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  • 學位論文

夏季集中噴淋於荷蘭牛經產乾乳牛的應用效果

Effect of Group Soaking on Holstein Multiparous Dry Cows in Summer

指導教授 : 徐濟泰

摘要


台灣為亞熱帶季風氣候,長期處於高溫及高濕度的環境,因此熱緊迫為夏季最常見的問題。台灣常見的降溫設備為頸夾灑水,此種方式除了增加畜舍相對濕度外,也會使料槽容易潮濕,且此灑水設備多設置於泌乳牛區,鮮少設置於乾乳牛區。已有研究指出乾乳期遭受熱緊迫對於隨後而來的產乳期之生產性能有負面影響。因此,本試驗研究目的為提供乾乳牛集中噴淋降溫處理,減少對於畜舍微環境的影響,並評估其降溫效果及對於牛隻的影響。 本試驗於桃園的一家商業乳牛場進行,分為兩個階段。試驗第一階段將可自動記錄體溫之溫度計置於牛隻陰道中,依照乳量及泌乳天數分為低產、中、高產及乾乳牛,每一類別乳牛設定兩隻進行降溫處理組及一隻對照組,進行頸夾噴淋及集中噴淋的降溫效果評估與比較。試驗第二部分探討乾乳牛於不同時期開始進行集中噴淋,牛隻依照開始降溫時期分為乾乳組(Dry,六頭)、轉換期組(Transition,六頭)及不進行降溫的對照組(Control,六頭),評估降溫處理對於微環境的影響、牛隻分娩前生理、行為表現及分娩後產乳表現、繁殖表現及犢牛生長狀況的影響。 試驗第一階段結果顯示在中、高產牛不論是實施集中噴淋或是頸夾噴淋,其陰道溫度皆顯著低於處理前(P<0.01),綜合比較兩種降溫方式,顯示集中噴淋處理前後的陰道溫度差顯著高於頸夾噴淋(P<0.01),兩種降溫方式擇優於乾乳牛及低產牛實施集中噴淋,處理組處理後陰道溫度皆顯著低於處理前(P<0.01)。試驗第二階段分娩前結果顯示,不論在白天或晚上實施降溫處理後的牛隻,其呼吸速率及核心溫度皆顯著低於處理前(P<0.01),較多的全日步伐(P<0.05),而乾乳組具有較長的反芻時間(P<0.05)。分娩後產乳表現無顯著差異。繁殖表現部分乾乳組產後初次發情所需天數較短(P<0.05),對照組及轉換組有胎衣滯留發生。犢牛出生重在三組之間無顯著差異,但乾乳組的犢牛至二月齡前的日增重有較多的趨勢(P<0.1),代表乾乳組犢牛體重差異隨著年齡增長會與其他兩組而增加。畜舍微環境部分,則是集中噴淋區噴頭以下的區域隨著噴淋裝置的啟動,使該區域之相對濕度及溫濕度指數高於乾乳牛休息區域(P<0.01)。 綜合上述,在夏季提供乾乳牛整個乾乳期集中噴淋使分娩前的生理、行為表現及分娩後的繁殖表現更好,且集中噴淋對於牛隻休息區域無影響,可提供酪農另一種降溫參考模式。

關鍵字

乾乳牛 噴淋 降溫處理 繁殖表現 微環境

並列摘要


Taiwan has a subtropical monsoon climate and is subject to extended periods of high ambient temperature and relative humidity. Thus, heat stress becomes an important negative factor on dairy cow performance in summer. The most common cooling setup in Taiwan is the feed bunk soaking which will increase the relative humidity of the barn, and make the feed trough wet. Feed bunk soaking is mostly installed in the lactating cow pen, and is rarely installed in the dry cow pen. Studies have indicated that heat stress during the dry period has a negative impact on the performance in the subsequent lactation period. Therefore, the aim of this study is to provide dry cows with group soaking cooling treatment to reduce the impact on the microenvironment of the barn, and to evaluate its cooling effect and the impact on cows. This study conducted at a commercial dairy farm in Taoyuan and divided into 2 parts. In the first part of study, we put the thermometer which can automatically record the body temperature into cow’s vagina. According to milk yield and day-in-milk, the cows were divided into low yield, medium yield, high yield and dry cows. In each group, 2 cows were assigned to the treatment group and 1 cow to the control group to evaluate the cooling effect and difference between feed bunk soaking and group soaking. The second part of the experiment studied the cooling effect difference of group soaking starting at different periods. The cows were divided into the cooling during entire dry period (Dry, n=6), the cooling during transition period (Transition, n=6) and that without cooling (Control, n=6). The effects of cooling treatment on the microenvironment, antepartum physiological and behavioral performance, postpartum milking, reproductive performance and growth performance of calves were monitored. The results of the first part showed that the virginal temperature of middle and high yield cows was lower than that before treatment (P<0.01) for both feed bunk soaking and group soaking. The virginal temperature change after the group soaking is significantly higher than that of the feed bunk soaking. Accordingly, group soaking was tested again on low yield and dry cows, the virginal temperature of treatment group after treatment was lower than that before treatment (P<0.01). In the second part, the respiration rate and core temperature of dry cows with group soaking during the day or night time were significantly lower than before treatment (P<0.01), and they also had more daily footsteps (P<0.05). The Dry group had more rumination time than the other two groups (P<0.05). After calving, the milking performance had no difference among three groups. Lower first estrus day was observed in Dry group (P<0.05). Retained placenta were found in Transition and Control groups. There was no deference in calves birth weight among three groups. The daily weight gain in 2 months after birth was tended to be higher in Dry group (P<0.1). The difference in body weight of calves in the Dry group increased with age compared with the other two groups. The under soaker area in the group soaking had higher relative humidity and THI than dry cow pen (P<0.01). In conclusion, group soaking for dry cows throughout the entire dry period in summer can improve the prepartum physiological condition and postpartum reproductive performance, and the group soaking has no effect on the dry cow pen microclimate, which can provide another cooling practice for dairy farmers.

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