Evaluation of Oestrous Detection in Dairy Cattle Comparing an Automated Activity Monitoring System to Visual Observation

The objective of the study was to evaluate an automated activity monitoring (AAM) system for oestrous detection in dairy cows. Specifically, we set out to determine the oestrous detection efficiency and accuracy of the AAM system and to compare reproductive performance of cows detected either by AAM, by visual observation (VO) or by at least 1 of the 2 methods (EOM). A total of 1004 potential cow‐periods from 348 cows were analysed. Oestrous detection rates (EDR) were calculated for 21 day (VWP+21), 42 day (VWP+42), and 63 day (VWP+63) after voluntary waiting period (VWP). Oestrous detection rate did not differ between AAM (42.1%) and VO (37.3%) during VWP+21 (p > 0.05) but was significantly higher in EOM (56.3%, p < 0.05). Oestrous detection by AAM achieved an efficiency (number of correctly detected oestruses/total number of cow‐periods*100) of 35.6% and an accuracy (number of correctly detected oestruses/(number of true+ false oestruses)*100) of 83.8%. Visual observation resulted in an efficiency of 34.3% and accuracy of 75.1%. Pregnancy rate at 200 DIM was higher in AAM (66.8%) and EOM (68.8%) than in VO (57.1%, p < 0.05). Cows detected by AAM (p < 0.05) showed a 1.37 times greater risk to conceive than cows detected by VO as the reference (p < 0.05). The results show that an automated activity monitoring system can support oestrous detection in dairy cattle. The exclusive use of such a system, however, cannot be recommended.     

Aquagrams of Raw Milk for Oestrus Detection in Dairy Cows

The purpose of this research was to develop rapid and cost‐effective method for oestrus detection in dairy cows by means of near infrared spectroscopy and aquaphotomics, using raw milk from individual cows. We found that aquaphotomics approach showed consistent specific water spectral pattern of milk at the oestrus periods of the investigated Holstein cows. Characteristic changes were detected especially in foremilk collected at morning milking. They were reflected in calculated aquagrams of milk spectra where distinctive spectral pattern of oestrus showed increased light absorbance of strongly hydrogen‐bonded water. Results showed that monitoring of raw milk near infrared spectra provides an opportunity for analysing hormone levels indirectly, through the changes of water spectral pattern caused by complex physiological changes related to fertile periods.     

Treatment of Unobserved Oestrus in a Dairy Cattle Herd with Low Oestrous Detection Rate up to 60 days Post-partum

The efficiency of treatments for unobserved oestrus and their effect on the reproductive performance of a dairy cattle herd with low oestrous detection rate till 60 days post‐partum (dpp), attributed to the declivous and slippery concrete floor were investigated. The herdsman requested advice in order to improve the mean days open of the herd, but no investments were allowed because a new unit was about to be built. Due to the low oestrus detection rate of the herd, the breeding policy was to inseminate at the first detected post‐partum oestrus. Cows were examined at 20–30 dpp to assess uterine involution, ovarian activity and prevalence of reproductive disorders and, at 60 dpp if no previous oestrus was detected. Each examination included palpation per rectum, ultrasound scanning and collection of a blood sample for plasma progesterone (P4) measurement. Cows with unobserved oestrus till 60 dpp were allocated either to a treatment group (n=139) or to a control group (n=139). Three treatments were used: (a) injection of PGF_2α (PG) upon detection of a corpus luteum (CL; n = 30), cows not observed in oestrus being re‐injected 11–12 days later. AI was at oestrus; (b) PRID (n=35) or Crestar (n=74) devices kept in situ for 12 and 9 days, respectively, were associated to an injection of PG and of equine chorionic gonadotrophin (eCG) at device removal. Cows were double‐fixed time‐inseminated at 48 and 72 h after device removal. All treated cows were examined at 48–72 h after treatment to confirm oestrus. The percentage of cows detected in oestrus up to 60 dpp remained unchanged through the trial (35 and 47% for years before intervention: 1994–95; 51 and 48% for years of intervention: 1996–97). In contrast, the oestrous detection rate was high both in treated (93%) and control (100%) cows. This possibly resulted from an improvement in the oestrous detection efficiency of the herd's personnel and from examination of cows at 48–72 h after treatment. Treated and control cows had identical conception rate (CR; 36 and 37%, respectively) and reproductive performance. However, the mean days open of the herd in 1996 was significantly improved in comparison with previous years (mean ± SEM: 134 ± 6, 126 ± 5, 110 ± 4 and 114 ± 5 days, for years 1994, 1995, 1996 and 1997, respectively, p < 0.05, ANOVA ). Conception rate to AI up to 40 dpp was significantly reduced, compared with the period between 60 and 100 dpp but, mean days open were significantly improved in cows inseminated up to 60 dpp, compared with thereafter (p < 0.05).     

