泌乳牛の主要ミネラル出納におよぼす高温環境の影響

DOI Web Site 被引用文献1件

書誌事項

タイトル別名
  • Effect of Hot Environmental Temperature on Major Mineral Balance in Lactating Cows
  • ヒニュウギュウ ノ シュヨウ ミネラル スイトウ ニ オヨボス コウオン カン

この論文をさがす

抄録

Four lactating Holstein cows were housed in two independently controlled climatic rooms, each housing 2 open-circuit respiration chambers. Two of the cows were exposed to temperatures in the order 18°, 26°, and 30°C and 60% RH for 2 weeks per treatment, while the other two were exposed to the same temperatures in reverse order.They were fed concentrate and Italian ryegrass hay in the chambers.Body weight, milk yield, and hay intake significantly decreased with increasing temperatures, and concentrate intake, water intake, and block salt intake tended to decrease at high temperatures.Dietary levels of major minerals were almost adequate for lactating cows.There were no significant differences in major mineral concentrations in milk between treatments, although P and Mg concentrations in milk tended to decrease with higher temperatures.Major mineral intake, excretion, and secretion in milk decreased with higher temperatures.Decreased major mineral excretion may be due to decreased mineral intake.Major mineral absorption, which tended to decrease above 26°C, may be due to decreased major mineral secretion in milk.Results suggest that the major mineral absorption of lactating cows may be affected by heat stress and decrease above 26°C.Heat stress in summer reduces the feed intake, milk yield, and milk composition of dairy cattle, and increases potassium (K) and sodium (Na) requirements.In the previous paper, we suggested that calcium (Ca), phosphorus (P), and magnesium (Mg) requirements for dry cows may increase in hot weather, since the maintenance requirement increases with temperatures above 27°C and/or apparent absorption decreases at 32°C.<BR>Since increasing dietary Na and K may affect milk yield, milk composition, and the physiological and endocrine responses of cattle, it may be possible to increase the productivity of heat-stressed cattle with increased dietary Na and K.Therefore, it is important to assess the major mineral requirements for dairy cattle in hot weather in order to improve productivity in hot temperatures.Also, the major mineral requirements of dry cows in hot weather has been estimated previously.This study was, therefore, conducted to evaluate the effects of hot environmental temperatures on the major mineral balance in lactating cows.

収録刊行物

  • 日本畜産学会報

    日本畜産学会報 58 (9), 764-770, 1987

    公益社団法人 日本畜産学会

被引用文献 (1)*注記

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