Supplementing rumen‐protected methionine to lactating multiparous dairy cows did not improve reproductive performance

There is evidence that supplementing methionine has positive effects on uterine environment, oocyte quality and embryo development in cattle. Thus, the objective of this study was to evaluate reproductive traits of cows supplemented with rumen‐protected methionine (RPM) during early to mid‐lactation in comparison with an untreated control group (CON). An additional focus was on the effect of puerperal diseases on reproductive performance parameters in RPM‐supplemented group MET and in CON. A total of 1,709 multiparous Holstein‐Friesian cows were enrolled in this field trial conducted on a commercial dairy farm in Slovakia. Cows were allocated at approximately 12 days post‐partum (dpp) to either CON or MET, the latter supplemented with 25.0 g–27.2 g RPM per cow per day incorporated into the total mixed ration (TMR) until leaving the study pen at approximately 140 dpp. The amount of RPM was calculated based on individual feed ingredients analysis and adjusted during the study period when TMR changed. Cows were monitored during the post‐partum period by vaginal examination (day 5 pp), measuring of beta‐hydroxybutyrate in blood (3, 5, and 8 dpp) and by vaginal examination, uterine cytology and measuring of back fat thickness by ultrasound (all at 31 ± 3 dpp). Compared with CON, cows supplemented with RPM did not show better reproduction performance parameters (first service submission rate, days to first service, conception risk, days open 140). Results from binary logistic regression model for the risk of conception showed that metritis had a significant effect, but the supplementation of methionine had not. Results of Cox regression analysis for the odds of conception within 140 dpp revealed only metritis and clinical endometritis as significant factors. In conclusion, supplementation of RPM had no beneficial effect on reproductive performance in this study farm compared with an untreated control group.     

架子牛肥育综合技术研究

该文从架子牛的选购、驱虫、肥育期的饲养管理、日粮营养等方面做了系统的研究。结果表明,选择2～3岁的夏洛来牛或西门塔尔牛的改良后代,采用高能量高蛋白质日粮可以获得较高的经济效益。     

冬小麦秸秆不同处理饲喂肉牛的效果观察

将冬小麦秸秆经微贮、氨化处理后进行饲喂肉牛增重育肥试验,对照牛喂自然干麦秸。48 头供试牛(每组16 头),试验结果为:喂微贮麦秸组头均日增重0.89kg,喂氨化麦秸组头均日增重0.84kg,对照组头均日增重0.57kg。试验组与对照组比较差异极显著(P< 0.01),两试验组差异不显著(P> 0.05)。将各组耗料(包括精料、粗料)、增重按市价进行效益分析,60 天试验期结束,微贮组平均每头获得114.00 元,氨化组平均每头获利63.13 元,对照组平均每头亏损14.36 元。冬小麦秸杆处理后饲喂肉牛效果明显。微贮法优于氨化法,成本低,易操作,饲喂效果好,在农区应大力推广。     

A filter-assisted culture method for isolation of Treponema spp. from bovine digital dermatitis and their identification by MALDI-TOF MS

Digital dermatitis (DD) is a major infectious foot disease of cattle worldwide. Some DD stages are associated with lameness, and the disease has significant economic and animal welfare consequences. The pathogenesis of the disease is not yet fully understood, but Treponema spp. have been associated consistently with clinical cases. Isolation of these fastidious bacteria is difficult and cumbersome. We describe an improved method enabling the culturing of the 3 Treponema spp. (T. pedis, T. phagedenis, and T. medium) from bovine foot specimens derived from DD lesions, using a combination of membrane filtering and subsequent growth on selective agar media. The entire procedure from sampling to verification of individual Treponema spp. takes up to 24 d. In addition, we established a MALDI-TOF MS–based identification method to be applied for confirmation of the different Treponema spp. This scheme provides an unambiguous, simple, and straightforward identification procedure for DD-associated Treponema spp.     

Potential use of lymphocyte blastogenic responses in diagnosis of bovine tuberculosis

A comparison of in vitro lymphocyte responses and delayed type tuberculin skin test responses was made in an animal experimentally exposed to a Mycobacterium bovis-infected animal and in cattle naturally infected with M. bovis. Tuberculin skin tests did not suppress in vitro lymphocyte responses to M. bovis PPD and to M. avium PPD tuberculin. The whole blood test used in these studies provided for considerable savings in time as compared to use of purified lymphocytes for evaluating in vitro cellular responses. Variations in the responsiveness of lymphocytes to specific mycobacterial antigens was observed, therefore, it is recommended that profiles be established using three or more tests conducted at 14-day intervals.     

