Journal articles on the topic 'Sow lactation oestrus'
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Downing, J. A. "An opportunity to revolutionise sow management." Animal Production Science 55, no. 12 (2015): 1411. http://dx.doi.org/10.1071/an15270.
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Research in any area of animal production can provide the opportunity to change how the system operates and is managed. The reliance on having to wean lactating sows to re-mate them has limited the commercial options for sow management. The desire to limit lactation length to maximise the litters per sow per year concurrently creates major challenges for such-aged piglets weaned abruptly. These issues are discussed in the review. This management system also fails to recognise that sows have the potential to spontaneously ovulate in lactation even when housed in farrowing crates. Inhibition of luteinising hormone release is the basis of lactational anoestrus with the suckling stimulus providing the strongest afferent signal to this inhibitory system. Any management strategy that reduces this inhibition has the potential to trigger lactational oestrus. In this review, group housing of sows, boar exposure and intermittent suckling are identified as strong stimuli that can promote lactational oestrus. Removing the need to wean sows to mate them offers further opportunities to change the way lactating sows are managed. One option is a two-stage lactation system in which the sows are housed in farrowing crates for the first 10–14 days and then moved to group accommodation for the remainder of lactation. This system provides welfare benefits for the litter in the early stage of lactation and then the benefits of less confinement for the sows in later lactation. Group lactation would also lend itself to the implementation of stimuli to assist the mating of sows in lactation, such as piglet separation and/or boar exposure. It also accommodates the mating of sows that spontaneously ovulate in lactation. Removing the need to wean sows to re-mate them provides the opportunity to increase weaning age and implement a gradual weaning, helping to attenuate the post-weaning growth check and potentially limiting antimicrobial use in weaner pigs.
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Close, W. H., and C. E. Sharpe. "The influence of nutritional status during lactation on the energy metabolism of the weaned sow." Proceedings of the British Society of Animal Production (1972) 1991 (March 1991): 120. http://dx.doi.org/10.1017/s0308229600020705.
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It is generally recognised that the nutritional and metabolic status of the sow during lactation can influence its subsequent reproductive capacity. Thus sows which mobilise large quantities of body weight during lactation have extended weaning to oestrus intervals and reduced litter sizes. However, it is not known how nutrition during lactation may influence metabolic efficiency in the post-weaning period, especially in relation to the accumulation of body reserves. The present experiment was therefore designed to investigate the effect of feeding level during lactation on nutrient partitioning and metabolic efficiency in the weaned sow.
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Costa, A. N., and M. A. Varley. "The effects of altered suckling intensity, boar exposure in lactation and gonadotropins on endocrine changes, fertility and the incidence of lactational oestrus in multiparous sows." Animal Science 60, no. 3 (June 1995): 485–92. http://dx.doi.org/10.1017/s1357729800013369.
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AbstractOne of the more promising techniques for the improvement of sow productivity has been the use of partial weaning or the separation of the sow and litter for periods of between 3 to 12 h/day towards the end of lactation. The purpose of the present study was to examine changes in steroid hormone concentrations, oestrus and fertility responses in lactating sows subjected to altered sucking, boar exposure and gonadotropins in mid lactation and at weaning. Thirty-two crossbred sows were allocated at random to one of four experimental treatments. Treatment 1 sows (no. = 8) were separated from their respective litters for 3 h/day from 12 days post partum through until weaning which was carried out at 21 days post partum. Treatment 1 sows were also given in-pen boar exposure for 1 h/day between day 12 post partum and weaning. Treatment 2 sows (no. = 8) were given the same protocol of litter separation (LS) and boar exposure (BE) as in treatment 1 and they were also given a combination of gonadotropins (Gn) on day 17 of lactation. Treatment 3 sows (no. = 8) were given LS + BE as above and the sows were injected with Gn on the day of weaning. Treatment 4 sows were controls given no LS, BE or Gn (no. = 8). During lactation, treatment 1 sows exhibited significantly (P < 0·05) reduced progesterone concentrations compared with treatment 2 sows. There were no other significant effects of treatment for any of the periods considered. The separation of sows from their piglets with or without gonadotropic treatment did not result in lactational oestrus in any treated sows. No significant treatment differences were found in the subsequent litter size (piglets born alive or total number of piglets). In conclusion, the present results have demonstrated no significant effects of LS, BE and Gn treatment during lactation on sow and litter performance. This was associated with low levels of peripheral plasma progesterone in all lactating sows.
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van Wettere, W. H. E. J., and L. M. Staveley. "Multi-suckling and sow-piglet separation: effects on lactation oestrus." Animal Production Science 55, no. 12 (2015): 1518. http://dx.doi.org/10.1071/anv55n12ab030.
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Rigat, J., S. A. Edwards, and P. R. English. "The influence of parity on lactational oestrus in a multisuckling system for sows." Proceedings of the British Society of Animal Science 1999 (1999): 187. http://dx.doi.org/10.1017/s1752756200003422.
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The occurrence of ovulation in the sow after parturition is usually inhibited for the duration of suckling. A system of management in which lactating sows are mated and conceive, therefore routinely commencing a successful pregnancy concurrent with lactation, would obviate the need for early weaning of piglets and promote adoption of economic systems incorporating more extensive lactation housing. Previous studies have shown that first parity sows rarely show ovulation during lactation when group-housed in multisuckling systems with multiparous sows, and suggested that reduced food intake through social competition and/or higher suckling intensity were responsible for this (Hulten, 1997). The object of this experiment was to investigate, in a more controlled way, the factors contributing to this parity effect by removing the possibility of social interactions between primiparous and multiparous sows, and investigating possible dietary influences within parity.
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Rydhmer, Lotta. "Genetics of sow reproduction, including puberty, oestrus, pregnancy, farrowing and lactation." Livestock Production Science 66, no. 1 (September 2000): 1–12. http://dx.doi.org/10.1016/s0301-6226(99)00170-0.
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Patterson, J. L., M. N. Smit, S. Novak, A. P. Wellen, and G. R. Foxcroft. "Restricted feed intake in lactating primiparous sows. I. Effects on sow metabolic state and subsequent reproductive performance." Reproduction, Fertility and Development 23, no. 7 (2011): 889. http://dx.doi.org/10.1071/rd11015.
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The effects of feed restriction (60% of anticipated feed intake; Restrict; n = 60) during the last week of a 21-day lactation in primiparous sows compared with feeding at 90% of anticipated feed intake (Control; n = 60) on sow metabolic state, litter growth and sow reproductive performance after weaning were compared. Metabolisable energy (ME) derived from feed was lower, ME derived from body tissues was higher and litter growth rate was reduced (all P < 0.05) in Restrict sows during the last week of lactation. Treatment did not affect weaning-to-oestrus interval, pregnancy rate, ovulation rate, embryonic survival or the number of live embryos (P > 0.05) at Day 30 of gestation: However, embryo weight was greater (P < 0.05) in Control than in Restrict sows (1.55 ± 0.04 vs 1.44 ± 0.04 g, respectively). These data suggest the biology of the commercial sow has changed and reproductive performance of contemporary primiparous sows is increasingly resistant to the negative effects of lactational catabolism. Overall, catabolism negatively affected litter weaning weight and embryonic development of the next litter, but the extent to which individual sows used tissue mobilisation to support these litter outcomes was highly variable.
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Jones, G. M., S. A. Edwards, A. G. Sinclair, F. E. Gebbie, J. A. Rooke, S. Jagger, and S. Hoste. "The effect of maize starch or soya-bean oil as energy sources in lactation on sow and piglet performance in association with sow metabolic state around peak lactation." Animal Science 75, no. 1 (April 2002): 57–66. http://dx.doi.org/10.1017/s1357729800052838.
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AbstractThe effects of different energy sources in the lactation diet on sow and piglet performance were assessed in association with effects on the metabolic state of the sow around peak lactation. Either maize starch (S) or soya-bean oil (F) was added to a basal diet to provide 0·34 of total digestible energy (DE) intake, such that the experimental diets provided the same daily intakes of DE and crude protein. Twenty-four multiparous sows were allocated between two groups at farrowing, each given one of the two dietary treatments for a lactation period of 28 days. Sow weight and backfat (P2) as well as individual piglet weights were measured on a weekly basis. Litter sizes were standardized to 10 piglets. Milk samples were collected from sows on days 8, 12, 17, 21 and 25 of lactation to measure milk composition and prolactin concentrations. Blood samples were taken via an ear vein catheter from a subsample (7 S, 6 F) of sows on day 14 of lactation; two pre- and seven post-feeding samples were taken at 60-min intervals to measure plasma prolactin, insulin, glycerol, triglyceride, non-esterified fatty acid, urea, b-hydroxybutyrate and glucose concentrations. There was no effect of energy source on sow weight or P2 loss or on subsequent weaning-to-oestrus interval. Sows offered starch weaned more piglets than sows offered soya-bean oil (9·4 v. 8·4, P < 0·05). Litter weight gains were higher for S than F sows in week 3 of lactation (2·2 v. 1·7 kg/day, P < 0·05), irrespective of litter size. Significantly increased plasma urea and b-hydroxybutyrate concentrations and lower post-prandial increases in plasma glucose and insulin concentrations were observed in F sows around peak lactation. Neither milk nor plasma prolactin concentrations were significantly affected by dietary treatments. The metabolic indices indicated that the F diet was more limiting in dietary glucose availability, which was associated with impaired milk yield as indicated by poorer litter performance. In conclusion, this study suggests that starch is superior to fat as an energy source in sow lactation diets, particularly in the later stages of lactation.
