Identification of lactic acid bacteria in the feces of dairy cows fed whole crop maize silage to assess the survival of silage bacteria in the gut

In order to assess the survival of lactic acid bacteria (LAB) in whole crop maize silage in the gut of dairy cows, one representative silage sample and three different feces samples were collected from dairy cows on three dairy farms in Hua Bei, China and three dairy farms in Kyushu, Japan. The composition of the bacterial community was examined by denaturing gradient gel electrophoresis and quantitative polymerase chain reaction. Lactobacillus acetotolerans was detected in all bunker‐made maize silage samples, regardless of the dairy farm or sampling region from which they were sourced. A total of eight LAB species were detected in the maize silage samples, of which three (L. acetotolerans, L. pontis and L. casei) appeared to survive digestion. The populations of L. acetotolerans in silage and feces were 10^6–7 and 10^3–4 copies/g, respectively, indicating that, even for the LAB species showing potential survival in the gut, competition in this niche may be harsh and the population may substantially decrease during the digestion process. It may be difficult for silage LAB to survive in the gut of silage‐fed dairy cows, because marked decrease in population can take place during the digestion process, even for surviving species.     

大豆黄酮对奶牛血清钙、磷及葡萄糖水平的影响

本研究选用40头胎次、产奶量、泌乳期相近的中国荷斯坦奶牛随机分成4组(n=10),试验组奶牛日粮中分别添加45、60和75mg/kg大豆黄酮,在试验前及试验开始后第10天、第20天和第30天颈静脉采血,测定4组奶牛血清钙、磷和葡萄糖水平。结果表明:与对照组相比较,试验1组中血清钙、磷和葡萄糖变化均不显著(P>0.05);试验2组仅血清钙在第30天时显著高于对照组(P<0.05);试验3组第10天和20天时血清钙水平显著高于对照组(P<0.05),第30天时血清钙水平极显著高于对照组(P<0.01),而血糖水平仅第30天显著高于对照组(P<0.05)。     

牛冷冻精液稀释液中草药配方的初步研究

通过比较以淫羊藿为主要成分的单方及复方中草药提取液对牛冷冻精液解冻后精子活率、畸形率、顶体完整率及低温保存时间的影响，以期开发牛冷冻精液中式稀释液。将三种不同配方的淫羊藿提取液分别以6．25％、12．5％、25．0％、50．0％的体积分数添加于稀释液中，制作牛颗粒冻精，利用干解冻法（40～42℃）解冻后分别检查精子活率、畸形率和顶体完整率，评定其品质。结果表明：配方三取得了较佳的冷冻效果。其提取液添加12．5％时精子冻后活率平均达到0．56，极显著高于其他各组（P〈0．01）：精子顶体完整率最高达到76．80％。畸形率仅14．61％，低温保存时间长迭138h。配方三最有利于生产牛冷冻精液。     

产犊季节、胎次及牛场对荷斯坦牛泌乳性能的影响

本研究收集了3个千头以上奶牛场共8872条相关信息,采用多因素方差分析法分析了不同产犊季节、胎次和牛场对泌乳天数、305d校正奶量、305d脂肪产量、305d蛋白产量和全泌乳期产奶量5个泌乳性能指标的影响。结果表明,不同产犊季节、胎次和牛场都极显著影响奶牛的该5项泌乳性能（P〈0．01）。夏季和秋季产犊奶牛的泌乳性能较为理想。夏季产犊奶牛的泌乳天数和全泌乳期产奶量最高,其他三个泌乳性能指标都位居第二;秋季产犊奶牛的305d校正奶量、脂肪产量和蛋白产量都显著高于其他三个季节（P〈0．05）,泌乳天数和全泌乳期产奶量也仅次于夏季。头胎牛的各项泌乳性能都显著高于其他胎次的奶牛（P〈0．05）,其次为2胎产犊奶牛。随着胎次的增加,泌乳性能的各项指标都有不同程度的降低。不同的牛场极显著地影响奶牛的泌乳性能（P〈0．01）。     

