月份与母猪产仔数及活仔率的关系

经１１７０５窝（胎）次母猪各月份产仔数和３７３３窝（胎）次母猪各月份活产仔数的数理分析，其产仔数，活产率受不同月气温，相对湿度等综合生态因子影响。特别是８月份是母猪全年繁殖力最差的月份，８月份配种，１１月份产仔数最少，平均窝产１３．６６头（全年平均窝产仔１４．７４头）；８月份的活仔率８７．０９％（全年平均活仔率９１．２４％）。     

高温对母猪产仔数的影响

根据杭州市种猪试验场2004、2005两年共2236胎长白母猪的正常分娩记录,就夏季高温造成的热应激对月平均产仔数、平均产活仔数和平均死仔数3个性状的影响进行分析。结果表明,从2月份起平均产仔数和平均产活仔数上升,6月份平均值达全年最高,7月份以后明显下降,下半年各月份的平均产仔数普遍低于上半年,8月份平均每窝产死仔数达1.08头,为全年最高值。可见热应激对母猪产仔数的影响持续半年之久,应重视母猪的防暑降温工作。     

气候因子对母猪繁殖性能的影响

通过249窝(胎)次母猪于2003￣2005年各月份产仔数、活仔数、断奶头重的统计分析,研究不同月份的气温、相对湿度等主要气候因子对母猪繁殖性能的影响。分析结果表明7月份平均气温最高,母猪繁殖力最低。从而提示在母猪生产中应该注意在高温季节加强饲养管理、改善环境条件,并合理     

影响大白种猪产仔数的因素分析

研究选取了北京某国家生猪核心育种场2016年6月-2018年6月2 470窝法系大白种猪,分析其繁殖性能,研究不同胎次、分娩月份对大白母猪的生产性能的影响。结果表明:5胎的窝均总仔数(12.77头)显著高于其他胎次,但是5胎的死胎、木乃伊胎数也显著高于其他胎次,3胎的窝均活仔数显著高于其他胎次。不同分娩月份大白母猪窝均总产仔数7月份最高(12.78头),1月份最低(11.14头),按季节来看,春夏季节显著高于秋冬季节。保持母猪合理胎次结构,夏秋季节做好防暑降温,是生产过程中保持猪群高繁性能的主要措施。     

胎次、产仔月份对长大二元母猪产仔性能的影响

为确定母猪最佳使用年限和产仔月份,同时为后备母猪的选种提供指导,研究统计分析了胎次、产仔月份对长大二元母猪产仔性能(总产仔数、产活仔数)的影响。结果表明,长大母猪1~6胎的总产仔数和产活仔数随胎次呈增加趋势,第6胎达到高峰,分别为11.88头和11.28头,极显著高于第1、2和8胎次(P0.01);3~6胎的产仔性能较好,7胎之后出现显著下降趋势。3月份的总产仔数、产活仔数最高,12月份最低,且3月份的总产仔数、产活仔数显著高于12月份(P0.05)。第2胎与第3胎、第3胎与第4~5胎、第4胎与第5胎的总产仔数呈极显著正相关(P0.01);第2胎与第4胎的总产仔数呈显著正相关(P0.05);第2胎与第3胎、第3胎与第4~5胎的产活仔数均呈现极显著正相关(P0.01);第2胎与第4胎、第4胎与第5胎的产活仔数均呈显著正相关(P0.05)。综上所述,该猪场长大二元母猪3~6胎的产仔性能较好,且以3月份的产仔性能为佳;第2胎产仔性能可作为后备母猪选留的重要依据。     

胎次对母猪产仔性能的影响

根据福建某种猪场的生产记录,应用SPSS软件对不同胎次的3588窝大白、长白和杜洛克纯种母猪的窝产仔数、窝产活仔数等进行统计分析。结果表明,在大白、长白和杜洛克纯种母猪中,胎次对窝产仔数和窝产活仔数的影响极显著(P<0.01),平均窝产仔数、窝产活仔数最高均为第6胎,分别为11.44和10.26头,最少均为第1胎,分别为9.49头和8.56头。     

