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Roseworthy, Australia

van Wettere W.H.E.J.,University of Adelaide | Herde P.,Pig and Poultry Production Institute | Hughes P.E.,Pig and Poultry Production Institute
Animal Reproduction Science | Year: 2012

Conducted during the Australian summer, this experiment evaluated the reproductive performance of sows receiving a diet supplemented with betaine, a potent organic osmolyte and methyl donor. Large White/Landrace/Duroc sows (n= 450) ranging in parity from 1 to 7 (parity 2.9 ± 0.10, mean ± SEM), and mated between the 11th of January and 11th February were used. The treatments compared the effects of two gestation diets (standard (Stand) compared to betaine (Bet) supplemented) and two parity groups (parities one and two (P1/2) versus parity three and greater (P3+) on pregnancy outcomes and litter size. The betaine diet was fed from d 3 ± 1 post-mating until farrowing, with betaine content of the diet altered during gestation to ensure a daily intake of 7.6-9.0. g/sow. Liveweight (LW) and LW gain were unaffected by gestation diet; however, on d 1 of lactation P2 backfat (P2) tended (P= 0.07) to be greater for standard compared to betaine fed sows (22.5 ± 0.42 compared to 21.5 ± 0.42. mm). P2, LW and LW gain were greater (P< 0.05) for P3+ compared to P1/2 sows. Sow farrowing rate (0.79) was unaffected by gestation diet. Total litter size was greater (P< 0.05) for Bet3+ (13.6 ± 0.35) sows compared to Stand3+ (12.1 ± 0.34), BetP1/2 (12.1 ± 0.36) and StandP1/2 (12.3 ± 0.38) sows. In conclusion, this is the first study to demonstrate that gestational betaine supplementation during summer increased litter size of sows with greater numbers of parities. © 2012.

Van Wettere W.H.E.J.,University of Adelaide | Smits R.J.,Rivalea Australia Pty. Ltd. | Hughes P.E.,Pig and Poultry Production Institute
Animal Production Science | Year: 2013

Maternal intake of B-vitamin and methyl donors can affect sow prolificacy. A total of 1079 Large White/Landrace sows (parities 2-9 at mating) were used in a 2 by 2 by 2 factorial design to determine the effects of two levels of betaine supplementation (0 versus 3 g added betaine/kg feed), two levels of folic acid plus vitamin B12 supplementation (0 versus 20 mg/kg folic acid plus 150 g/kg vitamin B12) during gestation, and two parity groups (parity 2 and 3 versus parity 4 and greater) on litter size and pregnancy outcomes. The number of sows returning to oestrus post-insemination, as well as the number of early (Day 30) and late (Day 30) pregnancy losses were recorded. At farrowing, the total number of piglets born, the number of piglets born alive and dead, as well as the number of mummified fetuses were recorded. Pre-prandial blood samples were collected from a subset of 20 sows/treatment on Days 3, 30 and 107 of gestation to analyse homocysteine. The incidence of early pregnancy loss was reduced (P 0.001) by folic acid plus vitamin B12 supplementation (0.03 versus 0.07). There was a significant interaction between parity at mating (parities 2 and 3 versus parity 4 and greater) and the addition of betaine or folic acid plus vitamin B12 to the gestation diet on litter size. Litter size was higher (0.5 piglets; P 0.05) for betaine supplemented, compared with unsupplemented, parity 4 plus sows. Folic acid plus vitamin B12-supplemented parity 2 and 3 sows gave birth to more (P 0.05) piglets than all other treatment groups. Folic acid plus vitamin B12 supplementation decreased (P 0.001) plasma homocysteine concentration by 2.2 and 2.8 M, respectively, on Days 3 and 107 of gestation. However, betaine supplementation decreased (P 0.05) homocysteine on Day 3 only. Overall, folic acid plus vitamin B12 supplementation decreased incidences of early pregnancy failure and increased litter size in early parity sows, while betaine increased litter size in older parity sows.

van Wettere W.H.E.J.,University of Adelaide | Mitchell M.,University of Adelaide | Revell D.K.,University of Adelaide | Revell D.K.,Center for Environment and Life science | Hughes P.E.,Pig and Poultry Production Institute
Theriogenology | Year: 2011

