Influence of arrival weight, season and calf supplier on survival in Holstein beef calves on a calf ranch in California, USA

On a yearly basis, large calf ranches rear thousands of neonatal cattle for replacement heifers, veal or dairy beef. Dairy beef ranches obtain bull-calves from multiple sources and with questionable colostrum intake histories. Such ranches accumulate large amounts of data that could be used to help them with calf purchasing and on-farm management practices to avoid losses. Our purpose was to describe some calf purchase factors associated with mortality in neonatal calves raised on a single large calf ranch. Computerized records describing 120,197 bull-calves purchased between January 1997 and November 1998 were used in a survival analysis. Risk factors for mortality within the first 4 weeks after arrival on the ranch included body weight on arrival, month of arrival, and the calf supplier. The strength of the effects was conditional on the week after arrival to the ranch.     

Prevalence of Tritrichomonas fetus in a bull population and effect on production in a large cow-calf enterprise

OBJECTIVE: To determine prevalence of infection with tritrichomonas fetus in a bull population; assess influence of age, breed, and grouping; assess effects on measures of cow performance (pregnancy rate, weaning percentage, weaning weight); and estimate test sensitivity. DESIGN: Epidemiologic study. ANIMALS: 1,383 bulls and records for 28,471 cows bred by these bulls in the immediate past breeding season. PROCEDURE: Bulls in 11 cattle units on a large ranch were tested for T fetus colonization by vigorous preputial scraping and protozoologic culture until no newly infected bulls were identified. Bull infection prevalence within units was calculated and correlated to production measurements reported for each cattle unit. RESULTS: Mean prevalence of T fetus-infected bulls was 11.9% (range, 0 to 35.9%). Significant difference was detected between mean age of infected bulls (5.5 years) and noninfected bulls (3.9 years). Difference in prevalence among breeds was found, although other factors may have influenced this finding. Cow performance measurements (weaning percentage, mean weaning weight, and adjusted mean weaning weight/exposed cow) for cows exposed by breeding to bull groups with the highest prevalence of infection (35.9%) were significantly different from mean values for the entire study population. Test sensitivity for this study (73%) was less than that reported in other studies. CLINICAL IMPLICATIONS: T fetus infection in a natural service beef herd has an adverse impact on several production measures: Severity of impact is related to prevalence of infection in the bull population, where prevalence is bull age and population dependent.     

Economic impact of ticks and tick-borne diseases on cattle production systems around Lake Mburo National Park in South Western Uganda

A longitudinal economic impact study of Ticks and Tick-Borne Diseases (TTBDs) in cattle around Lake Mburo National Park (LMNP) was done. Impact was valued using Uganda Shilling (Ug. Shs) (exchange rate of 1USD to Ug. Shs 1,420). The costs for controlling TTBDs was constituting 85.6 ± 3.2% (pastoral) and 73.8 ± 4.2% (ranches) to total disease control costs. The main costs were on tick control, constituting 83.1% (ranches) and 87.9% (pastoral). In pastoral herds, the costs were negatively correlated to herd size (r = −0.99). The mean annual cost per cattle for controlling TTBDs for ranch and pastoral herds was similar Ug. Shs 5,900 ± 545. The mean annual Economic Cost (EC) of TTBDs per cattle was not significantly different (p > 0.05) between pastoral (Ug. Shs 6,700 ± 580) and ranch herds (Ug. Shs 7,600 ± 970). The mean annual EC per cattle was negatively correlated (r = −0.99) with herd size in pastoral systems contrary to positive correlation (r = 0.99) observed among the ranches. The major component of EC of TTBDs of 88.2% (pastoral) and 78.6% (ranches) was due to their control. The other component was owed to mortality, which was positively correlated (p < 0.01) to the ranch herd size. The total annual EC of TTBDs around LMNP was Ug. Shs 437,754,600 (USD 308,144).     