胎次、产仔月份及纯繁/杂交对母猪产仔性能的影响

本研究统计分析了部分非遗传因素(胎次、产仔月份及纯繁/杂交)对长白、大白和杜洛克母猪产仔性能(总产仔数、产活仔数及初生窝重)的影响,旨在为后备母猪的选种提供指导。结果表明,2~5胎仔猪的初生窝重较重;其中2、3胎的初生窝重极显著高于头胎及6胎之后的仔猪初生窝重(P<0.01)。3月份总产仔数、产活仔数及初生窝重极显著高于其他月份(P<0.01),且11月份初生窝重显著低于其他月份(P<0.05)。长白纯繁母猪在产活仔数方面极显著优于大白纯繁母猪和长白×大白杂交母猪(P<0.01);在初生窝重方面,大白×长白杂交母猪的初生窝重极显著高于大白纯繁母猪和长白×大白杂交母猪(P<0.01)。第2胎与3~4胎、第3胎与第4胎的总产仔数呈极显著正相关(P<0.01)。综上所述,该猪场母猪3~6胎的产仔性能较好,且以1~4月份的产仔性能为佳;配种方式以长白纯繁和大白×长白杂交为宜;第2胎产仔性能可作为后备母猪选留的重要依据。     

深部输精技术对母猪产仔性能的影响研究

为了研究猪深部输精技术与常规输精技术对经产母猪产仔性能的影响,试验将56只大约克经产母猪平均分为2组,第Ⅰ组的经产母猪采用深部输精技术输精,第Ⅱ组的母猪采用常规输精技术输精。结果表明:第Ⅰ组母猪窝平均总产仔数11.56头,窝平均产活仔数10.16头,窝平均产健仔数8.84头;第Ⅱ组母猪窝平均总产仔数10.20头,窝平均产活仔数9.32头,窝平均产健仔数9.04头。深部输精比常规输精母猪窝平均总产仔数多1.36头(P0.05),窝平均产活仔数多0.84头(P0.05),但窝平均产健仔数少0.20头(P0.05)。说明深部输精技术可以提高母猪的窝平均总产仔数和窝平均产活仔数,对母猪的窝平均产健仔数没有显著影响。     

金华母猪与大约克母猪繁殖性能比较

根据某金华母猪保种场2010年7月至2014年3月1 655窝次金华母猪与577窝次的大约克母猪的生产记录,从怀孕天数、畸形率和死仔率、总产仔数和产活仔数、头均初生重、头均断奶重等5个方面比较不同胎次之间金华母猪与大约克母猪繁殖性能的差异。结果表明,随着胎次的增加,金华母猪和大约克母猪怀孕天数均有延长的趋势,大约克母猪较金华母猪波动小;畸形率与死仔率没有明显表现出与胎次的相关性;金华母猪的最高总产仔数出现在第8胎(13.04±2.88头)、大约克母猪的最高产仔数出现在第6胎(12.97±2.85头);金华母猪和大约克母猪所产仔猪头均初生重、头均断奶重均表现出与胎次的相关性。     

气候生态因子对母猪繁殖性能的影响

通过２４９窝次母猪各月份产仔数，活仔数，断奶头重的统计分析，研究不同月份的气温，相对湿度等主要气候生态因子对母猪繁殖性能的影响。分析结果表明７月份气温最高，也是母猪繁殖力最低的月份。     

Factors affecting piglet mortality in loose farrowing systems on commercial farms

Crating sows in farrowing systems greatly restricts their normal behaviour (e.g. movement, nest-building, leaving the nest site for defecation), which is usually justified by the assumption that piglet mortality is higher with loose-housed sows. Based on experiments showing that this is not the case, farrowing crates were banned in Switzerland in 1997, with a 10-year transitional period. Since then, many farms have introduced loose farrowing systems, enabling an analysis of risk factors for piglet mortality in crateless farrowing systems based on a large sample size. Data from a Swiss sow recording scheme (UFA2000) were analysed using generalised linear mixed-effects models with an underlying Poisson distribution. Average total piglet mortality for the years 2002 and 2003 on 99 farms (N = 12457 litters) with loose farrowing systems amounted to 1.36 liveborn piglets per litter. The number of crushed piglets was 0.64 piglets per litter, whereas the number of piglets that died for other reasons was 0.72 piglets per litter.Herd size, pen size, possibility of confinement of the sow, presence of piglet protection bars and year of data collection did not significantly influence total piglet losses, losses due to crushing and losses due to reasons other than crushing. With greater litter size at birth, significantly more losses occurred due to all reasons (total, crushed, others). Total piglet mortality and losses for reasons other than crushing were significantly higher in older sows. Losses were therefore mainly attributable to sow-related characteristics rather than to the design of the farrowing pen.     