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Hatet, G., S. A. Edwards, K. Gall, and D. S. Arey. "Effect of three lactation housing systems on sow and piglet performance and behaviour." Proceedings of the British Society of Animal Production (1972) 1994 (March 1994): 189. http://dx.doi.org/10.1017/s0308229600027343.
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Confinement of sows in farrowing crates and early weaning of piglets are two major areas of concern in relation to animal welfare in intensive pig production systems. In this project, two alternative lactation systems in which these potential stressors are absent or reduced were evaluated.36 sows and litters were used in an experiment to evaluate, from weekly performance records and observations of behaviour, two alternative strategies for housing and management during lactation in comparison with a conventional current system: (1)Family system (F): Sows were housed throughout in groups of four with voluntary access farrowing pens. Piglets remained with the sows for 12 weeks and a boar was introduced after 3 weeks to induce oestrus.(2)Multisuckling system (M): Sows farrowed in individual crates but were grouped in fours in straw pens after 2 weeks. Piglets remained with the sows for 12 weeks and a boar was introduced after 3 weeks.(3)Conventional commercial system (C). Sows remained in part-slatted, unbedded farrowing crates throughout a four week lactation. Piglets weaned into flat decks and transfered after four weeks into fully slatted grower pens.
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Franek, S. P., and G. Bilkei. "Effect of Gonadotropins during Hot Summer Season Given at Different Times after Weaning on Selected Reproductive Indicators of the Sow." Acta Veterinaria Brno 77, no. 2 (2008): 193–98. http://dx.doi.org/10.2754/avb200877020193.
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The experiment was performed on a large indoor herd during a hot season period in Alföld, Hungary. The post-weaning sows (F1 and F2 of Large White × Landrace mated to Duroc boars (mean parity 3.4 +/-0.7 SD; mean body condition 3.01 +/-0.3 SD, previous lactation length of 28.3 +/-1.5 d) were divided into four groups of similar body condition, lactation length and parity and were treated as follows: Group 1: sows (n = 420) were injected subcutaneously with 400 I.U. of Gonadotropinum sericum (pregnant mare serum gonadotropin, PMSG [eCG]) and 200 I.U. of Gonadotropinum chorionicum (human choriongonadotropin, HCG [hCG]) one day after weaning. Group 2: sows (n = 405) received subcutaneously 4 ml of saline injection one day after weaning. Group 3: sows (n = 425), purposely chosen from among animals that did not show heat within 7 days after weaning, were treated on day 7 post-weaning with PMSG and HCG as the animals in group 1. Group 4: sows (n = 415) purposely chosen from among animals that did not show heat within 7 days after weaning, were treated on day 7 post-weaning as group 2. Sows expressing oestrus, sows ovulating after treatment, treatment to oestrus intervals and follicular sizes were evaluated. The number of sows expressing oestrus, sows ovulating, and treatment to oestrus intervals differed between the groups (group 1 vs. 2: P < 0.05, group 3 vs. 4: P < 0.01). The sows treated with PMSG and HCG on day 7 post-weaning (group 3) had smaller (P < 0.05) follicular diameters compared to the sows that were treated one day after weaning. Group 4 sows had a smaller follicular diameter (3.6 +/- 0.6 mm) compared to group 1 (P < 0.001) and 3 (P < 0.01). The present results show that the gonadotropin treatment one day after weaning or in the case of anoestrus 7 days after weaning overrides the negative effects of the hot summer season and effectively prevents seasonal infertility of the breeding sow.
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Hughes, P. E. "The effects of food level during lactation and early gestation on the reproductive performance of mature sows." Animal Science 57, no. 03 (December 1993): 437–45. http://dx.doi.org/10.1017/s1357729800042776.
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AbstractSeventy-six Large White × Landrace sows from parities 2 to 6 were allocated to one of four treatments at day 110 of gestation on a parity and live-weight basis. The four treatments involved food levels of either 3 or 6 kg/day during a 28-day lactation followed by either 1·75 or 3·50 kg/day during the first 28 days of gestation. Litter size suckled was standardized at 10 piglets wherever possible. Live weight and backfat changes were monitored in all sows and litter growth and survival rates were recorded. Post weaning all sows were given daily boar contact and mated twice at the first observed oestrus. A single blood sample was collected from each sow at days 7, 14, 21 and 28 of gestation for determination of plasma progesterone concentration. Data on litter size and piglet birth weights were collected at the subsequent parturition. Sows low-fed during lactation lost significantly more live weight (31·2v.5·8 kg,P< 0·01) and P2 backfat (3·6v.1·9 mm,P< 0·05) in lactation than did high-fed sows. Underfeeding the lactating sow also significantly reduced the weaning weight of the litter (62·3v.68·7 kg for low-v.high-fed sows,P< 0·05), but did not significantly change either creep food intake by the litter or pre-weaning mortality rate. Parity 2 sows weaned significantly heavier piglets and litters than did sows from parities 3 to 6 (7·48 and 74·9 kgv.6·72 and 63·8 kg respectively,P< 0·01). Food level in lactation did not significantly influence the length of the rebreeding interval (6·3v.7·3 days for high-v.low-fed sows) and although there was a two-fold difference in the proportion of sows failing to exhibit oestrus post weaning (0·08v.0·16 for high-v.low-fed sows) this difference was also not significant. Lactation food level did not significantly influence either sow live-weight or backfat change in gestation, plasma progesterone concentrations during early gestation or subsequent litter size. However, sows low-fed in lactation did tend to produce fewer piglets in the subsequent litter (9·54v.10·75 piglets born alive for low- and high-fed sows respectively,P= 0·062). Post-weaning reproductive performance was significantly affected by sow live weight (P< 0·05) and backfat (P< 0·01) at parturition, and live weight (P< 0·01) and backfat (P< 0·05) at weaning, but not by changes in these parameters during lactation. Food level in early gestation did not significantly influence either plasma progesterone concentrations, the size of the subsequent litter (10·09v.20·29 piglets born alive for high- and low-fed sows respectively) or mean piglet birth weight (1·27v.2·22 kg for high- and low-fed sows respectively). It is concluded that (1) both lactation food level and parity may alter pre-weaning piglet growth, and (2) the effects of lactation food level on the subsequent reproductive performance of mature sows appear to be different from those seen in parity 1 sows.
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Carrolli, C. M., P. B. Lynch, M. P. Boland, F. H. Austin, and J. F. Roche. "The Effect of Feed Intake on the Reproductive Performance of First Parity Sows." Proceedings of the British Society of Animal Production (1972) 1993 (March 1993): 131. http://dx.doi.org/10.1017/s0308229600024570.
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Thirty to forty per cent of sows in Irish herds are culled annually, one third of which are for reproductive problems such as anoestrus, anovulation and small litter size. Causes of reproductive failure include genetic, nutritional, environmental and behavioural factors. Failure to meet the nutritional requirements of sows during lactation and after weaning results in losses of liveweight and body fat (due to mobilization of body reserves) which can subsequently compromise reproductive performance. Although sows normally exhibit oestrus within one week of weaning, Sterning et al. (1990) observed that a large proportion of first parity sows showed a delayed return to oestrus. This results in a longer farrowing interval, fewer litters per sow per year and a reduction in herd output. The effects of malnutrition on reproduction are more severe in first parity than in multiparous sows (Kirkwood and Aherne, 1985). The objective of this study was to investigate the effects of low feed intake during lactation and postweaning on the subsequent reproductive performance of first parity sows.
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King, R. H., and A. C. Dunkin. "The effect of nutrition on the reproductive performance of first-litter sows 3. The response to graded increases in food intake during lactation." Animal Science 42, no. 1 (February 1986): 119–25. http://dx.doi.org/10.1017/s0003356100017803.
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ABSTRACTSeventy-two animals were used in an experiment to study the response of first-litter sows to graded increases in daily food intake during a 28-day lactation. Six food intakes, ranging from 1·5 to 4·8 kg/day were compared. The results showed that both live-weight loss and backfat loss during lactation increased linearly as food intake decreased (P < 0·01).Subsequent ovulation rate was unaffected by food intake but both weaning to mating interval (Y,, days) and the proportion of sows exhibiting oestrus within 8 days of weaning (Y2)improve d linearly with increase in daily food intake during lactation (X, kg) (P < 0·01); the respective linear regressions being Y, = 39·0 - 6·26 and Y2 = 0·198A - 0·15. A sub-group of 24 gilts which were older at first conception (340·5 v. 213·5 days; P < 0·01) exhibited oestrus sooner after their first litters were weaned (12·8 v. 22·1 days; P < 0·05) than the remaining 48 younger animals.Nitrogen balance increased linearly with food intake (P < 0·01) but even at the highest food intake, nitrogen balance remained negative (−15·5 g N per day). Food intake had no effect on the growth rate of piglets to 3 weeks of age but in the 4th week of lactation there was a quadratic increase in piglet growth rate as sow food intake increased (P < 0·01).
