影响新疆褐牛产奶量的相关因素分析

对1997年至2003年之间,乌鲁木齐种牛场462头新疆褐牛成年母牛的产犊间隔、产犊月份、胎次、犊牛初生重、犊牛性别等基础资料进行统计分析,研究上述因素与产奶量之间的关系.结果表明:产犊间隔、产犊月份、胎次对产奶量有极显著的影响;犊牛性别对产奶量无显著影响(P＞0.05).     

影响奶牛产犊间隔的因素分析

对江苏省徐州市某奶牛场约800头荷斯坦奶牛1998到1999年产犊间隔与产犊季节、产奶量、产犊胎次、犊牛初生重、犊牛性别等基础资料进行统计分析,结果表明产犊季节对产犊间隔有极显著的影响(P＜0.01);奶牛的产奶量对产犊间隔也有极显著的影响(P＜0.01);产犊胎次、犊牛初生重及犊牛性别对产犊间隔无显著影响(P＞0.05).     

影响奶牛产犊间隔因素的分析

经对徐州市某奶牛场约800头荷斯坦奶牛1998到1999年产犊间隔与产犊季节、产奶量、产犊胎次、犊牛初生重、犊牛性别等基础资料进行分析，结果表明：产犊季节对产犊间隔有极显著的影响（P＜0.01）；奶牛的产奶量对产犊间隔也有极显著的影响（P＜0.01）；产犊胎次、犊牛初生重及犊牛性别对产犊间隔无显著影响（P＞0.05）。     

非遗传因素对新疆褐牛产奶量的影响

为了探讨非遗传因素对新疆褐牛305d产奶量的影响,收集了新疆乌鲁木齐种牛场1985～2008年751头新疆褐牛的17962条月测定记录。采用最小二乘法分析了年度、季节、胎次、产犊间隔、初产月龄等5个非遗传因素对新疆褐牛产奶量的影响。结果:年度、胎次、产犊间隔对产奶量的影响极显著(P<0.01);季节和初产月龄对产奶量的影响不显著(P>0.05)。提示:稳定的饲养管理有利于提高奶牛的产奶量;合理的调整产犊季节对提高产奶量是有利的;适当增加2～5胎经产母牛的比例有利于提高群体产奶量;新疆褐牛产犊间隔在360～390d时产奶量最高;初产月龄应控制在24～27月龄。     

影响奶牛产犊间隔的因素分析

对江苏省徐州市某奶牛场约800头荷斯坦奶牛1998到1999年产犊间隔与产犊季节、产奶量、产犊胎次、犊牛初生重、犊牛性别等基础资料进行统计分析,结果表明:产犊季节对产犊间隔有极显著的影响(P<0.01);奶牛的产奶量对产犊间隔也有极显著的影响(P<0.01);产犊胎次、犊牛初生重及犊牛性别对产犊间隔无显著影响(P>0.05)。     

影响奶牛产犊间隔变化因素的分析

经对苏州市牛奶公司一牧场和无锡市马山牛奶公司约１０００头荷斯坦牛１９９１年到１９９５年产犊间隔与产犊季节、产奶量、胎次、犊牛初生重、犊牛性别的关系分析：产犊季节对产犊间隔有极显著的影响；产奶量对产犊间隔有极显著的影响；犊牛的初生重、性别对产犊间隔无显著影响；胎次对产犊间隔无显著影响，但存在极显著差异。牛群产犊间隔作为衡量繁殖力水平的主要指标之一，受人为管理和自然因素的双重影响，而人为管理因素起主导作用     

影响奶牛产犊间隔的因素分析

对西宁某奶牛场1993—2000年中国荷斯坦奶牛的配种、产犊记录和产奶量记录进行了统计分析，结果表明：胎次和产犊季节对奶牛产犊间隔没有显著影响(P＞0．05)；产奶量在6000kg以上奶牛的产犊间隔板显著长于4000kg以下的奶牛(P＜0．01)，显著长于产奶量在4000—4999kg奶牛的产犊间隔(P＜0．05)。     

