Fontes de lipídios em vacas no período de transição

Abstract

Twenty nine Holstein cows were blocked according to the expecting calving dates and were allocated in three treatments: to evaluate the effect of different fat sources on milk production and quality, and plasmatic and hepatic parameters during the transition period. Cows were fed experimental diets through four weeks before calving to 12 weeks after calving. Diets were isonitrogenous and isoenergetic supplemented with whole flaxseed (WFL), whole linola (WLO) and a source of calcium salts of palm oil. Cows from MEG treatment had higher milk production and higher daily lactose yield, but had the severest negative energetic balance. Cows from WLO treatment had higher production of cis-9, trans-11 18:2 fatty acids when compared to WFL, but were similar to MEG. The production of cis-9, cis-12, cis-15 was higher for cows from MEG treatment. There was no treatment effect for the plasmatic parameters. There was no treatment effect on the hepatic concentrations of total lipids, triglyceride and glycogen. Still, there was no treatment effect for the enzymatic activities of superoxide dismutase and glutathione peroxidase; however cows from WFL treatment had higher enzymatic activity of catalase on week four postpartum. Supplementing whole flaxseed in dairy cows diets during the transition period was not an effective way to improve production, plasmatic and hepatic parameters.