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Yang, H., P. R. Eastham, P. Phillips, and C. T. Whittemore. "Reproductive performance, body weight and body condition of breeding sows with differing body fatness at parturition, differing nutrition during lactation, and differing litter size." Animal Production 48, no. 1 (February 1989): 181–201. http://dx.doi.org/10.1017/s0003356100003901.
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ABSTRACTOne hundred and two Large White × Landrace Fl hybrid sows were allocated over four parities in a factorial design to two levels of target P2 backfat thickness at parturition (20 mm, F v. 12 mm, T), two levels of lactation feeding {ad libitum, H v. 3 kg/day, L), and two sizes of sucking litter (six v. 10). Sows attained 13 mm P2 when first mated at 126 kg live weight. Fatness (P2, mm) at weaning was significantly influenced by target fatness at parturition (14·2 v. 9·3), lactation feeding level (13·7 v. 10·0), and litter size (12·7 v. 11·0). Changes in backfat (P2, mm) during 28-day lactation were significantly influenced by target fatness at parturition (—5·0 v. —2·5), lactation feeding (-2 0 v. —5·4), and litter size (—2·9 v. -4·6). Sow live weight (kg) at weaning was significantly influenced by target fatness at parturition (211 v. 192), lactation feeding (218 v. 186), and litter size (208 v. 196). Changes in live weight (kg) during 28-day lactation were significantly influenced by target fatness at parturition (—26 v. — 12), lactation feeding (—5 v. —31), and litter size (—12 v. —25). With multiparous sows only, total food intake during 28-day lactation was negatively related to total food intake in pregnancy. Change in backfat (P2, mm) during 28-day lactation = -0·28 - 0·27 P2 at parturition + 0·04 lactation food intake — 0·50 litter size. Change in live weight (kg) during 28-day lactation = -3·8 — 0·15 live weight post partum + 0·36 lactation food intake — 3·3 litter size. Sows with target fat levels of 20 mm P2 at parturition had better food conversion efficiencies than sows with target fat levels of 12 mm. Target fatness at parturition, and especially lactation food intake, but not litter size, significantly influenced the interval (days) from weaning to oestrus in parity 1 (9·1 v. 14·2 and 7·8 v. 15·3, but 11·6 v. 11·5), while n i subsequent parities only litter size influenced the interval (days) from weaning to oestrus (6·0 v. 8·0). Birth weight (kg) of piglets was influenced only marginally by target fatness at parturition (1·4 v. 1·2) in parity 1, and not by the other factors, or in subsequent parities. Piglet growth rate was affected by both target fatness at parturition and litter size, but by lactation feeding level only in the last week of lactation. The relationship between fatness at weaning (mm) and the weaning to oestrus interval (days) for primiparous sows can be expressed as 26·6 — 1·28 P2. High level feeding in lactation imparted production and efficiency benefit in both primiparous and multiparous sows, while pregnancy feeding to a target of 20 mm rather than 12 mm at parturition was of benefit for primiparous sows.
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Barnett, J. L., P. H. Hemsworth, G. M. Cronin, E. C. Jongman, and G. D. Hutson. "A review of the welfare issues for sows and piglets in relation to housing." Australian Journal of Agricultural Research 52, no. 1 (2001): 1. http://dx.doi.org/10.1071/ar00057.
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This review of sow welfare addresses all aspects of housing for adult female pigs, including the issue of piglet welfare during lactation. It puts the issue of sow welfare in perspective by briefly outlining different approaches to the scientific assessment of welfare, the ‘feelings, preference, nature, and the functional or homeostasis’ approaches. We believe the last approach currently offers science the best assessment of welfare and is the approach that is utilised in this review. It involves comparing housing or husbandry systems and risks to welfare on the basis of relative changes in biological (behavioural and physiological) responses and corresponding decreases in fitness (growth rate, reproductive performance, or health/injury/immunology). The review discusses the following areas: (i) housing of individually housed pregnant pigs, with subsections on tethers, stalls, reproductive performance, exercise, and new stall designs; conventional, alternative, and outdoor group housing with subsections on aggression, electronic feeding stations, ecoshelters, and other alternative group housing designs; and other issues, such as lameness, culling, straw and other substrates, diet and hunger, quality of stockpeople, and housing around mating including oestrus detection and mating; and (ii) farrowing and lactating pigs with subsections on farrowing crates and alternative farrowing systems, stress around farrowing and during lactation, maternal behaviour and piglet survival, and sow and piglet injury and lameness. Conclusions and recommendations arising from the review include the need for public education to provide an informed consumer base that will result in some consensus on welfare issues among diverse interest groups and the need for industry education that results in better animal welfare and a sustainable industry. Some specific research recommendations include space allowance and the duration of housing for individually housed pigs, welfare issues of breeding sows in ecoshelters, piglet mortality in alternative systems, aggression in conventional and large groups, bedding, and hunger.
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Mullan, B. P., and I. H. Williams. "The effect of body reserves at farrowing on the reproductive performance of first-litter sows." Proceedings of the British Society of Animal Production (1972) 1988 (March 1988): 41. http://dx.doi.org/10.1017/s0308229600016809.
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Recent work in the United States (Reese, Moser, Peo, Lewis, Zimmerman, Kinder and Stroup 1982) and in Australia (King and Williams, 1984) has clearly shown that nutrition during lactation can affect the fertility of young sows. If first-litter sows are restricted in food intake during lactation, so that they lose body weight and backfat, they take longer to return to oestrus after weaning than their counterparts fed ad libitum. To reproduce successfully the sow must have some mechanism(s) of monitoring its nutritional status, preferably before conception takes place. It is difficult to imagine mechanisms capable of monitoring body reserves per se. It is more likely that the sow can monitor changes in its body reserves, for example, by measuring the rate of lipid mobilized from adipose tissue or the rate of protein breakdown from muscles, or both.Crossbred gilts (Landrace x Large White) were selected at about 45 kg body weight (approx 3 months of age) and allocated to treatment according to litter and live weight. A total of 22 groups each of 24 animals was selected. Within each group gilts were fed (13.0 MJ DE/kg, 160 g/kg CP) either ad libitum (High), 2.0 kg/day (Medium) or 1.8 kg/day (Low) from selection through until mating.
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Ferguson, E. M., C. J. Ashworth, M. G. Hunter, P. Penny, J. Slevin, and S. A. Edwards. "The effect of feeding a high fibre diet from mid lactation until breeding on subsequent litter size of sows." BSAP Occasional Publication 31 (2004): 175–79. http://dx.doi.org/10.1017/s0263967x00040398.
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AbstractThe feeding of high fibre diets to sows prior to ovulation has been shown to have beneficial effects on embryo viability, leading to a possible increase in piglet litter size. This trial was conducted to look at the effect of feeding sows a high fibre diet from mid lactation until breeding on subsequent litter size on a commercially run farm. The sows used were either Large White or Large White x Landrace in genotype and ranged from parity 1 to 7. The sows were allocated to receive either a cereal-based control diet (C), or a high fibre diet (HF) of similar specification but containing unmolassed sugar beet pulp (USBP) at a 20% inclusion rate during lactation and 40% from weaning to oestrus. The diets were fed from day 11 of lactation until oestrus. The sows were inseminated at oestrus and then fed a standard gestation diet until farrowing. The trial was conducted over a 3-month period and in total 198 sows received the HF diet with the rest of the sows over the 3-month period acting as controls (496) on the cereal-based diet. The effect of the diet on total litter size and the number of piglets born alive per sow was analysed in a general linear model (Minitab release 12.1). The combined results for both breed types showed that sows fed the HF diet had a significantly higher number of piglets born (12.37 ± 0.27 versus 11.41 ± 0.26, P<0.01) and a higher number of piglets born alive (11.47 ± 0.26 versus 10.85± 0.26, P<0.01) compared to 130 control fed sows matched for farrowing week. The difference in piglet litter size was still apparent when all the control sows farrowing over the 3 month trial period were included in the statistical analysis, with values of 12.47 ± 0.27 versus 11.79 ± 0.15 (P<0.05) for total number of piglets born and 11.77 ± 0.26 versus 11.16 ± 0.14 (P<0.05) for the number of piglets born alive for the HF and control diet respectively. Based on the results from this trial and previous studies, feeding a diet with a high content of USBP during late lactation and prior to insemination can increase the total number of piglets in the litter and the number of piglets born alive. This effect is less marked in crossbred sows with high baseline performance.
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Varley, M. A., and T. Atkinson. "Weaning at birth: the effect on the reproduction of the sow." Animal Science 41, no. 3 (December 1985): 375–82. http://dx.doi.org/10.1017/s0003356100036448.
