Frequencies of bovine PrP gene polymorphisms in Holstein and Japanese Black bulls in Japan

We screened for Japanese Black and Holstein bull sire samples to detect single nucleotide polymorphisms (SNPs) involving animo‐acid substitutions in the bovine prion gene in the entire coding region of the PRNP gene. Although three silent SNPs were found, we could not detect any SNP with animo‐acid substitution. We also examined the polymorphism of the octapeptide repeat number in these samples. There was no homozygous bull with repeat number 5. The frequency of heterozygous (6/5) bulls was 8% in the Japanese Black bull and 4% in the Holstein bull, respectively. The bull samples used in this study contain popular elite sires, so it appears that the polymorphisms of prion protein (PrP) are rather difficult to find in these two breeds in Japan, except for polymorphism of the octapeptide repeat number.     

Presumptive 1/29 autosomal translocation in Australian cattle.

A cytogenetical study was made of 9 descendants of a Charolais bull, heterozygous for a presumptive 1/29 translocation, three of the dams of some of these descendants, and three unrelated bulls which were mated to some of the descendants. Photographic karyotypes of Giemsa stained and C-banded chromosomes were prepared for each animal. The dams of the progeny showed no chromosomal abnormalities indicating that translocations were inherited from the sire. Three daughters of the Charolais bull and two of his grand daughters were heterozygous for the translocation, with a modal chromosomal number of 59, while the remaining three daughters and their progeny possessed normal karyotypes. No phenotypic abnormalities were observed in the animals examined. Measurements of the arms of the chromosomes suggested that the translocation chromosome (a large submetacentric) contained chromosomes 1 and 29. The submetacentric translocation chromosome had a single C-band, the two submetacentric X chromosomes showed no C-bands and each acrocentric autosome had a single C-band. All cattle heterozygous for the translocation showed normal fertility.     

北京地区荷斯坦牛脊椎畸形综合征的调查研究

脊椎畸形综合征（Complex Vertebral Malformation,CVM）是由常染色体上SLC35A3基因单碱基突变（G→T）引起的隐性遗传疾病,该基因隐性纯合（CV/CV）时奶牛致死,但CVM携带者表现正常,所以CVM携带者公牛可以通过人工授精技术传播CVM缺陷基因。本研究利用PCR-SSCP方法对北京地区242头公牛样品和403头母牛样品进行了检测分析,研究结果表明,在所检测的样本中,荷斯坦种公牛和母牛CVM携带率分别为8.82%和5.71%,CVM基因频率分别为4.41%和2.85%。通过系谱追踪发现,CVM遗传缺陷的共同祖先是美国名牛＂Penstate Ivanhoe Star＂（USA.1441440,CV）。通过剔除CVM携带者公牛可以有效地控制CVM遗传缺陷的传播,但是,我国许多CVM携带者公牛冻精依然在商业化使用,所以有效地监控CVM携带者在奶牛群中的状况对CVM防控计划是有益的。     

Determination of serum insulin concentration during intravenous glucose tolerance testing of healthy bulls

OBJECTIVE: To determine the insulin response curve during IV glucose tolerance testing of mature Holstein bulls. ANIMALS: 8 Holstein bulls between 5 and 8 years old and weighing between 911.5 and 1035.5 kg. PROCEDURE: A 50% glucose solution was rapidly administered IV so that each bull received a mean dose of 258 mg of glucose/kg of body weight. Serum glucose and insulin concentrations were determined before and 30, 60, 120, and 240 minutes after glucose infusion. RESULTS: Serum glucose concentrations 30 and 60 minutes after infusion were significantly greater than baseline concentration. Concentrations returned to baseline values 120 minutes after infusion. Serum insulin concentration was significantly greater 30 minutes after glucose administration, compared with baseline and 240-minute concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Intravenous glucose tolerance testing of mature Holstein bulls resulted in a characteristic insulin response curve. Baseline and peak insulin concentrations were higher in these bulls, compared with values reported for mature Norwegian Red cows.     

Noninfectivity of semen from bulls infected with bovine leukosis virus

An opportunity for study of the potential role of semen in the transmission of bovine leukosis virus (BLV) was provided when a Jersey herd was found to be BLV-seronegative. This was a closed herd; new genetic material had been introduced by artificial insemination (AI), using semen collected and processed at 7 AI centers in the United States. Of 66 donor bulls from which semen had been collected for AI use in the herd during the 5 years the herd remained seronegative, 24 were consistently BLV-seropositive and 2 became seropositive for BLV during the study. Semen collected from the BLV-seropositive bulls accounted for 1,019 semen units, representing 48.3% of the semen purchased. The maintenance of BLV seronegativity in this herd for 5 years, when semen from BLV-seropositive bulls was used for AI, provided evidence for the lack of infectivity of BLV in bovine semen.     

