 months will achieve a substantial proportion (between 53 and 81%) of direct response for performance at later ages (16 and 22 months).
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Dierking, Shannon L., Harold J. Monegue i Merlin D. Lindemann. "PSIX-19 The impact of piglet nursing location along the sow udder line on piglet gain and subsequent weaning weight". Journal of Animal Science 98, Supplement_3 (2.11.2020): 183–84. http://dx.doi.org/10.1093/jas/skaa054.325.
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Abstract Piglet weaning weight is a critical factor that influences post-weaning growth and performance. Weaning weight is a function of birth weight and the amount and nutrient density of the milk consumed during lactation. Milk production is influenced by sow mammary gland development and diet consumption but may also be a biological function of teat location along the udder line. The objective of this study was then to determine the effects of piglet nursing location along the udder on overall piglet gain and weaning weight. A total of 1,078 individual piglets were observed during the nursing period at three time points during lactation. The teat pairs along the udder line were labeled from anterior to posterior (1-7, respectively) to define nursing location. At the end of the lactation period, the observed piglet nursing location was evaluated for both actual weaning weight and overall piglet weight gain during lactation. Data were evaluated by analysis of variance with the statistical model utilizing litter size as a covariate. As expected, when litter size was utilized as a covariate, there was a significant effect on piglet weaning weight (P < 0.0001), and there was both a linear and quadratic effect of location (L, P < 0.0001; Q, P = 0.0009) on both weaning weight and lactation piglet gain. Heavier piglets were weaned from more anterior teats (teat pairs 1-4), with the numerically heaviest piglets weaned from teat pair 4 (6.12 kg), with the lowest weight piglets being weaned from teat pair 7 (5.17 kg). Piglet weight gain during lactation was impacted by litter size (P < 0.0001), but nursing location did not affect lactation weight gain (P = 0.57). Due to the differences in piglet weights at weaning, it can be concluded that piglet nursing location influences overall piglet weaning weight.
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DINKEL, C. A., W. L. TUCKER i D. M. MARSHALL. "SOURCES OF VARIATION IN BEEF CATTLE WEANING WEIGHT". Canadian Journal of Animal Science 70, nr 3 (1.09.1990): 761–69. http://dx.doi.org/10.4141/cjas90-095.
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Milk production, body condition, body weight and individual feed records for 196 2-yr-old heifers and their calves were used to evaluate sources of variation in weaning weight and its two major components, total energy consumption for the year and efficiency of energy use, defined as weaning weight divided by total energy for cow and calf. Four breed groups of cows including 29 Hereford, 73 Simmental × Hereford, 68 Angus × Hereford and 26 Tarentaise × Hereford were represented over the 6-yr period. Long-horn bulls sired the calves in all but the first 2 yr when Angus bulls were used. Sources of variation were evaluated by fixed model least squares and multiple regression analyses. The least squares analysis indicated the Hereford and Angus × Hereford differed only in level of condition both at calving and at weaning, with the Angus cross slightly fatter. The Simmental cross was highest in calving condition and equal to the Angus in weaning condition. The Simmental and Tarentaise crosses were similar and significantly different from the other breed groups in milk production and weaning weight of first calves. The Tarentaise cross was different from the other three groups in cow weight at weaning, cow efficiency and condition at weaning. The Tarentaise cross and Hereford group had lowest total cow and calf energy consumption, with Simmental cross highest and Angus cross intermediate. The Simmental cross achieved a high weaning weight through high energy consumption and slightly above average efficiency, while the Tarentaise group utilized high efficiency along with low energy consumption. The breed of dam by sex of calf interaction was significant for cow efficiency which has some implication for efficiency experiments that depend on group feeding. Standard partial regressions indicated that year followed by cow condition at weaning and milk production were leading sources of variation in weaning weight and efficiency. Year and cow weight at weaning were leading sources for total energy consumption. Cow weight at weaning was of least importance in determining weaning weight and efficiency. Key words: Weaning weight, cow efficiency, energy consumption, beef cattle
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Littlejohn, Brittni P., David G. Riley, Don A. Neuendorff, Charles R. Long, Thomas H. Welsh i Ronald D. Randel. "304 Transgenerational influence of prenatal stress on temperament, birth weight, and weaning weight of Brahman calves". Journal of Animal Science 97, Supplement_3 (grudzień 2019): 3. http://dx.doi.org/10.1093/jas/skz258.003.
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Abstract The objective was to evaluate the transgenerational influence of prenatal transportation stress (PNS) on temperament, birth weight, and weaning weight in Brahman calves. Dams were derived from multiparous cows that were transported for 2 h at 60, 80, 100, 120, and 140 d of gestation (n = 48) or maintained as Controls (n = 48). Heifers born to Transported or Control cows were followed through maturity and their calves (n = 79; 35 calves born to Control dams and 44 to PNS dams) studied across multiple years. Calf birth and weaning weights were recorded. Calf temperament at weaning was evaluated utilizing pen score (PS; 1=calm and 5=excitable), exit velocity (EV; m/sec), and temperament score (TS; (PS+EV)/2). Data were analyzed using mixed linear models. Fixed effects included dam treatment, calf sex, and birth season nested within birth year (season nested within year was identified as an efficient parameterization). Calf sire was a random effect. Birth weight was not affected by dam treatment, calf sex, or season nested within year (P > 0.1). Weaning weight was greater in males than females (P < 0.01). Weaning weight was affected by season nested within year (P < 0.01). DOA at weaning was a covariate for weaning weight (0.74±0.09 kg; P < 0.01), but not PS, EV, or TS (P < 0.1). Weaning weight was not affected by dam treatment (P > 0.1). TS was affected by season nested within year (P = 0.04) but not dam treatment or calf sex (P > 0.1). EV was not affected by dam treatment, calf sex, or season nested within year (P > 0.1). PS was affected by season nested within year (P < 0.01) but not calf sex (P > 0.1). Calves born to PNS dams had greater (P = 0.02) PS than calves born to Controls (3.17±0.20 and 2.58±0.22, respectively). There was a transgenerational influence of PNS on temperament but not birth or weaning weight.
