加強環境衛生和畜群管理措施對乳牛群副結核亞型鳥分支桿菌(Mycobacterium avium subsp. paratuberculosis)盛行率之影響

The Effect on the Prevalence Rates of Mycobacterium avium subsp. paratuberculosis Infection Following with Strengthening Sanitation and Herd Management in Dairy Herds

彭明發(Ming-Fa Peng)

指導教授 ： 吳永惠

國立屏東科技大學/農學院/獸醫學系所/碩士(2013年)

https://doi.org/10.6346/NPUST.2013.00079

摘要

副結核亞型鳥型分支桿菌 ( Mycobacterium avium subsp. paratuber- culosis ；MAP )感染所引起之副結核病 ( paratubeculosis ) 在反芻獸是一種以不能恢復之消耗性、下痢和死亡為特徵之慢性腸炎。由於MAP可在各種環境中存活很久，且易經由糞口傳染，或由無症狀帶原者傳入無感染群和其後代，導致副結核病已廣泛分佈於世界各地乳牛場。由於太過複雜之控制措施往往不能被酪農持續實施，本研究因而擬評估較易於施行之控制方法如加強環境衛生和餵犢消毒牛乳對MAP盛行率之影響，以作為輔導酪農戶控制牛副結核病之依據。首先，篩選5場 ( A-E場 ) 血清抗體ELISA檢驗和糞便PCR檢驗之MAP盛行率相近之乳牛場作為供試場，A、B兩場實施犢牛與母牛飼養環境加強清潔，並每週定期消毒1次，而將此兩場稱為「加強環境衛生場」；C、D兩場餵犢牛之飲乳先62-65℃消毒 1-3 小時，而將此兩場稱為「犢牛餵予消毒乳場」；E場不改變飼養管理方式，餵犢牛之飲乳並無消毒，而被當作「對照組」。然後在處理後，每隔3-4個月1次共4次採樣，每次各場採20頭成牛進行血清抗體ELISA檢驗，而每次糞便PCR檢驗採樣包括採全部高床上犢牛 ( 1-3月齡，稱為「架上小牛」)、10頭飼養於水泥地面小牛 ( 6-12月齡，稱為「下架小牛」) 及10頭成牛 ( 2-5歲 )。最後，再將處理後4次採樣之MAP盛行率變化來與處理前比較，並評估供試5場間MAP盛行率之差異性。結果如下：1). 糞便PCR檢驗之MAP盛行率在處理後第一次採樣起，在「加強環境衛生場」 ( A、B場 ) 和「犢牛餵予消毒乳場」( C、D場 )，其小牛 ( 架上小牛和下架小牛 ) 及成牛，均有較多次比處理前盛行率呈現顯著 ( P<0.05 ) 或明顯下降，而對照場 ( E場) 則無論是小年或成牛僅有較少次明顯但不顯著 ( P<0.05 ) 之下降。2). 在血清抗體ELISA檢驗方面，MAP盛行率在A、B、C和E場，在處理後之首二次並未無顯著 ( P<0.05 ) 之下降，但在第3和/或第4次則出現顯著 ( P<0.05 ) 之下降；D場則始終無明顯或顯著 ( P<0.05 ) 之下降。以上結果顯示，易於施行之MAP控制方法 ( 加強環境衛生和餵予犢牛消毒乳)，可防止感受性動物 ( 尤其犢牛 ) 曝露於MAP感染，而降低整個牛群之MAP盛行率。

關鍵字

副結核病 ； 副結核亞型鳥型分支桿菌 ； 副結核病控制策略 ； 乳牛

並列摘要

Paratuberculosis caused by Mycobacterium avium subsp. paratuber- culosis ( MAP ) is a chronic enteritis characterized by irreversible wasting, diarrhea and death in ruminants. The disease had extensively distributed in dairy herds worldwide, because MAP can survive in various environment for very long period, and easily through the fecal-oral route transferred, or from a subclinically infected carrier transmit to noninfected herd and their offspring. Because the complicated control measures usually not be practiced by dairy farmers persistently, the efficacy on MAP-prevalence rates of more easily performable control measures such as strengthening the sanitation and fed calves with sterilizing milk will be evaluated in this study, which could be took as a basis for guiding the farmers to control bovine paratuberculosis. First, Five dairy herds (A to E herd ) with near MAP-prevalence rates in serum-antibody ELISA and feces-PCR tests were selected. On the A and B herds, the cleaning of the environments reared calves and cows were strengthened and the disinfection were periodically one time per week for the calving area and barn, and two herds were referred to a “strengthening sanitation herds ” in this study. On the C and D herds, the milk fed the calves were sterilized at 62-65℃ for 1-3 hours, and two herds were referred to a “calves fed with sterilizing milk herds ” in this study. On the E herd, the mode of feeding and management were not changed, the milk fed calves were not sterilized, the herd was referred to a “control herds ”. Then, four times of samplings at a 3 to 4 months intervals after treatments were performed for the serum-antibody ELISA and feces-PCR tests. Serum-antibody ELISA test was conducted in 20 adult cows per herd per times of samplings. Feces-PCR test was conducted in all calves rearing in the elevated floor ( 1-3 months old, call for “calf reared on the elevated floor ” ) and 10 heads of 6-12 months-olds calves rearing on the concrete floor ( call for “calf moved off the elevated floor ” ) and 10 adult cows ( 2-5 years-old ). Finally, the changes of MAP-prevalence rates in the four times of samplings after treatments were compared with the primary rates before treatments, and the differences of MAP-prevalence rates among the five farms were analysed. The results are as follows, (1).The MAP-prevalence rates of feces-PCR test from the first sampling after treatments are more times of remarkable ( P<0.05 ) or obvious decrease in calves (calves reared on and moved off the elevated floor ) and adult cows in the “strengthening sanitation herds ” ( A and B herds ) and “calves fed with sterilizing milk herds ” ( C and D herds ). On the other hand, the MAP- prevalence rates are a less times of obvious but not remarkable ( P<0.05 ) decrease in the “ control herd ” ( E herd ), either calves or adult cows. (2).Remarkable ( P<0.05 ) decrease on the MAP- prevalence rates of serum antibody-ELISA test aren’t found in the first two times of, but in the third and/or fourth samplings after treatments in the A, B, C and E herds but not D herd. The results revealed that the easily performable control measures ( strengthening sanitation and calves fed with sterilizing milk ) can protect susceptible animals ( especially calf ) from exposure to MAP, and decrease the MAP-prevalence rates in the dairy farms.

並列關鍵字

Paratuberculosis (Johne’s disease) ； Mycobacterium avium subsp. paratuberculosis ； Control strategies of paratuberculosis ； Dairy cattle

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