长白种猪优化选配减少近交畸形的研究

以华南某1 500头规模种猪场2009年到2010年1 502窝长白猪分娩信息进行优化、选配减少近交畸形的研究,结果显示血缘选配优化时将近交系数控制在1%比3%效果明显,平均产活仔数从10.39头/窝提高到10.46头/窝(P＞0.05),畸形率从10.30%下降到4.79%(P＜0.01);对其中402窝出现畸形仔猪...     

Prevalence of congenital abnormalities in pigs

The prevalence of congenital defects in piglets in a large intensive piggery was determined by autopsy examination of piglets dying in the first week of life and from records kept by the farm staff. A total of 1908 piglets was examined at autopsy and 14,535 were born over the period of the survey. The prevalence of defects on this farm was estimated to be 2.9% of all piglets born, and at least one piglet with a congenital defect was found in 17.4% of litters. Of the piglets dying in the first week 9.5% had a defect and of these 8% had multiple anomalies. The mean litter size at birth for litters with a malformed piglet was 10.9 compared with 9.9 for litters without a malformed piglet. The total preweaning loss in litters containing a malformed pig was higher (29.8%) than that in litters without malformations (17.4%). The antepartum and parturient deaths in litters with a malformed piglet were 35% higher than normal litters. Parturient and anteparturient deaths amounted to 7.5% of piglets born and the total preweaning mortality was 19.9%. Sixty-six per cent of these mortalities occurred within the first week of life. The litter size at birth increased with parity as did the prevalence of litters containing malformed piglets. Neonatal loss was about 2 pigs per litter for all parities. Litter size at birth in litters containing a malformed pig was consistently higher by one pig per litter from all parities, but parturient (7.1%) and anteparturient (1.4%) deaths were also higher in these litters than in litters without malformations (5.1% and 1.2% respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Investigation on the Production Performance of gE Antibody Positive Sows in Pig Farms Infected with Wild Type Pseudorabies Virus

Pseudorabies (PR) is caused by the Pseudorabies virus (PRV). It is an acute and hot highly contagious disease infecting livestock and a wide range of wild animals. In order to investigate the relationship between latent infection of Pseudorabies virus and sow production performance,this study collected production parameters of first-parity sows with wild virus gE positive and negtive in a Pseudorabies positive stable intensive farm, including total litter size, healthy litter size, weak litter size, stillbirths, mummified fetus, litter weight, number of weaning live, number of weaning qualified and weaning weight. And compared the production performance of PRV gE antibody negative and positive sows in the same intensive pig farm. The study showed that each PRV gE antibody negative sow could produce 11.96 live piglets per parity. Additionally, PRV gE antibody negative sow could provide more alive, weaning and weaning qualified piglets per parity than infection sows, which were 0.63, 0.18 and 0.28, respectively. Although the average birth weight and average weaning weight of piglets produced by PRV gE antibody positive sows were higher than those produced by negative sows, the weaning qualified rate of antibody negative sows was higher than that of antibody positive sows, indicating that the weaning live piglets produced by antibody negative sows had higher uniformity. In summary, the production performance of PRV gE antibody positive sows was lower than that of the negative sows. Eradication of PR can bring higher profit to the pig farm. Pig farm should actively eradicate the PR.     

伪狂犬病病毒野毒感染猪场的gE抗体阳性头胎母猪生产成绩调查

伪狂犬病（Pseudorabies，PR）是由伪狂犬病病毒（Pseudorabies virus，PRV）感染多种野生动物及家畜引起的急性、热性的高度接触性传染病。为掌握PRV隐性感染对头胎母猪生产成绩的影响，本研究跟踪调查某一PRV野毒阳性稳定万头母猪场中野毒gE抗体阴性和阳性的头胎母猪总产仔数、健仔数、弱仔数、死胎数、木乃伊胎数、仔猪初生窝重以及断奶活仔数、断奶合格仔数、仔猪断奶重等不同生产成绩指标，探索相同饲养条件下伪狂犬病对头胎母猪各生产指标的影响。结果发现，每头PRV野毒gE抗体阴性头胎母猪每窝平均可产11.96头活仔猪，比gE抗体阳性母猪每胎次多产活仔0.63头，以及每胎次可多提供0.18头断奶活仔，每胎次多提供0.28头断奶合格仔。虽然PRV野毒gE抗体阳性母猪所产仔猪初生均重及断奶均重均高于gE抗体阴性母猪所产仔猪，但gE抗体阴性母猪所产仔猪断奶合格率高于gE抗体阳性母猪，表明其断奶活仔整齐度更高。综上，PRV野毒gE抗体阳性的头胎母猪生产成绩低于gE抗体阴性母猪，伪狂犬病的净化可为猪场带来更高的经济效益，表明伪狂犬病的净化至关重要。     