Putative urinary pheromone of bulls involved with breeding performance of primiparous beef cows in a progestin-based estrous synchronization protocol

The objective of this study was to determine if factors associated with the biostimulatory effect of bulls alter breeding performance of primiparous, suckled beef cows using a progestin-based estrous synchronization protocol. We tested the hypotheses that the estrous synchronization response and AI pregnancy rates differ among cows exposed to bulls, continuously exposed to bull urine, and exposed to fence-line contact with bulls or cows not exposed to bulls or bull urine. Data were collected from 3 experiments performed over consecutive years. Cows were assigned to the following treatments: bull exposure (BE; n = 26) or no bull exposure (NB; n = 25) in Exp. 1, bull urine exposure (BUE; n = 19) or steer urine exposure (SUE; n = 19) in Exp. 2, and fence-line contact with bulls (BFL; n = 26) or no bull exposure (NB; n = 26) in Exp. 3. Synchronization protocols in each experiment included the use of a controlled internal drug release device (d -10), PGF(2alpha) (d -3), and GnRH and fixed-time AI (TAI; d 0). Cows that were observed in estrus by 60 h after PGF(2alpha) were inseminated 12 h later. Cows not observed in estrus by 60 h after PGF(2alpha) were TAI at 72 h and given GnRH (100 mug). Pregnancy was determined by ultrasonography 35 d after TAI. In Exp. 1, 2, and 3, cows were exposed directly to bulls, bull urine, or bull fence-line contact for 35, 64, and 42 d, respectively. Data were analyzed between treatments within each experiment. The proportion of estrous cycling cows did not differ between treatments at the beginning of each experiment; however, more (P < 0.05) BE and BFL cows were estrous cycling at the beginning of the estrous synchronization protocol than NB cows in Exp. 1 and 3. The proportion of cows that showed estrus and interval to estrus after PGF(2alpha) did not differ between treatments in Exp. 1 and 3. However, in Exp. 2, more BUE cows tended (P = 0.09) to have shorter intervals to estrus and to exhibit estrus after PGF(2alpha) than SUE cows. Overall, AI pregnancy rates were greater (P < 0.05) for BE and BUE cows than for NB and SUE cows in Exp. 1 and 2, respectively. There was no difference in AI pregnancy rates between BFL and NB cows in Exp. 3. The presence of bulls and exposure to bull urine appeared to improve breeding performance of primiparous beef cows using a progestin-based estrous synchronization protocol, whereas fence-line bull exposure was insufficient to cause this biostimulatory effect. We propose that a novel urinary pheromone of bulls may be responsible for the enhancement of fertility in the primiparous, postpartum cow.     

Genomewide analysis of bull sperm quality and fertility traits

Because the priority of AI industry is to identify subfertile bulls, a predictive model that allowed for the prediction of 91% bulls of low fertility was implemented based on seminological (motility) parameters and DNA status assessed both as DNA fragmentation index (DFI) and by TUNEL assay using sperm of 105 Holstein–Friesian bulls (four batches per bull) selected based on in vivo estimated relative conception rates (ERCR). Thereafter, sperm quality and male fertility traits of bulls were explored by GWAS using a high‐density (777K) Illumina chip. After data editing, 85 bulls and 591,988 SNPs were retained for GWAS. Of 12 SNPs with false discovery rate <0.2, four SNPs located on BTA28 and BTA18 were significantly associated (LD‐adjusted Bonferroni <0.05) with the non‐compensatory sperm parameters DFI and TUNEL. Other SNPs of interest for potential association with TUNEL were found on BTA3, in the same chromosome where associations with non‐compensatory in vivo bull fertility were already reported. Further suggestive SNPs for sperm membrane integrity were located on BTA28, the chromosome where QTL studies previously reported associations with sperm quality traits. Suggestive SNPs for ERCR were found on BTA18 in the vicinity of a site already associated with in vivo bull fertility. Additional SNPs associated with ERCR and sperm kinetic parameters were also identified. In contrast to other, but very few GWAS on fertility traits in bovine spermatozoa, which reported significant SNPs located on BTX, we have not identified SNPs of interest in this sexual chromosome.     