内蒙古地区西门塔尔牛亲子鉴定微卫星标记筛选

研究旨在筛选适合于我国肉牛亲子鉴定的微卫星标记,以内蒙古乌拉盖地区368头西门塔尔牛为实验材料,利用荧光引物PCR和ABI3730测序仪对12个微卫星标记进行基因型检测,应用Cervus3.0软件统计12个微卫星标记的遗传多态性。结果表明:其中4个微卫星标记扩增效率较低,被剔除;其他8个微卫星的多态性丰富,平均等位基因数为11.38,平均期望杂合度为0.6686,平均多态信息含量为0.6354,适合于我国肉牛亲子鉴定。     

Ranch-management factors associated with antibody seropositivity for Neospora caninum in consignments of beef calves in Texas, USA

A study was conducted with a 1998 retained-ownership population of Texas (USA) beef calves to determine the ranch-management practices associated with calf seroprevalence to Neospora caninum. Management practices of 76 Texas ranches that consigned 760 calves to a retained-ownership feedlot program were reviewed from a mailed questionnaire. Ninety-nine of 760 (13%; 95% CI, 9.4%, 17.7%) calves were positive to N. caninum and 59% of the ranches consigned at least one positive calf. In the logistic multiple-regression model which controlled for overdispersion, increased odds of calf-level seropositivity was associated with seasonal calving patterns, with stocking>1cow/calfunit/2.2ha, using a round-bale feeder, allowing wildlife access to the weaning supplement, and self-reared replacement heifers. However, decreased odds of seropositivity was associated with using a cattle-working dog and with using a self-contained cattle feeder. There was substantial overdispersion due to ranch.     

An Example of Yak Paternity Assignment by Microsatellite Genotyping

12 cattle microsatellite DNA markers were used for establishing the paternity of 4 Datong Yak calves.The results indicated that paternity can be assigned by use of exclusion method directely when the mother is clearly known and data of all likely sires were obtained. The more the alleles of a locus possessed, the more effectively the paternity can be assigned. Not only the microsatellite DNA marker is a promising tool in establishment of yak detail pedigrees, but also can provide us information of reproductive efficiency of the bull(s) based on the numbers of calves it produced in the herd, which will be useful in speeding up the processes of yak genetics improvement.     

Paternity tests in multisired beef herds by blood grouping

The number of offspring sired by individual bulls in multisired beef herds was determined by blood grouping. Six series of tests, each having from 3 to 18 bulls as possible sires,, yielded from 35 to 114 dam-offspring pairs. The paternity was established for 45 to 90 % of the calves tested in each series. The rest were cases with either more than 1 bull not being excluded as the possible sire, or all bulls excluded from being the sire. The causes for the non-established paternities are discussed. Highly significant differences were found in the number of offspring sired by each bull. In each series, bulls ranking in the top third of the siring order sired 65–100 % of the calves with established paternities. Since a minority of the bulls sired the majority of the calf-crop, the generally recomended number of bulls for herds on the range can perhaps be reduced.     

Use of SNP genotyping to determine pedigree and breed composition of dairy cattle in Kenya

High levels of inbreeding in East African dairy cattle are a potential concern because of use of a limited range of imported germplasm coupled with strong selection, especially by disease, and sparse performance recording. To address this, genetic relationships and breed composition in an admixed population of Kenyan dairy cattle were estimated by means of a 50K SNP scan. Genomic DNA from 3 worldwide Holstein and 20 Kenyan bulls, 71 putative cow‐calf pairs, 25 cows from a large ranch and 5 other Kenyan animals were genotyped for 37 238 informative SNPs. Sires were predicted and 89% of putative dam‐calf relationships were supported by genotype data. Animals were clustered with the HapMap population using Structure software to assess breed composition. Cows from a large ranch primarily clustered with Holsteins, while animals from smaller farms were generally crosses between Holstein and Guernsey. Coefficients of relatedness were estimated and showed evidence of heavy use of one AI bull. We conclude that little native germplasm exists within the genotyped populations and mostly European ancestry remains.     