影响新疆地区荷斯坦牛产犊间隔的因素分析

为了探讨各种因素对新疆地区荷斯坦牛产犊间隔的影响,本文采用SAS8.1软件对影响产犊间隔的因素进行最小二乘方差分析。不同场地对产犊间隔的影响不显著(P0.05);不同胎次对产犊间隔有显著的影响(P0.05),产犊间隔随胎次增加有延长的趋势;不同产犊季节对产犊间隔有极显著的影响(P0.01),冬春季节的产犊间隔明显高于夏秋季节;不同产奶量对产犊间隔有极显著的影响(P0.01),产犊间隔随着产奶量的增加而延长。产犊季节和产奶量是影响产犊间隔的主要因素。     

影响荷斯坦牛妊娠期长短的因素分析

妊娠期长短是影响奶牛繁殖性能以及牧场经济效益的重要性状之一。为探索影响荷斯坦奶牛妊娠期长短的因素,本文收集了江苏省某奶牛场2016年1月至2017年4月正常健康产犊的荷斯坦牛产犊记录共7 164条。用一般线性模型对犊牛性别、胎次、产犊季节、是否产双犊、犊牛初生重、产犊时母牛体况评分和是否使用性控精液对妊娠期长短的影响进行分析。结果表明:胎次、犊牛性别、产犊季节、产犊时母牛体况评分、犊牛初生重以及是否使用性控精液极显著影响妊娠期长短(P0.01),2胎母牛的妊娠天数显著高于1胎和3胎;产公犊牛母牛的妊娠期显著高于产母犊的奶牛;春季产犊的奶牛妊娠期最长,冬季则最短;产犊时母牛体况评分越高,其妊娠期越短;犊牛初生重越大,则母牛的妊娠期越长;采用性控精液的奶牛妊娠期显著短于非性控精液配种的奶牛;是否产双犊对妊娠期长短无显著性影响(P0.05)。该结果为控制荷斯坦奶牛妊娠期长短,提高其繁殖性能和经济效益等方面提供了科学依据。     

非遗传因素对荷斯坦牛305天产奶量的影响

为了探讨非遗传因素对荷斯坦牛305 d产奶量的影响,笔者收集了新疆呼图壁种牛场牧一场1996-2005年度荷斯坦奶牛生产性能记录资料,通过采用SAS 8.1软件的最小二乘方差分析,分析了年度、季节、产犊间隔和胎次对荷斯坦牛305 d产奶量的影响。结果表明,年度、产犊间隔和胎次对产奶量的影响差异极显著（P<0.01）;季节对产奶量的影响差异不显著（P>0.05）。本研究结果为进一步对遗传参数估计提供效应值划分的依据。     

中国荷斯坦牛干奶期长度的群体特征及其与生产性能的关系

本研究旨在探究北京地区中国荷斯坦牛干奶期长度（DPL）的变化规律及其变异对奶牛各项生产性能的影响，包括产奶性能、繁殖性能、初乳品质和乳房健康。收集了北京地区34个牧场出生于2009—2018年136 231头中国荷斯坦牛的干奶日期、生产性能记录、繁殖性能记录等。通过整理试验牛群的干奶记录，揭示了北京地区中国荷斯坦牛1胎和2胎DPL的群体规律，利用固定模型分析了胎次、产犊季节、场-产犊年和初产月龄对DPL的影响；此外，利用固定模型分析了DPL的变异对日产奶量、乳脂率、乳蛋白率、首末次配种间隔（interval from first to last insemination，IFL）、产犊至首次配种间隔（interval from calving to first insemination，ICF）和初乳品质的影响，利用Logistic回归过程分析了DPL的变异对首次配种受胎率（conception rate of first insemination，CR）、首次配种56 d不返情率（56-days non-return rate of first insemination，NRR56）、难产率和乳房健康的影响。研究结果显示，北京地区中国荷斯坦牛DPL平均为58.81 d，胎次、产犊季节、场-产犊年和初产月龄均对DPL有显著影响（P<0.05）。DPL的变异对日产奶量、乳蛋白率、ICF、CR、NRR56、难产率和乳房健康有显著影响（P<0.05）。干奶期短的奶牛测定日平均乳蛋白率、CR和NRR56更高；DPL适中的奶牛测定日平均产奶量更高、乳房健康水平更好、ICF更短、难产率更低。本研究在国内利用大规模牛群数据揭示了中国荷斯坦牛DPL的群体规律，可为中国规模化奶牛场提升管理水平提供参考。     

