Am-In Nutthee, Kirkwood Roy N
Department of Obstetrics, Gynaecology and Reproduction, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand (Am-in); School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy 5371, Australia (Kirkwood).
Can J Vet Res. 2019 Jul;83(3):228-230.
The objective of this study was to determine whether feeding altrenogest (AT) to primiparous sows with smaller litters during the last week of lactation would improve their fertility. At day 21 of a 28-day lactation, 40 primiparous sows nursing ≤ 8 pigs were assigned equally to 2 groups, either to be fed 20 mg per day of AT for the last 7 days of lactation or to serve as untreated controls. To detect estrus, sows had daily fence-line contact with a mature boar. At estrus detection, sows were subject to an ovarian examination with transrectal ultrasound and preovulatory follicles (≥ 0.6 mm) were counted. Sows were artificially inseminated at estrus detection and again 24 hours later. Compared to controls, the AT-fed sows had longer weaning-to-estrus intervals (WEIs; < 0.001), more pre-ovulatory follicles ( < 0.001), and larger subsequent litter sizes ( = 0.03). Farrowing rates were unaffected by treatment. These data suggest that sows nursing small litters are more likely to initiate a follicular phase during lactation, but that feeding AT prevents this and increases ovulation rate and subsequent litter size.
本研究的目的是确定在泌乳期最后一周给产仔数较少的初产母猪饲喂烯丙孕素（AT）是否会提高其繁殖力。在28天泌乳期的第21天，将40头哺乳≤8头仔猪的初产母猪平均分为2组，一组在泌乳期的最后7天每天饲喂20毫克AT，另一组作为未处理的对照。为了检测发情情况，母猪每天与一头成年公猪在围栏边接触。在检测到发情时，用经直肠超声对母猪进行卵巢检查，并对排卵前卵泡（≥0.6毫米）进行计数。母猪在检测到发情时进行人工授精，并在24小时后再次授精。与对照组相比，饲喂AT的母猪断奶至发情间隔时间更长（WEIs；<0.001），排卵前卵泡更多（<0.001），随后的产仔数更大（=0.03）。产仔率不受处理的影响。这些数据表明，哺乳仔猪数少的母猪在泌乳期更有可能进入卵泡期，但饲喂AT可防止这种情况发生，并提高排卵率和随后的产仔数。
