THE OBJECTIVE OF THIS STUDY WAS TO COMPARE THE GOODNESS OF FIT OF FOUR LACTATION CURVE MODELS: Wood's Gamma model (WD), Wilmink (WL), and Pollott's multiplicative two (POL2) and three parameters (POL3) and to determine the environmental factors affecting the complete lactation curve of F1 dairy sheep under organic management. A total of 5,382 weekly milk yields records from 150 ewes, under orga...

In 1995, the multiple-trait across country genetic evaluation procedure replaced regression-based conversion equations as the preferred method for international genetic comparisons of dairy bulls. In the present study, February 1999 estimated breeding values of 632 foreign Holstein bulls that were used in Canada, Germany, Italy, The Netherlands, Sweden, and the US were compared with January 199...

Aim: The aim was to compare standard lactation curve models using fortnightly milk records in Frieswal cattle. Materials and Methods: A total of 2904 fortnightly milk yield (FMY) records from 132 Frieswal cattle maintained at Military Farm, Bareilly, Uttar Pradesh were taken for study. The Wood (WD), Morant and Gnanasakthy (MG), Mitscherlich x Exponential (ME), and Wilmink (WK) models were fitt...

The objectives of this study were: (i) to compare five models (Wood, Cobby & Le Du, Wilmink, Cappio Borlino, Djikstra) for describing the lactation curve of Chios sheep, (ii) to identify variation in lactation parameters related to environmental factors (season) and animal factors (parity). A data base on 61,705 recordings of daily milk production obtained from an automatic milking system was u...

A full-brother method was used to develop conversion equations that predict US Holstein ETA for milk, fat, and protein yields from French EBV. Regression coefficients were ratios of genetic standard deviations of sires for the two populations adjusted for the genetic correlation between countries. Based on data from full brothers, the regression coefficients were used to determine the base diff...

BACKGROUND The modelling of lactation curve provides guidelines in formulating farm managerial practices in dairy cows. The aim of the present study was to determine the suitable non-linear model which most accurately fitted to lactation curves of five lactations in 134 Gir crossbred cows reared in Research-Cum-Development Project (RCDP) on Cattle farm, MPKV (Maharashtra). Four models viz. gamm...

In this issue of CKJ, McQuarrie et al. have explored the relationship between socioeconomic status and outcomes among Scottish patients with a renal biopsy diagnosis of primary glomerulonephritis. Patients in the lower socioeconomic category had a twofold higher risk of death. No significant differences were observed on progression to end-stage renal disease (ESRD) requiring renal replacement t...

Data from 113 lactations across 76 cows between the years 2002 to 2004 were used to determine the effect of strain of Holstein-Friesian (HF) dairy cow and concentrate supplementation on milk production, body weight (BW), and body condition score (BCS; 1 to 5 scale) lactation profiles. New Zealand (NZ) and North American (NA) HF cows were randomly allocated to 1 of 3 levels of concentrate supple...

We analyzed 152,145 test-day records from 7317 first lactations of Holstein cows recorded from 1995 to 2003. Our objective was to model variations in test-day milk yield during the first lactation of Holstein cows by random regression model (RRM), using various functions in order to obtain adequate and parsimonious models for the estimation of genetic parameters. Test-day milk yields were...