Post-partum Reproductive Performance of Sanga Cattle in Smallholder Peri-urban Dairy Herds in the Accra Plains of Ghana

The reproductive performance of 76 Sanga cows was studied from February 1995 to July 1996 in smallholder peri-urban dairy systems in the coastal savanna zone of the Accra plains of Ghana. The interval from calving to resumption of cyclic ovarian activity was 101±7 days; that from calving to conception was 152±4 days; gestation length was 292±16 days; and the calving interval was 444±16 days. The effects of location, season of calving, parity, body condition score and sex of calf were studied. Calving to cycling interval was significantly shorter in the dry season than in the wet season, and decreased significantly with increasing body condition score. Calving to conception interval was affected only by location. Gestation length was not affected by any of the variables studied. Calving interval was affected by location, season of calving, parity and body condition score. It is concluded that long post-partum anoestrus leads to prolonged calving intervals and poor reproductive performance. Feed supplementation to improve the nutritional status and body condition score of cows and early weaning of calves could be introduced to enhance reproductive performance.     

产犊季节对北京地区荷斯坦奶牛Wood泌乳曲线参数的影响探究

本研究通过对北京地区1998-2016年28个场区的奶牛生产性能测定（DHI）数据进行分析,旨在比较不同产犊季节对1~3胎奶牛泌乳曲线相关参数的影响。使用Wood模型对1~3胎不同产犊季节群体和个体泌乳曲线进行拟合,并获得相应胎次下不同产犊季节奶牛泌乳曲线参数a、b、c （分别代表泌乳潜力、产奶量上升至顶峰速率、产奶量达到顶峰后下降速率）、泌乳曲线二级参数Per、PY （分别代表泌乳持续力、泌乳峰值）及305 d产奶量（305MY）。群体和个体水平的曲线拟合采用SAS 9.2中NLIN模块进行,采用混合线性模型分析不同产犊季节对各胎次奶牛泌乳曲线参数的影响。结果显示：产犊季节对Wood泌乳曲线的泌乳潜力、达到峰值的上升速率、达到峰值后的下降速率、泌乳峰值及305MY均有显著影响（P<0.05）,对于泌乳持续力没有显著影响（P>0.05）。夏季产犊牛泌乳曲线整体低于其他产犊季节,且胎次越高趋势越明显,1胎牛受到的影响较小;从胎次上分析,头胎牛泌乳持续力极显著高于经产牛（P<0.01）;头胎牛夏季产犊305MY比其他产犊季节的低274.33~490.17 kg,经产牛夏季产犊305MY比其他产犊季节的低440.76~930.68 kg。以上结果提示,北京地区牛场应注重做好经产牛和头胎牛的防暑降温工作,注意调整配种时间,避免夏季产犊牛过多,造成损失。     

The effect of non-genetic factors on the reproductive performance of Sanga and Friesian × Sanga crossbred dairy cattle breeds kept under hot and humid environment