Similarity in the incidence of mastitis in the daughters of related bulls

The overall prevalence of mastitis in the cow population, selected with respect to sire relatedness, was 12%. As positive for mastitis the cows with positive bacteriological findings in milk were considered. In order to objectify the evaluation by regarding the lactation number achieved, the index of morbidity In was introduced (In = number of positive findings/lactation achieved). Using this index, the groups of halfsisters--daughters of bulls and their sons--were compared and within-group variances were calculated. Differences in In between the groups of unrelated bulls were highly significant (P less than 0.01). In the progeny of sons of the same bull no significant differences were found. This indicates the role of genotype in the susceptibility to mastitis. Mean In value was 0.04 and 0.05 for the progeny of Czech Pied and Friesian breed, resp. No marked differences were observed between the groups of daughters of related bulls. The portion of Staphylococcus infections in the total number of positive findings was higher in the progeny of Friesian bulls (26.3 and 19.8% for the first and the second generation, resp.) than in the progeny of Czech Pied bulls (16.2 and 16.5% for the first and the second generation, resp.).     

Relationships among growth hormone and prolactin secretory parameter estimates in Holstein bulls and their predicted differences for lactational traits

Selection of dairy sires is based on the production records of their female ancestors, half-sibs and daughters. No trait expressed by the sire is used. Concentrations of growth hormone (GH) and prolactin (PRL), hormones produced in both males and females that are fundamental in lactation, may be correlated with production. A study was conducted to determine whether measures of these hormones in the sire would be useful predictors of lactational ability of daughters. Blood samples were collected at 15-min intervals for 8 h from 26 Holstein bulls (5.5 yr of age) that had one progeny summary available. Plasma concentrations of GH and PRL were quantified and the mean and baseline concentrations and the frequency and mean amplitude of the secretory peaks were determined for each bull. Concentrations among these values and bulls' predicted differences (PD) were determined. Significant negative correlations were detected for frequency of GH peaks and PD for yield of milk, fat and protein; correlations were positive for PRL baseline concentrations and PD for fat and protein (P less than .10), and correlations were negative for frequency of PRL peaks and PD for milk, fat and protein (P less than .10). Addition of estimates of bull hormone secretory parameters to breeding values based on performance of relatives considerably improved the accuracy (R2) for predicting progeny performance from sire information. Certain characteristics of the patterns of GH and PRL secretion may be heritable and aid in identification of superior dairy animals.     

Beef breed bulls versus selected dual purpose bulls in producing calves for meat production

The mating of small beef type bulls (Angus, Eringer) to reduce difficulties at first calvings is increasingly applied in Switzerland. In contrast to this, calf producers refuse to use large type beef bulls on their cows because of direct and indirect damages due to increased calving problems. It proved to be an attractive alternative to use specially selected dual purpose bulls tested for ease of calving and high growth rate but low dairy performance, so called M-bulls (Meat bulls), out of the regular AI testing programme for Braunvieh and Simmentals.From 1974 to 1976, Charolais, Limousin and Piemontese bulls were included in the AI testing programme and compared with Braunvieh- and Simmental-M-bulls. Data included progeny from 47 bulls, 7936 calvings, 1137 animals with carcass gains, and 130 dissected carcasses. If calving performance and net gains are considered, the M-bulls compete well with the foreign breeds. If, in addition, the amount of meat in the carcass is taken into account, then Charolais and Piemontese crosses are superior. The problem is one of distributing gains and losses among calf producers, feeders and butchers. It needs specially tested bulls with emphasis on ease of calving out of the specialized beef breeds or sire lines to persuade the dairy farmer to cross his cows.     

Some observations on the semen of bulls persistently infected with bovine virus diarrhoea virus

As a result of screening procedures employed for animals entering the AI service, two bulls were identified as being persistently infected with bovine virus diarrhoea virus by isolation of the virus from blood. Semen was collected on two occasions from these bulls; its quality as measured by density and motility was poor. Gross abnormalities of the sperm head, termed 'collapsed' heads, were seen in 28 to 45 per cent of sperm from one bull and in 1 per cent of sperm from the other. The collapsed heads were small and the whole head or its anterior part had the appearance of a dried pea. Electron microscopy showed the defect to consist of convoluted nuclear material with membrane-bound vacuoles and invaginations containing membranous debris and lamellar structures. In the 'high incidence' bull there was a corresponding increase in enlarged sperm heads. The 'low incidence' bull had sperm with heads of similar mean size to sperm from control bulls but with an increased variance. The semen was diluted in a lactose diluent, frozen and stored in liquid nitrogen. The distribution of viral antigen was determined and virus was isolated from several fractions of the semen, both before and after processing and cryopreservation. In one animal raw semen failed to yield virus but virus was recovered after processing, suggesting that raw semen may not be suitable for the efficient detection of the virus.     

