Abstract #T267

# T267
Metabolic profile, feeding behavior and production responses of lactating dairy cows supplemented with a combination of osmolite feed ingredients (I.C.E.) and submitted to high temperature and humidity environment.
J. Franck1,2, F. Terra3, A. Barbosa1,2, M. N. Corrêa1,2, F. A. B. Del Pino1,2, D. B. Araújo3, E. Schmitt*1,2, 1Federal University of Pelotas, Capão do Leão, Brazil, 2NUPPEC, Capão do Leão, Brazil, 3Cargill Animal Nutrition, Campinas, Brazil.

The Internal Cooling Elements (I.C.E.) is a commercial feed technology designed and manufactured by Cargill, containing a combination of key ingredients, such as amino acids, minerals and other osmolites, that have been used as a nutritional alternative to reduce body temperature and sustain dairy cows performance during heat stress. We hypothesized that I.C.E. supplementation for lactating dairy cows submitted to high temperature and humidity environment would overcome the effects of heat stress and improve performance. Sixteen lactating, multiparous Holstein cows (65 ± 15 d in milk) were balanced for previous milk production, body condition score, parity, somatic cell count, and randomly assigned to either receive (GICE; n = 8) or not (CG; n = 8) I.C.E., 60 g/cow daily (as-fed basis) for 6 weeks. Cows were kept in a free-stall barn with the same management, feeding and cooling system during experimental period. Diets were iso-energetic for both treatment groups. Temperature and humidity logger was used to record environmental data and temperature-humidity index. All animals received a collar with a sensor to monitor and register rumination, activity and idleness time (C-Tech HealthyCow, Chipinside, Santa Maria, Brazil). Blood samples were collected and recorded every 3 d after first milking. Average THI during the role experiment period was 71.6 (59.6 min.; 83.6 max.). Higher serum albumin (2.6 ± 0.43 vs. 2.4 ± 0.47 mg/dL, P = 0.03) and lower urea nitrogen (27.1 ± 5.4 vs. 28.0 ± 5.7 mg/dL, P = 0.02) were observed for GICE, suggesting changes in protein metabolism. No difference on NEFA concentration between the treatment groups. The GICE presented higher rumination time (P < 0.01) according the day’s hour (7am: 33,2 vs. 29,0 min; 11 a.m.: 30,2 vs. 23.25 min, 17pm: 31.3 vs. 26,2min, 19pm: 29,9 vs. 22,6 min, 22pm: 31,0 vs. 24,3 min). The milk production also was higher in GICE (27.08 ± 3.2 vs. 24.92 ± 3.2 kg / d; P = 0.05). These results indicate that I.C.E. supplementation may mitigate the negative effects of heat stress in lactating dairy cows, increasing milk production.

Key Words: heat stress, rumination, THI