Anthelmintic resistance in cattle nematodes on 13 south-west Victorian properties

Objective To report the level of anthelmintic resistance on 13 commercial cattle properties in south-west Victoria, Australia. Procedure Between 2006 and 2009 worm egg count reduction tests were conducted on calves on the 13 properties. Samples were collected 10–14 days post anthelmintic treatment and worm egg counts and larval differentiation tests were conducted. Resistance was defined if there was less than 95% reduction (lower confidence limit <90%) in the faecal worm egg count for the particular genus. Results The percentage of properties with anthelmintic resistance in at least one species was 54% for benzimidazole (BZ), 100% for levamisole (LEV) and for ivermectin (IVM) it was 100% for the half-dose (0.1 mg/kg) and 62% for the full dose (0.2 mg/kg). A substantial frequency of resistance was detected in Ostertagia ostertagi to BZ (5/11), LEV (3/3) and IVM (5/11), in Trichostrongylus spp. to BZ (4/7) and in Cooperia spp. to IVM (6/11). No resistance to LEV was detected in Trichostrongylus or Cooperia spp. Suspected IVM-resistant Trichostrongylus spp. and BZ-resistant Cooperia spp. were only detected on one property each. Conclusion This is the first Australian report of macrocyclic lactone-resistant O. ostertagi in the refereed literature. The frequency of resistance in O. ostertagi to BZ, LEV and IVM and in Trichostrongylus spp. to BZ in the present study appears higher than levels detected in the 2004–05 New Zealand survey, whereas the resistance frequency in Cooperia spp. to IVM and BZ was less.     

夏季皖东牛与荷斯坦牛皮肤汗腺及其散热调节特征

为了探究夏季高温时皖东牛与荷斯坦牛皮肤组织形态和皮肤散热调节特征的差异,在30℃以上的夏日,选择皖东牛和荷斯坦牛母牛各4头,屠宰后采集颈部、肩部、背部、腹部、臀部和腿部6个部位的皮肤样本,通过HE染色切片分析皮肤的汗腺(SWG)与皮脂腺(SEG)的分布与形态,测定皮肤组织乙酰胆碱(ACh)浓度及乙酰胆碱转移酶(AChT)和酯酶(AChE)活力,采用RT-qPCR和Western blot检测皮肤组织乙酰胆碱M3受体(ACh M3R)、一氧化氮合酶(eNOs)及水通道蛋白5(AQP5)mRNA和蛋白的表达。结果:部位间比较,皖东牛与荷斯坦牛表皮厚度均为背部最厚,颈部最薄(P<0.05)。品种间比较,皖东牛平均皮肤厚度较高,平均表皮厚度较薄(P<0.05);汗腺密度与皮脂腺密度品种间无显著差异(P>0.05);皖东牛汗腺和皮脂腺的平均长度、直径、深度、体积均显著增加(P<0.05)。肩部、背部和臀部皮肤对比:夏季皖东牛和荷斯坦牛皮肤组织ACh浓度品种间无显著差异(P>0.05),部位间以臀部最高,肩部次之,背部最低(P<0.05)。ACh M3R和AQP...     

Sequence diversity and molecular evolutionary rates between buffalo and cattle

Identification of genes of importance regarding production traits in buffalo is impaired by a paucity of genomic resources. Choice to fill this gap is to exploit data available for cow. The cross‐species application of comparative genomics tools is potential gear to investigate the buffalo genome. However, this is dependent on nucleotide sequences similarity. In this study, gene diversity between buffalo and cattle was determined using 86 gene orthologues. There was approximately 3% difference in all genes in terms of nucleotide diversity and 0.267 ± 0.134 in amino acids, indicating the possibility for successfully using cross‐species strategies for genomic studies. There were significantly higher non‐synonymous substitutions both in cattle and buffalo; however, there was similar difference in terms of dN– dS (4.414 versus 4.745) in buffalo and cattle, respectively. Higher rate of non‐synonymous substitutions at similar level in buffalo and cattle indicated a similar positive selection pressure. Results for relative rate test were assessed with the chi‐squared test. There was no significance difference on unique mutations between cattle and buffalo lineages at synonymous sites. However, there was a significance difference on unique mutations for non‐synonymous sites, indicating ongoing mutagenic process that generates substitutional mutation at approximately the same rate at silent sites. Moreover, despite of common ancestry, our results indicate a different divergent time among genes of cattle and buffalo. This is the first demonstration that variable rates of molecular evolution may be present within the family Bovidae.     