无公害饲料预混剂及中草药在乳牛生产上的应用试验效果

40头产乳牛,10头一组,随机分为无公害预混剂＋中草药组（1组）、无公害预混剂组（2组）、中草药组（3组）和对照组。试验30天,结果表明：①无公害预混剂具有明显促进产乳增长作用,试验末期比初期（1、2组平均）产乳增长13．54％、料乳比下降11．93％、饲料成本下降10．69％,而无预混剂组（3组和对照组平均）依次为-22．39％、-28,87％、-30．3％（p〈0．01）;②中草药具有改善牛乳品质作用,中草药组（3组）牛乳总固体12．7％、乳蛋白3．0％、乳脂肪3．5％,分别比未加中草药组（对照组）高1．1（p〈0．01）、0．3（p〈0．05）和0．2（p〉0．05）个百分点;每千克牛乳中Cu、Fe、Mn、Zn含量,加中草药的1组分别比未加中草药组的2组高0．0152mg（p〈0．05）、0．243mg（p〉0．05）、-0．014mg（p〉0．05）和1．15lmg（p〈0．05）;加中草药组的3组分别比对照组高0．0179mg（p〈0．05）、0．72mg（p〉0．05）、0．0492mg（p〈0．05）和0．287mg（p〉0．05）．     

Across-breed validation study confirms and identifies new loci associated with sexual precocity in Brahman and Nellore cattle

The aim of this study was to identify candidate regions associated with sexual precocity in Bos indicus. Nellore and Brahman were set as validation and discovery populations, respectively. SNP selected in Brahman to validate in Nellore were from gene regions affecting reproductive traits (G1) and significant SNP (p ≤ 10^–3) from a meta-analysis (G2). In the validation population, early pregnancy (EP) and scrotal circumference (SC) were evaluated. To perform GWAS in validation population, we used regression and Bayes C. SNP with p ≤ 10^–3 in regression and Bayes factor ≥3 in Bayes C were deemed significant. Significant SNP (for EP or SC) or SNP in their ±250 Kb vicinity region, which were in at least one discovery set (G1 or G2), were considered validated. SNP identified in both G1 and G2 were considered candidate. For EP, 145 SNP were validated in G1 and 41 in G2, and for SC, these numbers were 14 and 2. For EP, 21 candidate SNP were detected (G1 and G2). For SC, no candidate SNP were identified. Validated SNP and their vicinity region were located close to quantitative trait loci or genes related to reproductive traits and were enriched in gene ontology terms related to reproductive success. These are therefore strong candidate regions for sexual precocity in Nellore and Brahman.     

张掖地区围栏育肥牛场防风墙后不同风速对肉牛场环境及肉牛生产性能的影响

本试验旨在研究防风墙在不同遮蔽距离的减风效果以及风速对牛生产性能的影响。选取初始体重差异不显著的40头牛随机平均分布在选定的4个牛栏中,根据牛栏距防风墙的远近分为2组,测定其日增重。同时根据牛场实际条件和天气状况布置测点,对测点的风速、温度等其他环境指标和肉牛的产热进行现场实测与计算分析。结果表明:安装防风墙的围栏育肥牛场在墙后1.2 m高度,水平遮蔽距离10倍墙高的范围内,可折减风速40%～70%;防风墙后的最佳遮蔽区域是在距离防风墙2～4倍墙高处、水平遮蔽距离6倍墙高距离范围内,风速折减效果明显,最大折减率可达70%左右;肉牛平均体重为480 kg,在外部风冷指数为-15.61的条件下,安装防风墙的围栏育肥牛场的风冷指数可以降低到-9.00,每头牛每小时可减少热量损失3.31 MJ;由于距离防风墙的远近不同,肉牛日增重相差0.15 kg/(头·d),但差异不显著(P>0.05)。     

Pathological characteristics of thyroid glands from Japanese Black Cattle living in the restricted area of the Fukushima Daiichi Nuclear Power Plant accident

To study the effect of ionizing radiation on thyroid glands, 66 Japanese Black cattle residing in the restricted area of the Fukushima Daiichi Nuclear Power Plant in 2013–2017 were pathologically examined. There were no clinical symptoms of thyroid disease in these cattle. Three cases of goiter and seven of atrophy were found in two among the four farms examined. Cases of goiter exhibited normal morphological structure without mass or nodule formation in thyroid glands. Cellular atypia or capsular invasion of the follicular epithelium was absent. The estimated integrated dose of external radiation in goiter cases ranged from maximum 797 mSv to minimum 24 mSv. All lobules in the seven atrophic thyroid glands were affected, but pathological findings, such as inflammatory cell infiltration or stromal fibrosis, were not observed. The estimated integrated dose of external radiation in atrophic thyroids ranged from maximum 589 mSv to minimum 8 mSv. Immunohistochemical analysis of anti‐nitroguanosine and the TUNEL method in goiter and atrophic thyroid glands did not reveal any positive findings. The present study indicates that there was no significant relationship between a radiation effect and pathological findings in any thyroid glands.     

Comparison of urine and blood as a convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium

Blood and urine were compared to clarify which is a better sample for estimating the concentration of radioactive cesium in muscles of live cattle. The most probable concentration of ¹³⁷Cs in muscles was 21.0 times that in blood, and the error of this estimation was 28%. The concentration of ¹³⁷Cs in blood was estimated accurately using urine samples. The estimation error did not increase so much (33%), even when the concentration of ¹³⁷Cs in muscles was estimated using urine samples. On the other hand, the maximum volume of blood that can be collected with one syringe is 50 ml, whereas it is easy to collect 1,000 ml of urine. It took at least 360 min to confirm that a cow meets the legal standard by inspecting 50 ml of blood. However, with 1,000 ml of urine, a 20 min measurement time was sufficient for this purpose. This difference in the required measurement time is critically important for practical use. In addition, urine can be collected by farmers themselves, whereas the blood collection requires a veterinarian. Therefore, urine is a more convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium.