Effects of transportations, a high lactose diet and ACTH injections on the white blood cell count, serum cortisol and immunoglobulin G in young calves

Twelve calves were subjected to 5 different, consecutive treatments considered to induce stress. These included a) transportations for 4–8 h at temperatures just above or well below 0°G at the start of the experiment and 6 and 11 weeks later, b) feeding a high lactose diet and c) ACTH injections.The transportations resulted in a transient suppression in the level of serum IgG, and increase of Cortisol, blood neutrophils and lymphocytes. One and 2 weeks after the first transportation, the lymphocyte count was suppressed.Intramuscular injections of ACTH also resulted in temporary increases in serum Cortisol, blood neutrophils and lymphocytes, but no obvious changes in IgG. Thus, the suppressed levels of IgG which were seen after the transportations did not appear to be directly related to the increased level of Cortisol.The high lactose diet was not accompanied by a significantly higher frequency of diarrhoea and lower mean weight gain. The IgG level did not appear to be influenced by the lactose level of the diet, and calves fed a high lactose diet responded similarly to transportation as calves fed a normal type of milk replacer. Apart from some diarrhoea, no health problem occurred.     

果洛地区初生和1岁牦犊牛生长发育规律研究

对果洛地区1岁和当年生犊牛各7头，跟踪测定体重1年，结果：当年生犊牛体重呈平稳上升趋势，一年内增重44.61kg，1岁犊牛夏秋季生长较快，春季补偿生长迅速，科季体重有所下降，一年内增重42.06kg。     

Evaluation of the prophylactic potential of an immunomodulator against respiratory disease in calves

The prophylatic effect against respiratory disease in feedlot calves of an immunomodulator, based on an inactivated avipox virus preparation, was evaluated in a double blind, placebo controlled field trial. The effect of the immunomodulator on phagocytosis and on the reactivity of the lymphocytes was also tested.On the day of arrival at the feedlots and 3 days later 257 calves were injected with either the immunomodulator or with placebo. All calves were then observed for respiratory disease and treatments were recorded. The immunomodulator did not reduce the frequency of disease, compared to the placebo. Thirty percent of the calves treated with the immunomodulator and 27 % of the controls were treated with antibiotics for respiratory disease.The cell mediated immune reactivity of 7 calves treated with the immunomodulator and of 7 untreated calves was tested. Monocytes isolated from the animals were examined for their ability to ingest latex beads and lymphocytes from the animals were examined for their response to different mitogens. Sera from each of the two groups were also investigated for the effect on phagocytosis. No difference in these parameters was observed between the two groups.     

Pharmacokinetics, urinary excretion and dosage regimen of levofloxacin following a single intramuscular administration in cross bred calves

The pharmacokinetics and urinary excretion following single intramuscular administration of levofloxacin at a dose of 4 mg/kg was investigated in seven male cross bred calves. Appreciable plasma concentration of levofloxacin (0.38 ± 0.06 µg/ml) was detected at 1 min after injection and the peak plasma level of 3.07 ± 0.08 µg/ml was observed at 1 h. The drug level above MIC₉₀ in plasma was detected up to 12 h after administration. Rapid absorption of the drug was also evident by the high value of the absorption rate constant (2.14 ± 0.24 /h). The overall systemic bioavailability of levofloxacin, after intramuscular administration, was 56.6 ± 12.4%. The high value of AUC (7.66 ± 0.72 mg . h/ml) reflected the vast area of body covered by drug concentration. Extensive distribution of the drug into various body fluids and tissues was noted by the high value of Vd_area (1.02 ± 0.05 l/kg). The high ratio of AUC/MIC (76.6 ± 7.25) obtained in this study indicated excellent clinical and bacteriological efficacy of levofloxacin in calves. The elimination half-life and MRT were 3.67 ± 0.4 h and 5.57 ± 0.51 h, respectively. The total body clearance (Cl_B) was 204.9 ± 22.6 ml/kg/h. On the basis of the pharmacokinetic parameters, a suitable intramuscular dosage regimen for levofloxacin in calves would be 1.5 mg/kg repeated at 12 h intervals.     

Pcr studies on the potential sites for latency of BHV-4 in calves

The aim of the study was to examine various tissues of experimentally infected calves for the BHV-4 genome so as to detect in which cells the virus persists during the latent phase of the infection. The presence of the bovine herpesvirus type 4 genome was detected by a nested PCR in a variety of tissues collected from two susceptible calves experimentally infected 62 days earlier. Mild clinical signs of bronchitis, an elevated body temperature for 2–3 days, and a slightly increased number of blood leukocytes were observed in both inoculated calves. BHV-4 was demonstrated in seven samples from the 12 different parts of the nervous system tested from each calf (29.1%), from the cornea, from lymph nodes near to the inoculation site, from the gallbladder and from the bone marrow. Thus a member of the predominantly lymphotropic Gammaherpesvirinae subfamily was detected in neural tissue and other organs that have never been associated with persistence.     