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Surek, D., L. M. Almeida, J. C. Panisson, E. L. Krabbe, S. G. Oliveira, G. C. Alberton i A. Maiorka. "Impact of birth weight and daily weight gain during suckling on the weight gain of weaning piglets". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 71, nr 6 (grudzień 2019): 2034–40. http://dx.doi.org/10.1590/1678-4162-10786.
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ABSTRACT This study evaluated the effect of birth weight and weight gain during the suckling phase on the piglet daily weight gain during the nursery phase (21-61 days of age). Piglets (n= 534) derived from 55 first-parity sows were weighed at birth, weaning, and end of the nursery phase. The data were analyzed according to a completely randomized experimental design, with three classes of birth weight (BW) and two classes of weight gain during the suckling phase (SDWG). High BW and low SDWG piglets were 0.2kg lighter at weaning than low BW and high SDWG animals (P< 0.05). However, at the end of the nursery phase, this situation was inverted, with high BW and low SDWG piglets 2.20kg heavier (P< 0.05). Low BW and high SDWG piglets were heavier at weaning and at the end of the nursery phase than low BW and low SDWG piglets (P< 0.05). At the same time, intermediate and high BW and low and high SDWG piglets presented body weight differences at weaning (P< 0.05), but not at the end of the nursery phase (P< 0.05). Piglets with 1.25 to 2.30kg BW and low weight gain during suckling presented a partial compensatory growth during the nursery phase.
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Francis, D. A., G. I. Christison i N. F. Cymbaluk. "Uniform or heterogeneous weight groups as factors in mixing weanling pigs". Canadian Journal of Animal Science 76, nr 2 (1.06.1996): 171–76. http://dx.doi.org/10.4141/cjas96-026.
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A series of trials evaluated the behavior and performance of pigs grouped into three main categories at weaning: (1) unmixed litters, (2) mixed into uniform body weight groups (light, medium and heavy) and (3) mixed into heterogeneous weight groups. The effects of grouping on performance criteria were conflicting among trials and with time after weaning. In trial 1, heterogeneous groups had lower (P = 0.09) average daily gain to 5 d after weaning than intact litters. The reverse was observed in trial 2. In trial 3, uniform weight groups grew more rapidly (P < 0.01) than heterogenous groups. These treatment differences persisted through 19 d post-weaning for pigs in trials 1 and 2 but were no longer evident in trial 3. Play/fight behavior was highest (P < 0.01) among uniform weight groups resulting in an increased wounding score for head and shoulders of pigs in medium and heavy weight groups. In trial 1, structures which allowed individuals to hide their heads were available for the first 5 d but did not affect behavior or wounding. In trial 2, pigs from the three main groupings were mixed again on day 19 into three new groupings (unmixed, uniform weight or heterogenous weight). There were no performance differences among the nine grouping combinations 40 d after weaning. We conclude that if litter groups cannot be maintained after weaning, it may be advantageous to mix newly weaned pigs into uniform weight groups although the benefit is not consistently present. If space is limited, the greatest benefit would be to group light weight pigs together. Key words: Pigs, weanlings, behavior, lesions, head hides, mixing
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A. S. Oramari, Rabee. "Genetic Evaluation of Some Productive Traits in Maraz Goats". Journal Of Duhok University 23, nr 2 (14.12.2020): 62–70. http://dx.doi.org/10.26682/ajuod.2020.23.2.9.
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This study was carriedout at the private project of Maraz goats at Bamerny sub-district/Amadiya district /Duhok governorate/Kurdistan Region of Iraq, and consists of 71 does, 8 bucks, as well as 234, 171 and 162 kids at birth, weaning and six month of age, respectively during two kidding seasons (2015-2016) and (2016- 2017). Milk traits consist of 121 records of each daily (DMY), total (TMY), pre-weaning (PRMY), peak milk yield (PKMY) and time to peak (TPMY), and 120 records of post weaning milk yield (POMY). Animal Model Program for single trait was used to predict the breeding value (PBV) and the real producing ability (RPA) for animals depending on one trait and then these values were ranked in descending order for each sex for selection. Rank correlation was calculated between estimates for both kid body weights and milk yield traits. The average breeding values for sires, dams, male kids and female kids were 0.1322, 0.0845, 0.0369 and 0.0247 kg for birth weight and 0.9877, 0.6804, 2.0072 and -0.6406 kg for weaning weight and 1.4295, 2.0184, 3.0952 and -1.0623 kg for six-month weight, respectively. Rank correlation coefficient (P≤0.001) between the breeding value estimates of birth weight and each of weaning weight and six-month weight were 0.36 and 0.28, respectively and between weaning weight and six-month weight was 0.84. Also the average RPA of 71 dams was estimated depending on their kid body weights at birth, weaning and six-months old were 0.0784, 3.7027 and 4.9492 kg, respectively. Also rank correlations coefficient were estimated between real producing ability of birth weight and each of weaning weight and six-month weight were 0.37 and 0.26, respectively and between weaning weight and SMWT was 0.81. In addition, the average producing ability were estimated for 71 Maraz does depending on their (DMY), (TMY), (PRMY), (PRMY), (PKMY) and (TPMY) were 0.0312, - 7.0378, -3.6234, -2.4199, 0.0477 and 0.2724 kg, respectively. Also rank correlations between real producing ability of all milk traits have been estimated and it was significant except between TPMY and each DMY, PRMY and PKMY, the significant correlation between RPA of milk traits assist to select the best animals and improve the herd genetically.
