Tolone Marco, Larrondo Cristian, Yáñez José M, Newman Scott, Sardina Maria Teresa, Portolano Baldassare
Dipartimento Scienze Agrarie e Forestali, Università degli Studi di Palermo, Viale delle Scienze, Palermo, 90128, Italy.
Faculty of Veterinary and Animal Sciences, University of Chile, Av. Santa Rosa, La Pintana, Santiago, 11735, Chile.
BMC Vet Res. 2016 Jul 28;12(1):158. doi: 10.1186/s12917-016-0781-x.
Mastitis resistance is a complex and multifactorial trait, and its expression depends on both genetic and environmental factors, including infection pressure. The objective of this research was to determine the genetic basis of mastitis resistance to specific pathogens using a repeatability threshold probit animal model.
The most prevalent isolated pathogens were coagulase-negative staphylococci (CNS); 39 % of records and 77 % of the animals infected at least one time in the whole period of study. There was significant genetic variation only for Streptococci (STR). In addition, there was a positive genetic correlation between STR and all pathogens together (ALL) (0.36 ± 0.22), and CNS and ALL (0.92 ± 0.04).
The results of our study support the presence of significant genetic variation for mastitis caused by Streptococci and suggest the importance of discriminating between different pathogens causing mastitis due to the fact that they most likely influence different genetic traits. Low heritabilities for pathogen specific-mastitis resistance may be considered when including bacteriological status as a measure of mastitis presence to implement breeding strategies for improving udder health in dairy ewes.
乳腺炎抗性是一个复杂的多因素性状，其表达取决于遗传和环境因素，包括感染压力。本研究的目的是使用重复性阈值概率动物模型确定乳腺炎对特定病原体抗性的遗传基础。
最常见的分离病原体是凝固酶阴性葡萄球菌（CNS）；在整个研究期间，39%的记录和77%的动物至少感染过一次。仅链球菌（STR）存在显著的遗传变异。此外，STR与所有病原体（ALL）之间存在正遗传相关性（0.36±0.22），CNS与ALL之间也存在正遗传相关性（0.92±0.04）。
我们的研究结果支持由链球菌引起的乳腺炎存在显著遗传变异，并表明区分引起乳腺炎的不同病原体的重要性，因为它们很可能影响不同的遗传性状。在将细菌学状态作为乳腺炎存在的一种衡量标准以实施改善奶山羊乳房健康的育种策略时，可能需要考虑病原体特异性乳腺炎抗性的低遗传力。