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AbstractThirty-six Landrace × Large White sows were allocated at random to one of three treatment groups. Sows on treatment A (no. = 6) did not lactate at all and the piglets from these sows were removed at birth. Sows on treatment B (no. = 15) lactated for 1 day after parturition and sows on treatment C (no. = 15) acted as controls and lactated for 42 days. The reproductive performance of each treatment group was recorded and all sows were bled every 2nd day from parturition to 30 days post partum. All blood samples were assessed for oestradiol-17β and progesterone concentrations. In treatments A and B, a high proportion of anoestrous sows was seen (0·28). None of the sows in treatment C became anoestrous. The mean interval from weaning to the onset of oestrus for treatments A and B (19·0 (s.e. 6·5) days and 19·7 (s.e. 3·8) days respectively) were not significantly different, while that for treatment C (5·6 (s.e. 0·4) days) was significantly shorter (P < 0·01). The number of piglets born alive at the subsequent farrowing for treatments A, B and C respectively was 7·3 (s.e. 0·8), 9·1 (s.e. 0·8) and 10·5 (s.e. 0·67) (P < 0·05). The calculated annual sow productivity (piglets born alive per sow per year), excluding the first litter born, for treatments A, B and C respectively was 18·4, 22·8 and 22·9. Weaning at, or close to, parturition did not, therefore, influence sow productivity compared with weaning after 6 weeks of lactation.
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van Barneveld, R. J., and R. J. E. Hewitt. "Reducing variation in pork production systems through maternal and pre- and post-weaning nutrition strategies." Animal Production Science 56, no. 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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Lesskiu, P. E., M. L. Bernardi, I. Wentz, and F. P. Bortolozzo. "Effect of body development from first insemination to first weaning on performance and culling until the third farrowing of Landrace x Large White swine females." Arquivo Brasileiro de Medicina Veterinária e Zootecnia 67, no. 2 (April 2015): 465–73. http://dx.doi.org/10.1590/1678-6897.
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The aim of this study was to verify the association of sow body weight development until the 1st weaning with reproductive performance, piglet production and culling rate until the 3rd farrowing in 196 primiparous sows using logistic regression models. Each 10kg increase in weight gain in the 1stpregnancy (OR= 0.63), weight at 1st farrowing (OR= 0.70), weight at the 1st weaning (OR= 0.73) or weight gain from the 1startificial insemination (AI) to the 1st weaning (OR= 0.67) decreased the percentage of primiparous sows with long weaning-to-oestrus interval - WOI (>5 days). An increasing lactation length and an increase in the number of weaned piglets were responsible for respectively decreasing (OR= 0.77-0.80, per day of lactation) and increasing (OR= 1.52-1.59, per piglet weaned) the percentage of sows with long WOI. Sows with <159.5kg at weaning had higher odds of non-farrowing (NFR) compared to sows with >170kg (OR= 4.73). Sows with <17.5kg of gain from the 1st AI to the 1st weaning had higher odds (OR= 4.88) of NFR than sows gaining >30kg. Each additional lactation day decreased the NFR (OR= 0.74). Females weighing <139kg at the 1st AI had higher percentages of small numbers of total born in the second parity (STB2, OR= 2.00) and over three parities (OR= 3.28) compared to those weighing ≥139kg. Sows with weight gain <25kg at the 1st pregnancy had higher odds of STB2 (OR= 3.01) compared to sows gaining >35kg. Each 10kg of increase in weight at the 1st weaning or in weight gain from the 1stAI to the 1stweaning decreased the total culling rate (OR= 0.71 and 0.73, respectively) and culling for reproductive reasons (OR= 0.57 and 0.61, respectively). The culling rate until the 3rdfarrowing was also increased in sows with a smaller first litter size. The results show that not only reaching a minimum weight at the 1st AI but also having an adequate body weight gain until the 1st weaning is important for the reproductive performance, productivity and retention of Landrace x Large White Danbred sows in the herd.
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Zhou, Yuanfei, and Jian Peng. "PSXI-6 Effects of different feeding strategies during gestation on the reproductive performance of crossbred Landrace-Yorkshire sows." Journal of Animal Science 97, Supplement_3 (December 2019): 388. http://dx.doi.org/10.1093/jas/skz258.772.
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Abstract This study was conducted to investigate the effects of different feeding strategies during gestation on the reproductive performance of sows. A total of 1121 American Landrace-Yorkshire (YL) crossbred sows and parity from 1 to 4 were assigned randomly to “North American System” feeding pattern or “Danish System” feeding pattern during gestation basing on the backfat thickness and body weight. Sows received the same diet and fed ad libitum during lactation. Results showed that over the entire gestation period, there was also no difference in average daily feed intake and total feed intake between two groups (P > 0.05). “Danish System” group has significantly improved the backfat thickness at gestation 30 d (P < 0.01). At 110 d of gestation, there was no difference of the backfat thickness between two groups (P > 0.05). “Danish System” group had significantly increased the total number of born (P = 0.02) and born alive (P = 0.04). The number of total born (P = 0.04), stillborn (P = 0.05) and mummies (P = 0.02), had significantly different in between parities of sows. Mummies had significantly interaction effect (P = 0.01). No different was observed for the number of weaned pigs, litter weight at weaning, piglet weight, and weaning to oestrus interval between two groups. However, a significant increase of litter weight at weaning, piglet weight, was associated with increased parity of sow (P < 0.01). The results of the present investigation showed that “Danish System” group could significantly increase the litter size and number born alive. Our findings point to the importance that the Danish system can be applied to North American genotypes.
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Bleach, Emma C. L., Richard G. Glencross, and Philip G. Knight. "Association between ovarian follicle development and pregnancy rates in dairy cows undergoing spontaneous oestrous cycles." Reproduction 127, no. 5 (May 2004): 621–29. http://dx.doi.org/10.1530/rep.1.00190.
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Ovarian follicle development continues in a wave-like manner during the bovine oestrous cycle giving rise to variation in the duration of ovulatory follicle development. The objectives of the present study were to determine whether a relationship exists between the duration of ovulatory follicle development and pregnancy rates following artificial insemination (AI) in dairy cows undergoing spontaneous oestrous cycles, and to identify factors influencing follicle turnover and pregnancy rate and the relationship between these two variables. Follicle development was monitored by daily transrectal ultrasonography from 10 days after oestrus until the subsequent oestrus in 158 lactating dairy cows. The cows were artificially inseminated following the second observed oestrus and pregnancy was diagnosed 35 days later. The predominant pattern of follicle development was two follicle waves (74.7%) with three follicle waves in 22.1% of oestrous cycles and four or more follicle waves in 3.2% of oestrous cycles. The interval from ovulatory follicle emergence to oestrus (EOI) was 3 days longer (P < 0.0001) in cows with two follicle waves than in those with three waves. Ovulatory follicles from two-wave oestrous cycles grew more slowly but were approximately 2 mm larger (P < 0.0001) on the day of oestrus. Twin ovulations were observed in 14.2% of oestrous cycles and occurred more frequently (P < 0.001) in three-wave oestrous cycles; consequently EOI was shorter in cows with twin ovulations. Overall, 57.0% of the cows were diagnosed pregnant 35 days after AI. Linear logistic regression analysis revealed an inverse relationship between EOI and the proportion of cows diagnosed pregnant, among all cows (n = 158; P < 0.01) and amongst those with single ovulations (n = 145; P < 0.05). Mean EOI was approximately 1 day shorter (P < 0.01) in cows that became pregnant than in non-pregnant cows; however, pregnancy rates did not differ significantly among cows with different patterns of follicle development. These findings confirm and extend previous observations in pharmacologically manipulated cattle and show, for the first time, that in dairy cows undergoing spontaneous oestrous cycles, natural variation in the duration of post-emergence ovulatory follicle development has a significant effect on pregnancy rate, presumably reflecting variation in oocyte developmental competence.
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Soede, N. M., B. Laurenssen, M. Abrahamse-Berkeveld, R. Gerritsen, N. Dirx-Kuijken, P. Langendijk, and B. Kemp. "Timing of lactational oestrus in intermittent suckling regimes: Consequences for sow fertility." Animal Reproduction Science 130, no. 1-2 (January 2012): 74–81. http://dx.doi.org/10.1016/j.anireprosci.2011.12.015.
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Pryce, J. E., L. A. Wilson, and P. M. Visscher. "Effects of selection for production on maiden heifer fertility traits." Proceedings of the British Society of Animal Science 1999 (1999): 49. http://dx.doi.org/10.1017/s1752756200002040.
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There is evidence from UK field data to suggest that selection for milk yield has led to a deterioration in the fertility of lactating dairy cows (Pryce et al., 1997). As cow fertility may be affected by metabolic load and lactation effects, it is important to investigate the fertility of non-lactating heifers. Since 1973 selection line (S) cows at the Langhill Dairy Cattle Research Centre have been bred to bulls with the highest predicted transmitting abilities for weights of fat plus protein (PTA F+P) available in the UK, while the control line (C) are of about UK average genetic merit for PTA F+P. Results using data from lactating Langhill cows show that S cows have calving intervals that are, on average, 12 days longer than C cows, which is a combination of poorer conception rates and a delay in first observed oestrus (Pryce et al., 1999). The objective of this study was to investigate the effect of selection for PTA F+P on the fertility of maiden heifers at Langhill.
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Smith, MJ. "Male-induced oestrus and ovulation in female brush-tailed bettongs (Bettongia penicillata) suckling a young in the pouch." Reproduction, Fertility and Development 6, no. 4 (1994): 445. http://dx.doi.org/10.1071/rd9940445.
