Growth performance, metabolic and endocrine traits, and absorptive capacity in neonatal calves fed either colostrum or milk replacer at two levels

Colostrum (CO) contains high amounts, whereas whole milk and milk replacer (MR) contain small amounts, of bioactive and growth-promoting substances, such as IGF-I. An experiment was designed to study the effects of feeding CO or MR on the first 3 d to neonatal calves, followed by whole milk up to d 7, at low and high density. Intestinal absorptive capacity, plasma metabolite and hormone concentrations, and growth performance were measured during the 1st wk of life. Body weight increased (P < .05) similarly in calves fed low or high amounts of CO but did not rise in MR-fed calves. Loose feces were more frequent (P < .05) and absorption of xylose on d 5 was lower (P < .01) in MR- than in CO-fed calves, but there were no effects of feeding density within CO-fed or within MR-fed groups. However, high feeding density within CO-fed groups enhanced (P < .05) total protein, globulin, triglyceride, cholesterol, and insulin concentrations, whereas in the initially high and low MR-fed groups only plasma glucose and insulin after the first meal and plasma NEFA on d 2 were modified (P < .05) by different feeding density. Thus, feeding different amounts of CO partly influenced protein and fat metabolism in calves during the 1st wk of life, but it did not measurably affect intestinal function. However, feeding different amounts of MR, in the absence of CO, barely affected metabolic and endocrine traits and absorptive capacity. Thus, high density CO feeding, and therefore a high supply of nutrients, together with greater amounts of bioactive and growth-promoting substances influenced neonatal metabolism and growth more than a high density of MR feeding containing only small amounts of bioactive and growth-promoting substances. Factors in addition to nutrient density seem to be important for the development of neonatal calves.     

Initial results of genomic scans for ovulation rate in a cattle population selected for increased twinning rate

Genomic scans were conducted with 273 markers on 181 sires from a cattle population selected for increased twinning rate to identify chromosomal regions containing genes that influence ovulation rate. Criteria used for selecting markers were number of alleles, ease of scoring, and relative position within linkage group. Markers were multiplexed or multiple-loaded on the gels to reduce the costs and labor required to obtain genotypic data. This approach reduced the number of gels by 45% when compared with running each marker independently. Male animals selected for the genomic scan sired the majority of the population. A modified interval analysis was used in a granddaughter design to compare effects of each allele within sire for 10 different sire families. The midparent deviation of the son's estimated breeding value for ovulation rate was used as the phenotype. Forty-one potential peaks were identified with a nominal significance level < or = 0.05. The 10 peaks with the highest significance levels (P < 0.02) were selected for further analysis. Markers were genotyped across daughters of the sire where nominal significance was found for each of the 10 peaks. One peak (BTA5, relative position 40 cM) was found to be nominally significant in the daughters. The nominal significance levels were P = 0.01 for the sons (n = 32) and P = 0.02 for the daughters (n = 94) of sire 784403. A combined genomewide significance value (P = 0.07) was calculated that accounted for the 10 analyses with sons and the 10 analyses with daughters. These results strongly suggest that this region contains a gene(s) that is involved in the follicular recruitment and development process.     

Assessment of defined antigens for the diagnosis of bovine tuberculosis in skin test-reactor cattle

The continued use of purified protein derivative (PPD) tuberculin is considered to be the main factor which limits the specificity of diagnostic tests for bovine tuberculosis (TB). This study evaluated a whole blood interferon-gamma (IFN-gamma) assay and compared the diagnostic potential of PPD with two tuberculosis-specific antigens, ESAT-6 and MPB70. To provide estimates of sensitivity and specificity, responses were measured in 180 skin test-reacting cattle, of which 131 were confirmed as tuberculous, and in 128 cattle from TB-free herds. For the skin test reactors, there was a positive correlation between the IFN-gamma responses to PPD from Mycobacterium bovis (PPDB) and PPD from Mycobacterium avium (PPDA), indicating cross-reactivity between these complex antigens which are the basis of the skin test. In comparisons of the ESAT-6 IFN-gamma test with a PPD IFN-gamma test (using PPDB compared with PPDA), there was a decrease in sensitivity (76.3 per cent vs 89.3 per cent), but a clear increase in specificity (99.2 per cent vs 92.2 per cent). The provision of high specificity, even with lower sensitivity, offers major benefits for testing in areas with a low incidence of TB.     

