Changes in ruminal fermentation and mineral serum level in animals kept in high temperature environments

Revista Brasileira de Zootecnia

Salles, Fernando André²  Salles, Márcia Saladini Vieira²  Conti, Renata Maria Consentino³  Zanetti, Marcus Antonio¹  Titto, Evaldo Antonio Lencioni¹ 

[1] USP;APTA Ribeirão Preto, Ribeirão Preto;Anhanguera Educacional

关键词: ammoniacal nitrogen;    dry matter ingestion;    heat stress;    macromineral;    micromineral;    volatile fatty acids RESUMOPara verificar o efeito da temperatura ambiente na fermentação ruminal do alimento e nas concentrações de minerais em bovinos em crescimento;    foram utilizados 12 bezerros machos (peso médio inicial de 82;    9 ± 7;    7 kg com 100 dias de idade);    durante 38 dias;    em delineamento experimental de blocos ao acaso;    com medidas repetidas no tempo e duas temperaturas ambiente: ambiente termoneutro (24ºC) e ambiente de estresse por calor (33ºC);   

DOI  :  10.1590/S1516-35982010000400025

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

In order to evaluate the effect of environmental temperature on ruminal fermentation and on mineral levels of growing ruminants, it was used 12 male calves (initial average weight 82.9 ± 7.7 kg, 100 days of age), were employed in a randomized block design (by weight) experiment, with repeated weight measurement and two environmental temperatures: thermoneutral (24ºC) and heat-stressed (33ºC), during 38 days. The animals exposed to 33ºC presented lower dry matter ingestion, lower T3 (triiodothyronine) serum level, higher ammoniacal nitrogen (NH3-N) level in the rumen liquid, and higher rectal and body temperatures during all the experimental period when compared to the animals kept in thermoneutral environment (24ºC). The animals kept under heat stress environment (33ºC) presented higher calcium serum level, which was the highest on 31st day and the lowest on the 38th day of the experiment; phosphorus level was the lowest during all the experimental period; sodium level was lower on the 17th, 31st and 38th experimental days. Potassium and zinc levels were lower after 24 days; copper level was lower until the 24th day; magnesium level was higher until the 17th day, if compared to the ones from the animals kept in thermoneutral environment (24ºC). The heat-stressed animals presented higher levels of ammoniacal nitrogen in the ruminal liquid and a decrease in the phosphorus, sodium, potassium and zinc serum levels. These results show the necessity of changes on feed management to ruminants in temperatures over the thermal comfort limits so that performance loss is decreased.

【 授权许可】

CC BY-NC