Impacts of lactation physiology at higher and average yield on composition, properties and health indicators of milk in Holstein breed
2010
Sojkova, K.,Agrovyzkum Rapotin, Vikyrovice (Czech Republic) | Hanus, O.,Agrovyzkum Rapotin, Vikyrovice (Czech Republic) | Riha, J.,Agrovyzkum Rapotin, Vikyrovice (Czech Republic) | Gencurova, V.,Agrovyzkum Rapotin, Vikyrovice (Czech Republic) | Hulova, I.,Agrovyzkum Rapotin, Vikyrovice (Czech Republic) | Jedelska, R.,Agrovyzkum Rapotin, Vikyrovice (Czech Republic) | Kopecky, J.,Agrovyzkum Rapotin, Vikyrovice (Czech Republic)
The differences in milk indicators were evaluated in four Holstein herds with either high yielding cows (H1) or cows with average milk yields (H2). The files with 224 and 234 individual milk samples were collected in summer and winter during three years. The files were balanced in factors of lactation. H1 had higher genetical value and had even better nutrition according to the milk yield (MY) which was higher by 43%. The studied high MY factor had statistically significant influence on the following milk variables: fat, lactose, solids non fat, alcohol stability, rennet curds firmness, crude protein, casein, true protein, fat/true protein ratio. Selected differences were as follows (H1 vs. H2): fat: 3.68+/-0.77 vs. 3.99+/-0.93%; casein: 2.50+/-0.27 vs. 2.59+/-0.29%; true protein: 2.99+/-0.30 vs. 3.09+/-0.33%. Other 16 milk variables (e.g. somatic cell counts: 289 x 10*3/mL in H1 vs. 210 x 10*3/mL in H2), urine, ratio of urea nitrogen in the non protein nitrogen, acetone, pH and rennet curds firmness were not influenced significantly. The differences in milk indicators between the two groups did not indicate problems of the health status. The high MY reached by the genetic improvement of animals does not result in impaired quality of raw milk. Surprisingly, MY and urine content in milk did not correlate positively.
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