大额牛与黄牛本交的效果观察

[目的]通过大额牛与黄牛杂交的试验来为探索种间杂交的研究提供依据。[方法]用2头大额牛公牛与20头黄牛母牛圈舍混养分别进行本交试验。[结果]表明,大额牛能与黄牛进行本交使母牛受孕,受孕率达50%。[结论]不仅证实了大额牛与黄牛的种间杂交可行性,也为牛种间杂交改良提供强有力的科学依据。     

散养湘西黄牛精液的采集与异地冷冻保存技术研究

通过散养湘西黄牛的精液采集与冷冻保存,有利于收集多个优良血缘,降低种公牛站内种公牛的饲养成本。2010年5月,在张家界市永定区湘西黄牛保种区,挑选年龄为2~4岁,特级种公牛10头,进行精液采集与冷冻保存。结果表明：10头未调教的公牛中,除2头（3号、7号）没有采精调教成功外,其它8头都可采精。每次采精3回,平均每次的射精量在2.33~7.66 mL、平均每次原精密度在7.18×108~1.51×109之间变化。不同个体的射精量与密度没有显著相关性。冻后细管精液在37~39℃温水中进行解冻,冻后活力在0.35~0.45之间,均能达到国家牛冷精液生产标准要求,10头公牛中有8头共生产冷冻精液3537支。因此,在保种区域现场采精,稀释处理后送至种公牛站实施湘西黄牛冻精生产的方法是可行的。     

Surgery of the prepuce and penis.

Diseases involving the reproductive tract of bulls are a significant cause of economic and genetic loss to beef (eg, cow-calf units) and dairy (eg, bull studs) cattle producers. Injury or infectious disease may cause these abnormalities. Some injuries are amenable to surgical treatment. Surgical restoration of breeding bulls allows preservation of genetics and economic productivity for the owner of affected bulls. Accurate selection of surgical candidates is necessary to optimize prognosis.     

基因芯片技术在晋南牛种公牛选育中的应用

为了更好的保护开发利用晋南牛,确保晋南牛的遗传多样性,本研究应用基因芯片技术,对晋南牛进行群体遗传特性的检测及后备种公牛的遗传评估,为晋南牛的分子辅助选育与保种提供理论与技术支持。采集18月龄健康、体重相近（（350±20）kg）的荷斯坦牛、和顺肉牛、西门塔尔牛、延边牛及利木赞牛血样各10份,及晋南牛后备公牛血样25份,根据不同牛品种分为6组,其中前5组每组10个重复,晋南牛后备公牛25个重复。应用Illumina SNP 50K高密度牛SNP芯片进行基因型检测,分析比较晋南牛的群体遗传特征,运用亲缘矩阵计算晋南牛后备公牛的亲缘系数,同时用BLUP进行遗传评估。结果表明,晋南牛在遗传结构上与荷斯坦牛、和顺肉牛、西门塔尔牛及利木赞牛关系较远,与延边牛较近,为中国地方品种群体;对晋南牛后备公牛进行遗传评估,得出了牛的基因组胴体重方差育种值排名,JN23的胴体重倍数性状标准差最大,从基因组水平可选作肉用种公牛;应用亲缘分析对晋南牛后备公牛家系进行分类,避免群体间的近交。本研究对晋南牛后备公牛进行了遗传评估、近交家系分析、传统表型选择及遗传疾病检测,最终选留的种公牛为JN07、JN23、JN05、JN08、JN02、JN13、JN19、JN14,通过多种选育方法结合提高了公牛的选择准确性,为晋南牛的群体选育提高奠定了基础。     

