Effects of environmental temperature conditions on nitrogen excretion in lactating cows
1999
Terada, F. (National Inst. of Animal Industry, Kukizaki, Ibaraki (Japan)) | Kurihara, M. | Higuchi, K. | Purnomoadi, A. | Enishi, O.
To clarify the effects of environmental temperature on nitrogen excretion in feces and urine, the results of 64 nitrogen balance trials with 32 lactating cows conducted in environmentally controlled rooms (18 degrees C 60% RH, 28 degrees C 60% RH) were used. The results obtained were as follows: 1) Feces excretion decreased as dry matter intake decreased and there was no difference in urine excretion between temperature conditions. Fecal nitrogen excretion, milk nitrogen and retained nitrogen significantly decreased under the high temperature condition (p0.01), and urinary nitrogen excretion increased (p0.05). 2) Total nitrogen excretion (ratio to nitrogen intake) in 28 degrees C was 7% more than in 18 degrees C. 3) Nitrogen accession per 4% fat corrected milk (FCM) yield decreased as FCM increased, however, there was no effect of environmental temperature. Moreover, it was indicated that nitrogen excretion/FCM yield under the high temperature conditions could be estimated using the prediction equation based on FCM, dry matter intake and crude protein content in a diet
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