The objective was to investigate the effects of moderate restriction of pre- and peri-pubertal liveweight gain on ovarian development and oocyte meiotic competence. At 70 d of age, and 27.7 ± 0.4 kg liveweight (LW), 64 Large White/Landrace crossbred gilts were allocated to two treatment groups (n = 32 gilts/treatment); one group was fed to attain a LW of 70 kg at 161 d of age (LIGHT), while the other group was fed to reach 100 kg LW (HEAVY). At 161 d of age, half of the gilts in each group (n = 16) were fed to gain LW at 0.5 kg/d (LOW), while the remaining half (n = 16) were fed to gain LW at 1.0 kg/d (HIGH) between 161 and 175 d of age, at which point they were killed and ovaries collected. For each gilt, surface antral follicles were counted and aspirated according to three size categories: 1-2.9 mm (small); 3-6 mm (medium); and > 6 mm (large). Follicles were pooled for each size class and treatment. Cumulus-oocyte-complexes (COC) recovered from small and medium follicles were matured in vitro (IVM) for 44 to 46 h, and meiotic maturation assessed. There was an effect of treatment (LIGHT versus HEAVY) on the number of medium sized follicles: 25.1 ± 2.59 versus 34.3 ± 2.60 (P < 0.05). The ovaries of LOW gilts had more small follicles and fewer medium follicles compared to those of HIGH gilts: 92.8 ± 8.35 versus 59.8 ± 5.24, and 25.1 ± 2.59 versus 32.5 ± 2.86 (P < 0.05). Target LW at 161 d did not affect meiotic progression of oocytes. However, LOW compared to HIGH LW gain between 161 and 175 d resulted in fewer oocytes reaching MII (0.40 versus 0.54; P < 0.05). In conclusion, moderately restricting feed intake impaired follicle growth beyond 3 mm and reduced oocyte meiotic competence. Further, although a carry-over effect of long-term feed restriction on follicle growth was evident, acute changes in feed intake during the 14 d prior to ovary collection had the greatest effect on oocyte nuclear maturation in vitro. © 2011 Elsevier Inc.

Kennaway D.J.,University of Adelaide | Hughes P.E.,Pig and Poultry Production Institute | van Wettere W.H.E.J.,University of Adelaide
Animal Reproduction Science | Year: 2015

Puberty in pigs is often delayed during late summer and autumn, with long daylength the most likely cause. We hypothesised (1) that gilts born around the shortest day would have a later release from the negative feedback actions of estradiol than gilts born around the spring equinox and (2) melatonin treatment would result in an earlier release from estradiol negative feedback and advance the onset of puberty in gilts born around the spring equinox. We first determined the optimal number of estradiol implants required to monitor the release from estradiol negative feedback in ovariectomised gilts. Secondly we determined whether melatonin implants altered negative feedback in 4 cohorts of ovariectomised gilts born between the winter solstice and spring equinox, and in the following year whether melatonin altered the time of the first ovulation in 5 cohorts of intact gilts born between the winter solstice and spring equinox. Plasma LH and FSH increased between 126 and 210. d of age (P< 0.001) in each cohort (season), but there was no effect of cohort, melatonin treatment or interactions (P> 0.05). Age at first detection of elevated plasma progesterone in untreated, intact gilts decreased across the 4 cohorts (P< 0.05). Melatonin treatment of intact gilts failed to advance the age of puberty irrespective of their season of birth (P> 0.05). In conclusion, while we confirmed that estradiol sensitivity is decreased as gilts age, we failed to demonstrate any effects of season or melatonin on estradiol feedback or melatonin on puberty. © 2015 Elsevier B.V.

Terry R.,University of Adelaide | Kind K.L.,University of Adelaide | Weaver A.C.,University of Adelaide | Hughes P.E.,Pig and Poultry Production Institute | van Wettere W.H.E.J.,University of Adelaide
Livestock Science | Year: 2015

This study evaluated the effect of full physical boar exposure at different stages of lactation on the incidence of lactation oestrus in both primiparous and multiparous sows. A total of 38 primiparous (PP) and 80 multiparous (MP) sows (parity 2-6; 3.1±0.18) of Large White×Landrace genetics were individually housed in conventional farrowing crates from 1 week before expected farrowing until weaning on day 27.5±0.08 post-parturition. The experiment was designed as a 2×4 factorial, incorporating the two sow parity groups, and boar exposure commencing on one of four days post-farrowing (days 10, 14 and 18 of lactation and weaning). The eight treatments were as follows: PP sows, boar exposure starting on day 10 (n=10), day 14 (n=9), day 18 (n=9) and weaning (n=10); MP sows boar exposure starting on day 10 (n=20), day 14 (n=20), day 18 (n=20) and weaning (n=20). According to treatment, sows were taken daily to a detection mating area where they received 20. min of boar exposure and were artificially inseminated at the first observed oestrus. A significant effect of replicate on the incidence of lactation oestrus was found; specifically, the proportion of sows expressing a lactation oestrus was lower in replicate 4 (autumn) than in the other three replicates (winter/spring; 0.15 versus 0.51; P<0.01). In replicate 1-3, a significantly higher proportion of MP compared to PP sows experienced a lactation oestrus (0.63 versus 0.36; P<0.05). Lactation oestrus expression was lower for MP sows starting boar exposure on day 14 compared to day 18 post-partum (0.38 versus 0.79, respectively; P<0.05), but was similar for days 10 and 18 of lactation (0.69 versus 0.79, respectively; P<0.05). Commencing boar exposure on day 18 as opposed to day 10 post-partum significantly reduced the interval from boar exposure to lactation oestrus expression (4.5±0.8 versus 7.7±0.8 days, respectively; P<0.05). Therefore, full physical boar exposure stimulated a high proportion of lactation oestrus in multiparous sows; however, season impacted this expression, and first parity sows are less likely than multiparous sows to express a lactation oestrus. In conclusion, there appears to be no benefit in commencing boar exposure before day 18 post-partum to stimulate a lactation oestrus. © 2015 Elsevier B.V.

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