The value of using DNA markers for beef bull selection in the seedstock sector

The objective of this study was to estimate the value derived from using DNA information to increase the accuracy of beef sire selection in a closed seedstock herd. Breeding objectives for commercial production systems targeting 2 diverse markets were examined using multiple-trait selection indexes developed for the Australian cattle industry. Indexes included those for both maternal (self-replacing) and terminal herds targeting either a domestic market, where steers are finished on pasture, or the export market, where steers are finished on concentrate rations in feedlots and marbling has a large value. Selection index theory was used to predict the response to conventional selection based on phenotypic performance records, and this was compared with including information from 2 hypothetical marker panels. In 1 case the marker panel explained a percentage of additive genetic variance equal to the heritability for all traits in the breeding objective and selection criteria, and in the other case to one-half of this amount. Discounted gene flow methodology was used to calculate the value derived from the use of superior bulls selected using DNA test information and performance recording over that derived from conventional selection using performance recording alone. Results were ultimately calculated as discounted returns per DNA test purchased by the seedstock operator. The DNA testing using these hypothetical marker panels increased the selection response between 29 to 158%. The value of this improvement above that obtained using traditional performance recording ranged from $89 to 565 per commercial bull, and $5,332 to 27,910 per stud bull. Assuming that the entire bull calf crop was tested to achieve these gains, the value of the genetic gain derived from DNA testing ranged from $204 to 1,119 per test. All values assumed that the benefits derived from using superior bulls were efficiently transferred along the production chain to the seedstock producer incurring the costs of genotyping. These results suggest that the development of greater-accuracy DNA tests for beef cattle selection could be beneficial from an industry-wide perspective, but the commercial viability will strongly depend on price signaling throughout the production chain.     

务川黑牛不同杂交组合屠宰性能及肉质研究

实验旨在了解安格斯牛、利木赞牛和西门塔尔牛与务川黑牛杂交一代的产肉性能和肉品质。随机选取24月龄安务F1、利务F1、西务F1和务川黑牛公牛各3头,测定其屠宰性能和肉品质指标。结果表明:3种牛对务川黑牛杂交改良效果显著(P<0.05),屠宰率、肉骨比以利务F1牛最高,胴体重、净肉重、净肉率以安务F1牛最高,眼肌面积以西务F1牛最高;利务F1牛的熟肉率最高,安务F1牛的剪切力最低,肉色L45min、a45min、b45min值以西务F1牛色泽最亮,安务F1牛肉粗脂肪含量显著低于务川黑牛,利务F1牛肉与务川黑牛肉大理石纹都为3级,安务F1和西务F1牛肉大理石纹则为2级;系水力、滴水损失、水分、蛋白质、pH在不同杂交组合之间差异不显著。综合产肉性能和肉品质考虑,建议选择利木赞牛和安格斯牛作为务川黑牛杂交改良的父本进行推广。     

Serological evidence of Neospora caninum infections in beef bulls in six counties of the Corrientes province,Argentina

The purpose of the present work was to identify Neospora caninum infections in beef bulls belonging to 19 herds from six counties located in the Corrientes province, Argentina. The presence of antibodies to N. caninum was evaluated in 305 serum samples of bulls (Bos taurus and Bos indicus). Age and breed were recorded. An indirect fluorescent antibody test was used to determine specific antibodies. The number of bulls with natural Neospora-infection was 15 of 305 (4.9%). No association between serologic status and breed (odds ratio (OR), 0.53; 95% CI, 0.18-1.53) was found. Neospora-infected beef bulls were identified in the present work. The bull role in bovine neosporosis and the risk of horizontal transmission for cows should be investigated.     

Peripheral circulating insulin-like growth factor-I and -II in cattle

Interrelationships between circulating concentrations of the insulin-like growth factors (IGF-I and IGF-II) were investigated in 235 blood samples taken from 145 healthy beef or dairy calves, bulls and cows of different breeds and ages. Autoradiography of Western ligand blots indicated different IGF binding protein (IGFBP) profiles between sera from different categories of cattle. Each IGF radioimmunoassay was validated by determining the effects of IGFBPs, ligand and contraligand, as well as serial dilution and comparison with results obtained after molecular sieve chromatography in acid. In female cattle mean values for IGF-I varied from 5.1 nmol/l in postparturient Holstein cows to 18.5-20.5 nmol/l in growing beef heifers, while mean IGF-II concentrations ranged from 30.0 nmol/l in the cows to 14.7-15.7 nmol/l in the beef heifer calves. In male cattle mean serum IGF-I ranged widely from 8.2 nmol/l in 1-day-old Holstein calves to 67.4 nmol/l in 16-month-old Simmental-type bulls. Mean IGF-II concentrations decreased from 22.9 nmol/l in 1-day-old Holstein bull calves to 11.9 nmol/l in 12-month-old beef bulls. Thus, total molar IGF concentrations were fairly stable in female cattle (24.7-35.1 nmol/l) but extended from 27.3 nmol/l to 81.8 nmol/l in the male cattle. The tendency for a reciprocal relationship between serum concentrations of these growth factors was most obvious in the periparturient cows.     

