Investigations on renal excretion of sodium in dairy cattle

Serum and urine were taken from healthy dairy cattle from 22 different farms. 214 animals belonged to the Swiss Brown breed and 210 were crossbreds of Simmental-Red Holstein. The animals were given at least 70 g of sodium chloride with their daily feed ration. On 6 farms sodium chloride was offered ad libitum in form of licks, which was presumed to be sufficient for covering their needs. Concentrations of sodium (UR Na), potassium (UR K) and creatinine were analyzed from serum and urine and fractional excretion of Na and K was calculated. Concentrations of sodium and potassium in urine from all cows (mean +/- sd) was 60.9 +/- 44.7 mmol/l and 370.7 +/- 66.9 mmol/l respectively. The FE values were 0.954 +/- 0.939% for sodium and 173.1 +/- 54% for potassium. In 5.5% of the animals values for UR Na < 10 mmol/l were found. There were no significant differences, however, were found in sodium and potassium excretion among farms. Urine samples of at least 10 animals should be analyzed in order to have a reliable estimation of the supply with sodium chloride within a herd. Our results do not support the hypothesis that low sodium excretion would be a predisposing factor for Bovine Dilative Cardiomyopathy in Simmental-Red Holstein cattle.     

Heat stress and effect of shade materials on hormonal and behavior response of dairy cattle: a review

In tropical countries, at high temperatures, several physiological rearrangements occur in cows as they attempt to facilitate heat dissipation and/or reduce metabolic heat production. Following exposure to heat, cattle appear to acclimatize within 2–7 weeks. The failure of homeostasis at high temperatures may lead to reduced productivity or even death. The situation is even worse when humidity adds to high temperature. Livestock with elevated body temperature exhibit lower DMI and growth with less efficiency, reducing profitability for dairy farms in hot and humid climates. Shading of feed and water also offers production advantages. Although several elaborate methods for reducing heat stress in cows have been reported, simple shade materials appear to be the most cost-effective methods that are currently applicable to tropical developing countries. Different materials are being used to provide shade during warm weather. The shade material determines the microclimate—it should be light, strong, durable, weatherproof, good looking and a bad conductor of heat, and free from tendency to condense moisture inside. This review discusses various shade materials and their advantages and disadvantages in different situations.     

Investigations into an outbreak of tuberculosis in a flock of sheep in contact with tuberculous cattle

Tuberculosis, associated with Mycobacterium bovis infection, occurs infrequently in sheep. A sheep flock, which was potentially exposed to a high level of infection from in-contact tuberculous cattle, was examined for evidence of infection. Six sheep that had given a positive reaction to the comparative intradermal tuberculin test were examined post mortem. Tuberculous lesions were present in four of these sheep. Lesion morphology and distribution in the sheep was similar to that in cattle. M. bovis was cultured from the lesions and the isolates were strain typed by spoligotyping and variable number of tandem repeats (VNTR) typing. Tuberculin-reacting sheep also reacted positively to an assay for in vitro release of interferon-gamma. This paper describes the first report of an outbreak of tuberculosis in sheep in either Britain or Ireland. The report describes immunology and pathology findings and, using molecular typing techniques, suggests that the sheep had been infected from in-contact cattle.     

热应激对奶牛血液中内毒素含量和抗氧化指标的影响

选用16头健康的中国荷斯坦奶牛,随机分为两个处理（夏季组和冬季组）,每个处理8个重复,每个重复1头牛。当夏季组奶牛牛舍温湿度指数（THI）〉72的时间连续达到15d,冬季组牛舍THI〈72的时间连续达到15d时,颈静脉采血15mL制备血清,检测血清中内毒素、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）的活性,以及丙二醛（MDA）的含量。结果表明：夏季热应激可导致奶牛血清内毒素、MDA含量极显著升高,SOD和GSH-Px活性极显著和显著（P〈0.05）下降。     

Bovine growth hormone gene polymorphism affects stress response in Japanese Black cattle