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Female brush-tailed bettongs isolated from males usually do not come into oestrus or ovulate. Individuals isolated during pregnancy and at parturition do not ovulate post partum and are in the unusual condition for a macropodoid of suckling a pouch young but lacking a quiescent corpus luteum or a diapause embryo. Females in this condition were tested for their ability to come into oestrus and to ovulate after re-introduction to the male. When returned to the male on Day 1 of lactation, females generally mated before Day 2 and ovulated; at all later stages of lactation, six or seven days after being returned to the male > or = 50% of females came into oestrus, mated and ovulated. The vaginal smears of most females in isolation were typical of post oestrus on Day 2; after being returned to the male on Day 11, these females came into oestrus in seven days, mated and ovulated. The results show that suckling a young in the pouch does not suppress ovulation in this species provided that an adult male is present. Moreover, the results indicate that the mechanism of male-induced ovulation 24 h post partum differs from that of the remainder of the pouch suckling period.
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Muro, B., R. Carnevale, M. Mendonça, D. Leal, M. Torres, D. Nakasone, G. Ravagnani, et al. "54 Altrenogest supplementation during early pregnancy improves swine embryonic development." Reproduction, Fertility and Development 31, no. 1 (2019): 152. http://dx.doi.org/10.1071/rdv31n1ab54.
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Progesterone (P4) is of paramount importance in the establishment and maintenance of pregnancy for mammals. Progesterone stimulates the endometrial secretion of several molecules involved in conceptus growth and development during the peri-implantation period. Indeed, several studies involving ruminants have reported that exogenous P4 supplementation is related to increased early embryo development, higher levels of interferon tau, and improved pregnancy rate. However, there is a lack of information about P4 supplementation during early pregnancy regarding swine embryonic development. Additionally, some of the few studies involving pigs have shown an impaired pregnancy rate when supplementation was performed before Day 6 of pregnancy. Thus, the objective of this study was to evaluate the effects of progesterone/progestin supplementation from Day 6 of pregnancy on total number of embryos (TE), pregnancy rate (PR), embryo development, and maternal serum 17β-oestradiol concentration (17β-E). A total of 31 crossbred, 2 to 6 parity sows were used. All sows were inseminated every 24h through the first oestrus following a 21-day lactation, and ovulation was detected by transrectal real-time ultrasound to determine Day 0 of pregnancy. On Day 6 of pregnancy, animals were randomly allocated to one of the following groups: CON (n=11), non-supplemented sows; RU (n=11), sows supplemented daily with 20mg of Altrenogest-Regumate® from Day 6 to 12 of pregnancy; and PG (n=9), sows supplemented with 2.15 mg/kg of long-acting P4 IM on Day 6 of pregnancy. Sows were treated with altrenogest p.o. as a top dressing over a small portion of feed. Blood samples were collected from 12 sows (4 per group) on Day 12 of pregnancy to measure the level of plasma 17β-E by radioimmunoassay. Sows were slaughtered on Day 28 of pregnancy. The uterus from each sow was collected and embryos were counted to determine TE. Embryos were individually separated from their placentas, weighed, and crown-to-rump length was determined. Data were analysed by the SAS program. All variables were analysed by PROC-MIXED t-test. Statistical difference was considered when P<0.05. The PR did not differ among groups (91, 90, and 88%, for CON, RU, and PG, respectively; P>0.05). No difference was observed among groups for TE and 17β-E level (P>0.05). However, embryonic weight and crown-to-rump length differed among the 3 groups (P<0.001). The RU-treated sows had heavier and bigger embryos when compared with the other groups. In contrast, PG-treated sows had the lowest averages for the same variables (weight: 1.39±0.01, 1.46±0.02, and 1.22±0.01; crown-to-rump: 21.07±0.08, 21.61±0.11, and 20.66±0.11; for CON, RU, and PG, respectively). In conclusion, altrenogest supplementation from Day 6 to 12 of pregnancy increases size and weight of porcine embryos, whereas 2.15mg kg−1 of long-acting P4 on Day 6 of pregnancy decreased these variables when compared with non-supplemented sows. Research was supported by FAPESP Grant 2017/00290-0.
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Wechsler, B. "Rearing Pigs in Species-Specific Family Groups." Animal Welfare 5, no. 1 (February 1996): 25–35. http://dx.doi.org/10.1017/s0962728600018303.
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AbstractIn the Family Pen System piglets and fatteners grow up in species-specific family groups that correspond to the normal social organization of domestic pigs. The feasibility of a technologically improved version of this alternative housing system, originally designed by Alex Stolba, was tested on a commercial farm for two and a half years. Eighty-one litters were born in three family groups within this period. Average cycle length was 170 ± 24 (SD) days, resulting in 2.15 litters per sow per year. All piglets were suckled for at least seven weeks. In 53.8 per cent of the cycles lactational oestrus occurred before the piglets were seven-weeks-old. The litters of sows which did not show lactational oestrus were artificially weaned and returned to the family group as soon as the sow had been served. At the beginning there were problems with piglet health and crushing, but in the last 21 months of the study there was a stable reproductive performance of 19.5 piglets (28-days-old) reared per sow per year (n = 53 litters). Sows that had been raised themselves in the Family Pen System reared 21.4 piglets per year (n = 25 litters). In conclusion, the technologically improved version of the Family Pen System was found to be practicable on a commercial farm.
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Menzies, Brandon R., Thomas B. Hildebrandt, and Marilyn B. Renfree. "Unique reproductive strategy in the swamp wallaby." Proceedings of the National Academy of Sciences 117, no. 11 (March 2, 2020): 5938–42. http://dx.doi.org/10.1073/pnas.1922678117.
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Reproduction in mammals requires distinct cycles of ovulation, fertilization, pregnancy, and lactation often interspersed with periods of anoestrus when breeding does not occur. Macropodids, the largest extant species of marsupials, the kangaroos and wallabies, have a very different reproductive strategy to most eutherian mammals whereby young are born at a highly altricial stage of development with the majority of development occurring over a lengthy lactation period. Furthermore, the timings of ovulation and birth in some species occurs within a very short interval of each other (sometimes hours). Female swamp wallabies have an oestrous cycle shorter than their pregnancy length and were, therefore, speculated to mate and form a new embryo before birth thereby supporting two conceptuses at different stages of pregnancy. To confirm this, we used high-resolution ultrasound to monitor reproduction in swamp wallabies during pregnancy. Here, we show that females ovulate, mate, and form a new embryo prepartum while still carrying a full-term fetus in the contralateral uterus. This embryo enters embryonic diapause until the newborn leaves the pouch 9 mo later. Thus, combined with embryonic diapause, females are continuously pregnant and lactating at the same time throughout their reproductive life, a unique reproductive strategy that completely blurs the normal staged system of reproduction in mammals.
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Smith, MJ. "Duration of embryonic diapause in the brush-tailed bettong, Bettongia penicillata (Potoroidae): effect of age of quiescent corpus luteum." Reproduction, Fertility and Development 8, no. 4 (1996): 807. http://dx.doi.org/10.1071/rd9960807.
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It has been shown that changes to the frequency of sucking by the pouch young do not affect the time of reactivation of the quiescent corpus luteum and diapause embryo in Bettongia penicillata; these observations led to the suggestion that the corpus luteum may have an inherent maximum duration of quiescence. The aim of the present study was to investigate the effect of the age of the corpus luteum on the timing of its reactivation. Ovulation fails to occur post partum in female B. penicillata isolated from males, and the introduction of a male B. penicillata induces oestrus in females suckling a young in the pouch. Oestrus was induced from Day 23 of lactation to Day 76, in different females, and the corpus luteum became quiescent. All parturitions occurred between Day 95 and Day 103 of lactation (average, Day 98.8), at the time expected if the corpus luteum had been formed post partum. Duration of quiescence of the corpus luteum ranged from 60 days to 10 days, compared with 83.9 +/- 0.43 days in females that mated post partum. The results show that the age of the corpus luteum does not affect the timing of its redevelopment and release of the embryo from diapause near the end of the period of the young being suckled within the pouch.
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Bó, G. A., A. Cedeño, A. Tribulo, S. Andrada, R. Tribulo, J. L. Barajas, J. Ortega, M. Pellizari, and R. J. Mapletoft. "7 INFLUENCE OF ESTRUS EXPRESSION AND TREATMENT WITH GnRH ON PREGNANCY RATES IN BEEF CATTLE SYNCHRONIZED WITH PROGESTERONE DEVICES AND ESTRADIOL AND INSEMINATED AT A FIXED-TIME." Reproduction, Fertility and Development 29, no. 1 (2017): 111. http://dx.doi.org/10.1071/rdv29n1ab7.
