Alteration models to prodict lactation curves for dairy cows

Sudarwati, H.; Djoharjani, T.; Ibrahim, M. N. M.

doi:1995.8.4.365

Article

Ruminant Nutrition and Forage Utilization

Asian-Australasian Journal of Animal Sciences 1995;8(4): 365-368.
https://doi.org/10.5713/ajas.1995.365 Published online August 1, 1995.

Alteration models to prodict lactation curves for dairy cows

H. Sudarwati, T. Djoharjani, M. N. M. Ibrahim

Abstract

Lactation curves of dairy cows were generated using three models, namely; incomplete gamma function(model 1), polynomial inverse function(model 2) and non-linear regression(model 3). Secondary milk yield data of 27 cows which had completed 6 lactations were used in this study. Milk yield records(once a week) throughout the lactation and from the first three months of lactation were fitted to the models. Estimation of total milk yield by model 3 using the data once a week throughout the lactation resulted in smaller % bias and standard error than those generated from model 1 and 2. But, model 2 was more accurate in predicting the 305-day milk yield equivalent closer to actual yields with smaller bias % and error using partial records up to 3 months. Also, model 2 was able to estimate the time to reach peak yield close to the actual data using partial records and model 2 could be used as a tool to advise farmers on appropriate feeding and management practices to be adopted.

Keywords: Models; Lactation Curves; Cows