Serum enzyme changes in newborn calves fed colostrum

In 10 newborn Holstein calves, which were initially bottle-fed on pooled colostrum, there were transient increases in several serum enzymes. Within a few hours, the mean serum gamma-glutamyl transferase (gammaGT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), acid phosphatase (ACP), and lactate dehydrogenase (LDH) activities increased 62.5, 2.4, 2.0, 1.8 and 1.3 fold, respectively. In two other calves given initial feeds of enzyme-free pasteurized milk, there were similar increases in serum enzymes, except serum gammaGT. Correct interpretation of serum enzyme activities in newborn calves must take into account the normal increases which occur after feeding colostrum. Serum gammaGT was the only enzyme to increase markedly as a result of its absorption from colostrum. The other serum enzymes are presumably released from the tissues of the calf. The increased activities of serum CK observed in some newborn calves probably resulted from trauma during birth or increased muscular activity after birth.     

Effect of immunized egg proteins on the performance and neonatal diarrhoea incidence in newborn calves

The aim of this study was to assess the effects of feeding immunized egg proteins (IEP) on the health and performance of newborn dairy calves. Sixty-four Holstein calves, both male and female, were divided over two treatments. Calves either received IEP or a placebo (PCB) in their colostrum and calf milk replacer (CMR) for the first 14 days of their life. Until day 49, CMR was offered at 15% of birth weight (BW), at 10% on days 49–57 and at 5% on days 57–63. In addition, calves received starter concentrate, chopped straw and water from 3 days old until 70 days old at the end of study. Individual CMR and concentrate intake were measured daily whilst BW was recorded weekly. Visual faecal scoring and health observations were conducted daily. Faecal samples were collected weekly up to 4 weeks and during the first 4 days of scouring to screen for presence of Cryptosporidium parvum, rotavirus, coronavirus, E. coli and Salmonella. Results indicated that feeding IEP increased BW (p < .05) at 42 and 56 days old, and BW also tended (p = .06) to be higher after weaning at 63–70 days old compared to the PCB group. When analysed using a repeated measures model, compared to feeding PCB, feeding IEP increased total concentrate consumption (p = .001) by 3.6kg/calf. Over the entire study, daily water intake was higher (p = .002) for the IEP group when compared with the PCB group. In the IEP group, 12 calves were scored as scouring whereas there were 14 calves in the PCB group. There were no significant differences between treatments in faecal pathogen load of neither healthy nor scouring calves. In conclusion, supplementing IEP during the first 14 days of calf life improved the performance of newborn calves. Further work is warranted to understand the mode of action of IEP in calves.     

雄性梅花鹿仔鹿越冬期配合日粮适宜蛋白质水平的研究

为探讨不同蛋白质水平配合日粮对雄性梅花鹿仔鹿越冬期蛋白质消化率及生产性能的影响,试验选用18头雄性梅花鹿仔鹿随机分成4组,分别饲喂4种不同蛋白质水平的配合日粮（平均粗蛋白质水平分别为8.71%、11.88%、15.66%和17.95%）,进行饲养试验及消化试验。结果表明,仔鹿越冬期配合日粮适宜蛋白质水平为15.66%。     

Vitamin E status of healthy Swedish cattle

Using high pressure liquid chromatography the serum concentration of vitamin E was measured in dairy cows fed either hay or silage as their main roughage, in calves fed milk-replacer, and in young intensively fed bulls. The concentrates fed to the cows, calves and bulls were supplemented with 5–10, 25 and 5–10 mg DL-α-tocopheryl acetate per kg, respectively, and the milk-replacer for the calves was supplemented with 50 mg DL-α-tooopheryl acetate per kg powder. Cows fed silage as their main roughage had higher serum vitamin E concentrations (: 3.8–5.2 mg/l) than cows fed only hay (: 2.5–4.1 mg/1). Lactating cows had higher vitamin E concentrations than dry cows (: 4.1–5.2 and 2.5–3.8 mg/l, respectively) and calves and bulls had much lower vitamin E concentrations (: 1.4 and 1.2 mg/l, respectively) than cows. Thirty per cent of the calves and 41 % of the bulls had serum vitamin E concentrations less than 1.0 mg/l, suggesting that in these animals the conventional level of supplementation of feeds with DL-α-tocopheryl acetate in Sweden is probably inadequate for the prevention of nutritional muscular degeneration and other negative effects.     

肉牛繁育场哺乳犊牛腹泻探讨

哺乳犊牛腹泻由多种原因造成,是犊牛养殖中相对常见的问题,在发病初期如得不到及时控制将造成严重损失,笔者结合牧场实践与现实情况,重点阐述了肉牛繁育场哺乳犊牛腹泻发病原因,同时分析、总结相关问题,针对性的提出肉牛繁育场哺乳犊牛腹泻管控方案,为行业内养殖者在处理哺乳犊牛腹泻时提供参考依据。