於乳山羊懷孕末期將丙二醇作為飼料添加物對妊娠毒血症的預防效果

Abstract

生產仔畜，是經濟動物養殖中重要的一環，除了供應新生仔畜來補充被淘汰的或售出的動物，懷孕生產伴隨的產乳亦是酪農業主要的經濟來源，因此懷孕期對母畜的照顧尤為重要。妊娠毒血症是羊隻懷孕時常見的疾病，特指懷孕末期發生的高血酮症。高血酮症是當反芻動物處在能量負平衡的狀態，身體代謝脂肪並生產能量，導致體內酮體濃度升高。妊娠毒血症如果沒有治療處理，其死亡率可以將近100%，且發生過妊娠毒血症的羊隻，即使經過治療而回復也仍可能有難產以及在分娩過程中死亡，或是發展成胎衣滯留或是子宮炎。丙二醇是常被用作治療或預防反芻動物妊娠毒血症的口服血糖前驅物之一。反芻動物吃進丙二醇相當於單胃動物吃進葡萄糖，比起治療藥物更趨近於營養補充物，因此希望在懷孕末期給予羊隻額外補充丙二醇，研究此舉是否能提供羊隻預防妊娠毒血症的效果。 本試驗在羊隻分娩前一個月額外補充丙二醇，確認懷孕羊隻的預產期之後，將懷孕羊隻三種處理隨機分為三組：控制組（control, C）：不餵食丙二醇；試驗組一（propylene glycol low, PGL）：每日餵食30 g丙二醇；試驗組二（propylene glycol high, PGH）：每日餵食50 g丙二醇。檢測懷孕羊分娩前一個月的血酮、血糖及血中游離脂肪酸的濃度變化，與記錄母羊的產仔數、產後體重、產乳表現以及仔羊出生體重和出生後的體重變化。 試驗結果顯示分娩前一個月C組與給予丙二醇的組別相比（PＧ, PGL+PGH）有較高的血酮、較低的血糖與較高的血中游游離脂肪酸（1.04 vs. 0.49, 59.71 vs.66.13, 0.26 vs. 0.1, p<0.05）。各處理組之間的仔羊出生體重與體重變化並無差異。母羊分娩後的體重各組皆分別維持在一個範圍內無劇烈起伏。在校正乳產量、乳高峰乳量與到達產乳高峰的時間上，三組並無顯著差異。乳脂率三組無顯著差異，而乳蛋白濃度PGL組高於C組。

綜觀本次實驗結果，分娩前最後一個月每日額外給予懷孕羊隻30–50 g丙二醇的補充，能改善懷孕母羊分娩前血中酮體、血糖及血中游離脂肪酸的濃度，但並未對分娩後的各項表現造成明顯的影響。

Reproduction can provide newborn animals for replacing culled animals or animals being sold, and the following lactation is the major income source of dairy farmers making it important for economic animal farming industry. Thus the care of pregnant animals is non-negligible. Pregnancy toxemia is a common disease for pregnant goats, which develops hyperketonemia, a metabolic disturbance, at the end of gestation. Hyperketonemia is defined as an increase in blood ketone bodies above the normal reference range, caused by the mass mobilization of fat when goats suffering a negative energy balance. Without treatment, the mortality rate can approach 100%. Treated goats that recover may have dystocia and die during parturition or develop retained placenta and metritis. Propylene glycol is a common therapy as glucose precursor. Propylene glycol to ruminant animals is as glucose to monogastric animals, and it’s rather a nutrient supplement than a medical prevention or treatment. The purpose of this study is to investigate the effects of feeding propylene glycol as feed additive at late stage of pregnancy on preventing dairy goats from pregnancy toxemia. Pregnant goats were randomly divided into three groups after confirming the pregnancy and expected date of kidding: control group (C, 0 g/day), propylene glycol low dosage (PGL, 30 g/day) and propylene glycol high dosage (PGH, 50 g/day). Recorded the concentration of blood β-hydroxybutyrate (BHBA), blood glucose and plasma free fatty acids, litter size, body weight of postpartum and lactation performance of goats and birth weight and weight change of kids. Results presented that group C showed higher blood BHBA, lower blood glucose and higher plasma free fatty acids compared with group PG (groups gaved propylene glycol, PGH + PGL) (1.04 vs. 0.49, 59.71 vs.66.13, 0.26 vs. 0.1, p<0.05). The birth weight and weight change of kids were no significantly different among groups. The postpartum weights of all groups were kept in a range respectively. Adjusted milk yield, milk peak yield and time of peak yield were no significantly different among groups. The milk protein content of PGL were higher than C (p<0.05). The milk fat content didn’t show significantly difference among groups. In conclusion, providing 30-50 g propylene glycol at the last month of gestation are benefit to lower the blood BHBA, higher the blood glucose and lower the plasma free fatty acids, but not enough to affect the performance after kidding.