Zeleke Mandefrot M, Kenyon Paul R, Flay Kate J, Aberdein Danielle, Pain Sarah J, Peterson Sam W, Ridler Anne L
School of Veterinary Science, Massey University, Private Bag 11222, 4410 Palmerston North, New Zealand.
School of Veterinary Medicine, Wolaita Sodo University, Wolaita Sodo P.O. Box 138, Ethiopia.
Animals (Basel). 2021 Sep 28;11(10):2831. doi: 10.3390/ani11102831.
In non-dairy ewes, udder defects hinder the survival and weight gain of their pre-weaned lambs. The objectives of this study were to determine the effects of palpable udder defects on milk yield, somatic cell count (SCC), and milk composition in non-dairy Romney ewes. Ewes with a history of udder defects or normal udders were selected for the study. Of a total of 48 ewes that lambed, 30 ewes reared at least one lamb, and were milked six times, once weekly, for the first six weeks of lactation. Udder halves were palpated and scored at each milking event. Multivariate linear mixed models examined the impacts of udder defects on udder-half and whole-udder milk yield, SCC, and milk composition (fat, protein, lactose, total solids, and solids non-fat (SNF)). Across the six examinations, 24.7% of the total 352 udder-half examinations were observed to be defective. Udder halves that were defective at least once produced on average 57.9% less ( < 0.05) milk than normal udder halves, while normal udder halves with a contralateral defective half yielded 33.5% more ( < 0.05) milk than normal udder halves. Successive occurrence of both hard and lump udder defect categories in an udder-half, udder defect detection early in lactation, and a high frequency of udder defect detection were all associated with udder-half milk yield loss ( < 0.05). At the whole-udder level, no differences in milk yield ( > 0.05) were observed between those with one udder-half defective and both normal udder-halves. However, udders in which one udder half was categorised as hard but progressed to lump and remained as lump until 42 days of lactation produced less ( < 0.05) milk compared with normal udders. With the exception of SNF, there were no significant associations ( > 0.05) between milk composition parameters and udder defect. Overall, these findings emphasise the importance of udder health in non-dairy ewes and the potential effect of udder defects on their lambs.
在非奶用母羊中，乳房缺陷会影响其断奶前羔羊的存活和体重增加。本研究的目的是确定可触及的乳房缺陷对非奶用罗姆尼母羊产奶量、体细胞计数（SCC）和乳汁成分的影响。选择有乳房缺陷病史或乳房正常的母羊进行研究。在总共48只产羔的母羊中，30只母羊至少饲养了一只羔羊，并在泌乳的前六周每周挤奶一次，共挤奶六次。每次挤奶时都对乳房的两半进行触诊并评分。多变量线性混合模型研究了乳房缺陷对乳房半侧和整个乳房的产奶量、SCC以及乳汁成分（脂肪、蛋白质、乳糖、总固体和非脂固体（SNF））的影响。在六次检查中，在总共352次乳房半侧检查中，有24.7%被观察到存在缺陷。至少有一次出现缺陷的乳房半侧平均产奶量比正常乳房半侧少57.9%（<0.05），而对侧乳房半侧有缺陷的正常乳房半侧比正常乳房半侧产奶量多33.5%（<0.05）。乳房半侧连续出现硬乳房缺陷和肿块乳房缺陷类别、泌乳早期检测到乳房缺陷以及乳房缺陷检测频率高均与乳房半侧产奶量损失相关（<0.05）。在整个乳房水平上，一侧乳房半侧有缺陷的母羊与两侧乳房半侧均正常的母羊之间在产奶量上未观察到差异（>0.05）。然而，与正常乳房相比，一侧乳房半侧被归类为硬乳房但发展为肿块乳房并在泌乳42天前一直保持肿块状态的乳房产奶量较少（<0.05）。除了SNF外，乳汁成分参数与乳房缺陷之间没有显著关联（>0.05）。总体而言，这些发现强调了非奶用母羊乳房健康的重要性以及乳房缺陷对其羔羊的潜在影响。
