乳牛轉換期產前白蛋白與球蛋白比率與發炎狀態、能量代謝、行為、疾病及搾乳表現之關聯

報告時間：2025-6-20
報告地點：407
指導老師：王建鎧
學生：莊博翔

乳牛於轉換期面臨劇烈的生理與免疫調節壓力，包括負能量平衡與發炎反應，若調節失衡則易導致多種疾病。懷孕後期肝臟產蛋白能力下降，而白蛋白與球蛋白比率 (Albumin-to-Globulin Ratio, AGR) 可同時反映發炎狀態與肝功能變化，為人類常用的病理評估指標，但於乳牛轉換期中相關研究相對有限。因此本研究旨在探討牛隻產前AGR高低與乳牛轉換期之生理健康與擠乳表現之關聯性。本實驗依產前第14天AGR中位數將牛隻分為高AGR組 (H-AGR, AGR>1) 與低AGR組 (L-AGR, AGR≦1)，並分別評估兩組牛隻於產前 (-14及-7天) 與產後 (0、2、4、7、14及21天) 之健康、生理指標、行為與擠乳表現。結果顯示，H-AGR於產前與產後 皆具較高的AGR值，而白蛋白濃度兩組間在產後無顯著差異。H-AGR 的牛隻產後直腸溫度顯著較高、總膽固醇具較低的趨勢。能量代謝方面，H-AGR體態評分 (Body condition score, BCS)產前及產後皆顯著較高；且 β-羥基丁酸 (β-hydroxybutyric acid, BHBA) 濃度在產後顯著升高；非酯化脂肪酸 (Non-esterified fatty acid, NEFA) 僅於初產牛中顯著升高，顯示H-AGR牛隻可能面臨較高的能量代謝壓力。免疫細胞分析結果顯示，H-AGR牛隻之總白血球與單核球於產前呈現較高趨勢，產後則顯著上升。過往研究指出，乳房炎牛隻亦常觀察到單核球增加，且乳汁中單核球趨化因子基因表現上調，顯示其可能同時具備系統性與局部發炎反應。儘管疾病發生率兩組間無顯著差異，行為表現方面H-AGR組活動時間顯著增加，而採食與攝食時間皆顯著減少，可能與負面健康狀態相關聯。自動擠乳系統資料顯示，H-AGR組乳量較低，且乳汁導電度變異係數 (Coefficient of variation, CV) 顯著較高 (0.033 ± 0.002 vs. 0.024 ± 0.001)，提示其乳房健康風險可能較高。本研究亦觀察到，球蛋白在轉換期間的變動幅度明顯大於白蛋白，因此其變化較易被觀察與辨識。產前球蛋白濃度低於3 g/dL 被認為與產後健康風險增加有關，於本研究中，H-AGR牛隻產前球蛋白濃度為 2.981 ± 0.075 g/dL，推測可能存在免疫球蛋白濃度偏低的情形。此外，具較佳體液免疫反應能力的牛隻，其乳房炎發生率與嚴重度亦較低。綜上所述，產前 AGR 偏高未必代表健康，反而可能反映免疫準備不足與代謝調節失衡，在乳牛轉換期健康評估中應謹慎解讀。
 
 
 
關鍵字：乳牛、轉換期、白蛋白與球蛋白比率、發炎反應、負能量平衡、自動搾乳系統
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