Influence of Pregnancy, Parity and Stage of Lactation on Milk Yield and Composition in Crossbred Dairy Cattle

The present study was conducted to explore the effect of pregnancy, parity and stage of lactation on milk yield and milk composition in crossbred cattle maintained at Livestock Research Station, Thiruvazahmkunnu, Palakkad, under Kerala Veterinary and Animal Sciences University.The farm is located at latitude, longitude and altitude of 11 o 21' N, 76 o 21' E and 60-70 m above sea level and having a mean annual rainfall of 2,570 mm.Milk samples from 44 crossbred cows in different parity, stage of pregnancy and lactation were collected for seven consecutive days and composition was analyzed using Ekomilk Ultra pro milk analyzer (Milkana KAM 98-2A).The overall mean milk yield, fat, SNF, protein and lactose were 7.9 kg, 3.6%, 8.1%, 3.2% and 4.2%, respectively.Pregnant cows had significantly (p<0.05)lower milk yield (6.06 vs 8.30 kg) and significantly (p<0.05)higher lactose (4.35 vs 4.23%) and SNF per cent (8.28 vs 8.01%) when compared to non-pregnant cows.Order of parity didn't have any influence on milk yield nor on the milk constituents.The mean milk yields during the three stages of lactation (<100 days, 100-200 days and >200 days) were 9.23, 7.57 and 6.52 kg/day, respectively, with peak yield being observed during the first stage of lactation (<100 days).The stage of lactation had significant effect (p<0.05) on milk yield and fat per cent whereas the other components were not influenced by the stage of lactation.