A cross-sectional pilot study to estimate the prevalence of and risk factors for leptospirosis in South-Western Victorian dairy herds, 2017

Leptospirosis is a zoonosis, found worldwide, affecting many species of animals. We conducted a cross-sectional study to estimate the prevalence of Leptospira borgpetersenii sv Hardjo and Leptospira interrogans sv Pomona in cattle in dairy herds in South-Western Victoria, Australia. Fifty-three herds were enrolled in the study. Urine samples were collected from 15 late-lactation cows in each herd. A questionnaire was provided to herd managers at the time of each herd visit, asking them to describe the methods they used for controlling leptospirosis, including vaccination. Urine samples were pooled at the herd level and tested for leptospira spp. using real time PCR. Urine samples from individual cows within the positive pooled samples were then tested for Leptospira Hardjo and Leptospira Pomona using qPCR. Four of the 53 herds showed positive leptospirosis results giving an apparent prevalence of 8 (95% CI 2–18) leptospira-positive herds per 100 herds at risk. Based on the 53 completed questionnaires, leptospirosis vaccination programs were not compliant with label directions in 36 of the 52 vaccinated herds: 69 (95% CI 55–81) of 100 herd managers that routinely vaccinated for leptospirosis did not comply with label directions. One herd was completely unvaccinated. Based on our findings, we estimate that approximately 10% of dairy farms in South-Western Victoria are likely to be infected with leptospirosis. While most herds are vaccinating for leptospirosis, most are not doing so according to label directions. We conclude that herd managers need to be better educated regarding leptospirosis vaccination programs.     

Chlamydia psittaci: a suspected cause of reproductive loss in three Victorian horses

Chlamydia psittaci was detected by PCR in the lung and equine foetal membranes of two aborted equine foetuses and one weak foal from two different studs in Victoria, Australia. The abortions occurred in September 2019 in two mares sharing a paddock northeast of Melbourne. The weak foal was born in October 2019 in a similar geographical region and died soon after birth despite receiving veterinary care. The detection of C. psittaci DNA in the lung and equine foetal membranes of the aborted or weak foals and the absence of any other factors that are commonly associated with abortion or neonatal death suggest that this pathogen may be the cause of the reproductive loss. The detection of C. psittaci in these cases is consistent with the recent detection of C. psittaci in association with equine abortion in New South Wales. These cases in Victoria show that C. psittaci, and the zoonotic risk it poses, should be considered in association with equine reproductive loss in other areas of Australia.     

The complex relationship between welfare and reproduction in cattle

Using reproduction parameters as indicators for cattle welfare has limitations and, at best, these parameters should only be viewed as indirect indicators of welfare. On a farm level, measures such as fertility rates emphasize biological performance of the herd but fail to consider the welfare of individual animals. Even on an individual level, the relationship between reproductive effectiveness and animal welfare is complex. Good reproductive performance does not automatically signify good welfare, as domestication and targeted breeding programmes have led to prioritization of high productive and reproductive performance in most modern farm animal species. In this review, we synthesize literature regarding cattle husbandry, reproduction, welfare and their multidimensional relationships. We argue that practices such as artificial insemination or the use of sexed semen may provide potential welfare advantages as these practices reduce the risk of disease transmission and injury or enable selection of specific beneficial traits. Furthermore, they may offer a solution to current practices jeopardizing welfare, such as the management of surplus bull calves in the dairy industry. Conversely, the animals’ ability to perform natural behaviours such as oestrous expression, an aspect arguably contributing to welfare, is often limited on commercial farms; this limitation is particularly evident in housing systems such as tie stalls where movement is restricted. Moreover, common management practices such as oestrus manipulation may lead to negative attitudes in citizens who often regard naturalness as important element of animal welfare.     

Relationship between reproductive and productive traits in Holstein cattle using multivariate analysis

Multivariate procedures are used for the extraction of variables from the correlation matrix of phenotypes in order to identify those traits that explain the largest proportion of phenotypic variation and to evaluate the relationship structure between these traits. The reproductive traits (days from calving to first estrus [CFE], days from calving to last service [CLS], calving interval [CI] and gestation length [GL]) and milk production traits (milk yield at 305 days of lactation [MY305], peak yield [PY] and milk yield per day of calving interval [MYCI]) of 5,217 Holstein females (primiparous and multiparous) were measured. Principal component analysis (PCA) and factor analysis of the correlation matrix were used to estimate the correlation between traits. Analysis grouped the seven traits into three principal components and four latent factors that retained approximately 81.5% and 88.9% of the total variation of the data, respectively. The production variables exhibited positive phenotypic correlation coefficients of high magnitude (>.67). The phenotypic correlation estimates between the productive and reproductive traits were low, ranging from .13 to .22. A strong association (.99) was observed between CLS and CI. Our results indicate that multivariate analysis was effective in generating correlations between the traits studied, grouping the seven traits in a smaller number of variables that retained approximately 81% of the total variation of the data.     

