- 期刊
不同溫溼度指數對荷蘭泌乳牛乳產量與乳成分之影響
Impact of different THI levels on milk yield and composition of Holstein dairy cows
摘要
本研究旨在探討不同溫溼度指數（temperature-humidity index, THI）對荷蘭種泌乳牛產乳量與乳成分之影響。試驗期間自2015年至2017年，每天記錄畜舍溫度與相對濕度並計算THI，試驗使用共1,368筆DHI資料，依不同THI程度（THI＜72、THI72－78與THI＞78）下進行分析，分析項目包括乳量（daily milk yield, DMY）、乳脂率（milk fat percentage, MFP）、乳蛋白率（milk protein percentage, MPP）、乳糖率（milk lactose percentage, MLP）、乳無脂固形物（milk solids-not-fat percentage, MSNFP）、乳總固形物（milk total solid percentage, MTSP）、乳體細胞數（somatic cell counts, SCC）、乳體細胞分數（somatic cell score, SCS）及乳蛋白質與乳脂肪之比值（protein to fat ratio, PF）。結果顯示，畜舍每年12月份至隔年3月份THI皆小於72，而每年4月份及11月份THI則介於72－78之間，其餘每年5月份至10月份THI皆大於78。測定項目DMY、MFP、MLP、MSNFP及MTSP皆隨著THI增加而降低的現象。而SCC、SCS與PF則隨著THI增加有提高之趨勢。綜上所述，荷蘭種泌乳牛在熱環境下確實會對產乳性能產生負面的影響。因此，當THI大於72時，建議應採取減緩牛隻因熱緊迫所帶來的負面影響及可能帶來經濟上的損失之相關策略。
並列摘要
This study aimed at assessing the impact of temperature-humidity index (THI) on milk yield and composition of Holstein dairy cows. Experiment animals were carried out inside the barn and in a dairy farm. Daily ambient temperature and relative humidity were recorded and used to calculate the daily THI from 2015 to 2017. A total of 1,368 sets of complete Dairy Herd Improvement data were obtained and grouped by THI levels (THI ＜ 72, THI 72-78, and THI ＞ 78). These data included daily milk yield (DMY), milk fat percentage (MFP), milk protein percentage (MPP), milk lactose percentage (MLP), milk solids-not-fat percentage (MSNFP), milk total solid percentage (MTSP), somatic cell counts (SCC), somatic cell score (SCS), and protein to fat ratio (PF). The results showed that THI were less than 72 from December to March between 72 and 78 in April and November, and greater than 78 from May to October for each year. DMY, MFP, MLP, MSNFP, and MTSP were decreased with the increase of THI, but SCC, SCS and PF tended to increase with the THI. In conclusions, the results of this study indicated the seriousness of the negative effects of hot conditions on milk yield and composition. Thus, when the THI is greater than 72, measures should be taken to alleviate negative consequences of heat stress in dairy cows and related economic losses.