National genetic improvement programs for dairy cattle in the United States

Rate of genetic improvement for milk yield has been increasing in recent years. Cows born in 1986 were about 135 kg superior in breeding value for milk yield to those born in 1985. Over 2.2 million cows contribute new data to genetic evaluations for production traits annually. These evaluations are computed with an animal model that provides best linear unbiased predictions of transmitting abilities for milk, fat, and protein yields and fat and protein percentages. The model includes effects of management group, permanent environment, herd-sire interaction, and animal genetic merit. Unknown-parent groups represent the genetic merit of base populations defined by birth year and sex. Type appraisal data are collected by breed associations and are evaluated with a sire model. Holstein cow evaluations are computed using scores from all appraisals and a multitrait model; evaluations for other breeds are computed using all appraisal scores, a repeatability model, and a single-trait system. Dystocia data are collected by individual AI organizations and dairy records processing centers; they are analyzed by a categorical-trait sire model at Iowa State University with support from the National Association of Animal Breeders. The AI organizations have been extremely important in increasing rate of genetic progress by increasing numbers of young bulls sampled, increasing selection intensity of bull dams through multiple ovulation and embryo transfer, and shortening generation interval through the use of younger cows and some virgin heifers as bull dams. (ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of acrosomal defects on fertility of bulls used in artificial insemination and natural breeding

Four bulls that produced spermatozoa with a high percentage of abnormal acrosomes were individually placed in pens with females for 21 days. Frozen semen from 2 of the bulls was used for artificial insemination. One of the bulls was placed in a competitive mating situation with normal bulls at pasture. First service pregnancy rates were determined by transrectal ultrasonography 28 days after bull removal from breeding pens, or after the last artificial insemination. The results of competitive mating at pasture were determined from breeding observations, the phenotypic characteristics of calves sired, and blood typing for parentage. The results of these studies suggest that bulls that produce a high percentage of spermatozoa with indented acrosomes may have normal fertility when used in artificial insemination or in single sire mating; however, their fertility may be low when breeding competitively with bulls with normal spermiograms.     

Chlorpyrifos (Dursban 44r) toxicity in dairy bulls

The toxicity of Dursban 44 (chlorpyrifos) in dairy bulls in two large Northeastern A.I. bull centers is reported. One hundred eighty-five (185) bulls were treated at the first center and two hundred thirty-two (232) at the second. The application of this product resulted in the death of seven and one bulls, respectively. The knowledge and experience gained at the first center resulted in rapid diagnosis and specific treatment at the second and was felt to be a significant reason for the lower death rate. Typical, clinical signs of organophosphate poisoning were not exhibited in these two outbreaks. Specific diagnosis, treatment and the course of chlorpyrifos poisoning in Holstein bulls are discussed.     

荷斯坦牛脊椎畸形综合征分子诊断方法的建立与应用

脊椎畸形综合征(Complex Vertebral Malformation,CVM)是由常染色体上SLC35A3基因单碱基突变(G→T)引起的隐性遗传疾病,该基因隐性纯合(CV/CV)时奶牛致死,但CVM携带者表现正常,所以CVM携带者公牛可以通过人工授精技术传播CVM缺陷基因。本研究自行设计检测CVM特异性PCR引物,扩增长度为173bp,然后利用PCR-SSCP方法对186个公牛样品和140个母牛样品进行了检测分析,该方法简便快捷、准确率高,使用样品宽泛,适合大样本筛选。研究结果表明,在所检测的样本中,荷斯坦种公牛和母牛CVM携带率分别为11.3%和12.1%,并通过系谱追踪发现,CVM遗传缺陷的共同祖先是美国名牛"Penstate Ivanhoe Star"(USA.1441440,CV)。通过剔除CVM携带者公牛可以有效地控制CVM遗传缺陷,但是,我国许多CVM携带者公牛冻精依然在商业化使用,所以,有效地监控CVM携带者在奶牛群中的状况对CVM防控计划是有益的。     

Linear body measurements and muscle distribution in F1 Holstein x Friesian intact males

Influence of sire, dietary regimen and slaughter weight on wither height, body depth, heart girth, hip width and percentage of total muscle in each of nine commercial cuts of F1 Holstein X Friesian bulls (N = 260) was studied. Sires were full-blooded or percentage Holstein; dams were commercial and purebred Danish Friesians. The young bulls received 100, 75, 50 or 25% concentrates, with the remainder of the diet provided in the form of silage. Animals were serial-slaughtered at 340, 470 or 600 kg. Sire was a significant source of variation in many of the body measurements and muscle distributional variables that were evaluated. It was noted, however, that sire differences in percentage of total dissected muscle in Group III cuts (rib + loin + round + hindshank) of intact male progeny were of the order of 1% or less. Sire X diet and sire X slaughter weight interactions were statistically significant in some analyses. Muscular development in the neck region was more pronounced when bulls were fed a low-concentrate diet, rather than high levels of concentrates. Percentages of total muscle in the forequarter were highest (P less than .01) for the 470- and 600-kg bulls. Thus feeding bulls to heavier weights had an adverse effect (P less than .01) on percentage of total muscle in Group III cuts. Dietary influence on linear body measurements and muscle distribution in young, Holstein-cross bulls was negligible.     