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We have previously shown that expression of oestrus significantly influences the time of ovulation and pregnancy rates to timed-AI (P/TAI) in beef cattle synchronized with progesterone devices and oestradiol (Bó et al. 2016 Theriogenology 86, 388–396). Furthermore, delaying TAI from 48 h to 54–58 h after device removal improved P/TAI of those animals not showing oestrus by 48 h. The objective of the present study was to determine whether the administration of GnRH to those animals not showing oestrus by 48 h after device removal had an impact on P/TAI. Non-lactating and suckled beef cows and heifers (Bonsmara, Brangus, and Braford; n = 868), with a corpus luteum (CL) or a follicle ≥8 mm in diameter detected by ultrasonography (Mindray DP 30 Vet, 7.5 MHz, China) and body condition score 2 to 4 (1 to 5 scale) were synchronized in 3 replicates. On Day 0, animals received a progesterone device (DIB 0.5 g, Zoetis, Argentina) and 2 mg of oestradiol benzoate (Von Franken, Argentina). On Day 8, DIB were removed and cows received 0.150 mg of D+cloprostenol (Río de Janeiro, Argentina) plus 0.5 mg oestradiol cypionate (Cipiosyn, Zoetis). In addition, all cows were tail-painted on the sacrococcygeal area (CeloTest, Biotay, Argentina) at DIB removal and were observed to determine the expression of oestrus, according to the percentage of paint loss (PL) 48 h later. The animals that showed oestrus (PL > 30%) were recorded and TAI at that time while those with PL ≤ 30% (not in oestrus) were randomly allocated to receive 100 μg of gonadorelin (GnRH; Gonasyn, Zoetis) or no treatment and TAI between 54 to 58 h after DIB removal. Pregnancy was diagnosed by ultrasonography at 45 days after TAI, and data were analysed by logistic regression. There were no significant differences among replicates, inseminators, semen source or animal class (dry cows, suckled cows or heifers; P > 0.11). However, animals showing oestrus by 48 h after DIB removal had higher P/TAI (371/666; 55.7; P < 0.04) than those that did not show oestrus (96/202; 47.5%). Within animals not showing oestrus at 48 h, those that were in oestrus by the TAI at 54 to 58 h had higher P/TAI (71/124, 57.3%; P < 0.01) than those that did not show oestrus within that period (27/78; 34.6%). In addition, P/TAI was higher (P < 0.01) in animals that received GnRH (66/113; 58.4%) than in those that did not receive GnRH (30/89; 33.7%). In conclusion, the expression of oestrus significantly affected P/TAI in beef cattle synchronized with progesterone devices and oestradiol. Furthermore, treatment of animals not showing oestrus by 48 h after DIB removal with GnRH resulted in improved P/TAI performed 6 to 10 h later.
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Cedeño, A., A. Tribulo, S. Andrada, J. L. Barajas, J. Fonseca, A. Ruiz, R. Tribulo, H. Tribulo, R. J. Mapletoft, and G. A. Bó. "103 INFLUENCE OF ESTRUS EXPRESSION AND TREATMENT WITH GONADOTROPIN-RELEASING HORMONE ON PREGNANCY RATES IN RECIPIENTS SYNCHRONIZED WITH PROGESTERONE DEVICES AND ESTRADIOL AND TRANSFERRED AT A FIXED TIME." Reproduction, Fertility and Development 29, no. 1 (2017): 159. http://dx.doi.org/10.1071/rdv29n1ab103.
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An experiment was designed to evaluate whether expression of oestrus in recipients synchronized with progesterone devices and oestradiol affects pregnancy rates to a fixed-time embryo transfer (FTET). A secondary objective was to determine whether administration of gonadotropin-releasing hormone (GnRH) to those recipients not showing oestrus by 48 h after device removal had an effect on pregnancy rates. Mature, non-lactating beef recipients (Bonsmara, Brangus, and Braford; n = 729), with a corpus luteum (CL) or a follicle ≥8 mm in diameter detected by ultrasonography (Mindray DP 30, Shenzhen, China) and body condition score 2 to 4 (1 to 5 scale) were synchronized in 7 replicates. On Day 0, recipients received a progesterone device (DIB 0.5 g, Zoetis, Buenos Aires, Argentina) and 2 mg of oestradiol benzoate (Gonadiol, Zoetis). On Day 8, DIB were removed and recipients received 400 IU eCG (Novormon 5000, Zoetis) plus 0.5 mg of oestradiol cypionate (Cipiosyn, Zoetis) and 500 μg of cloprostenol (Cyclase, Zoetis). In addition, all cows were tail-painted on the sacrococcygeal area (CeloTest, Biotay, Buenos Aires, Argentina) at DIB removal and were observed to determine the expression of oestrus, according to the percentage of paint loss 48 h later. The animals that showed oestrus (paint loss >30%) were recorded, and those with paint loss ≤30% (not in oestrus) were randomly allocated to receive 100 μg of gonadorelin (GnRH; Gonasyn, Zoetis) or no treatment. On Day 17, all recipients were examined by ultrasonography and those with a CL ≥18 mm (G1), ≥16 and <18 mm (G2), or ≥14 and <16 mm (G3) in diameter received in vivo-produced frozen-thawed embryos by direct transfer or fresh in vitro-produced embryos. Pregnancy was diagnosed by ultrasonography at 23 days after FTET, and data were analysed by logistic regression. There were no differences between replicates, in vivo- and in vitro-produced embryos, or operators (P > 0.2). However, the proportion of recipients transferred and pregnant (P/FTET) was higher (P < 0.05) for those that showed oestrus at 48 h after DIB removal (422/454, 93.0% and 227/471, 48.2%) than those that did not show oestrus (109/211, 51.7% and 45/120, 37.5%). Within the recipients not showing oestrus, P/FTET was significantly higher (P < 0.05) in those that received GnRH (34/74, 45.9%) than in those that did not receive GnRH (12/46, 26.1%). There was a significant interaction (P < 0.05) between CL diameter and expression of oestrus. When recipients had CL ≥18 mm in diameter (G1), P/FTET did not differ (oestrus: 164/338, 48.5% v. no oestrus 30/65, 46.2%); however, when CL diameter was <18 mm and ≥14 mm (G2 and G3), P/FTET was higher (P < 0.05) in those that showed oestrus (37/85, 43.5%) than in those that did not show oestrus (11/43, 25.6%). Finally, P/FTET was higher (P < 0.05) in recipients with a CL (268/573, 46.8%) on Day 0 than in those with follicles >8 mm in diameter (4/18, 22.2%). In conclusion, the expression of oestrus significantly affected the percentage of recipients selected for embryo transfer and P/FTET. Furthermore, treatment of recipients not showing oestrus by 48 h after DIB removal with GnRH at that time increased P/FTET.
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Lindblom, C., P. Södersten, and P. Eneroth. "Effects of pup sucking behaviour on inhibition of sexual behaviour and ovulatory secretion of LH in lactating rats." Journal of Endocrinology 104, no. 3 (March 1985): 419–25. http://dx.doi.org/10.1677/joe.0.1040419.
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ABSTRACT The time-interval between parturition and the display of sexual receptivity varied between 13·5 ± 0·7 and 35·9 ± 2·5 days in rats with litters of between 1 and 24 pups. Body weight gain decreased and the avidity of pup sucking behaviour, measured by the latency before the pups, placed on the ventrum of an anaesthetized mother, attached to a nipple of the mother, increased as litter size increased. Litter-shifting procedures, which introduced asynchrony between the lactational age of the mother and the age of the pups, produced deficiencies in sucking behaviour and did not prolong the time-interval between parturition and the display of sexual receptivity by the mother. By keeping the lactational age of the mother in synchrony with the age of the pups and depriving the pups of maternal contact and nutrition every alternate day, the time-interval between parturition and the display of sexual receptivity by the mother was prolonged by 17 days, the avidity of pup sucking behaviour markedly enhanced and the body weight gain of the pups retarded in comparison with mothers and pups continuously living together. The results show that the display of the first postlactational behavioural oestrus and surge of pituitary LH secretion can be greatly delayed by an increase in the avidity of pup sucking behaviour. J. Endocr. (1985) 104, 419–425
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Sterning, Marie, Lotta Rydhmer, Lena Eliasson, Stig Einarsson, and Kjell Andersson. "A Study on Primiparous Sows of the Ability to Show Standing Oestrus and to Ovulate after Weaning. Influences of Loss of Body Weight and Backfat during Lactation and of Litter Size, Litter Weight Gain and Season." Acta Veterinaria Scandinavica 31, no. 2 (October 5, 1989): 227–36. http://dx.doi.org/10.1186/bf03547566.
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Lemes, K. M., L. A. Silva, E. C. C. Celeghini, M. A. Alonso, G. Pugliesi, H. F. Carvalho, F. J. Affonso, D. F. Silva, T. G. Leite, and R. P. Arruda. "175 FOLLICULAR DEVELOPMENT AND OVARIAN BLOOD FLOW IN MARES WITH EARLY OR LATE OVULATION POSTPARTUM." Reproduction, Fertility and Development 27, no. 1 (2015): 178. http://dx.doi.org/10.1071/rdv27n1ab175.