A study was conducted to assess the effect of non-genetic factors on the reproductive performance of Sanga and Friesian?×?Sanga crossbred dairy cattle kept at Amrahia Dairy Farm, Ghana. Records on 66 crossbred Friesian?×?Sanga and 105 purebred Sanga cattle from 2005 to 2012 were used. The effect of sex of calf (male or female), season of calving (major, minor and dry), year of calving (2005–2012) and parity (first to third) on birthweight, calving interval and age at first calving were determined. The data were analyzed using the general linear model procedures of GenStat (Discovery Edition). The effect of parity of dam, year of calving, season of calving and sex of calf were considered as fixed effects for evaluating the different reproductive traits. Data on calving and conception rates over the period were 74.3 and 76.1 %, respectively. The overall mean values for birthweight, age at first calving and calving interval obtained were 23.9?±?1.5 and 22.8?±?1.4 kg, 38.8?±?2.5 and 40.2?±?2.4 months and 390.8?±?12.5 and 413.6?±?12.1 days for the crossbred and Sanga, respectively. It was observed that all the major determinants of reproductive performance studied apart from birthweight were significantly influenced by year of birth, parity, season of calving and sex.     

影响江苏某牛场荷斯坦牛日产奶量和乳成分因素分析

[目的]探究江苏某牛场荷斯坦牛日产奶量和乳成分的影响因素。[方法]试验采集了该规模化牛场2018—2020年139 703条测定数据,并利用多因素方差模型对其进行系统的分析。[结果]不同胎次、测定季节、产犊季节、泌乳月对荷斯坦牛日产奶量、乳脂率、乳蛋白率、体细胞评分、乳尿素氮均有极显著影响(P<0.01)。产奶量与乳脂率、乳蛋白率、体细胞评分均存在极显著负相关。[结论]综上结果,在生产中,应结合胎次、季节、产犊时间、泌乳等多种因素,灵活调整牛群结构、生产规划和饲养管理,以实现提高产奶量和乳品质的目的。     

影响荷斯坦牛产奶量差的因素分析

产奶量差是奶牛个体同一胎次前后2个泌乳月产奶量的差值,可准确反映产奶量变化情况。为探究影响荷斯坦牛产奶量差的因素,本研究收集整理了江苏省某大型奶牛场2015-2018年55 193头次荷斯坦牛生产性能测定记录,并利用最小二乘法分析胎次、测定年度、产犊季节、泌乳月4个因素对荷斯坦牛产奶量差的影响。结果显示:胎次、测定年度、产犊季节、泌乳月及其交互作用对产奶量和产奶量差均有极显著影响(P<0.01)。其中,不同胎次、测定年度和产犊季节的荷斯坦牛总产奶量在第2个泌乳月增加最快,产奶量差为8.79kg;头胎第6泌乳月、二胎第7泌乳月和三胎及以上第6泌乳月产奶量下降最大,产奶量差分别为-2.86kg、-4.59kg和-6.13kg;2015-2018年4个测定年度中,第10、第6、第7、第6泌乳月产奶量降低最大,产奶量差分别为-2.26kg、-4.98kg、-4.44kg和-3.56kg;春季产犊的荷斯坦牛第4泌乳月、夏季产犊的荷斯坦牛第12泌乳月、秋季产犊的荷斯坦牛第9泌乳月、冬季产犊的荷斯坦牛第6或第7泌乳月产奶量下降最大,产奶量差分别是-4.34kg、-4.71kg、-5.36kg和-5.40kg。此外,产奶量差与泌乳持续力呈极显著正相关(P<0.01),与产犊间隔呈显著正相关(P<0.05),与泌乳天数、高峰奶、乳脂率、蛋白率、305d产奶量呈极显著负相关(P<0.01)。因此,产奶量差作为衡量奶牛产奶量变化的指标之一,可为牧场进行科学饲养管理提供参考。     

Effect of Parity,Season and FSH Treatment on the Calving Interval of Ayrshire Cows in the Tropics