注入嵌合法制作黄牛和水牛种间嵌合胚的初步研究

采用注入嵌合法初步建立了一套黄牛和水牛种间嵌合的程序与方法。采用机械剥离法或免疫外科法分离胚胎内细胞团(ICM),然后注入到已去除ICM的受体囊胚中构建形成水牛和黄牛的嵌合胚。结果发现,在用免疫外科法分离ICM时,抗血清的灭活温度从57℃升至63.5℃,ICM的获得数显著升高(0%vs100%,P<0.01),如若在分离培养液中添加6%的胎牛血清(FCS),ICM的获得数大大降低(97.6%vs0%,P<0.01)。采用免疫外科法分离得到的黄牛ICM进行水牛囊胚的ICM置换重组,重组胚的存活率与机械剥离法得到的ICM无显著差异(91.4%vs87.5%,P>0.05);但囊胚孵化率则显著提高(80%vs43.8%;P<0.05)。以上结果表明,⑴水牛和黄牛胚胎通过ICM置换获得的种间嵌合胚胎能继续发育;⑵用于黄牛ICM分离的兔抗牛抗血清需在63.5℃灭活30min,且分离需在无血清的培养液中进行;⑶通过分离ICM置换进行胚胎嵌合时,免疫外科法优于显微手术法。     

Genetic associations between accumulated productivity, and reproductive and growth traits in Nelore cattle

The total meat yield in a beef cattle production cycle is economically very important and depends on the number of calves born per year or birth season, being directly related to reproductive potential. Accumulated Productivity (ACP) is an index that expresses a cow's capacity to give birth regularly at a young age and to wean animals of greater body weight. Using data from cattle participating in the “Program for Genetic Improvement of the Nelore Breed” (PMGRN — Nelore Brasil), bi-trait analyses were performed using the Restricted Maximum Likelihood method based on an ACP animal model and the following traits: age at first calving (AFC), female body weight adjusted for 365 (BW365) and 450 (BW450) days of age, and male scrotal circumference adjusted for 365 (SC365), 450 (SC450), 550 (SC550) and 730 (SC730) days of age. Median estimated ACP heritability was 0.19 and the genetic correlations with AFC, BW365, BW450, SC365, SC450, SC550 and SC730 were 0.33, 0.70, 0.65, 0.08, 0.07, 0.12 and 0.16, respectively. ACP increased and AFC decreased over time, revealing that the selection criteria genetically improved these traits. Selection based on ACP appears to favor the heaviest females at 365 and 450 days of age who showed better reproductive performance as regards AFC. Scrotal circumference was not genetically associated with ACP.     

Inbreeding depression in Zebu cattle traits

The productivity of herds may be negatively affected by inbreeding depression, and it is important to know how intense is this effect on the livestock performance. We performed a comprehensive analysis involving five Zebu breeds reared in Brazil to estimate inbreeding depression in productive and reproductive traits. Inbreeding depression was estimated for 13 traits by including the individual inbreeding rate as a linear covariate in the standard genetic evaluation models. For all breeds and for almost all traits (no effect was observed on gestation length), the performance of the animals was compromised by an increase in inbreeding. The average inbreeding depression was ?0.222% and ?0.859% per 1% of inbreeding for linear regression coefficients scaled on the percentage of mean (β_m) and standard deviation (β_σ), respectively. The means for β_m (and β_σ) were ?0.269% (?1.202%) for weight/growth traits and ?0.174% (?0.546%) for reproductive traits. Hence, inbreeding depression is more pronounced in weight/growth traits than in reproductive traits. These findings highlight the need for the management of inbreeding in the respective breeding programmes of the breeds studied here.     

Reference ranges of hematology and lymphocyte subsets in healthy Korean native cattle (Hanwoo) and Holstein dairy cattle

There are no accurate reference ranges for hematology parameters and lymphocyte subsets in Korean native beef cattle (Hanwoo). This study was performed to establish reliable reference ranges of hematology and lymphocyte subsets using a large number of Hanwoo cattle (n = 350) and to compare differences between Hanwoo and Holstein dairy cattle (n = 334). Additionally, age‐related changes in lymphocyte subsets were studied. Bovine leukocyte subpopulation analysis was performed using mono or dual color flow cytometry. The leukocyte subpopulations investigated in healthy cattle included: CD2⁺ cells, sIgM⁺ cells, MHC class II⁺ cells, CD3⁺CD4⁺ cells, CD3⁺CD8⁺ cells, and WC1⁺ cells. Although Hanwoo and Holstein cattle are the same species, results showed several differences in hematology and lymphocyte subsets between Hanwoo and Holstein cattle. This study is the first report to establish reference ranges of hematology and lymphocyte subsets in adult Hanwoo cattle.     

