ABSTRACT
The present study was carried out using first lactation monthly test-day milk yield records of 466 crossbred (HF × Sahiwal) cattle calved from 2000 to 2018 sired by 89 bulls maintained at Directorate of Livestock Farms, GADVASU, Ludhiana. Mixed model analysis was carried out by least-squares maximum likelihood programme to study the effects of non-genetic factors on first full lactation milk yield (FFLMY), first lactation 305-day milk yield (FL305MY) and monthly test-day (TD) milk yield records of crossbred cattle. The least squares means of different monthly TD milk yields (1st to 11th) were 12.05 ± 0.42, 15.65 ± 0.42, 15.38 ± 0.44, 14.44 ± 0.43, 13.79 ± 0.41, 12.88 ± 0.40, 12.27 ± 0.42, 11.83 ± 0.37, 10.85 ± 0.42, 10.64 ± 0.45 and 10.28 ± 0.50 kg, respectively. For FFLMY and FL305MY the means were 4979.60±184.45 and 3818.17±103.26 kg. The effects of different AFC groups were non-significant on TDs and FL305MYs, whereas it was significant (p≤0.01) for FFLMY. The season was significant (p≤0.01) for all the monthly TDs whereas it was non-significant for FFLMY and FL305MY. The sire was significant (p≤0.01) for most of the TDs and FL305MYs except the later TDs (9th, 10th and 11th TD) and FFLMYs. The present investigation revealed the importance of non-genetic factors in performance evaluation of crossbred cattle based on monthly test-day milk yield, FL305MY and FFLMY records