酮病对泌乳早期乳牛体内代谢和内分泌的影响

随机选取某奶牛场10头患临床酮病乳牛和10头同期健康对照组乳牛，检测了2组乳牛血液10项指标，阐明了酮病对泌乳早期乳牛体内代谢和内分泌的影响。结果显示，酮病乳牛血糖浓度极显著降低（P〈O．01），血浆NEFA和BHBA的浓度明显增高（P〈O．01）；酮病乳牛血浆Ins、LP、NPY、E2的浓度和Ins／Gn比值均明显降低（P〈O．05），而血浆Gn浓度未明显升高，P4未明显降低（P〉0．05）。表明，酮病乳牛体内某些激素协调作用紊乱会妨碍酮病乳牛能量负平衡的缓解，并将对产后生殖机能产生不良影响。     

中国荷斯坦奶牛产奶量与乳品质互作关系探讨

以一个奶牛场的336头泌乳牛为研究对象,选取了降低产奶量前、降低产奶量期间、恢复产奶量期间和提高产奶量期间4个阶段,研究了每个阶段的产奶量与乳品质一些指标间的相关性。经分析,产奶量、乳蛋白质率、乳脂肪率、非脂乳固体含量、乳糖含量这5个指标相互之间均有极显著的正相关性。     

A case-control study to identify farm factors affecting fertility of dairy herds: univariate description of factors

Objective To identify farm factors which were associated with reproductive performance in dairy herds in New South Wales.
Procedure A survey was administered by face to face interview to examine the responses of producers drawn from 757 herds, which used the New South Wales Agriculture Department Dairy Herd Improvement scheme. A case-control approach was used to select a total of 126 herds from the first (top group - cases) and fourth quartiles (low group - controls) for intercalving interval.
Results We found that the estimated interval from calving to first mating was significantly different between groups (P = 0.03) and that the groups significantly differed in both their target for interval to first mating (P = 0.02) and their perceived optimum time for first mating (P = 0.04). Other factors associated with a longer intercalving interval included, use of embryo transfer programs (P = 0.08), younger managers (P = 0.02), fewer breedings per day (P = 0.01), a greater number of people detecting heats (P = 0.07), but less hours spent detecting heats while handling the cows (P = 0.11), and a failure to vaccinate bulls for campylobacteriosis (P = 0.14).
Conclusions Managers of herds with poorer reproductive performance did not intend to mate cattle as soon after calving as managers with better reproductive performance, were not as active in seeking veterinary advice on reproduction, and were attempting to treat reproductive diseases and disorders themselves.     

A free-choice intake of mineral blocks in beef cows during the grazing season and in winter

A herd of 25 beef cows were offered four types of mineral blocks (A, B, C, D) with a different Ca to P ratio (A 0.6:1, B 0.8:1, C 2:1 and D 3.6:1). The Mg content was identical in all blocks whereas the Na content was equal in B, C and D, while the Na content in A block was double. The mineral block intake was monitored for 1 year, which was broken down to the grazing period (Pa) and the winter period (Wi). The intake of pasture grass and winter forage was assessed and the feed chemical composition was analysed; based on the obtained values, a macroelement balance (for Ca, P, Mg, Na and K) was calculated.The results showed the forage diet met requirements for all the observed macroelements (except in Na). The macroelement intake from forage was considerably higher than from mineral blocks. There were significant seasonal (Pa versus Wi) differences in B and C blocks intake. The consumption of D block was relatively invariable all year round; block A was refused in both seasons though it contained the highest amount of highly deficient Na.It can be concluded that mineral content in forage meets beef cattle requirements for Ca, Mg and K, P content is just satisfactory, and Na content is insufficient. It appears that cows control, to some extent, the Ca to P ratio in their diet by choosing the appropriate type of mineral block. However, the preference or refusal of some types of mineral blocks regardless of the season suggests the influence of other factors affecting mineral block intake which were not the subject of our observation.     