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The postpartum period is characterised by the rapid uterine involution process and return of ovarian activity (foal heat), resulting in a fertile oestrus in most of the mares. However, the follicular development and selection processes during this period are not completely known in horses. We aimed to study the characteristics of follicular growth and vascular perfusion in the ovary during the early postpartum period in mares that demonstrated oestrous behaviour and had early (<10 days) or late (≥10 days) ovulation. Ten mares were scanned daily from the first day postpartum (Day 1) until the day of the first postpartum ovulation (Day 0). The animals were split in the early (n = 3) and late (n = 7) ovulation groups (averaged interval between parturition and ovulation: 8.0 ± 0.0 and 14.7 ± 1.2 days, respectively). For ultrasound exams a Duplex B-mode and colour Doppler instrument (M5VET®, Mindray, Shenzhen, China) was used with a multifrequency linear probe. Data were analysed for the main effects of group, day, and their interaction using the PROC MIXED procedure of SAS software (version 9.3, SAS Institute Inc., Cary, NC, USA). For the follicular growth, no difference (P > 0.05) was detected between the groups when the data were analysed for the days relative to ovulation (from Day 7 to Day 1). However, the dominant follicle was larger (P < 0.05) in the early-ovulated group (37.2 ± 1.6 v. 21.9 ± 1.1) in all days during early postpartum (Day 1 to Day 7). The number of follicles with >25 mm diameter was also greater (P < 0.05) in the early-ovulated group (1.1 ± 0.1 v. 0.1 ± 0.1) during the first 3 days postpartum. In addition, the late-ovulated mares showed greater number of follicles with 20–25 mm during Day 4 to Day 7 (2.0 ± 0.2 v. 0.7 ± 0.1). For the blood flow characteristics, no difference (P > 0.05) was detected in the coloured signals of blood flows in the follicular wall of the dominant follicle or in the ovarian pedicle ipsilateral to the largest follicle. Therefore, the characteristics of the follicle growth on the preceding days of ovulation were similar between the early- and late-ovulated mares and consistent with the follicular dynamics expected in non-pregnant and non-lactating mares. However, when the data were analysed for the days relative to parturition, a greater follicle development was present in mares that ovulate earlier during the postpartum period (<10 days). In conclusion, the results suggest that important events may occur previous to the parturition, resulting in an early follicle development, mainly in those mares that show heat signs and ovulate within 10 days postpartum. Research was supported by FAPESP process number 2010/10692-9 and CNPq process number 135954/2011-8.
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Webb, R., P. C. Garnsworthy, J. G. Gong, R. S. Robinson, and D. C. Wathes. "Consequences for reproductive function of metabolic adaption to load." BSAP Occasional Publication 24 (1999): 99–112. http://dx.doi.org/10.1017/s1463981500043119.
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AbstractAn effective method for enhancing milk production efficiency in dairy cows is to increase milk yield and significant progress has been achieved through intense selection, assisted by the application of new reproductive techniques. However this increased milk yield has been accompanied by a slow but steady decline in dairy cow fertility. The two main reasons for this reducing level of fertility appear to be selection for increased milk yield and large herd sizes, although the affect of the introduction of Holstein genes needs to be investigated. In addition, other negative consequences such as an increase in the incidence of metabolic diseases and lameness have been observed. This has given rise to public concern that the high-yielding dairy cow may be under a state of metabolic stress during peak lactation and therefore the welfare and performance of other body functions are compromised.The reason for this decline in fertility is not well understood, although a nutritional influence on the initiation of oestrous cycles, follicular growth, oocyte quality and early embryonic development has been implicated. In early lactation dietary intake is unable to meet the demands of milk production and most cows enter a period of negative energy balance. Negative energy balance has a broadly similar effect to undernutrition leading to a mobilization of body reserves. Furthermore diets high in rumen degradable protein lead to an excess of rumen ammonia, which before it is converted to urea by the liver and excreted in the urine, may cause an alteration in the reproductive tract environment reducing embryo survival. Such major changes in the metabolic and endocrine systems can therefore influence fertility at a number of key points.Possible reproductive sites where inadequate nutrition may have detrimental effects include: (i) the hypothalamic/pituitary gland where gonadotropin release may be impaired; (ii) a direct effect on the ovaries, where both follicular growth patterns and corpus luteum function may be directly influenced; (iii) the quality of the oocyte prior to ovulation may be reduced and coupled with an inadequate uterine environment will result in reduced embryo survival and (iv) there may be effects on subsequent embryo development. The initiation of normal oestrous cycles post partum is usually delayed in dairy cows with a higher genetic merit for milk production, confirming that intense selection towards high milk yield can compromise reproductive function. In addition, the effects of increased milk yield may include changes in circulating GH and insulin concentrations, which in turn alter both insulin-like growth factor (IGF) and IGF binding protein production. Nutrition has recently been shown to have a direct effect at the level of both the ovaries and the uterus to alter the expression of these growth factors.In conclusion, further knowledge is required to determine how the metabolic changes associated with high milk output reduce fertility. Identification and understanding of the mechanisms involved and the key sites of action responsible for compromised reproductive function, will enable the identification of possible indices for future multiple-trait selection programmes.
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Lacerda, T. F., R. B. G. C. Carvalho, M. G. Favoreto, and B. Loureiro. "11 PREGNANCY RATES AND ATP1A1 POLYMORPHISM IN THERMOTOLERANT HOLSTEIN COWS DURING SUMMER IN BRAZIL." Reproduction, Fertility and Development 29, no. 1 (2017): 113. http://dx.doi.org/10.1071/rdv29n1ab11.
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Maximum body temperatures (BT) registered in dairy cows have been used as an indicator of heat stress (HS). However, some studies have shown that the variation in BT, which represents energy requirements for BT regulation, is more representative of HS. Cows that show less variation in BT can be considered thermotolerant. The ATP1A1 gene is critical for maintaining homeostasis through the fluctuation of plasma K+ and Na+. Thus, this experiment was designed to (1) test the correlation between the coefficient of variation (CV) in BT and pregnancy rate after artificial insemination (AI) in the summer, and (2) identify polymorphisms in the ATP1A1 gene. Seventy lactating Holstein cows kept in a freestall system were used. To measure BT, an automatic thermometer coupled to a placebo intravaginal implant was kept in the cows, for 3 days, measuring the temperature every 5 min. The temperature CV for each animal was calculated as the ratio of the standard deviation to the mean. Each animal’s daily milk production was registered on the day of implant insertion. The animals used in the experiment were AI without hormonal synchronization, 12 h after presenting oestrus. Semen from Holstein and Gir breeds were used. After 30 days, pregnancy was diagnosed using an ultrasound. Animals were re-inseminated as they showed oestrus until they became pregnant. The number of AI necessary for each animal to become pregnant was calculated. DNA was extracted from tail hair from sixty cows used in the experiment. For polymorphism detection, primers from a fragment of the ATP1A1 gene (forward 5′-AGTGCTGCGTGAAACCTG-3′, reverse 5′-GTGATGTGTGGAATGGTGC-3′) were used. PCR reactions were performed and PCR products were electrophoresed on 1% agarose gel for visualisation of the fragment sizes. Then, the PCR products were purified and sequenced. The obtained sequences were analysed and edited using the BioEdit Software (http://www.mbio.ncsu.edu/BioEdit/BioEdit.html). Sequence alignment was performed using the virtual tool Clustal Omega. To exclude the effect of sire breed on pregnancy rate a logistic regression analysis using Proc Logistic (SAS for Windows, version 9.2; SAS Institute Inc., Cary, NC, USA) was performed. The correlation between temperature CV, milk production, and number of AI, and means and standard deviation were analysed by Pearson correlation coefficient using the Proc Corr of SAS. Mean milk production was 30.21 ± 7.4. Mean temperature CV was 1.32 ± 0.48. Mean AI was 1.97 ± 1.05. Results showed a positive moderate correlation between temperature CV and AI (0.33; P < 0.004). There was no correlation between milk production and CV or milk production and AI. One polymorphism, a G-A mutation, at nucleotide position 116,400,962 (exon 19) of the gene mRNA was identified in 5 animals (temperature CV: 1.04, 1.05, 1.24, 1.32, 1.41). This mutation represents an alteration from the amino acid aspartate to asparagine. In conclusion, animals that show less fluctuation in body temperature can present better pregnancy rates after AI. One novel polymorphism was identified but more studies are needed to associate it with thermoregulation.
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Revell, D. K., S. T. Morris, Y. H. Cottam, J. E. Hanna, D. G. Thomas, S. Brown, and S. N. McCutcheon. "Shearing ewes at mid-pregnancy is associated with changes in fetal growth and development." Australian Journal of Agricultural Research 53, no. 6 (2002): 697. http://dx.doi.org/10.1071/ar01140.