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Meyer, K. "Covariance matrices for growth traits of Australian Polled Hereford cattle". Animal Science 57, nr 1 (sierpień 1993): 37–45. http://dx.doi.org/10.1017/s0003356100006589.
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AbstractEstimates of covariance components due to direct and maternal effects among birth, weaning, yearling and final weight for Australian Polled Herefords were obtained by restricted maximum likelihood fitting an animal model. Data were obtained from commercial herds participating in the National Beef Recording Scheme and an across-herd genetic evaluation service. Analyses were carried out considering nine subsets of data, each comprising at least 3000 weaning, 1000 yearling and 500 final weight records which yielded a total of 30 506,17 105 and 9486 records for the three weights, respectively. Estimates of variances and genetic parameters varied considerably between data sets. Both genetic and permanent environmental effects were found to affect all traits except final weights significantly, with maternal environmental effects explaining proportionately more than 0·20 of the total variation in weaning weight. Estimates of the direct-maternal genetic correlation were consistently negative and moderate to strong, ranging from -0·34 to -0·82 for weaning weight. Maternal correlations between weaning and yearling weights were close to unity. Estimates of the direct genetic correlations among the three later weights were 0·8 or larger. Problems with this kind of analysis are discussed.
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Adeyanju, S. A., O. Akinokun i O. O. Ariyibi. "Preweaning Performances of Ndama Cattle". Nigerian Journal of Animal Production 3, nr 2 (16.01.2021): 117–23. http://dx.doi.org/10.51791/njap.v3i2.2521.
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Data on birth weight, preweaning daily rate of gain and weaning weight of Ndama beef cattle were obtained from routine records kept on the Fashola Livestock Farm between 1959 and 1964 and subjected to least-squares analysis to determine the effects of sex, month, year and sire on the performance characteristics. The results indicated that the Ndama weighed 16.95 kg at birth and 97.61 kg at weaning when adjusted to 205 days with a preweaning daily weigh gain of 0.38 kg. The bulls were significantly heavier at birth and weaning and also had a significantly higher preweaning daily weight gain than the heifers. Birth weight, preweaning daily rate of gain, and weaning weight showed significant sex, month, year and sire effects
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Rahnefeld, G. W., Doug Ward i G. M. Weiss. "A comparison of methods to evaluate beef cow productivity". Canadian Journal of Animal Science 73, nr 4 (1.12.1993): 971–75. http://dx.doi.org/10.4141/cjas93-098.
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The following were compared as measures of cow productivity: (A) calf weaning weight per mating opportunity; (B) calf weaning weight per mating opportunity with cow weight at weaning as a covariate; (C) calf weaning weight per mating opportunity per unit of cow weight at weaning; and (D) calf weaning weight per mating opportunity per cow metabolic weight (kg0.75) at weaning. Results indicate that the method described under (C) is best at reducing error followed closely by the method described under (D). The least satisfactory measure of cow productivity was (B). Key words: Beef cattle, cow efficiency, productivity
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Hatcher, S., J. Eppleston, K. J. Thornberry i B. Watt. "High Merino weaner survival rates are a function of weaning weight and positive post-weaning growth rates". Animal Production Science 50, nr 6 (2010): 465. http://dx.doi.org/10.1071/an09187.
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Survival and subsequent productivity of Merino ewe weaners (weaned in 2006 and 2007, respectively) on commercial properties in the New South Wales Central Tablelands were monitored through routine liveweight measurement until weaning of their own progeny from their maiden joining. Growth rates were calculated from the regular liveweight measurements with survival determined by the continuing presence of an individual animal at subsequent measurements. This study demonstrates that high weaner survival rates are a function of both weaning weight and post-weaning growth rates. Importantly, it indicates that low post-weaning growth rates can negate the survival benefit conferred by a high weaning weight such that weaners who were unable to sustain positive post-weaning growth rates were at high risk of death. Furthermore, classification of weaners into liveweight profile groups based on their weaning weight and post-weaning growth rates identified another group of weaners that are also at high risk of death. These weaners (14% of the mob) had above average weaning weights but low post-weaning growth rates and a mortality rate nearly 1.5 times that of the lightest cohort of weaners. High weaner survival rates about the 95% industry benchmark are possible if weaners show positive growth rates post weaning. Weaning weight continues to have a residual influence on the subsequent productivity of ewe weaners until they wean their first lambs. Maiden ewes that were heavier at weaning tend to have higher scanning percentages and are more likely to successfully rear their progeny to marking than their lighter weight counterparts. This finding should be taken into account when economic analyses of the benefits of alternative management strategies to promote weaner survival are undertaken.
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Walkom, S. F., A. N. Thompson, E. Bowen i D. J. Brown. "Weaner survival is heritable in Australian Merinos and current breeding objectives are potentially leading to a decline in survival". Animal Production Science 59, nr 1 (2019): 35. http://dx.doi.org/10.1071/an17151.
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There is little evidence to show that mortality rates during the period after weaning are improving over time in Australian sheep. The average mortality rate of Merino lambs during the post-weaning period has been estimated to be 5.2%. The present study explored the potential for producers to breed for improved survival rates during the post-weaning period and the potential impact this would have on key production traits. A total of 122526 weaner survival (mortality) records were obtained from 18 Merino flocks, between 1989 and 2014, encompassing a wide variety of Australian Merino sheep types and production systems. The heritability of weaner survival from a sire model was estimated to be 0.07 ± 0.01 and was significantly greater than zero. The survival of lambs post-weaning was significantly influenced by weaning weight, with higher survival rates observed in the heavier lambs. The phenotypic relationship with weight indicates that selection for heavier weaning and post-weaning weights, and in turn larger growth rates, will improve survival rates. There is genetic variation in weaner survival not explained by the relationship with weaning weight. Weight-corrected weaner survival was antagonistically genetically correlated with fleece weight. Due to these antagonistic genetic relationships selection based on popular MERINOSELECT indexes is leading to a very small reduction in the survival rate of lambs after weaning through to the post-weaning stage. To prevent a decline in weaner survival, producers are advised to record weaner survival and include it in their breeding objective.
