The use of bovine anti-PMSG serum in beef cattle after PMSG-superovulation.

Thirteen beef cows were superovulated using 4,000 i.u. of pregnant mare serum gonadotrophin (PMSG) on days 9 to 14 of the estrous cycle, followed by two injections of 500 micrograms prostaglandin F2 alpha analogue (PGF2 alpha) 48 and 55 hrs later. Seven of them were injected intramuscularly with bovine anti-PMSG serum 12 hrs after the first signs of estrus. The remaining 6 cows were served as controls and received no antiserum. Peripheral blood concentrations of progesterone (P) and estradiol-17 beta (E2) were compared in relation to the superovulatory responses. The injection of anti-PMSG serum did not significantly affect the numbers of the corpora lutea (CL), the anovulatory follicles and the transferable embryos at 7 to 8 days after superovulatory estrus, but increased the ratio of embryos classified as excellent or good quality. Although the plasma P concentration showed no significant differences between the anti-PMSG-treated and control cows, the plasma E2 concentration displayed a characteristic difference, suppressing the second E2 peak in the anti-PMSG-treated cows. It is concluded that the use of bovine anti-PMSG serum for PMSG/PGF2 alpha-treated cows at 12 hrs after the beginning of the estrus improves the quality of embryos recovered, probably due to inhibition of high estrogenic environment following ovulation.     

Distribution of lameness lesions in beef cattle: A retrospective analysis of 745 cases

The objective of this retrospective study was to characterize the relative prevalence of diagnoses and location of lameness lesions in beef cattle. Medical records from 2005 to 2012 were reviewed and 745 cases of beef cattle that had presented for lameness were identified. Information regarding signalment, lesion location, and cause of lameness was analyzed. The cause of lameness was localized to the foot in approximately 85% of cases; a hind limb was affected over 70% of the time. The lateral claw was most commonly affected in cases of both fore- and hind-limb lameness. The most common diagnoses of noninfectious etiology were screw claw, vertical fissure, and interdigital fibroma. Infectious foot disease accounted for only 20% of foot lameness. Routine foot trimming may be warranted in some herds to improve weight-bearing balance and alleviate lameness.     

Comparative evaluation of specific vaccines and immuno-modulators in disease control of beef cattle

Two field trials were undertaken to evaluate specific vaccines and Biological Response Modifiers (B.R.M.) with regard to disease control of beef cattle. Clinical data and laboratory results strongly suggested a genetically determined resistance to transportation stress of some cattle breeds, with possible important consequences on the occurrence of multi-factor diseases. Plenty of calves showed detectable levels of serum interferon and a remarkable activation of at least some lymphocyte populations in the first days after arrival. In general, B.R.M.-treated cattle could better react against environmental pathogens, as evidenced by both clinical and laboratory findings. Several data emerged that even the efficacy of specific vaccines could be largely accounted for by a positive modulation of non-specific immunity; this latter feature can be mainly referred to adjuvants and/or some bacterial antigens.     

The use of ultrasound in monitoring reproductive physiology of beef cattle.

Real-time, B-mode ultrasonography provides the opportunity to improve the methods of evaluation of ovarian function and diagnoses of pregnancy in beef cattle. Determination of the sex of a fetus early in pregnancy (d 55 to 85) and verification of embryo viability by monitoring fetal heartbeat are unique methods involving ultrasound scanning. These techniques and a method for evaluating the technique of artificial insemination can be used to improve reproductive management of cattle. The way in which ultrasound technology may have its greatest impact is as a tool for improving on the method of palpation per rectum for monitoring ovarian function and pregnancy in beef cows and heifers. Determination of fetal sex and monitoring embryo mortality are less likely to be applied regularly in herd management, but these procedures will be valuable in conducting research in reproductive physiology of beef cattle.     

Prevention and control of lameness in dairy cattle

The prevention and control of lameness are essential if a dairy herd is to return a profit. Breeding, feeding, housing, and management practices are all involved, and errors or omissions in any of these areas can result in catastrophic lameness. An accurate diagnosis and proper treatment are necessary to minimize losses when lameness occurs.     

Xylazine-induced hyperglycemia in beef cattle.

Intravenous administration of xylazine to beef cattle (10 animals, 0.2 mg/kg of body weight) resulted in rapid onset (less than 15 minutes) of hyperglycemia. Plasma glucose values increased to 195 +/- 15 mg/dl and 305 +/- 10 mg/dl at 15 minutes and 3 hours, respectively. Concomitantly, plasma insulin concentrations dropped from 23 +/- 2 microU/ml before xylazine to 5.8 +/- 0.7 microU/ml and 2.4 +/- 0.3 microU/ml at 15 minutes and 3 hours, respectively. Parallel decreases (20%) were observed for percentage of hemoglobin, red blood cell number, and packed cell volume. Plasma urea nitrogen was significantly (P less than 0.01) incrased within 3 hours of xylazine administration (6.7 +/- 0.9 mg/dl vs 11.4 +/- 0.7 mg/dl). Marked changes in concentrations of plasma-free fatty acids were not observed. Alternative means of anesthesia must be considered in those instances in which biopsy material is to be used for studies of carbohydrate metabolism in vitro.     

