REGRESSION ANALYSIS BETWEEN MILK YIELD AND LACTATION NUMBER OF DIFFERENT DAIRY COWS IN CHITTAGONG

Abstract

The study was conducted to know the performance of daily milk yield (DMY) and to estimate regression between average daily milk yield (DMY) and lactation number of different dairy cows. Duration of the study was two months of internship period at Patiya in Chittagong. A total of 100 (hundred) dairy cows of 03 (three) genotypes that is 50% Holstein-Friesian × 50% Local, 75% Holstein-Friesian × 25% Local and 50% Holstein-Friesian × 25% Sahiwal × 25% Local in 06 (six) commercial dairy farms were used for collecting data randomly through a structured questionnaire. The highest average value of daily milk yield (DMY) was 8.21 ± 0.24 in 50% Holstein-Friesian × 50% Local and the lowest average value of daily milk yield (DMY) was 5.44 ± 0.23 in 50% Holstein-Friesian × 25% Sahiwal × 25% Local. Out of 3 (three) mentioned genotype, 75% Holstein-Friesian × 25% Local fitted more with the regression line where the value of R2 (coefficient of determinant) was 0.467. It was found from the study that the daily milk yield (DMY) differed along with lactation number of 50% Holstein-Friesian × 50% Local, 75% Holstein-Friesian × 25% Local and 50% Holstein-Friesian × 25% Sahiwal × 25% Local. The highest daily milk yield (DMY) was found in those farms having good management practice, modern rearing system, supply of proper nutrition, trained and skilled farm owner