尿素氮检测在规模化奶牛场中的应用

尿素氮检测作为一种简便易行且对奶牛非侵害的技术手段越来越受到规模化牧场的重视,本文从尿素氮产生的机理、影响尿素氮浓度的因素、尿素氮的检测以及在生产中的应用展开论述,以供广大同行参考.     

Incidence of Error in Oestrus Detection Based on Secondary Oestrus Signs in a 24-h Tie-Stalled Dairy Herd with Low Fertility

Oestrus detection error and conception rates after AI based only on secondary oestrus signs were evaluated in a high yielding, 24-h tie-stalled dairy herd with low fertility, using milk progesterone profiles. Oestrus detection was based on the secondary oestrus signs such as restlessness, swelling, congestion of vulva and clear mucus discharge. Sixty eight AI conducted after observing the secondary oestrus signs in 44 animals were included in the study. Of the 68 AI, 53 (77.9%) were conducted in the follicular phase, and 13 (19.1%) and 2 (2.9%) were carried out in the luteal phase and during pregnancy, respectively. The overall error in oestrus detection based on milk progesterone profiles was 22.1%. The oestrus detection error did not differ significantly among different secondary oestrus signs. None of the AI conducted in the luteal phase resulted in conception, whereas 20.8% of AI conducted in the follicular phase resulted in conception. No significant difference in the conception rates among the groups of cows with different secondary oestrus signs was shown. The high incidence of oestrus detection error in this study might have been caused by the detection of cows in oestrus based only on secondary oestrus signs due to the confinement of animals. In conclusion, there was a high incidence of heat detection error in the 24-h tie-stalled dairy herd and oestrus detection based only on secondary oestrus signs resulted in low conception rate.     

河南洛阳地区流产奶牛感染性病原的分子检测

为调查洛阳地区引起奶牛流产的主要病原,于2013年7月至2014年3月,收集该地区6个奶牛场(或小区)共42头新鲜流产胎牛,及其母体的血液、阴道分泌物和鼻腔分泌物,计为42例样本,采用PCR或RT-PCR方法对所采集样本进行新孢子虫、弓形虫、胎儿三毛滴虫、布鲁菌、牛传染性鼻气管炎病毒(IBRV)和牛病毒性腹泻病毒(BVDV)6种常见流产病原的核酸检测。结果显示,被检样本总感染率为42.9%(18/42),其中新孢子虫感染率最高,为40.5%(17/42);:IBRV次之,为11.9%(5/42);胎儿三毛滴虫、布鲁菌、弓形虫和BVDV感染率分别为2.4%、2.4%、2.4%和0。14.3%(6/42)的被检样本存在混合感染,其中以新孢子虫十IBRV混合感染为主(50%,3/6)。结合被检流产奶牛的临床特征及饲养管理等因素,推断新孢子虫是导致该地区奶牛流产的最主要病原,本研究结果将为该地区有效防控奶牛流产提供科学依据。     

两种牛结核病检测方法对广西奶牛的检测

牛结核病现行防治政策是对牛尤其是奶牛进行检疫,淘汰结核病牛[1]。现在牛结核病应用较多的检疫方法有变态反应[2]、酶联免疫试验     

Twinning in Dairy Cattle

Twinning in dairy cattle is an unavoidable outcome of reproduction and is undesirable because it reduces the overall profitability of a dairy operation through negative effects on cows calving twins as well as on calves born as twins. Cows calving twins are at greater risk for many periparturient reproductive and metabolic disorders than nontwinning herdmates, and incidences of abortion, stillbirth, neonatal calf mortality, and reduced birth weight are greater among twin compared with singleton calves. Twinning is a complex trait with multiple causative factors, and empirical evidence supports a role for both genetic and environmental risk factors in cattle. Risk factors for twinning include genetics, season, parity, ovulation rate, and milk production. The observation that twinning has increased in the dairy cattle population over time suggests a concurrent change in one or more of these causative factors during this same period. At present, dairy farmers and their consultants are ill prepared to make sound-management decisions to mitigate the negative effects of twinning on their operations because of a lack of applied scientific data on management strategies for periparturient dairy cows carrying twin fetuses. A clear understanding of the factors responsible for twinning is essential for future development of strategies to manage twinning in dairy operations.     