窝产活仔数和初生重与仔猪早期断奶重及成活率的相关性研究

为研究猪窝产活仔数与初生仔猪个体重对21日龄早期断奶仔猪个体重及成活率的相关性,特选择一大型规模猪场2～6胎母猪在1个月内所产的118窝计1350头仔猪作为试验对象,要求所有初生仔猪均由亲本母猪带仔哺乳,且按窝产活仔数不同（6～17头）分组测定仔猪初生个体重和21日龄早期断奶仔猪窝个体均重,并观察断奶成活率,同时对其相关性状作方差及回归分析。结果表明,不同组间初生仔猪窝个体均重和21日龄早期断奶仔猪窝个体均重及断奶成活率差异显著（P〈0．05）;窝产活仔数对初生仔猪窝个体均重和21日龄早期断奶仔猪窝个体均重及断奶成活率呈极显著的负相关（R=-0．802、-0．851、-0．698,P〈0．01）;初生仔猪窝个体均重对21日龄早期断奶仔猪窝个体均重及断奶成活率呈极显著的正相关（R=0．837、0．741,P〈0．01）。试验结果表明,窝产活仔数越多,初生仔猪个体就越小,早期断奶也越轻,成活率也低;初生仔猪个体越大,早期断奶就越重,成活率也越高。只要通过科学合理的方法,适当控制猪窝产活仔数并提高初生仔猪个体重,能有效提高早期断奶仔猪的生长速度,并可获得更好的经济效益。     

Variability of piglet birth weights: A systematic review and meta-analysis

The objective of the study was to evaluate the effects of litter size and supplementation of functional amino acids on the piglet birth weight variability through of a systematic review and meta-analysis. PubMed, ISI Web of Science, Science Direct, Scopus and SciELO are the main used databases and were searched in January 2019 by using the following keywords and their combinations: within-litter birth, weight variability, piglets, litter size, sow, amino acids, gestation, uniformity, CV and/or SD. Of the 64 pre-selected articles, only articles presenting the coefficients of variation and/or standard deviations according to the litter size and different levels of amino acid supplementation in the sow diets during gestation were selected. The average birth weights of total and live piglets were 43% lower in litters from sows with high prolificacy than those from sows with low prolificacy. The weight variability was affected by high prolificacy sows, with increases of 4.04% and 4.54% in the coefficients of variation of total and born alive piglets respectively (p = .074; p = .009). The standard deviation increased by 180 g in born alive piglets to high prolificacy sows. The coefficients of variation of total and live piglets born from high prolificacy sows showed an increase of 4.04% and 4.54% respectively (p = .07; p < .05). There was a tendency for reduced weight variability with amino acids supplementation when considering the standard deviation of total born (p = .072). However, reproductive performance was not significantly influenced (p > .05). In conclusion, the average litter weight and the number of piglets born influence weight variability. Amino acids supplementation may reduce the birth weight variability between piglets. However, this effect depends on the amino acid used, the levels of supplementation and on other factors not completely addressed in this study. Thus, more research is necessary to fully elucidate this topic.     