The use of beef bull semen reduced the risk of abortion in Neospora-seropositive dairy cows

There is an evidence that the epidemiology of neosporosis differs in dairy and beef cattle, such that beef cattle carry a lower risk of abortion. The aim of the present study was to establish whether artificial insemination using semen from beef bulls could reduce the risk of abortion in dairy cows seropositive for the Neospora caninum parasite. Our study was based on yearly serological screening for neosporosis and on the confirmation of Neospora infection in aborted fetuses in two high-producing dairy herds with a mean 28% seroprevalence of N. caninum antibodies. The study population comprised of 273 pregnancies in seropositive animals: 156 pregnancies monitored after insemination using Holstein-Friesian semen and 117 after insemination using beef bull semen. Abortion rates for these animals were 28.2% (77 of 273), 34.6% (54 of 156) and 19.7% (23 of 117). Logistic regression analysis indicated no significant effects of lactation number and previous abortion on the abortion rate. Based on the odds ratio, a 1-unit increase in the Neospora antibody titre yielded a 1.01-fold increase in the abortion rate. The likelihood of abortion was two times higher for cows in one of the two herds and 2.8 times lower (one of 0.36) for pregnant cows inseminated with beef bull semen rather than Holstein-Friesian semen. Our results indicate that the use of beef bull semen can reduce the risk of abortion in dairy cows, and suggest that annual screening for neosporosis, specifically the antibody titre to the protozoan, could be an useful predictor of abortion risk in reproductive health programmes.     

Identification and Management of Critical Control Points in the Cow-Calf Enterprise for Achieving and Maintaining Consistency and Low Cost of Production: Summary of Feedlot and Carcass Performance and Overall Economic Results

Feedlot and carcass data were collected on an average of 20 steer offspring from 10 cooperating, southwestern Colorado cow-calf ranches that had previously been analyzed using the Integrated Resource Management-Standardized Performance Analysis (IRM-SPA) program. Averages and variation within and across ranches are presented. In general, variation observed was greater than desired by the beef cattle industry’s Long Range Plan carcass specification targets. Over all ranches, 59% of the cattle were outside of the desired specification ranges for one or more traits, although none of the ranches had insurmountable carcass challenges. The factors that affect low-cost production of a consistent beef product that meets the necessary standards for quality were also examined. Feed and labor costs were under control in most low-cost operations and managers had communicated goals to other people involved in the operation. There was no difference in feedlot performance between high- and low-cost cow-calf enterprises. High- and low-costs operators were equal in their ability to hit carcass targets.     

国内外肉牛遗传评估体系概况

种公牛的选育是肉牛育种工作的核心。传统选育肉用种公牛需要经过后裔测定进行选择,其优点是准确性高,但存在周期长、屠宰和肉质性状难以收集、成本高等问题,致其选择效率低。自2001年全基因组选择概念提出后,该技术迅速成为动植物育种领域研究的热点。利用全基因组选择进行肉用种公牛的选育,进行早期选择从而大幅度缩短世代间隔,可以提高繁殖性状等低遗传力性状的选择准确性,加快遗传进展,并大大降低育种成本。2014年,美国安格斯协会开始应用全基因组选择技术,其他欧美发达国家也陆续使用,肉牛育种进入基因组时代。中国自2017年开始使用全基因组选择技术选择青年肉用种公牛,并于2020年在全国范围内使用该技术进行基因组遗传评估。本文综述了国内外肉牛遗传评估现状,以期为我国肉牛育种工作提供参考和借鉴。