Application of the Vettest 8008 system for the biochemical analysis of vervet monkey plasma

A clinical biochemistry analyser designed specifically for veterinary use was used to analyse plasma samples from 24 vervet monkeys (Cercopithecus aethiops). Two millilitres of heparinised blood was collected from each of the 24 monkeys on four occasions at intervals of one week. Plasma was separated and analysed for the concentrations of triglycerides, cholesterol, total proteins, albumin, globulins, creatinine and blood urea nitrogen (BUN) and the activities of alkaline phosphatase (AP), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatine kinase (CK). The tests were easy to perform, used small volumes of plasma, and yielded consistent results for most of the analytes. The activities of CK and AP, but not AST, appeared to be influenced by haemolysis, and there were significant individual variations in the activity of LDH.     

Parasite control methods used by horse owners: factors predisposing to the development of anthelmintic resistance in nematodes

One hundred and fifty horse owners, primarily private owners and riding schools, replied to a questionnaire concerning the practices they used to control parasites. Twenty-seven had experienced a parasite problem. Faecal samples from 188 horses selected at random showed that worm control practices were generally successful; however, many owners were not following recommendations for slowing the development of resistant parasites. In 1996, 86 per cent of the owners were using either three or two classes of anthelmintic a year, and they used a median of six doses with a range from one to 11. Approximately half the owners, more commonly owners of up to five horses, picked up their horses' faeces at least once a week, but these owners also used more doses of anthelmintic a year than owners who did not pick up faeces. One-third of the owners manually removed Gasterophilus species eggs from the horses' hairs, but 94 per cent of them also used ivermectin. Many owners treated specifically for Anoplocephala species, cyathostome larvae and Gasterophilus species, and these owners were the most likely to use three classes of anthelmintic a year. One-hundred-and-seven owners replied to a second questionnaire asking for information about the factors that influenced their anthelmintic control practices. Many owners, particularly private owners, were not influenced by the cost of the anthelmintic. For the timing and frequency of treatment, and the choice of drug, owners were most influenced by advertisements, magazine articles and veterinary surgeons. In two magazines aimed at horse owners, the brands of drugs most frequently advertised were the brands most commonly used by the owners, and articles in the magazines recommended the use of three classes of drug per year. These results are discussed in relation to their influence on the development of anthelmintic-resistant nematodes.     

The effect of long-acting injectable selenium formulations on blood and liver selenium concentrations and liveweights of red deer (Cervus elaphus)

AIM: To evaluate the efficacy of a new long acting injectable selenium ( Se ) formulation to increase the Se status and prevent Se deficiency in red deer. METHODS: Groups of weaned red deer (four stags and six hinds/group) grazing pastures containing <30 mg Se/kg DM were injected subcutaneously with either 0.5, 1.0 or 2.0 mg Se/kg as a new formulation of BaSeO4 (Deposel Multidose), 1.0mgSe/kg of a current formulation (Deposel), or not treated. Blood Se concentrations and liveweight were measured nine times at intervals over 377 and 270 days, respectively. RESULTS: Both formulations of Se elevated blood Se concentrations from 105 nmol/l pre-injection for at least 377 days with peak levels of 1894, 1395 and 818 nmol/l for high, medium and low doses of Deposel Multidose, respectively, at 73141 days, and 1508 nmol/l at 73-141 days for the medium dose of Deposel, which persisted at similar levels for the duration of the study. Deposel Multidose produced fewer and less severe subcutaneous tissue reactions than Deposel. Pastures contained 10 to 30 mg Se/kg DM. There was no significant difference in growth rate between treated and control deer. There was a significant (p<0. 01) linear relationship (y = 1.25x + 71.6, R2=0.86) between blood (x) and liver (y) Se concentrations in the range of 120 - 2100 nmol/l for blood concentrations, and 200 - 3000 nmol/kg for liver concentrations. CONCLUSION: Injections of BaSeO4 in both formulations studied were effective in increasing the Se status of deer but the new formulation produced fewer and less-severe tissue reactions. Young growing red deer appear less sensitive to Se deficiency as measured by weight gain, than sheep and cattle, suggesting that reference ranges for those species are not appropriate for deer. There was a linear correlation between blood and liver selenium concentrations.     

