EFFECT OF NON-GENETIC FACTORS ON PRODUCTIVE AND REPRODUCTIVE PERFORMANCE IN CROSSBRED COWS MAINTAINED AT LIVESTOCK EXPERIMENT STATION, QADIRABAD DISTRICT SAHIWAL

Abstract

The present study was undertaken to evaluate the effect of non-genetic factors such as the period of calving, season of calving, and parity on economically important productive and reproductive traits in crossbred cows (Holstein Friesian × Sahiwal) maintained at livestock experiment station Qadirabad Sahiwal, Pakistan. The study ranged from 1995 to 2014 (20 years). The duration of 20 years was divided into 4 periods (P1, P2, P3, and P4) with each period consisting of five years. Each year was further divided into three seasons winter (November-February), summer (March- June), and spring (July-October) based on geo-climatic conditions prevailing in the region. The parameters used as indicators of reproductive performance in this study were age at first calving (AFC), days open (DO), dry period (DP) and calving interval (CI). The overall least squares mean and standard errors for these reproductive parameters were 1235.23±45.81, 202.08±6.75, 178.4±6.85 and 482±5.97 days, respectively. While productive parameters were lactation milk yield 305 d(LMY), daily milk yield, and Lactation length (LL), and the least squares mean and standard errors of these were 2471.44±78.44 kg,8.07±0.27kg and306.22±4.84 days, respectively. Twenty years (20) data of 641 lactation records of crossbred cows representing the variance analyses indicated that significant (P≤0.05) effect of season of calving on age at first calving (AFC), days open (DO), lactation length (LL), and lactation milk yield (LMY). Least-squares means illustrated that the period of calving also significantly (P≤0.00) affects lactation milk yield (LMY) lactation length (LL) and dry period (DP). Similarly, a significant (P≤0.00) effect of parity on lactation milk yield (LMY), dry period (DP), days open (DO), and calving interval (CI) was noted. It is therefore concluded that the reproductive and productive performance of these crossbred cows is affected by some non-genetic factors and breeders must consider the season of calving, period of calving and parity in the management program because they greatly affect the farm productivity and profitability and they must select animals with higher breeding values to be the parent of the next generation.