Steverink D W, Soede N M, Groenland G J, van Schie F W, Noordhuizen J P, Kemp B
Animal Health and Reproduction Group, Wageningen Institute of Animal Sciences, Wageningen Agricultural University, The Netherlands.
J Anim Sci. 1999 Apr;77(4):801-9. doi: 10.2527/1999.774801x.
This research was conducted to determine factors that influence duration of estrus, AI strategy, and reproduction results between and within commercial swine farms that use AI. Data from 15,186 sows and gilts on 55 farms for a period of 6.1+/-4.2 mo per farm were used in this study. The average duration of estrus was 48.4+/-1.0 h, ranging from 31 to 64 h, and was consistent from month to month within a farm (repeatability of 86%). Differences in duration of estrus between farms accounted for 23% of the total variation in duration of estrus. On most farms (n = 45), gilts showed a shorter (P < .05) duration of estrus than sows (40.8+/-1.1 h vs 48.5+/-1.0 h). The duration of first estrus after weaning was longer (P < .0001) compared with that of repeat-breeder sows (50.2+/-1.0 h vs 46.8+/-1.0 h). Duration of estrus decreased (P < .05) when interval from weaning to estrus increased from 4 to 6 d (56.0 +/- 1.2 h vs 45.8 +/-1.2 h). The regression of interval from onset to estrus to first AI and interval from weaning to estrus varied between farms and ranged from -7.4 to +1.3 h/d; four farms had a positive relationship. Farrowing rate decreased (P < .05) from 89.7+/-2.7% to 78.2+/-5.74 when the interval from weaning to estrus increased from 4 to 10 d. The litter size decreased (P < .05) from 11.7 to 10.6 pigs when the interval from weaning to estrus increased from 4 to 7 d. Compared with a single AI, double AI in sows and gilts resulted in a 4.3 and 7.0% higher (P < .05) farrowing rate, respectively. When the first AI was performed after expected ovulation, reproduction results were lower than when AI was performed before or at expected ovulation in sows. Duration of estrus was not related to farrowing rate or litter size in individual pigs. Number of inseminations per estrus, time of AI, and duration of estrus were correlated, which made it difficult to assess which of these factors was primarily related to the farrowing rate or litter size. Knowledge of average duration of estrus on farms and of factors that influence the duration of estrus on commercial farms can help to improve the efficiency of the AI strategy specific for each farm.
本研究旨在确定影响使用人工授精（AI）的商业猪场之间及场内发情持续时间、AI策略和繁殖结果的因素。本研究使用了来自55个猪场的15186头母猪和后备母猪的数据，每个猪场为期6.1±4.2个月。发情的平均持续时间为48.4±1.0小时，范围为31至64小时，且在一个场内各月之间保持一致（重复性为86%）。猪场之间发情持续时间的差异占发情持续时间总变异的23%。在大多数猪场（n = 45），后备母猪的发情持续时间比母猪短（P < 0.05）（40.8±1.1小时对48.5±1.0小时）。断奶后首次发情的持续时间比经产母猪长（P < 0.0001）（50.2±1.0小时对46.8±1.0小时）。当断奶至发情间隔从4天增加到6天时，发情持续时间减少（P < 0.05）（56.0±1.2小时对45.8±1.2小时）。从发情开始到首次人工授精的间隔以及从断奶到发情的间隔在不同猪场之间的回归范围为-7.4至+1.3小时/天；四个猪场呈正相关。当断奶至发情间隔从4天增加到10天时，产仔率从89.7±2.7%降至78.2±5.74%（P < 0.05）。当断奶至发情间隔从4天增加到7天时，窝产仔数从11.7头降至10.6头（P < 0.05）。与单次人工授精相比，对母猪和后备母猪进行两次人工授精分别使产仔率提高了4.3%和7.0%（P < 0.05）。当首次人工授精在预期排卵后进行时，母猪的繁殖结果低于在预期排卵前或预期排卵时进行人工授精的情况。个体猪的发情持续时间与产仔率或窝产仔数无关。每次发情的输精次数/人工授精时间和发情持续时间相关，这使得难以评估这些因素中哪一个主要与产仔率或窝产仔数相关。了解猪场发情的平均持续时间以及影响商业猪场发情持续时间的因素有助于提高每个猪场特定的人工授精策略的效率。
