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Artificial Shade and Supplementation Effects on Grazing Dairy Cows in Argentina

1996; Volume: 39; Issue: 1 Linguagem: Inglês

10.13031/2013.27503

2151-0059

Silvia Valtorta, M. Gallardo, Helena Castro, M.E. Castelli,

Milk Quality and Mastitis in Dairy Cows

Forty-eight grazing dairy cows in mid-lactation were randomly assigned to each of eight treatments combining the following factors: protection system (shade vs. no shade), supplementation (0 vs. 3.5 kg concentrate/cow/day) and cow parity (multiparous vs. primiparous). The study was conducted during the summer at Rafaela Experimental Station, Santa Fe, Argentina. Animal comfort, milk production and composition, Wisconsin mastitis test (WMT) and somatic cell count (SCC), grazing activity, and some blood biochemical parameters related to hydric balance were evaluated. Shade was provided by an artificial structure. Animals receiving protection were in a diurnal confinement system with water ad libitum. Supplement was offered in halves in both milkings. Protected animals presented lower afternoon rectal temperatures (TR) and respiration rates (RR) (p < 0.01), yielded more milk and protein (p < 0.05), and presented higher Na and lower K and urea serum concentrations (p < 0.05). Somatic cell count was not affected by shade treatment. Supplementation affected neither TR and RR nor blood biochemical parameters, but improved milk production in all groups. Grazing activity did not seem to be affected by treatment.