Reducing bias in the dairy cattle single‐step genomic evaluation by ignoring bulls without progeny

The number of genotyped animals has increased rapidly creating computational challenges for genomic evaluation. In animal model BLUP, candidate animals without progeny and phenotype do not contribute information to the evaluation and can be discarded. In theory, genotyped candidate animal without progeny can bring information into single‐step BLUP (ssGBLUP) and affect the estimation of other breeding values. We studied the effect of including or excluding genomic information of culled bull calves on genomic breeding values (GEBV) from ssGBLUP. In particular, GEBVs of genotyped bulls with daughters and GEBVs of young bulls selected into AI to be progeny tested (test bulls) were studied. The ssGBLUP evaluation was computed using Nordic test day (TD) model and TD data for the Nordic Red Dairy Cattle. The results indicate that genomic information of culled bull calves does not affect the GEBVs of progeny tested reference animals, but if genotypes of the culled bulls are used in the TD ssGBLUP, the genetic trend in the test bulls is considerably higher compared to the situation when genomic information of the culled bull calves is excluded. It seems that by discarding genomic information of culled bull calves without progeny, upward bias of GEBVs of test bulls is reduced.     

Induced gonadotropin release in adrenocorticotropin-treated bulls and steers

The effect of adrenocorticotropin hormone (ACTH) on plasma cortisol and on gonadotropin releasing hormone (GnRH)-induced release of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone was determined in nine Holstein bulls and 12 Holstein steers. Treatments consisted of animals receiving either GnRH (200 micrograms, Group G), ACTH (.45 IU/kg BW, Group A) or a combination of ACTH followed 2 h later by GnRH (Group AG). Group G steers and bulls had elevated plasma LH and FSH within .5 h after GnRH injection and plasma testosterone was increased by 1 h after GnRH injection in bulls. In Group A, plasma cortisol was elevated by .5 h after ACTH injection in both steers and bulls, but plasma LH and FSH were unaffected. In Group A bulls, testosterone was reduced after ACTH injection. In Group AG, ACTH caused an immediate increase in plasma cortisol in both steers and bulls, but did not affect the increase in either plasma LH or FSH in response to GnRH in steers. In Group AG bulls, ACTH did not prevent an increase in either plasma LH, FSH or testosterone in response to GnRH compared with basal concentrations. However, magnitude of systemic FSH response was reduced compared with response in Group G bulls, but plasma LH and testosterone were not reduced. The results indicate that ACTH caused an increase in plasma cortisol, but did not adversely affect LH or FSH response to GnRH in steers and bulls. Further, while testosterone was decreased after ACTH alone, neither ACTH nor resulting increased plasma cortisol resulted in decreased testosterone production in the bull after GnRH stimulation.     

Associations between sperm abnormalities, breed, age, and scrotal circumference in beef bulls

The objectives of this study were to determine the associations of breed, age, and scrotal circumference (SC), and their interaction, on the prevalence of sperm abnormalities in beef bulls in Alberta, Canada, and the percentage of satisfactory potential breeders identified during breeding soundness examination solely due to normal sperm morphology. Eosin-nigrosin stained semen smears and evaluation reports of 1642 bull breeding soundness evaluations were procured from 6 veterinary clinics in Alberta. Sperm morphology was determined for at least 100 sperm per bull. The most common defects were detached head [4.86% ± 5.71%; mean ± standard deviation (s)], distal midpiece reflex (6.19% ± 9.13%), and bent tail (1.01% ± 1.54%). Although breed, age, and SC did not significantly affect the prevalence of head or midpiece defects, morphologically normal or abnormal sperm, tail defects were more prevalent in Angus and Hereford bulls compared with other breeds. Overall, solely on the basis of sperm morphology, 1363 (83.0%) bulls were classified as satisfactory potential breeders and the remainder 279 (17.0%) as unsatisfactory (> 30% abnormal sperm, > 20% defective heads, or both). Although not significantly different, the breed with the highest percentage of satisfactory potential breeders was Limousin (90.6%) and the lowest was Hereford (78.8%). That 17% of bulls subjected to breeding soundness evaluation were designated as unsatisfactory solely on the basis of sperm morphology highlights its importance.