Produção e características físico-químicas e celulares do leite oriundo de quartos mamários de vacas com e sem mastite subclínica em três diferentes fases de lactação

Lactation stage and subclinical mastitis can change the bovine milk characteristics, with variations that produce consequences to the milk quality and quantity and prejudices to the quality of milk derivates. Animals between second and fifth lactations with same feeding and management were studied. The mammary quarters of cows were arranged in agreement stages of lactation: Stage 1 (two months after parturition); Stage 2 (intermediary months); and Stage 3 (two months before end of lactation). The milk characteristics studied were the milk production, somatic cells count (SCC), chloride levels, Dornic acidity, density, non-fat solids and cryoscopy. The mammary quarters with subclinical mastitis showed average values higher than healthy quarters to SCC and chloride levels in the three stages of lactation. The differences among the quarters to SCC were 354%; 609% and 318% to stages 1; 2 and 3, respectively, while to chloride levels the differences were 43%, 31% and 18%, respectively. The mammary quarters with subclinical mastitis showed minor average values when compared to the healthy quarters to Dornic acidity and milk production. The differences among the quarters to Dornic acidity were 17%; 16% and 21% to stages 1; 2 and 3, respectively, while to milk production the differences were 17%; 17% and 28%, respectively. There were not significant differences among ill and healthy quarters to the remaining characteristics.