Mistura melaço e uréia na alimentação de vacas leiteiras, durante a seca

A mixture of 90% molasses and 10% urea was fed during the winter dry season to supplement mature pasture as feed for crossbred dairy cows. Twelve cows, in 6 sequences, were used in an 84 day "Switchback-type" trial. Three treatments were tested: I) A mixture of molasses and urea furnishing approximately two-thirds of the protein nitrogen needed by the cows, II) the same mixture furnishing one-third of the nitrogen needed (the remaining two-thirds was supplied by a concentrate mixture), III) the needed protein nitrogen furnished by concentrates. The resulting average daily milk production (4% FCM) was: Treatment I - 8.42 kg, Treatment II - 8.91 kg, Treatment III - 9.09 kg. The difference between treatments I and III was significant (P<0.05). There was no significant difference in fat content. Considering only feed and milk prices in August of 1968, the best return was obtained by treatment II (NCr$2,00 per cow/day). Treatment III yielded (NCr$ 1,95) and treatment I (NCr$1,92). Cows in all treatments registered slight gains in weight. No harmful effects were observed in any of the animals.A mistura de 90$ 1,92 também por vaca/dia (menor produção e menor lucro entre todos os tratamentos); Tratamento II; 8,91 kg de leite e NCr$2,00 de lucro (o maior lucro); Tratamento III: 9,09 kg de leite (a produção mais alta) e NCr$ 1,92 de lucro (para cálculo desses lucros, só foram considerados os valores atuais - agosto de 1908 - dos alimentos, única variável no manejo dos animais). Somente foi significante (P = 0,05) a diferença entre os tratamentos I e III, não havendo significação estatística quanto ao teor de gordura. Houve sempre ligeiro ganho de peso, não sendo percebidos efeitos nocivos