The relationship between blood indicators of phosphorus status in cattle

BACKGROUND: Determining accurate body phosphorus status and requirements is important in ruminants because of environmental concerns of surface water pollution by overzealous phosphorus consumption in developed countries, and extensive regions of phosphorus deficiency in developing ones. Current indicators, such as concentrations of bone, plasma, fecal, and rumen inorganic phosphorus (Pi), fall short of this goal. In addition, plasma Pi (PPi) concentrations may be falsely increased by hemolysis during storage of blood samples. OBJECTIVES: The goals of this study were to: 1) compare whole blood Pi (WBPi), red blood cell Pi (RBCPi), and PPi concentrations in different groups of dairy calves and cows; 2) evaluate relationships among the concentrations of these indicators of phosphorus status; and 3) investigate the possibility of predicting RBCPi and PPi concentrations according to WBPi concentration. METHODS: Heparinized whole blood samples were obtained from 53 suckling calves, 29 weaned calves, 14 heifers, 20 dry pregnant cows, and 19 high-producing lactating dairy cows. Pi concentration was measured in plasma and in lysates of whole blood and packed RBCs using an automated phosphomolybdate method. PCV was determined using the microhematocrit method. Results were analyzed using 1-way ANOVA and regression analysis. RESULTS: Heifers and dry cows had significantly higher RBCPi concentrations, and weaned calves and dry cows had significantly higher WBPi concentrations, compared with other groups. In all groups, WBPi was significantly associated with other variables, including PCV. Regression models for each group were calculated to predict RBCPi and PPi concentrations according to WBPi concentration. CONCLUSION: Results of different blood phosphorus indicators vary according to age and stage of lactation. The models that predict PPi and RBCPi according to WBPi may have some value in estimating total body phosphorus status in cattle.     

秦川牛血红蛋白标记位点与体尺、体重的关系分析

对２２０头秦川牛血红蛋白位点与体尺,体重的关系分析表明：（１）在体高、十字部 胸深性状上,ＣＣ型的ＬＳＥ值明显高于ＡＣ型;（２）在胸宽、胸围、体长和体重性状上,ＢＢ型的ＬＳＥ值分别高于ＡＣ型;（３）确定血红蛋白位点Ｂ基因为秦川牛体尺、体重性状的优势基因。     

西门塔尔牛、安格斯牛杂交生产利用研究

为了探讨西门塔尔牛和安格斯牛杂交改良本地黄牛效果,采用西门塔尔牛和安格斯牛作为肉牛终端父本,分别与本地黄牛开展二元经济杂交,对杂交F1体重变化、屠宰性能数据进行了统计分析研究。结果表明：两者杂交F1均比本地黄牛生长速度快且产肉率高,可有效提高本地黄牛的屠宰性能。说明西门塔尔牛和安格斯牛改良本地黄牛杂交优势明显,可有效增加本地黄牛养殖的经济效益,值得推广。     

Association between single nucleotide polymorphisms (SNPs) and milk production traits in Italian Brown cattle

Italian Brown is a cattle breed largely exploited in the production of many dairy products in Italy, including typical and traditional cheeses. For this reason, the improvement of selection methods is of economic relevance while a deeper understanding of the genetic mechanisms regulating milk production is of general scientific interest. We selected a total of 561 samples, representing virtually all Italian Brown bull population, to test for association between milk production traits and 29 known genes harbouring 106 single nucleotide polymorphisms (SNPs). After filtering, a total of 31 SNPs in 22 candidate genes and 473 bulls were retained. Associations between each SNP and milk traits were tested by a mixed model approach, obtaining seven significantly associated SNPs, two of which (in β-Lactoglobulin) associated with all traits, and four (in Chemokin receptor I, αs1 casein, k casein, fatty acid synthase, thyroid hormone responsive and Oxytocin prepropetide genes) associated with at least one trait.     

单菌株与多菌株微生态制剂在提高奶牛产奶性能上的应用

文章综述了单菌株和多菌株微生态制剂在提高奶牛产奶性能上的应用,分析探讨了两种微生态制剂应用中存在的问题,并提出一些解决措施,为其进一步研究提供参考.