Inclusion of crude glycerin in the diet of dairy cows on intake, milk yield and composition

The objective of this study was to evaluate the effect of inclusion of crude glycerin (CG), corrected for protein with a byproduct of processing corn, mazoferm, on intake, production and composition of milk from Holstein cows. A total of 12 Holstein cows distributed in three Latin squares 4x4, with average production of 15 kg. The animals were fed four diets, protein and isocaloric, referring to four levels of replacement of corn grain by mixing PG-80, 0, 33.3, 66.6 and 100.0% based on the total dry matter, which corresponded respectively to 0, 40, 80 and 120 g of CG/kg dry matter. The cows were milked mechanically twice a day, making up the record of milk production of each experimental period and collected a sample of milk for evaluation of lactose, fat, protein, total solids and somatic cell count (SCC). Data were subjected to analysis of variance using the MIXED procedure of the Statistical Analysis System. The dry matter intake, the average milk production and milk production adjusted to 35 g fat / kg milk, were not affected (P>0.05) by the inclusion of GP-80 mixture in the diet. The nutritional composition of milk (fat, protein, lactose and total solids) was not affected by treatments (P>0.05). The use of crude glycerin in diets to meet protein and energy requirements of animals does not compromise the dry matter intake, production, composition and milk quality for cows of low production.