We investigate the associations between growth hormone (GH) gene polymorphism and behavioral and physiological responses to stressors and learning ability in Japanese Black cattle. Flight distance test was conducted in the first experiment. Steers with haplotype C of GH gene polymorphism avoided human approaches at a significantly greater distance than ones without haplotype C (C: 1.9 ± 0.9, non‐C: 1.0 ± 0.2 m, P < 0.05). An open‐field test was conducted in the second experiment. Behavioral responses did not differ significantly between steers with and without haplotype C. Increases of heart rates to dropping of iron pipes was significantly higher in steers with haplotype C (C:161.7 ± 21.8, non‐C:130.7 ± 31.3%, P < 0.05). Despite basal serum concentrations not being different between steers with and without haplotype C, serum cortisol in blood sampling immediately after severe confinement in a race tended to be higher in steers with haplotype C (P = 0.1). The maze test was conducted as the third experiment. There was no difference in performance in the maze test between steers with and without haplotype C. It is concluded that genetic polymorphism of GH may affect stress responses through GH concentration in steers.     

热应激对奶牛机体的影响及防控措施

随着全球气候变暖,以及奶牛产奶性能的提高,热应激成了影响我国奶牛生产的一大难题,尤其在南方高温高湿的夏季,奶牛极易发生热应激。本文就热应激对奶牛产奶量、乳品质和繁殖性能的影响等方面进行了综述,并提出了一些预防奶牛热应激的措施,以期指导生产实践,提高奶牛养殖的经济效益。     

Effect of cortisol infusion patterns and castration on metabolic and immunological indices of stress response in cattle

This study tested the hypotheses that: (1) either acute stress induced by Burdizzo castration, or cortisol infusion would modulate plasma glucose, insulin and growth hormone (GH) concentrations; and (2) immune modulation induced by cortisol would be dependent on the pattern, intensity and duration of circulating cortisol concentrations. Fifty 9.2-month-old Holstein×Friesian bulls (232±2.0 kg) were blocked by weight and randomly assigned to one of five treatments (n=10 per treatment): (1) sham handled control; (2) Burdizzo castration; (3) hydrocortisone infusion to mimic the castration-induced secretion pattern of cortisol; (4) hourly pulse infusion of hydrocortisone; and (5) sustained infusion of hydrocortisone for 8 h. Blood samples were collected intensively on day 0, and weekly from days 1 to 35. Castration acutely increased plasma cortisol, GH and haptoglobin concentrations, suppressed lymphocyte in vitro interferon-γ (IFN-γ) production, but had no effect on plasma glucose and insulin concentrations. Cortisol infusion to simulate the castration-induced secretion pattern of cortisol, and pulse infusion of cortisol did not suppress the IFN-γ production. A sustained infusion of cortisol resulted in the transient suppression of IFN-γ production. Moreover, the sustained cortisol infusion resulted in increased plasma glucose, insulin and GH concentrations. The overall 14-day feed intakes and 35-day growth rates were not affected by treatments. In conclusion, cortisol infusion to induce immune suppression in vivo occurred only at pharmacological doses. Within physiological ranges, cortisol was not associated with the suppression of immune function, indicating that during castration cortisol per se is not responsible for the suppression of in vitro IFN-γ production.     

Evaluation of the long-term immune response in cattle after vaccination against paratuberculosis in two Dutch dairy herds

In the past decades, vaccination against paratuberculosis in cattle was performed in The Netherlands only on a limited scale. Because of its interference with the diagnosis of bovine tuberculosis, vaccination was restricted to herds with a high prevalence of clinical cases of paratuberculosis and was meant to aid in the economical survival of the farm. Recently, a voluntary paratuberculosis certification program has started, based in part on serological screening of cattle of at least 3 years of age. Herds that have been vaccinated against paratuberculosis are, therefore, likely to encounter problems when entering this program.The aim of this study was to evaluate the immune response resulting from vaccination with a heat-killed paratuberculosis vaccine. Over a period of 12-14 years, new-born calves were vaccinated in two herds. The B-cell response was evaluated using both the complement-fixation test (CFT) and an enzyme-linked immunosorbent assay (ELISA) and the cell-mediated immune response was evaluated using the gamma-interferon assay. Data obtained show a marked and prolonged effect of the vaccination on both cellular and humoral immune responses, in particular to the paratuberculosis antigen but also to the bovine tuberculosis antigen, using the respective tests. These responses were detected rapidly after vaccination. The individual responses were highly variable between animals with respect to both the level and to the duration of the evoked immune response. No relation between the results obtained with the ELISA and the CFT was observed. In conclusion, for a large number of vaccinated cattle, a long lasting interference is to be expected with the presently available immunodiagnostic methods for both bovine tuberculosis and paratuberculosis.     