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Araújo, Cláudio Vieira de, Raysildo Barbosa Lôbo, Luis Gustavo Girardi Figueiredo, Cláudio Jonasson Mousquer, Monyka Marianna Massoloni Laureano, Thereza Cristina Borio dos Santos Calmon de Bittencourt i Simone Inoe Araújo. "Estimates of genetic parameters of growth traits of Nellore cattle in the Midwest region of Brazil". Revista Brasileira de Saúde e Produção Animal 15, nr 4 (grudzień 2014): 846–53. http://dx.doi.org/10.1590/s1519-99402014000400006.
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Records of birth weight (BW) and weights standardized to 210 (W210); 365 (W365) and 550 (W550) of age in the Nellore breed were used to estimate variance components of genetic effects and predict genetic values of sires. The model included the fixed effects of contemporary group and cow age at calving as co-variable, and the additive and maternal genetic, permanent maternal environmental, and temporary environmental random effects. Estimates of means and standard deviations for BW, W210; W365 and W550 were 32.76 ± 3.74; 184.30 ± 29.02; 240.31 ± 41.85 and 322.12 ± 60.77, respectively. A significant additive genetic variability was detected for all weights. The permanent maternal environmental variance showed greater relevance on weaning weight, and it was practically inexistent after weaning. For the maternal genetic variance, the estimate for birth weight was more significant as compared with weaning weight. The estimated heritability values for BW, W210; W365 and W550 were 0.37 ± 0.02; 0.36 ± 0.03; 031 ± 0.01 and 0.38 ± 0.02, respectively. Genetic correlations between birth weight and other weights were of low magnitude, with high values of weights at other ages. The use of sires of higher genetic value for total maternal effect makes it possible to use sires that are more positive for weaning weight and also for year and yearling weight.
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Eikje, E. D., i D. L. Johnson. "Adjustment factors for lamb weaning weight". New Zealand Journal of Agricultural Research 28, nr 2 (kwiecień 1985): 265–73. http://dx.doi.org/10.1080/00288233.1985.10420937.
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Matabane, Matshidiso B., Khathutshelo A. Nephawe, Ronald S. Thomas, Ayanda Maqhashu, Fhulufhelo V. Ramukhithi, Thivhilaheli R. Netshirovha, Jones W. Ng’ambi, Mammikele Tsatsimpe i Tshimangadzo L. Nedambale. "Pre-Weaning Growth Performance of Piglets at Smallholder Farms in Gauteng Province". Journal of Agricultural Science 10, nr 4 (5.03.2018): 18. http://dx.doi.org/10.5539/jas.v10n4p18.
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The objective of the study was to determine pre-weaning performance of piglets born following artificial insemination (AI) at smallholder farms of Gauteng province. Data from 496 piglets originating from 73 multiparous crossbred sows were used in the study. Litter size, number of piglets born alive, number of piglets weaned, birth and weaning weights were recorded. Data was analysed using the Proc Univariate procedure of SAS. The average litter size was 11.8. The average birth weight and weaning weights were 1.9 and 6.2 kg, respectively. No significant differences were found between male and female piglets for all the growth performance characteristics. Piglets born during winter had a significantly higher (P < 0.05) birth and weaning weight as compared to autumn and summer months. Season had a significant effect on birth and weaning weight (P < 0.01). However, sex of piglets had no significant effect on all the characteristics recorded (P > 0.05). The interaction between sex and season was only confirmed on the total number of weaned piglets (P < 0.01). A highly significant positive correlation was found between litter size and number of piglets born alive (r = 0.86) and total number of piglets weaned (r = 0.50). A highly significant correlation was found between total number of piglets born alive and total number of piglets weaned (r = 0.55). In conclusion, season of birth had the greatest impact on birth and weaning weight, with the highest birth and weaning weights recorded during winter season. However, sex did not affect the pre-weaning performance of piglets.
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Milne, J. A., Angela M. Sibbald, Heather A. McCormack i A. S. I. Loudon. "The influences of nutrition and management on the growth of red deer calves from weaning to 16 months of age". Animal Science 45, nr 3 (grudzień 1987): 511–22. http://dx.doi.org/10.1017/s0003356100002993.
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ABSTRACTThe effects of date of weaning, weaning live weight, autumn grazing management and level and pattern of winter nutrition in relation to summer grazing on the live-weight gain of farmed red deer calves to 16 months of age were tested in three experiments.In experiment 1, the effect of two weaning live weights (37 and 46 kg) in September and two levels of autumn and winter nutrition were examined with 48 calves. In October, live-weight gains were positively related to sward height and herbage mass. The calves lost live weight in November. Compensatory live-weight gains of 28 g/day occurred at summer pasture after the low level of winter nutrition. Weaning live weight had a major influence on live weight at 16 months of age.In experiment 2, the effects of maintenance, ad libitum and intermediate treatments were compared using 50 calves given a complete diet in winter. The intermediate treatment consisted of a maintenance followed by an ad libitum level of feeding. Compensatory live-weight gains of 49 g/day occurred at pasture with the intermediate treatment achieving complete live-weight compensation at 16 months of age.In experiment 3, the effect of two weaning dates (19 September and 14 November) on live-weight gain of calves and on the date of subsequent calving of hinds were compared with 34 lactating hinds. There was no difference in live-weight gain of calves between weaning dates but the subsequent calving date was delayed by 8 days from those hinds weaning in November.A management system is advocated with weaning in September, housing in November after grazing sown swards greater than 6 cm, a pattern of a low followed by a high level of nutrition in winter and the summer grazing of sown swards maintained at 4 to 6 cm.
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Rachmann Noor, R., A. Djajaneegara i L. Schüler. "Selection to improve birth and weaning weight of Javanese Fat Tailed Sheep". Archives Animal Breeding 44, nr 6 (10.10.2001): 649–60. http://dx.doi.org/10.5194/aab-44-649-2001.
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Abstract. In Indonesia, the Javanese Fat Tailed Sheep is a very popular domestic animal for its meat production However selection to increase body weight has never been done by local farmers. As a result the variability of body weight is high, and expected that application of a selection program can improve this trait Two Steps of selection were done in order to improve birth and body weight. In the first selection, the elite group was established by selecting the best 40 females and 3 males from 12500 sheep reared by local farmers based on their mature body weight and tail length. The control group was established by randomly selecting 40 females and 4 males In the second step of selection, the best 50 % females and 5 % males of the progeny of the elite group was selected based on their weaning weight and tail size. The first selection results indicate that there was a positive genetic progress in both birth and weaning weight. Selection had increased 7.17 % and 5.48 % of male and female birth weight respectively and 9.48 % and 9.78 % of male and female weaning weight, respectively. Positive genetic progresses of birth and body weight were also found after the second selection. Birth weights of males and females were 6.75 % and 7.20 % higher than those in the control group. Male and female weaning weights were 5.60 % and 8.19 % higher than those in the control group, however, selection for weaning weight did not affect reproductive traits.
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Lee, Chang-Woo, Chang-Sik Choi, Hwan-Sup Hwang, Yeon-Soo Park, Jun-Seok Song, Jung-Woo Choi i Jong-Bok Kim. "Relationships of Weaning Weight with Gestation Length, Birth Weight, and Pre-weaning Daily Gain in Hanwoo". Journal of Agriculture & Life Science 52, nr 3 (30.06.2018): 63–71. http://dx.doi.org/10.14397/jals.2018.52.3.63.
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Jankowiak, H., P. Balogh, A. Cebulska, E. Vaclavkova, M. Bocian i P. Reszka. "Impact of piglet birth weight on later rearing performance". Veterinární Medicína 65, No. 11 (26.11.2020): 473–79. http://dx.doi.org/10.17221/117/2020-vetmed.
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The piglet birth weight and its variance within a litter may be considered important traits that influence pig productivity in the first and later stages of rearing. 222 piglets were evaluated from the moment they were born until weaning, and then as fattening pigs until the end of the fattening (n = 207) in three birth weight groups. Negative consequences of an excessively low piglet birth weight were observed, including higher mortality until weaning and a lower average daily gain during suckling. The correlation coefficients between the piglet birth weight and the remaining indicators confirmed the negative impact of the low piglet birth weight, fattening performance and carcass slaughter value (P < 0.01). The regression analysis between the piglet birth weight and the growth rate during the whole rearing phases indicated that only the piglet growth rate from birth to weaning is determined by their birth weight.
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Wamnes, S., N. J. Lewis i R. J. Berry. "The performance of early-weaned piglets following transport: Effect of season and weaning weight". Canadian Journal of Animal Science 86, nr 3 (1.09.2006): 337–43. http://dx.doi.org/10.4141/a06-005.
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Two groups of 48 Cotswold piglets weaned at 17 ± 1 d of age were assigned to road or simulated transport during summer or winter. Following transport [Control (<20 min), 6 h, 12 h or 24 h], piglets were grouped by weaning weight (light, medium and heavy) in pens of four. Body weights were recorded on days 1–8, 10, 12 and 14. From an average weaning weight of 6.28 ± 0.09 kg, piglets lost on average 0.4 ± 0.1 kg. The minimum weight of 5.88 ± 0.1 kg was reached 2.24 ± 0.13 d post weaning and weaning weight was recovered at 3.55 ± 0.16 d post weaning. As transport duration increased from 6 to 24 h, total weight loss increased from 0.33 to 0.45 ± 0.022 kg (P < 0.01). Piglets transported by road in winter had a longer growth check (4.08 vs. 3.18 ± 0.18 d, P < 0.05) showed reduced percent ADG (5.37 vs. 6.61 ± 0.26%, P < 0.05) and lower feed conversion efficiency (FCE) (0.87 vs. 0.96 ± 0.01 kg, P < 0.01) than piglets transported by road in summer. Heavy piglets continued to lose weight longer than light piglets (2.26 vs.1.7 ± 0.16 d, P < 0.02), although relative weight loss was not affected. During winter piglets exposed to road transport required more time to recover their weaning weight than piglets exposed to simulated transport (4.08 vs. 3.04 ± 0.18 d, P < 0.05). While weaning is a confounding effect, these results suggest that longer transport (>12 h) and transport in winter may cause additional stress to early-weaned piglets. Some factors of road transport in winter, possibly driving differences or fluctuating temperatures also negatively affected piglet recovery from weaning. Key words: Early weaning, transport, pigs, season
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Arthur, PF, H. Hearnshaw, PJ Kohun i R. Barlow. "Evaluation of Bos indicus and Bos taurus straightbreds and crosses. III. Direct and maternal genetic effects on growth traits". Australian Journal of Agricultural Research 45, nr 4 (1994): 807. http://dx.doi.org/10.1071/ar9940807.