Costs and Returns of Camels,Cattle and Small Ruminants in Pastoral Herds in Eastern Ethiopia

Two questionnaire surveys (2×44) were conducted among pastoral households, using three grazing management systems. The average number of Tropical Livestock Units (250 kg) was 4.0 per member of the household. Milk production was the most important source of revenue (66% of the total) followed by sale of livestock (17%) and transport (16%). High mortality rates were recorded for all livestock. About 27% of the milk was sold fresh or as butter. Sedentary and transhumant grazing management systems showed similar levels of income, but nomads had a 2.6-fold higher overall net income. The average total gross income from the entire herd amounted to US$ 6382 per household per year. The calculated costs were 29% of the gross returns. The contribution to the total gross revenues of camels, cattle and small ruminants was 58%, 25% and 17%, respectively.     

Issues associated with the application to veterinarians of a mailed questionnaire regarding lower respiratory-tract disease in racehorses

This study evaluated a questionnaire investigating the attitudes and behaviours of veterinarians regarding the cause, diagnosis and treatment of lower respiratory-tract disease in racehorses. The questionnaire was sent to all non-student members (648) of the Australian Equine Veterinary Association: two mailings and a single telephone contact (each separated by four weeks). Subsequent phases were only administered to those who had not responded to earlier phases. In total, 467 (72.1%) of the 648 mailed questionnaires were returned. Of these, 354 were usable. The remaining 113 respondents gave various reasons for not completing the questionnaire; the most common (68%) was that horses were not a component of their practice. Those respondents working primarily with horses required fewer phases to return the questionnaire. Although deviating from previously described questionnaire designs, the described protocol provided a reasonable response rate.     

Microbiology. Action at a distance--bacterial flagellar assembly

The rotating motion of a helical flagellum enables a bacterium to swim toward positive stimuli and away from danger. But how is the flagellum, composed of many different proteins, assembled? In a Perspective, Macnab explains how subunits of the protein flagellin flow down a channel inside the flagellum and are then added to its tip through the action of a rotating pentameric cap complex (Yonekura et al.).     

Effects of repeat fenbendazole treatment in dairy calves with giardiosis on cyst excretion, clinical signs and production

In this 90-day study, 60 male Holstein dairy calves were experimentally infected with Giardia duodenalis. Calves were randomly blocked by weight into treatment (N=30) and placebo (N=30) groups. Beginning on study Day 0, calves in the treatment group were administered an oral dose of 5mg/kg of fenbendazole once daily for three consecutive days. Calves in the placebo group received a daily oral treatment of 5 ml of saline for 3 days. These treatments were repeated on Days 30 and 60 of the study. Fecal samples were collected from calves once per week and examined for the presence of Giardia cysts. Calves were monitored daily for clinical signs of intestinal disease and all episodes of diarrhea recorded. Calves were weighed once per week and total feed intake, on a dry matter basis, was calculated daily. Following each treatment, the number of calves shedding Giardia cysts in the fenbendazole group was reduced (p<0.001) compared to the saline group. Also, calves in the fenbendazole group had fewer cysts (p<0.05) detected in their feces following treatment compared with calves that received saline. Within 2 weeks post treatment, the number of infected animals and fecal Giardia cysts returned to placebo levels. This pattern of reinfection was consistent after every treatment period. Calves receiving fenbendazole had fewer total days with diarrhea (p<0.01) and the average number of days each calf had diarrhea was reduced (p<0.05), compared to the placebo group. There were no differences in mean body weight, average daily gain, or feed intake between the treatment or placebo groups. This study demonstrates that fenbendazole is an effective treatment for giardiosis, resulting in a clinical benefit and reducing the number of infective cysts shed by calves. However, this treatment regime had no impact on production parameters and reinfection occurred rapidly in these calves.