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A meta-analysis review of the effects of recombinant bovine somatotropin. 1. Methodology and effects on production
2003
Dohoo, I.R. | Leslie, K. | DesCôteaux, L. | Fredeen, A. | Dowling, P. | Preston, A. | Shewfelt, W.
This manuscript presents the results of a review of the effects of recombinant bovine somatotropin (rBST) on milk production, milk composition, dry matter intake, and body condition score that was carried out by an expert panel established by the Canadian Veterinary Medical Association (CVMA). The panel was established by the CVMA in response to a request from Health Canada in 1998 and their report was made public in 1999. A series of meta-analyses was used to combine data on production and nutrition related parameters that were extracted from all randomized clinical trials, which had been published in peer-reviewed journals or which were provided by Health Canada, from the submission by Monsanto for registration of rBST in Canada. A companion paper will present the results of the effects of the drug on measures of health, reproductive performance, and culling parameters. Recombinant bovine somatotropin was found to increase milk production by 11.3% in primiparous cows and 15.6% in multiparous cows; although there was considerable variation from study to study. While some statistically significant effects on milk composition (% butterfat, protein, and lactose) were found, they were all very small. Treatment increased dry matter intake by an average 1.5 kg/day during the treatment period and dry matter intake remained elevated on into the first 60 days of the subsequent lactation. Despite the increase in dry matter intake, treated animals had lower body condition scores at the end of the treatment period, and the reduced scores persisted through until the start of the subsequent lactation.
Show more [+] Less [-]Use of threshold serum and milk ketone concentrations to identify risk for ketosis and endometritis in high-yielding dairy cows
2003
Reist, Martin | Erdin, Daniel K. | Von Euw, Daniel | Tschümperlin, Kaspar M. | Leuenberger, Hans | Hammon, Harald M. | Künzi, Niklaus | Blum, Jürg W.
Objective-To use threshold concentrations of acetone and beta-hydroxybutyrate in milk and serum, respectively; identify risk for ketosis and endometritis; and assess analyses of blood and milk samples as predictors of risk for ketosis in high-yielding dairy cows. Animals-90 multiparous Holstein cows. Procedure-At intervals before and after parturition, blood samples were obtained for determination of glucose, nonesterified fatty acids, leptin, insulin, insulin-like growth factor-1, and beta-hydroxybutyrate concentrations. Samples of milk were obtained at similar intervals after parturition for determination of fat content and concentrations of acetone, protein, and lactose. Reproductive examination of each cow was performed weekly. Results-For each cow, threshold concentrations of acetone and β-hydroxybutyrate were calculated as 75th and 90th percentiles of maximum postpartum concentrations of acetone in milk (0.40 and 0.87 mmol/L) and β-hydroxybutyrate in serum (2.30 and 3.51 mmol/L). Significant decrease in milk production (442 to 654 kg of energy-corrected milk/305-day period per cow) was associated with acetone or beta-hydroxybutyrate in excess of threshold values. Milk acetone concentrations > 0.40 mmol/L were associated with 3.2 times higher risk for endometritis. Low plasma glucose, high serum beta-hydroxybutyrate, and high milk acetone concentrations during week 1 after parturition were indicators of increased risk for ketosis later during lactation. Conclusions and Clinical Relevance-Determination of milk acetone concentration during the week after parturition may identify cows at risk for ketosis and endometritis; with appropriate interventions, development of disease and production losses may be reduced.
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