甘肃省奶牛养殖小区污染状况检测及分析

根据甘肃省《家畜养殖业源产排污检测分析研究》项目,在武威市设立监测点对奶牛养殖小区产排污状况进行检测分析,重点分析了粪便、及污水中的主要污染物含量。结果表明,污染物对其周围环境产生了较为严重的影响,据此进行分析并提出建议。     

PCR方法检测奶牛粪便中鼠隐孢子虫

从含有鼠隐孢子虫卵囊的奶牛粪便中,直接提取 Ｄ Ｎ Ａ 用作 Ｐ Ｃ Ｒ 模板,用 １ 对人工合成的寡核苷酸作为 Ｐ Ｃ Ｒ 引物,扩增大小为 ５４０ ｂｐ 的特异片段。 Ｐ Ｃ Ｒ 产物经电泳鉴定,表明可从含隐孢子卵囊的奶牛粪便标本 Ｄ Ｎ Ａ 抽提物中扩增出目的片段,而其他几种寄生虫及阴性对照均不能扩增出特异片段。本方法的敏感性最低可检测到含卵囊 ４００ 个／ｍ Ｌ 的样本,具有敏感性高、特异性强的特点。     

应用DHI对某奶牛群生产性能的综合分析

应用DHI对某奶牛群生产性能进行综合分析,探索在奶牛牧场管理过程中,牛奶体细胞数SCC与奶牛产奶量、健康、胎次的关系,以期应用DHI提高奶牛生产性能。应用奶牛生产性能测定(DHI)体系对900头产奶牛进行测定和分析,发现在奶牛泌乳的各个阶段,随着牛奶体细胞数增高,各胎次奶牛产奶量呈逐渐下降趋势;体细胞数随着胎次的增加而上升,奶牛产奶量随奶牛胎次的变化而变化。奶牛存在产犊间隔长,繁殖障碍和营养问题,需采取相应的改进措施。     

荷兰的奶牛业

荷兰位于欧洲西部,1600万人口,大约41526平方公里国土面积,160万头泌乳奶牛,每头泌乳牛 305d平均产奶量 8000kg,每人每年平均消费牛奶300kg,有大量的乳制品出口（奶油,奶酪）。     

奶牛的发情鉴定与适时配种

1　正常发情征状奶牛属非季节性发情动物 ,只要营养充分 ,饲养管理良好 ,则可常年发情。奶牛发情持续期较短 ,从发情到排卵时间平均为 30 h。排卵时间一般在发情症状消失以后。大多数奶牛发情过程中都有爬跨现象 ,即母牛与母牛相互爬跨——俗称“同性爱”。多数奶牛都排单卵( 97% ) ,也有 3%的母牛可能排双卵 ,排多卵的极少 ,如果注射外源性激素 (如 PMSG、FSH) ,排卵数可增加 2 1 .6 %。一般右侧卵巢排卵多( 6 0 .5% ) ,左侧卵巢排卵少 ( 39.5% ) ;夜间排卵多 ( 85.2 % ) ,特别是在 0～ 6时排卵多 ,所以配种常在夜间。奶牛发情时 ,体温…     

Early Detection of Pregnancy and Embryonic Loss in Dairy Cattle by ELISA Tests

Over a 25-month period 8118 blood samples were assayed for the presence of the serum pregnancy specific-protein B (PSPB) and progesterone (P4) concentrations on three Hungarian large-scale dairy farms. Pregnancy (n = 4085) was checked by BioPRYN assay at 30-36 days post-insemination (PI). Samples from all cows that tested not pregnant and from cows with an optical density (OD) reading in the BioPRYN test that was between 0% and 30% above the cutoff OD value were tested for serum P4 concentration. According to serum P4 concentration, cows were assigned to three categories: high (>4 ng/ml), medium (2-4 ng/ml) and low (<2 ng/ml) serum progesterone. The authors predicted a presumed (low) or possible (medium) late embryonic loss (LEL) or maintenance of the pregnancy (high). A total of 710 LELs were detected (17.4%) and 31.8% of them were predicted because of a low OD value at 30-36 days after insemination. Lower PSPB serum level significantly refers for LEL (p < 0.0001). The prediction rate for the true embryonic loss was 31.8% when OD cutoff from 0% to + 30% of cutoff was examined while it was 62.5% when the threshold was OD cutoff of 0% to 10% of cutoff. The authors conclude that BioPRYN was useful for prediction of a part of LEL in dairy cows and serum P4 concentration in these cows related to the rate of LEL.     

一种基于奶牛反刍时间的发情鉴定新技术

反刍时间(rumination time,RT)是衡量奶牛健康状况的一个重要指标。近期研究结果表明,奶牛发情当天RT与非发情时相比显著下降。基于这样的研究结果,奶牛RT的变化可成为发情鉴定的一个新指标。作者就奶牛RT的变化与发情的关系,以及这种发情鉴定方法在奶牛生产中的应用前景进行综述,以期为提高奶牛生产效率提供依据。     

奶牛食盐中毒

食盐为奶牛重要的饲料成分之一，如采食过多或饲喂不当时，会发生中毒。现将我区某奶牛场发生的一起奶牛食盐中毒事故介绍如下：     

奶牛酮病的发病机理研究概述

奶牛酮病是高产奶牛的常见病、群发病,本文就奶牛酮病的病因、发病机理、临床症状及其防治策略进行简要的综述,旨在为奶牛疾病防控提供应对策略.