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This study investigated the effect of mid-pregnancy shearing (at Day 70 of pregnancy, P70) on herbage intake of grazing single- and twin-bearing ewes, lamb birth weight, and cold resistance of new-born lambs. At pregnancy diagnosis on P50, 30 single-bearing and 30 twin-bearing ewes were allocated either to be shorn at P70 (n = 15 for each pregnancy rank) or to remain unshorn to serve as controls (n = 15 for each pregnancy rank). All ewes were mated over a 3-day period with synchronisation of their oestrus. Herbage intake was measured indirectly from in vitro pasture digestibility and faecal output of grazing ewes, with the use of intra-ruminal chromium slow-release capsules, over six 5-day periods from P64 to P105. The weights of placental and fetal tissues were assessed in a subgroup of 16 ewes at P140 and P141. In the remaining sheep, lamb liveweight at birth and during lactation until weaning at 103 days of age was measured, and cold-resistance of new-born lambs was assessed by measuring summit metabolic rate (SMR) by indirect calorimetry. Ewe liveweight (corrected for fleece weight), condition score, and herbage intake during pregnancy were not affected by shearing treatment. Mid-pregnancy shearing did not affect placental weight, but increased the relative weights (i.e. g/kg liveweight) of fetal thyroid gland and lungs and reduced the relative weight of adrenal glands and heart. The ratio of secondary to primary wool follicles in near-term fetal skin was about 10% higher in offspring of shorn than of unshorn ewes. The metabolic rate of fetal hepatic tissue was increased by mid-pregnancy shearing, particularly in twin fetuses, possibly indicative of an increase in placental transport of nutrients to the fetuses. This conclusion is supported by the greater birth weight (average response 0.5 kg) of lambs born to ewes shorn at mid-pregnancy. Mid-pregnancy shearing also increased the SMR of new-born twin lambs by 16%, but decreased the SMR of singleton lambs by 26%. These results indicate that mid-pregnancy shearing can increase lamb birth weight without increasing ewe herbage intake or placental weight. An increase in the efficiency of nutrient uptake by the placenta is implied, and possible effects on the activity of thermogenic tissues are discussed.
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Hossain, K. M., and N. P. McMeniman. "EFFECTS OF DIETARY PROTEIN LEVEL UPON PERIPHERAL PLASMA PROGESTERONE CONCENTRATION AND CONCEPTION RATE IN DAIRY CATTLE." Khulna University Studies, May 27, 2001, 447–553. http://dx.doi.org/10.53808/kus.2001.3.1.0116-l.
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There have been concerns that high protein intake had a significant influence on blood components and uterine constituents in non-lactating dairy cows and on spcrmatozoal motility. There are study that show that as dietary crude protein (CP) is increased, there is a tendency of reduced fertility in dairy cows while other studies have suggested that there is no relationship between reproductive performance and dietary CP intake. The objective of the study was to investigate the effect of dietary CP intake on blood progesterone concentrations and conception rate in dairy cattle. Fourteen lactating Friesian cows were randomly divided into two equal groups, a control group - Low Protein (LP) and a treated - High Protein (HP) group. The cows’ oestrous cycles were synchronized and inseminated with frozen semen. Jugular blood samples were collected daily for at least 21 days after the first insemination starting on day of oestrus and then twice per week until they were 6-weeks of pregnant and then once per week until they were 12-weeks pregnant. The result showed that the progesterone concentrations in the control (LP) cows were significantly higher than in the treated (HP) cows during pre-conception oestrous cycles that did not result in pregnancy for 10 cows (5 in each group). Except on the last day of sampling (day 42), there were no differences in progesterone concentrations between the two groups of cows during first 6-weeks of pregnancy. The plasma progesterone concentrations were significantly lower in the HP group on days 45 and 52. However, dietary protein had no significant effect on overall group mean concentrations over this 6-week period (7 to 12 week) but the interaction, Group x time, was significant. The number of services per conception was lower for the cows fed the low CP diet. However, the median number of services per conception for the two groups was not statistically different. The results clearly indicated that cows fed the high CP rations had significantly reduced plasma progesterone concentrations when compared with those fed the low protein diet. The result also suggested that low progesterone concentrations particularly during the pre-conception oestrous cycle in the HP-fed groups were associated with a lower conception rate (32%) compared in the LP-fed group (54%).
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Garcia, Amélia Maria Lima, Charles Kiefer, Karina Márcia Ribeiro de Souza Nascimento, Cheila Roberta Lehnen, Luciano Hauschild, Camilla Mendonça Silva, Stephan Alexander da Silva Alencar, and Gabriela Puhl Rodrigues. "Meta-analysis of recommended digestible lysine levels for primiparous lactating sows." Ciência Rural 50, no. 11 (2020). http://dx.doi.org/10.1590/0103-8478cr20190418.
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ABSTRACT: A meta-analysis was carried out to evaluate the recommended levels of digestible lysine and its influence on the productive performance of primiparous lactating sows. The database consisted of 26 publications, 138 diets and 3,820 sows was developed from articles on the association between, lysine, crude protein and lactating primiparous sows. The digestible lysine levels of the studies ranged from 0.22 to 1.43% with average values of 0.85% digestible lysine in the diet, with consumption of 41.25 g day-1. The digestible lysine intake of sows was positively correlated (P<0.05) with feed intake, essential amino acids, crude protein, metabolizable energy, body weight loss sows, milk production, number and weight of piglets at weaning. Digestible lysine intake showed negative correlation (P<0.05) with backfat thickness at weaning and weaning to oestrus interval. It was observed a quadratic effect (P<0.01) of body weight loss sow and daily weight gain of piglets and a quadratic effect (P<0.01) in the weight of piglets at weaning due to increased dietary lysine level. The level of 1.04% of digestible lysine indicates less weight loss sows. The greater weight of piglets at weaning and increased daily weight gain of piglets was verified with the addition of 1.30 and 1.07% digestible lysine in the diet, respectively.
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Chakraborty, A., P. K. Pathak, L. K. Nath, J. Das, S. Bhuyan, D. Hazarika, and J. Dutta. "Evaluation of Knowledge Gain through Training Programmes on Scientific Pig Farming." Asian Journal of Agricultural Extension, Economics & Sociology, August 5, 2021, 88–92. http://dx.doi.org/10.9734/ajaees/2021/v39i830629.
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The present study was conducted with an objective of assessing the knowledge gained by trainees about various aspects of scientific pig farming organised by Krishi Vigyan Kendra, Lakhimpur. A total of 180 numbers of trainees participated in trainings on scientific pig farming over a period during 2019 and 2020 on random selection. The data were collected on pre and post completion of the training with the help of questionnaire which were distributed to the trainees before training. The questionnaire consisted of 13 different aspects on knowledge on Indian and exotic Pig Breeds, knowledge on selection of piglets, castration age of piglets, attainment of puberty in pigs, oestrus period of a sow, heat detection in gilt, gestation period of sow, care of young piglets, deworming in pigs, marketing age of pigs, feeding of lactating sow, knowledge on Vaccination of pigs and common diseases of pigs.
A score of one and zero score was assigned for each correct and incorrect response, respectively for analysis of knowledge gain. It was found that majority of the trainees were youths (52.22%), followed by Middle aged (32.22%) and Old age (15.55%).Majority of the trainees were from ST category (33.88%) followed by OBC (32.77%), General (21.11%) and SC (12.22%). Among those who attended training 32.22% had education till middle school level followed by primary 22.77, 16.11 % were found illiterate whereas 15% completed secondary, 10.55% higher secondary and 3.33 % completed education upto graduate level.
The overall knowledge of trainees on pre training evaluation was found to be 19.17% which ended up on a high note with 93.15% on post training evaluation, which is indicative of the positive impact of training on knowledge gain.
Evaluation of knowledge gain on various aspects of scientific pig farming showed that maximum knowledge was gained on vaccination in pigs (88.89%, Rank I) and minimum gain was in knowledge of gestation period of sow (54.44%, Rank XIII).
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Roth, Z., A. Arav, A. Bor, Y. Zeron, R. Braw-Tal, and D. Wolfenson. "Improvement of quality of oocytes collected in the autumn by enhanced removal of impaired follicles from previously heat-stressed cows." Reproduction, November 1, 2001, 737–44. http://dx.doi.org/10.1530/rep.0.1220737.
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The fertility of dairy cows decreases during the summer and remains low during the cooler autumn although the animals are no longer under heat stress. The aim of this study was to characterize a delayed effect of summer heat stress on oocyte quality in the autumn and to improve oocyte quality by enhanced removal of follicles damaged during the previous summer. Lactating cows (n = 16) were subjected to heat stress during the summer. In autumn, ovarian follicles (3-7 mm in diameter) were aspirated by an ultrasound-guided procedure during four consecutive oestrous cycles. Follicles were aspirated from control cows on day 4 and from treated cows on days 4, 7, 11 and 15 of each oestrous cycle. All cows received PGF(2alpha) and GnRH injections on days 19 and 21, respectively, and maintained cyclicity, as indicated by plasma progesterone concentrations. On day 4 of each cycle, the oocytes recovered were examined morphologically, matured and activated in vitro, and cultured for 8 days. In cycle 1 (early October) both groups showed low percentages of grade 1 oocytes, cleavage, four- and eight-cell embryos, morulae and parthenogenetic blastocysts. Subsequently, the number of grade 1 oocytes increased earlier (cycle 2) in treated than in control cows (cycle 3; P < 0.05). The cleavage rate in the control group remained relatively low throughout (32-58%), whereas in the treated group it increased from 40% (cycle 1) to 75% (cycles 3 and 4; P < 0.05). The number at each stage of embryo development increased slightly but remained low throughout in the control group, whereas in the treated group significant (P < 0.05) increases of all stages were observed in cycles 3 and 4. The results show a delayed effect of summer heat stress on oocyte quality and embryo development in the autumn. Enhanced removal of the impaired cohort of follicles led to earlier emergence of healthy follicles and high quality oocytes in the autumn.