苹果酸在肉牛生产上的应用研究

本试验研究在日粮中补充DL-苹果酸（MA）对肉牛干物质采食量（DMI）、甲烷（CH4）排放和瘤胃发酵的影响,采用二因素拉丁方设计。试验1,选取6头（年龄：19±1月）肉牛随机分成3组,每组日粮的MA（占干物质含量）分别为0、3.75%和7.5%;试验2,选取4头（年龄：48±1月）插有瘤胃瘘管的肉公牛,其日粮中的MA（占干物质含量）分别为0%、2.5%和5.0%。试验1结果表明,增加日粮中MA的含量可线性降低总干物质含量和肠道中总CH4的排放量（P〈0.001）;当MA含量为7.5%时,其CH4的排放量相比对照组要降低16%,占单位干物质CH4排放量也相应下降9%。在试验2中,随着MA水平的增加DMI和CH4排放量呈线性降低（P〈0.001）;随着日粮MA水平的增加乙酸、丁酸比例呈线性减少（P〈0.001）,丙酸呈线性增加（P=001）;随日粮MA水平的增加,瘤胃pH呈上升趋势（P=0.10）,原虫数呈线性减少（P=0.01）。总体来看,增加日粮中MA含量可降低CH4的排放,但同时DMI也有所减少,这可能对动物的生产性能带来负面影响。     

The use of elite nucleus units in beef cattle breeding

Simple plans for the formation and continuation of elite nucleus breeding units utilizing multiple ovulation and embryo transfer for the genetic improvement of beef cattle were investigated. Three policies of forming nucleus units were considered, each in relation to conventional breeding herds with a possible rate of annual genetic change of .17 phenotypic standard deviation (SD) units and also to breeding herds with no genetic improvement. The genetic improvement (as a genetic lift) from the formation schemes ranged from .43 to 1.38 SD units. Three policies for the continuation of the nucleus units were outlined. The best scheme resulted in almost double the total genetic change possible from conventional breeding herds over a 20-yr period. Transfer of these gains from nucleus to breeding herds and to the commercial herds also was considered. Some advantages and limitations to nucleus breeding schemes were discussed. The opportunity exists for progressive breeders, or groups, to make use of improved genetic evaluation systems (expected breeding values) and embryo transfer to greatly accelerate rates of genetic change in economic efficiency of beef cattle.     

Evaluation of antimicrobial use in dairy cattle,beef cattle and broilers in Japan using dosage-based indicators

The sales amount of antimicrobials intended for use in dairy cattle, beef cattle and broilers from 2008 to 2019 was evaluated for each antimicrobial class and administration route using dosage-based indicators. Our results revealed that the antimicrobial sales amount sold for use in dairy cattle in 2019 in terms of total weight of active ingredient, the number of defined daily doses (DDDs) (theoretical amount of biomass subjected to antimicrobial treatment in a year) and the number of treatment days (TDs) (theoretical number of days of treatment that an animal is subjected to in a year) calculated using Japanese DDD values (DDDjp values) was 36,751 kg, 8,261,848,000 kg·days and 15.5 days, respectively. Likewise, the antimicrobial sales amount sold for use in beef cattle and broilers in 2019 in terms of these metrics was 33,403 kg, 3,928,248,000 kg·days and 3.61 days, and 69,773 kg, 2,947,848,000 kg·days and 10.66 days, respectively. There was a considerable difference between the number of DDDs calculated using DDDjp values and that calculated using European DDD values (DDDvet values) for antimicrobial products sold for use in dairy and beef cattle. Our results also revealed that the sales amount of some antimicrobials, such as cephalosporins and quinolones represented larger proportions when calculated using dosage-based indicators than when calculated using the weight of active ingredient. Considering that Japanese veterinarians and farmers are more likely to conform to the Japanese dosage recommendations rather than the European ones, these results indicate the need for using dosage-based metrics, in particular metrics based on Japanese dosages rather than European dosages.     

Treatment of proximal hind-limb lameness in cattle

Lameness of the hind limb (tarsus and proximal) in cattle is considered from the viewpoint of diagnosis and prognosis. Indications and techniques for radiography are discussed, as well as when indicated.     

Cardiopulmonary effects of restraint in dorsal recumbency on awake cattle

The cardiopulmonary effects of dorsal recumbency were studied in awake cows restrained for surgical correction of left displaced abomasum. During the recumbent period, PaO2, PaCO2, arterial pH, and base excess values were significantly decreased. Heart rate, respiratory rate, blood hemoglobin concentrations, and rectal temperature increased significantly.     

Clinical and subclinical lameness in young fattenin cattle

Time dependent changes of subclinical and clinical lameness were analysed in 493 fattening bulls in three different herds with a total number of 30,621 animals. In the majority of cases subclinical lameness were observed which were caused by metabolic acidosis or deficiencies in mineral intake (P and probably Ca). The activity of alkaline phosphatase in plasma exhibited an increase and the dry matter in bone (tubera coxae) a decrease before the appearance of clinical symptoms. Changes in bone composition were accompanied by alterations of plasma Ca and P concentrations, which finally led to clinical lameness. Hence the diagnosis was verified by simple laboratory methods as the precondition for successful treatment and prophylaxis of lameness caused by metabolic disorders.     

Leptospirosis vaccination in beef cattle: use of decision tree analysis

Decision tree analysis was used to evaluate the economic benefits of leptospirosis vaccination in beef cattle. The analysis used estimated values for the cost of vaccination, the probability of calf losses from leptospirosis and the economic losses resulting from calf mortality to calculate the expected value of vaccination. A computer spreadsheet was used to calculate the expected value of the vaccination programme over a wide range of estimated costs and probabilities and to determine the break-even point at which vaccination becomes economic. A sensitivity analysis demonstrated that the outcome of the analysis was most dependent on calf value and the probability of calf loss due to leptospirosis. The analysis was relatively insensitive to changes in vaccine cost, vaccine efficacy and herd fertility.