Czech Journal of Animal Science - In Press
Herd management practices associated with bulk tank somatic cell count in dairy farms on Western TürkiyeOriginal Paper
Tarık Ayyılmaz, Can Uzmay
The objective of this study was to determine the associations between bulk tank somatic cell count (BTSCC) and herd management practices in dairy farms on Western Türkiye. The material of the study consisted of registered 81 dairy farms. The farms were visited at approximately one-month intervals. Somatic cell count was determined electronically in the milk samples. According to the average BTSCC values of the farms, 2 different BTSCC categories were created (low: ≤400 103 cells/mL with 40 farms and high: >400 103 cells/mL with 41 farms). A questionnaire form was created to determine the herd management practices. The association between herd management practices and BTSCC categories was evaluated using logistic regression analysis. According to multivariate analysis, the probability for a farm belonging to the low BTSCC category increased when maintaining clean resting surface to cows, having a calving pen, applying pre-milking teat disinfection, and shutting off vacuum to the claw before removing the milking cluster. In addition, the probability for a farm belonging to the low BTSCC tended to be high when not preferring a non-stanchion barn with a hard floor (concrete etc.) as resting surface in milking cow housing. According to univariate analysis, the probability for a farm belong to the low BTSCC category was increased significantly when; maintaining cleaner exercise area, cooling the cows, keeping records about udder health, ensuring that the teats are dry while attaching the milking cluster, applying post-milking teat disinfection, and having an automatic cluster remover. Consequently, if improvements are made in these management practices, the incidence of udder health problems and consequently BTSCC will decrease.
Gompertz – Putter - Gompertz: Resolving two centuries of debate on laws of biological growthOriginal Paper
Robert Gous, Gerald Emmans
The function of Gompertz (1825) can be derived from the growth equation of Putter (1920), using the modified form proposed by Kuhleitner et al. (2019). The genetic relative growth rate is derived as RG = dlnW/dt = BG.ln(AG/W). The genetic characteristics are AG, mature weight, and BG, the rate parameter; the state variable is weight, W. The integrated form is W = AG.exp-(-exp-(G0 + BG.t)), where G0 = -ln(-ln(W0/AG)) and W = W0 when t =0. The phenotypic equation is RP = qE.RG, where qE≤1 is a measure of the quality of the environment. This function is consistent with data, collected where qE can reasonably be assumed to be 1, on the post-hatching growth of domestic and wild altricial birds, and with data from both the pre-natal and post-natal growth of domestic mammals. The mean value of the rate parameter, scaled to AG0.27, for mammals and precocial birds unselected by humans, is about 0.037, with considerable variation in avian species. Human selection for growth traits in poultry has nearly doubled the value. The mean value for six altricial species was found to be nearly three times as that for the average precocial species. The Gompertz function is consistent with data collected where the environment is not limiting. It follows logically that any function that is inconsistent with the Gompertz is inconsistent with relevant data, and therefore not a sufficient description of genetic growth.