Determination of reference intervals for metabolic profile of Hanwoo cows at early,middle and late gestation periods

Background

Metabolic profile was initially designed as a presymptomatic diagnostic aid based on statistical analyses of blood metabolites to provide an early warning of certain types of metabolic disorder. However, there is little metabolic profile data available about Korean Hanwoo cows. Therefore, this study aimed to determine the reference intervals of metabolic profile for Korean Hanwoo cows.

Methods

Healthy animals (2,205) were selected and divided into early (day 1 to 95), middle (day 96 to 190) and late (day 191 to 285) period according to their gestating period. Metabolic profile including total protein (TP), albumin (Alb), urea (UREA), glucose (Glu), total cholesterol (T-Cho), long-chain fatty acid (LCFA), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), creatinine (Crea), calcium (Ca), inorganic phosphorous (iP) and magnesium (Mg) were analyzed using a TBA-40FR automatic biochemical analyzer. The data of Korean Hanwoo cows were then compared to those of the Japanese Wagyu cows.

Results

Most of the data of the Korean Hanwoo cows were relatively higher than those of Japanese Wagyu cows, with the exception of Glu and GGT. This may indicate that the nutritional level of feed for the Korean Hanwoo cows was higher than that of the Japanese Wagyu cows because of the different feeding system. In particular, relatively higher levels of UREA and LCFA were observed in the Korean Hanwoo cows, and this may also contribute to the low reproduction efficiency.

Conclusions

These findings may provide some theoretical basis for understanding the reproductive and feeding situation of Korean Hanwoo cows.     

Factors associated with morbidity,mortality, and growth of dairy heifer calves up to 3 months of age

Calfhood disease is an important problem on many dairy operations that can have substantial effects on heifer survival and productivity, and has economic and welfare impacts. Neonatal calf diarrhea (NCD) and bovine respiratory disease (BRD) are the most common causes of morbidity and mortality in young dairy cattle. The objective of this observational study was to investigate factors associated with the risks of morbidity and mortality, and with growth, in commercial dairy heifers calves. A total of 2874 heifer calves from 19 commercial dairy farms in Minnesota and Ontario were enrolled at 1–7 days of age and followed for approximately 3 months. Using cut-points of serum total protein of 5.2 and 5.7 g/dl, the incidences of failure of transfer of passive immunity (FTPI) were 11 and 32%, respectively. A cut-point of 5.7 g/dl was the most predictive of BRD before 5 weeks of age (sensitivity = 40%, specificity = 69%). The positive predictive value was poor (PPV = 18%), but the negative predictive value was good (NPV = 87%). A cut-point of 5.2 g/dl was most predictive of death before 5 weeks of age (sensitivity = 27%, specificity = 89%, PPV = 5%, NPV = 98%). Serum total protein during the first week of life was a poor predictor of NCD. Over 23% of calves were treated for diarrhea. Risk factors were weight at enrollment, other diseases before 2 weeks of age, and an interaction between season of birth and herd-level incidence of NCD. Almost 22% of calves were treated at least once for BRD. Factors associated with an increased risk of BRD included herd-level incidence of BRD, season of birth, navel dipping, other diseases before 2 weeks of age, failure of transfer of passive immunity, and manual control of temperature in pre-weaning housing. Administration of supplemental antibody products at birth was associated with a reduced incidence of BRD. Overall mortality was 3.5%. Risk of mortality was increased by treatment for BRD and other diseases. The mean average weight gain was 0.95 kg/day (range: 0.11–1.62 kg/day; SD = 0.2). Twinning status, FTP, treatment for NCD or other diseases, and month of birth influenced body weight. This study illustrated relationships among various diseases, mortality, and growth. Furthermore, it demonstrated the importance of colostrum for protection against BRD and improved growth performance, while bringing into question the optimal method of determining failure of transfer of passive immunity.