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Data on Brahman and Hereford cattle and their crosses were used to estimate direct additive, direct heterosis, maternal additive and maternal heterosis effects for pre-weaning and post-weaning liveweights, average daily gain (ADG) and height at various ages. The cattle were born at Grafton, N.S.W., and raised on high, medium and low quality pastures until weaning. During the post-weaning period, the steers were grown in three environments in New South Wales, while the heifers remained at Grafton. Genetic effects were estimated by regression and the additive components expressed as deviations from Hereford effect. Weaning weight and pre-weaning ADG of Hereford calves (both sexes) were 237.8 kg and 827 g/day on high, 210.5 kg and 704 g/day on medium, and 128.3 kg and 425 g/day on low quality pastures respectively. Post-weaning ADG of Hereford steers (weaning to 36 months) and heifers (weaning to 30 months) was 296 and 240 g/day respectively. Direct heterosis was significant (P<0.05) for most traits. Estimates of direct heterosis for weaning weight were 24.9 and 20.2 kg, and for pre-weaning ADG were 79 and 68 g/day, on high and medium quality pastures respectively. Direct heterosis for ADG of steers (weaning to 36 months) and heifers (weaning to 30 months) was 91 and 76 g/day respectively. Estimates of maternal heterosis for weaning weights were 14.9, 30.9 and 37.8 kg and for pre-weaning ADG were 31 (not significant), 105 and 153 g/day, for high, medium and low quality pastures respectively. Maternal heterosis for ADG of steers (weaning to 36 months) was -47 g/day. There was a negative direct additive effect on post-weaning ADG in environments where pasture quality was good, but the effect was not significant on poor quality pasture. Maternal additive effect was negative for birth weight for high and medium quality pastures and positive for weaning weight and pre-weaning ADG on low quality pasture. The performance of untested crosses can be predicted from the estimates and models provided.
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Ekanayake, Lukshman Jay, Rene Anne Corner-Thomas, Lydia Margaret Cranston, Paul Richard Kenyon i Stephen Todd Morris. "Lambs Weaned Early onto a Herb-Clover Mix Have the Potential to Grow at a Similar Rate to Unweaned Lambs on a Grass-Predominant Pasture". Animals 10, nr 4 (2.04.2020): 613. http://dx.doi.org/10.3390/ani10040613.
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Liveweight gain of lambs weaned early at a minimum live weight of 14 kg, at ~50 days of age, onto a herb-clover mix was compared with lambs that remained unweaned on a grass-predominant pasture or a herb-clover mix until conventional weaning (at ~99 days of age). Over two years, twin sets of lambs that had a minimum live weight of 14 kg were randomly allocated to one of three treatments: (1) Early weaning of lambs onto a herb-clover mix (HerbEW); (2) ewes and lambs grazing a herb-clover mix until conventional weaning (HerbCW); and (3) ewes and lambs grazing a grass-predominant pasture until conventional weaning (GrassCW). HerbEW lambs had slower (p < 0.05) growth rates than GrassCW lambs between early weaning and conventional weaning in 2016 and were 800 g lighter (p < 0.05) at conventional weaning. In 2017, however, both HerbEW and GrassCW had similar (p > 0.05) growth rates and did not differ (p > 0.05) in live weight at conventional weaning. HerbCW lambs had a greater (p < 0.05) growth rates than both HerbEW and GrassCW lambs in both years. Lambs weaned early onto a herb-clover mix have the potential to achieve live weights similar to lambs unweaned on grass-predominant pasture. Further research, however, is required to understand conditions under which early-weaned lambs can achieve similar live weights.
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Agea, Ivan, María-Luz García, Agustín Blasco i María-José Argente. "Litter Survival Differences between Divergently Selected Lines for Environmental Sensitivity in Rabbits". Animals 9, nr 9 (25.08.2019): 603. http://dx.doi.org/10.3390/ani9090603.
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A divergent selection experiment on environmental sensitivity was performed in rabbits. The aim was to estimate the correlated response in kit weight and survival, litter weight, and weight distance from birth to weaning. The weight distance was calculated as the absolute value of the differences between the individual value and the mean value of its litter. The relationship between the probability of survival at 4 d of age, and the weight at birth, was studied. Environmental sensitivity was measured as litter size variability. A total of 2484 kits from 127 does from the low line, and 1916 kits of 114 does from the high line of the 12th generation were weighed. Both of the lines showed similar individual and litter weights at birth and weaning, and a similar survival rate at birth, and at 4 d of age. The survival rate at weaning was higher in the low line (0.67 and 0.62; P = 0.93). The weight distance was higher at birth, but lower at weaning in the low line (47.8 g and 54.1 g; P = 0.98). When the weight at birth was high, the kits had a higher survival rate. In conclusion, selection for environmental sensitivity showed a correlated response in the kits’ survival, and in the homogeneity of litter weight at weaning.
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Nangoy, Marfiane M., M. T. Lapian, M. Najoan i J. E. M. Soputan. "PENGARUH BOBOT LAHIR DENGAN PENAMPILAN ANAK BABI SAMPAI DISAPIH". ZOOTEC 35, nr 1 (5.03.2015): 138. http://dx.doi.org/10.35792/zot.35.1.2015.7223.
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THE EFFECT OF BIRTH WEIGHT WITH THE APPEARANCE OF THE PIGLETS UNTIL WEANING. The purpose of this research is to determine the corellation of birth weight with the appearance of the piglets until weaning. This research used the method of observation. Results or data obtained in this research, piglets from each parent is divided into 3 categories: high, medium, low. Retrieval of data held on a new born piglets, piglets aged 1 week until the time of weaning. Parameters observed in this research is the birth weight of piglets per head, body weight gain, the weight of piglets, and mortality (MRTA) piglets before weaned (%). Data were analyzed and presented descriptively, which is describing and explaining the general picture of direct observation. Based on the results of this research we concluded that litter size piglets, determines how high the birth weight, weaning weight, body weight gain, and mortality. The greater the birth weight more likely to obtain a high weaning weight as in this research the highest birth weight is 1.64 kg after weaning reached 7.54 kg. Keywords: Birth Weight, Piglets, Weaning
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Schreurs, N. M., P. R. Kenyon, P. C. H. Morel i S. T. Morris. "Meta-analysis to establish the response of having heavier mature ewes during gestation on the birthweight of the lamb and the weaning weight of the ewe and lamb". Animal Production Science 52, nr 7 (2012): 540. http://dx.doi.org/10.1071/an11292.
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There is much uncertainty about feeding ewes to maximise the performance of progeny and of the ewe itself to weaning. This includes questions about feeding the ewe to influence the lamb’s birthweight for lamb survival, feeding to augment the ewe’s lactation to maximise the lamb’s growth potential before weaning and feeding the ewe to increase the probability of having multiple offspring. The objective of this study was to carry out a meta-analytic study to consider the response of having heavier mature ewes during gestation on lamb and ewe performance measured by birth and weaning weights. The birthweight of singleton lambs was the greatest, twins were intermediate and triplets the lowest (5.8, 4.8 and 4.1 kg, respectively; P < 0.001). A similar trend (P < 0.001) was observed for the weaning weight of the lamb (29.1, 25.2 and 23.7 kg for lambs weaned as a single, twin or triplet, respectively). The liveweight of ewe at weaning was greater (P < 0.001) for those ewes that failed to wean a lamb (69.6 kg) or weaned a single lamb (67.8 kg) compared with ewes that weaned twin and triplet lambs (64.8 and 65.3 kg; respectively). A greater ewe liveweight during gestation gave different responses on the lamb birthweight, lamb weaning weight and the weaning weight of the ewe and this was dependent on birth and weaning rank category of the lamb (P < 0.05). Overall, the response of heavier ewes on lamb birthweights and ewe and lamb weaning weights was small compared with the effect of birth and weaning rank of the lamb.
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Hendricks, Meagan, Douglas Eborn, Kaylee R. Kipp, Caleta M. Willis i Megan P. Owen. "120 Performance Effects on Weaned Calves using 3 Weaning Strategies and Nutritional Supplementation". Journal of Animal Science 98, Supplement_2 (1.11.2020): 45–46. http://dx.doi.org/10.1093/jas/skz397.104.
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Abstract The objective of this study was to compare nutritional and management strategies on performance of beef calves at weaning. Forty crossbred beef calves were assigned to receive either nutritional supplementation (Drench) 3 wks prior to weaning and again at weaning or nothing (Cntrl). In addition, calves were assigned 1 of 3 weaning treatments: 1) abrupt weaning with complete separation (Abrupt); 2) 4d fence line weaning with cows allowed to interact with calves through a fence for 4 d before removal (4Fence); and 3) 7 d fence line weaning with cows allowed to interact with calves through a fence for 7 d before removal (7Fence). Calves were blocked by sex and BW. Nutritional supplementation consisted of an oral drench (5cc/100 lbs. BW; Cellarator Turbo Drench; ADM Animal Nutrition; Quincy, IL). Calves were weighed at weaning, 7 d after, and 85 d after weaning. At weaning, average age of calves was 213 ± 19 d and average weight 224 ± 30 kg. Average final weight of calves was 279 ± 33 kg. Weight differences between weaning and 7 d after weaning and weaning and 85 d after weaning were analyzed using Proc Mixed with nutritional supplementation, sex, and weaning duration as fixed variables. Calves receiving Drench gained more (P < 0.05) 1 wk after weaning (7.9 vs. 3.7 kg, respectively). Weight gains 85 d after weaning were not different (P > 0.05) 7 d after weaning. Weight gain in calves assigned to 4Fence and 7Fence treatments were not different (P < 0.05) but gained more (P < 0.05) than Abrupt calves (8.5 vs. 7.6 vs. 1.2 kg, respectively). Weight gains 85 d after weaning were not different (P > 0.05) between weaning treatments. In conclusion, nutritional supplementation and fence-line weaning improved calf performance 1 wk after weaning but not after 3 mo.
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Ososanya, T. O. "Effect of broiler litter supplementation on reproductive performance of West African Dwarf sheep". Nigerian Journal of Animal Production 42, nr 2 (30.12.2015): 180–86. http://dx.doi.org/10.51791/njap.v42i2.2667.
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Four low cost feed samples were formulated using 0, 25, 50 and 75% levels of broiler litter processed into feed along with other feed ingredients. Sixteen (16) primiparous West African Dwarf (WAD) ewes aged between twelve and eighteen months old were dewormed using Ivermectin and dipped against ticks and fleas using diazintol. Oestrus was artificially synchronized in all the ewes using Iml of Prostaglandin - 2Fα administered intramuscularly, the animals were mated with rams of known fertility and lineage bred. Ewes were evaluated in a pregnancy trial while the lambs born were evaluated in a pre weaning growth trial. All the ewes were weighed before conception and bimonthly thereafter until parturition. The parameters studied were weight at mating, weight before and after parturition, weight changes during pregnancy, weight changes in lactation and nursing, lambs birth weights and daily weight of lambs, dam's weight at weaning and gestation length. Results obtained showed weight at mating, weight before mating, weight at parturition, gestation length, weight gain in pregnancy, weight change in lactation and nursing, lambs birth weights and daily weight gain of lambs were significantly affected (p<0.05) while dam's weight at weaning and lambs' weaning weight were not affected (p>0.05). Results of this study indicate that inclusion of broiler litter up to 50% in feed mixtures of ewes has no deleterious effect on the performance and health status of ewes during pregnancy and lactation.
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Gholizadeh, M., G. Rahimi Mianji, M. Hashemi i H. Hafezian. "Genetic parameter estimates for birth and weaning weights in Raeini goats". Czech Journal of Animal Science 55, No. 1 (25.01.2010): 30–36. http://dx.doi.org/10.17221/1703-cjas.
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The aim of the present study was to estimate variance components and genetic parameters for birth and weaning weights in Raeini goats. The data were collected from the Breeding Centre of Raeini (BCR) cashmere goats in Kerman province of Iran from 1986 to 2008. Random effects included direct and maternal additive genetic effects, maternal permanent environmental effects with direct-maternal genetic covariance and random residual effects. Variance and covariance components and genetic parameters were estimated using the DFREML program by fitting six single-trait animal models. Depending on the model, h<sub>d</sub><sup>2</sup> varied from 0.057 to 0.323 for birth weight and from 0.043 to 0.229 for weaning weight. Estimates of <I>m</I><sup>2</sup> ranged from 0.016 to 0.289 for birth weight and from 0.01 to 0.184 for weaning weight. The maternal permanent environmental effect was significant for both traits and ignoring maternal effects in the model caused the overestimation of direct heritability.
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Kramarenko, S., A. Kramarenko, S. Lugovoy, D. Balan i K. Zemoglyadchuk. "The effects of breed, sire and environmental factors on the birth and weaning weight of lambs". UKRAINIAN BLACK SEA REGION AGRARIAN SCIENCE 108, nr 4 (2020): 70–78. http://dx.doi.org/10.31521/2313-092x/2020-4(108)-9.
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The effects of breed, sire and environmental factors on the birth and weaning weight of lambs The aim of this study was to determine the effect of some important factors influencing on the birth and weaning weight variability in lambs. Data from 2603 ewes was included in the analysis, where 3961 lambs were obtained during the five years of the research. Data was tested using analysis of variance (ANOVA) with the GLM procedure of Minitab Release 13.1. Our results presented significant influence on the year of lambing, breed, ram genotype, age of a dam, type of a birth (litter size), sex of a lamb and on the birth weight and weaning weight of lambs. Keywords: birth and weaning weight of lambs; ram genotype; year of lambing; age of ewes; litter size (type of birth); sex of a lamb; the Ascanian fine-fleece breed.
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van Barneveld, R. J., i R. J. E. Hewitt. "Reducing variation in pork production systems through maternal and pre- and post-weaning nutrition strategies". Animal Production Science 56, nr 8 (2016): 1248. http://dx.doi.org/10.1071/an15396.
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Variation is inherent in any biological system and is a challenge to manage in modern pork-production businesses. In the case of the growing and finishing herd, inherent variation within a population of pigs represents a significant cost as a result of the need to select on farm to meet market specifications, poor matching of diet specifications to nutrient requirements, grading losses, higher pre-weaning mortality, and challenges associated with health management. As a consequence, any management practice that can be applied to reduce variation at the point of sale has the potential to improve the profitability and overall efficiency of a pig enterprise. The present paper considers nutritional interventions of sows during gestation, lactation and the weaning to oestrus interval to minimise inherent variation in the progeny and then pre- and post-weaning nutrition of piglets to limit further variation. Prior to birth, there are many factors that can influence variation in the birthweight and growth potential of the progeny. In gestating sows, dietary energy will not influence variation in birthweight, but supplementation with free arginine and glutamine will reduce variation in birthweight of piglets born and piglets born alive. In lactating sows, maintenance of feed intake to optimise milk production and minimise weight loss of the sow during lactation not only minimises variation in progeny weight at weaning, but enhances subsequent birthweight heterogeneity due to the influence of the sow’s metabolic status on follicle and oocyte quality. Supplementation with dextrose during the weaning to oestrus interval can also reduce variation in birthweight due to a pronounced effect on plasma glucose and insulin concentrations. Prior to weaning, light weight piglets appear to have an enhanced capacity for growth compared with their larger counterparts. To this end, split suckling has been shown to reduce weaning-weight variation, despite no effect on average growth rate or weaning weight for litters with nine piglets or more born alive. Supplemental milk before weaning has reduced variation in weaning weights, but creep feeding has proved equivocal in this regard. Post-weaning, it appears that remedial feeding strategies will do little to improve the growth potential of light-weight pigs, and while high specification diets may contribute to a slight reduction in variation at slaughter, this strategy is unlikely to be economically viable. As with many aspects of commercial pork production, it would seem that the greatest potential to reduce variation in the slaughter weight of market pigs vests with careful management of gestating and lactating sows, with some potential for dietary interventions to further reduce variation in birth and weaning weights.
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Olayemi, M. E., O. A. Osinowo, N. I. Dim i L. O. Eduvie. "ESTIMATE OF GENETIC AND PHENOTYPIC PARAMETERS FOR LITTER SIZE AND WEANING WEIGHT IN YANKASA SHEEP". Nigerian Journal of Animal Production 24, nr 2 (11.01.2021): 106–9. http://dx.doi.org/10.51791/njap.v24i2.2307.
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Data on 964 and 1150 weaning weight and litter size records respectively, collected over a 10years period on Yankasa Sheep breeding project at the National Animal Production Research Institute (N.A.P.R.I), Zaria, were used in the study. The analysis was for estimation of genetic and phenotypic parameters for litter size and weaning weight in Yankasa sheep. Estimates of heritability for litter size and weaning weight were obtained from paternal half sib intraclass correlation. The genetic and phenotypic relationship between the litter size and weaning weight were estimated from the covariance and variance components of the two traits. Least squares means of 1.18±0.02 and 10.67±0.11 were obtained for litter size and weaning weight, respectively. Heritability (h2) estimates of 0.18±0.07 and 0.63±0.01 were obtained, respectively, for litter size and weaning weight. Genetic and phenotypic correlations of 0.83±0.052 and 0.23±0.094 respectively, were obtained, between weaning weight and litter size