Effect of urea supplemented and urea treated straw based diet on milk urea concentration in crossbred Karan-Fries cows [India]
2005
Dhali, A. (National Research Centre for Mithun, Nagaland (India). Division of Animal Production) | Kumar Mehla, R. (National Dairy Research Institute, Karnal (India)) | Kumar Sirohi, S. (National Dairy Research Institute, Karnal (India))
The effect of urea supplemented and urea treated straw based diet on milk urea concentration was evaluated. Six multiparous crossbred Karan-Fries (Holstein Friesian x Tharparkar) cows were blocked into three groups of nearly equal body weight, DIM, milk yield and milk fat content and were randomized into a 3 x 3 Latin square design with 3-week period. The animals were fed 3 experimental diets: 1) green maize, wheat straw and concentrate mixture; 2) green maize, wheat straw, concentrate mixture (urea supplemented) and molasses; 3) green maize (4% of total DM), 4% urea treated wheat straw and concentrate mixture. Intake of DM and CP did not vary across the diets. Intake of DCP was found significantly higher in diet 2, while ME and NEL intakes were found significantly lower in diet 3 but did not differ between diets 1 and 2. Average milk and plasma urea concentrations (mg dlE-1) were found 29.2 +- 2.6, 45.3 +- 0.9, 34.5 +- 2.3 and 28.9 +- 2.4, 36.6 +- 1.4, 33.9 +- 2.2, respectively in diet 1, 2 and 3. Urea concentration in morning milk samples was found significantly lower than in noon or evening samples in all the three diets. Urea concentration in milk and plasma was closely correlated (r = 0.94) and the regression equation developed was: plasma urea = 8.90 (0.89) + 0.79 (0.02) milk urea. Intake (g) of DCP and CP per unit (MCal) of ME was more closely associated with milk urea concentration. The study revealed that urea supplementation and urea treated straw based diet increased urea concentration significantly in milk and plasma. Morning milk urea values estimated at a time gap of 15 hr since last major feeding may be considered as the lowest level and can be used to monitor feeding adequacy or reproductive performances in dairy cows
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