Congenital biliary atresia and jaundice in lambs and calves

An outbreak of congenital biliary atresia and jaundice is described, in which approximately 300 crossbred lambs and 9 crossbred calves died. The affected animals failed to thrive, developed jaundice and white scours and died within 4 weeks of birth. A common feature of this outbreak and a similar occurrence 24 years previously was the grazing of plants growing on the exposed silt foreshores of Burrinjuck Dam by ewes and cows in the early stages of pregnancy. Epidemiological and pathological findings suggested that a toxic insult to the foetus in early gestation caused choledysgenesis and biliary atresia, leading to diffuse, subacute to chronic cholangiohepatopathy and cirrhosis.     

Strategies for mastitis control: dry cow therapy and culling

SUMMARY The effects of three selection strategies for dry cow therapy on prevention of new infections and rate of antibiotic usage were compared. Quarter infection status of 1044 cows in 12 herds was determined by bacteriological methods at drying off, calving and three to five months into the following lactation. Cows that were uninfected at drying off were randomly allocated to treatment (whole udder, dry cow therapy) and non-treatment groups. Infected cows were randomly allocated to whole udder or infected quarter only treatments. The strategies compared were blanket treatment (treat all quarters of all cows), selective cow treatment (treat all quarters of any cow infected in one or more quarters) and selective quarter treatment (treat infected quarters only). Selective cow treatment was identified as the preferred strategy. Blanket treatment resulted in increased antibiotic usage (15.5 vs 6.4 tubes per infection eliminated) with no additional benefit, and selective quarter treatment resulted in a higher new infection rate (6.4%vs 3.9% quarters) in the dry period. The prevalence of infection within a herd at drying off had no influence on new infection rates in the dry period or early lactation. The cure rate after dry cow treatment (mean of 66%) decreased significantly with increasing age (P < 0.001). Cows infected in the previous lactation contributed over 76% of infections at calving and nearly 70% at mid-lactation. To lower the incidence of mastitis in a herd, a greater emphasis on culling of older infected cows and prevention of new infections during lactation is needed.     

Time Empty and Ketone Body Status in the Early Postpartum Period of Dairy Cows

This study aimed to assess the effect of ketone body status early postpartum on time empty in 74 multiparous dairy cows under field conditions. Animals were equally distributed across eight farms and were controlled by the same herd‐fertility‐monitoring programme. Cows were visited twice antepartum and six times postpartum at weekly intervals between 0530 and 0830 a.m. On these occasions, body condition scores and milk yields were measured, blood and milk samples were taken, cows were gynaecologically examined, and parameters of reproduction were recorded. Cows with a time empty of less or more than 80 days were classified as early and late conceiving cows (EC and LC, respectively). A time empty of 80 days results in calving‐to‐calving intervals of 1 year and classification based on this threshold value resulted in groups of equal size and equal distribution of EC and LC within farms. Ketone bodies measured were β‐hydroxybutyrate in blood and acetoacetate and acetone in blood and milk. Blood and milk ketone body concentrations, as well as the ratios of acetoacetate and acetone to β‐hydroxybutyrate, over the first 6 weeks postpartum were higher in LC than in EC, whereas plasma glucose and non‐esterified fatty acids and milk fat, protein and urea concentrations did not exhibit clear differences between groups. Ketone body concentrations were as good predictors of time empty as ketone body ratios and might have practical impact in herd‐fertility‐monitoring programmes.     

Effects of N‐acetyl‐cysteine and N‐acetyl‐cysteine‐amide Supplementation on In Vitro Matured Porcine Oocytes

This study was conducted to evaluate the effects of different concentrations of the antioxidant N‐acetyl‐cysteine (NAC) supplemented to the maturation medium on porcine embryo development. Concentrations of NAC and its synthetic derivative, NAC‐amide (NACA) were evaluated for effects on nuclear maturation, fertilization success and embryo development. Concentrations of NAC (0, 0.5, 1.0, 1.5, 2.0, 2.5 and 5.0 mm ) were supplemented to maturing oocytes, and embryo development was analysed at 48 and 144 h post‐fertilization. There were no differences among cleavage rates for any of the treatment groups. Blastocyst formation for 1.5 mm NAC (56.5 ± 9.2%) was higher (p < 0.05) than all other supplementations. There were no differences in nuclear maturation or fertilization or in cleavage rates when comparing 1.5 mm NAC and 1.5 mm NACA supplementation to the control. Blastocyst formation for 1.5 mm NAC (44.4 ± 4.7%) and 1.5 mm NACA (46.2 ± 3.4%) supplementation were higher (p < 0.05) than the control (32.1 ± 6.2%) oocytes. These results indicate that supplementing 1.5 mm of NAC or NACA to the oocyte maturation medium increased the percentage of viable embryos reaching the blastocyst stage of development.     

Eclogitic diamond formation at jwaneng: No room for a recycled component

Eclogitic diamonds have a large range of delta13C values, whereas peridotitic diamonds do not. Paired delta15N-delta13C-N variations in 40 eclogitic diamonds from the Jwaneng kimberlite in Botswana show that neither the influence of recycled biogenic carbon nor the global and primordial heterogeneity of mantle carbon are likely for the origin of the large delta13C range; the data instead support a fractionation process. It is proposed that carbonatitic mantle melts from which diamonds crystallize undergo different evolutions before diamond precipitation, when percolating through either a peridotite or an eclogite. These different evolutions, reflecting the presence or absence of olivine, can account for their respective delta13C distributions.     

Neurological diseases of ruminant livestock in Australia. II: toxic disorders and nutritional deficiencies

The second in this series of clinical reviews on neurological diseases in ruminant livestock in Australia examines toxic disorders associated with plant and microbial toxins as well as the neurological effects of vitamin and mineral deficiencies. The aim of these reviews is to assist in the surveillance of neurological diseases, especially the transmissible spongiform encephalopathies.     

Animal industry and veterinary science in eastern New Guinea: World War II to Independence, 1975

We have described the efforts of the Australian administration of the Territory of Papua and New Guinea (TPNG) to establish a veterinary service and viable animal industries. These efforts began with planning before the end of World War II in 1945 and continued until independence in 1975. Whereas pre-war cattle had mostly been used to control grass on plantations, post-war, the objective was to use the country's extensive, unoccupied grasslands for cattle production. During this period, the cattle population increased from 4000 to more than 150,000. The greatest success was achieved in herds with crosses of Bos indicus and Bos taurus owned by expatriates. The only serious disease constraint on production was myiasis due to Chrysomya bezziana, a parasite throughout New Guinea and South-east Asia. Attempts were made to increase the productivity of the indigenous pig population. Success was limited by a failure to manage inadequate nutrition and internal parasites and to fully understand the cultural aspects of pig ownership. Similar problems inhibited chicken production in villages. The serious viral infections of pigs and birds were absent from TPNG, but a border with Indonesian Papua represents a potential route for the incursion of animal diseases exotic to both Papua New Guinea and to Australia.