A total of 607 calving intervals on 99 Ayrshire cows with parities from 1 to 10 and belonging to one dairy herd at Iringa in the southern highlands of Tanzania were analysed to study the effect of parity and season or month of calving on the subsequent calving interval. In addition, 22 calving intervals incorporating a superovulatory cycle were compared with those of 52 controls that had calved around the same period.The average (mean±SEM) age at first calving was 985±16 days. The effect of parity on calving interval was highly significant (p<0.001). Cows that calved in December, at the beginning of the rainy season, exhibited the shortest calving interval (404±13), while those that calved in September/October, in the dry season, exhibited the longest average calving interval (466±20 days), although this difference was not significant. Prior treatment with follicle-stimulating hormone to induce superovulation, significantly lengthened the average calving interval (579±28 vs 457±15 days; p<0.001).It was concluded that both parity and FSH treatment affected the calving interval. However, season (rainy vs dry) or month of calving did not influence this interval.     

Relationships between N'Dama cow body condition score and production performance under an extensive range management system in Southern Senegal: calf weight gain, milk production, probability of pregnancy, and juvenile mortality

This study aimed to determine the relationships between N'Dama cows body condition score (BCS) and (i) calf growth and the milk collected; and (ii) the probabilities of pregnancy and juvenile mortality. Animals from 10 herds ranging from 20 to 210 animals in herd size were followed monthly in an extensive range management system in Southern Senegal between 1993 and 1998. For daily weight gains and milk collected, linear mixed-effects models were fitted between calving and 6 months postpartum. Cow lactation was included as random effect, with an unstructured variance-covariance matrix. Calving season, parity, herd size, and calving BCS were the fixed effects. For the probabilities of pregnancy and juvenile mortality, survival models for grouped data were fitted on a monthly scale. The model selection was based on the Akaike information criteria. In large herds, calving BCS had little effect on milk production. In small herds, calves born to cows scoring ≥2.5 points at calving grew quicker and their dam were more milked. The relative difference in milk production between thin and fat cows averaged 23%. The relative gain was higher in the cool dry season than in the other seasons, and for primiparous than for multiparous cows. Except during the hot dry season, the probability of pregnancy was twice as high for cows scoring ≥2.5 points the two previous months than for other cows. The BCS had no effect on calf survival until 1 year of age in large herds. In small herds, calves born to thin cows at calving showed a survival at 1 year more than five points lower than calves born to fatter cows. The threshold of 2.5 points on a five-point scale is pertinent to describe the production performance of N'Dama cows in such a breeding context.     

Effects of calving induction on subsequent milk yield and reproductive performance of cows from seasonally mated New Zealand dairy herds

AIM: To identify some production and reproductive effects of calving induction in seasonally calving herds. METHODS: Forty seasonally calving herds entered on the DairyMAN management information system and whose milk yield and reproductive data were recorded, including pregnancy diagnosis results, were included in the study. Cows with an induced parturition were compared with normally calving contemporaries that had the same lactation number and calved at the same time. RESULTS: Milk yield was 1.2 +/- 0.2 litres/cow/day less over the entire lactation for cows induced to calve, with the greatest difference being 2.5 +/- 0.4 litres/cow/day measured in early lactation. The effects on milkfat and protein yield were similar, with 0.04 +/- 0.01 kg/cow/day less milkfat (p < 0.0001) and 0.03 +/- 0.01 kg/cow/day less protein (p < 0.0001). A higher milkfat percentage (+ 0.09 +/- 0.04 %) (p < 0.0001) and protein percentage (+ 0.10 +/- 0.02%) (p < 0.0001) for cows that were induced to calve reduced the effect of a lower milk yield on milkfat and protein production. The first service conception rate for cows induced to calve was 54.4 +/- 3.3%, which was significantly less (p = 0.03) than for cows that calved normally (59.5 +/- 3.3%). Cows induced to calve had a pregnancy rate at the end of mating of 91.4 +/- 2.1%, which was also significantly less (p <0.0001) than for cows that calved normally (93.6 +/- 1.7%). The 21-day submission rates were not significantly different between groups. CONCLUSIONS: This study indicates that, under some New Zealand management conditions, the induction of calving is associated with reduced daily milk yield and inferior reproductive performance.