养殖规模对不同胎次母猪生产力的影响

为了比较不同规模猪场不同胎次母猪繁殖力的高低,本研究采集了106家不同规模猪场母猪的详细生产数据。按母猪实际存栏头数将猪场划分为<1 000、1 000~5 000、5 000~10 000和≥10 000头4个规模,分析不同规模猪场母猪1~9胎次活仔率、健仔率、畸形仔率、死胎率、木乃伊率、断奶活仔率及窝均产总仔数、窝均产活仔数、窝均产健仔数、窝均产死胎数、窝均断奶活仔数、窝均出生个体重、窝均出生窝重等相关繁殖指标的差异。结果表明,在胎次相同的情况下,猪场活仔率、健仔率和断奶活仔率随着饲养规模的扩大呈逐渐升高的趋势,而畸形仔率、死胎率和木乃伊率则呈相反趋势。母猪实际存栏头数≥10 000头的猪场1~7胎次（第4胎除外）的活仔率、健仔率和断奶活仔率均显著高于<1 000头猪场（P<0.05）,而与其他两个规模猪场差异不显著（P>0.05）。母猪存栏数<1 000头的猪场1、2、3、5、7胎次的死胎率显著高于其他3个规模猪场（P<0.05）。各个胎次的窝均产总仔数、产活仔数、产健仔数、畸形仔数、死胎数、木乃伊数、出生窝重都随着猪场饲养规模的扩大呈逐渐降低的趋势。<1 000头的猪场第2、3胎的母猪窝均产总仔数、产活仔数、产死胎数、窝均断奶活仔数、窝均出生窝重均显著高于其他3个规模猪场（P<0.05）。综上,养殖规模对不同胎次母猪生产力均产生较大影响,中大规模猪场（≥1 000头）的母猪繁殖力整体上低于小规模猪场（<1 000头）,但仔猪的体况和成活率要优于小规模猪场。     

Effects of Dextrose Plus Lactose in the Sows Diet on Subsequent Reproductive Performance and within Litter Birth Weight Variation

Effects of dextrose plus lactose in sow’s feed were tested on subsequent reproductive performance and within litter birth weight variation. During the last week of gestation and lactation, sows were either fed a commercial lactation diet (Control: C), or an isocaloric diet containing 25 g/kg dextrose plus 25 g/kg lactose (Treatment: T). In the subsequent weaning‐to‐oestrus interval (WEI), all sows received the same amount of a commercial feed, but T sows were supplemented with 150 g dextrose plus 150 g lactose per day. Weight and backfat changes were recorded as well as litter characteristics during the treatment period and the subsequent parity. No significant effect of treatment was found on the subsequent reproductive performance, including the number of piglets born, although the number of live born piglets was 0.51 larger (p = 0.31) and weight of the live born piglets was 84 g higher in the T sows (p = 0.07) than in the C sows. When sows were categorized in sows with 12 or less and more than 12 total born piglets in the previous litter, treatment of sows with dextrose plus lactose resulted for the group with 12 or less piglets in a strong increase in subsequent total born piglets (13.97), whereas in the untreated sows the subsequent litter size was 11.89. In the group with more than 12 total born piglets, no effect of treatment was found (interaction between previous litter size and treatment p = 0.03). The within litter variation in birth weight in the subsequent litter was numerically lower in the T sows. We concluded that the use of dextrose and lactose during lactation and WEI seems to enhance litter size in sows with low previous litter size and seems to have the potential to reduce the within litter variation in birth weight.     

The importance of a high feed intake during lactation of primiparous sows nursing large litters

The objective of this study was to investigate whether nursing a large number of piglets has negative effects on lactation and postweaning performance of primiparous sows and whether a greater lactation feed intake can prevent possible negative effects. Data were recorded on 268 ad libitum-fed sows of three genotypes (G1, G2, and G3) in an experiment where litter size was standardized to 8, 11, or 14 piglets during a 4-wk lactation. Compared to G1 and G2, G3 sows were heavier (P < 0.05) and leaner (P < 0.05) at weaning of their litters, lost similar amounts of BW and backfat, and their piglets grew faster (P < 0.05). Compared to G1, feed intake during lactation was higher for G3 sows (P < 0.05), and their risk of a prolonged weaning-to-estrus interval was lower (P < 0.01). Daily feed intake by sows was not affected by litter size in G1 and G3, but it was quadratically affected in G2 (P < 0.05), with a maximum at 10.8 piglets. Backfat loss of the sows increased linearly with litter size (P < 0.05) in G1 and G3. In G2, backfat loss increased only at litter sizes > 9.8 piglets (P < 0.01). Body weight loss of the sow and litter weight gain increased linearly with litter size (P < 0.001). Per extra piglet nursed, sows had a 23% (P < 0.01) higher probability of a prolonged weaning-to-estrus interval. A higher daily feed intake during lactation reduced tissue loss of the sow, increased litter weight gain (P < 0.01), and reduced the probability of a prolonged weaning-to-estrus interval (by 42% per extra kilogram; P < 0.01). Sows with a lower daily body weight loss during first lactation had a larger second litter (1.28 piglets/kg; P < 0.01), and their probability of a prolonged weaning-to-estrus interval was reduced by 61% per kilogram (P < 0.001). With increasing litter size, it is therefore recommended to reduce body weight loss during lactation by stimulating daily feed intake and by genetic selection.