两狗牙根品种对干旱胁迫反应的差异

在新疆农业大学试验场,通过人为控水和长期自然干旱的环境下,对成坪草坪草新农一号狗牙根和喀什狗牙根进行了形态观测,同时测定了细胞膜相对透性、叶片水分饱和亏缺(WSD)、可溶性糖含量、游离脯氨酸(Pro)含量、淀粉含量、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量等若干生理生化指标。结果表明,在干旱胁迫下(0~60 d),新农一号狗牙根比喀什狗牙根叶片枯黄发生率高(4.3%~75.2%),膜系统受伤害程度大(超过30%),维持MDA/SOD平衡能力低(0.61~3.38),形态适应性较弱。但在渗透调节物质对干旱的调节能力上,比喀什狗牙根强。不同部位受害程度的大小为叶<茎<根茎<须根。     

Perioperative stress response in the dog: effect of pre-emptive administration of medetomidine

OBJECTIVE: To determine the effect of medetomidine on the stress response induced by ovariohysterectomy in isoflurane-anesthetized dogs. STUDY DESIGN: Prospective randomized study. ANIMALS: Twelve healthy adult female purpose-bred dogs, weighing 16.8 to 25 kg. METHODS: Two treatments were randomly administered to each of twelve dogs at weekly intervals: (1) Saline injected IM followed in 15 minutes by isoflurane anesthesia (ISO) induced by mask and maintained at an end-tidal concentration of 1.8% for 60 minutes; and (2) Medetomidine, 15 ug/lkg IM followed in 15 minutes by isoflurane anesthesia (ISO&MED) induced by mask and maintained at an end-tidal concentration of 1.0% for 60 minutes. One week after completion of these two treatments, all dogs were ovariohysterectomized. six receiving each treatment (SURG and SURG&MED). Central venous blood samples (10 mL) were obtained immediately before medetomidine or saline (baseline) and at 30, 75, and 195 minutes and 24 hours after administration of medetomidine or saline in ISO and ISO&MED. In SURG and SURG&MED, samples were obtained immediately prior to injection of medetomidine or saline (baseline) and at 30 (before skin incision), 45 (after severence of the ovarian ligament), 75 (after skin closure), 105 (30 minutes after skin closure, dog recovered and in sternal recumbency), 135, 195, 375 minutes, and 24 hours after the initial sample. Samples were analyzed for epinephrine, norepinephrine, adrenocorticotrophic hormone (ACTH), cortisol, insulin, and glucose. Data were analyzed by analysis of variance and where significant differences were found, a least significant difference test was applied. RESULTS: Premedication with medetomidine prevented or delayed the stress response induced by ovariohysterectomy in isoflurane-anesthetized dogs. CONCLUSIONS: The stress response induced by ovariohysterectomy, although significant, is of short duration. Medetomidine safely and effectively reduced surgically-induced stress responses. CLINICAL RELEVANCE: Surgically induced stress responses can be obtunded or prevented by administration of medetomidine.     

Phosphorus deficiency in cattle on two farms in canterbury

A New Zealand canine herpesvirus isolate was inoculated into three 2-day-old puppies via the intraperitoneal route, two other puppies from the same litter being retained as in-contact controls. All pups were left suckling the bitch.

One inoculated pup died of misadventure. The remaining inoculated pups, and one in-contact pup, died with clinical signs of herpesvirus infection, the virus being subsequently recovered from a number of tissues. The remaining in-contact pup also developed typical disease, but recovered, virus being detected only in the tonsils. Lesions were detected in the diseased puppies in a wide variety of organs, and were consistent with previously published reports. No evidence of disease was detected in the bitch, but both she and the recovered pup developed neutralizing antibodies to the virus.