Wicki M, Fassier T, Huau C, Corbière F, Rupp R
GenPhySE, Université de Toulouse, INRAE, ENVT, 31326, Castanet Tolosan, France; Institut de l'Elevage, Castanet Tolosan 31321, France.
Domaine de Bourges, INRAE, Osmoy, F-31326, France.
J Dairy Sci. 2025 Jan;108(1):623-634. doi: 10.3168/jds.2024-25113. Epub 2024 Sep 27.
Immune competence is a key factor in the health and resilience of dairy ruminants. The aim of this study was to study IgG concentration in serum shortly after birth and in colostrum of lactating animals as proxy of passive immune transfer and colostrum quality, respectively, and thus provide new health and resilience indicators for selection. Data from 424 female kids and 203 primiparous goats, reared on an INRAE experimental farm, were analyzed. The IgG concentration was measured in kid serum and goat colostrum, respectively, using the radial immunodiffusion technique. Linear models were used to identify factors of variation in serum and colostrum IgG concentration, and health events were monitored for 5 wk after birth to measure the effect of passive immune transfer on kids' health. We found a significant effect of serum IgG level on hindquarters cleanliness score (as a proxy of digestive troubles) and nasal and ocular discharge. As expected, the absorption of IgG in the days following birth is essential to ensure the passive transfer of immunity from the mother to the youngster, and provide immune protection. Genetic parameters were estimated for serum IgG concentration in kids and for colostrum characteristics in primiparous goats. Heritability of serum IgG in kids was not significantly different from zero. This low value, with large SE, may be due to the limited sample size and large environmental variability likely not accounted for. Especially, we could not adjust for the amount of IgG that was ingested by the kid, which can have a significant effect on serum IgG and possibly on heritability estimates. Heritability of colostrum traits were moderate, with estimates of 0.25 (±0.16), 0.35 (±0.16), and 0.25 (±0.16) for IgG concentration, IgG mass, and colostrum volume, respectively. Genetic correlations with milk production showed high standard errors due to small numbers. However, estimates suggest a negative genetic association between production and IgG concentration in colostrum (genetic correlation = -0.44 ± 0.33), probably linked to a positive association with total colostrum volume. The significant heritabilities that were estimated for the first time demonstrate the existence of genetic control of colostrum quality in goats, and open up opportunities for selection in this species.
免疫能力是奶用反刍动物健康和恢复力的关键因素。本研究的目的是分别研究出生后不久幼畜血清中的IgG浓度以及泌乳动物初乳中的IgG浓度，以此作为被动免疫转移和初乳质量的指标，从而为选育提供新的健康和恢复力指标。对法国农业科学院实验农场饲养的424只雌性羔羊和203只初产山羊的数据进行了分析。分别采用放射免疫扩散技术测定羔羊血清和山羊初乳中的IgG浓度。使用线性模型来确定血清和初乳IgG浓度的变异因素，并在出生后5周监测健康事件，以衡量被动免疫转移对羔羊健康的影响。我们发现血清IgG水平对后躯清洁度评分（作为消化问题的指标）以及鼻眼分泌物有显著影响。正如预期的那样，出生后几天内IgG的吸收对于确保免疫从母体向幼畜的被动转移以及提供免疫保护至关重要。对羔羊血清IgG浓度和初产山羊的初乳特性进行了遗传参数估计。羔羊血清IgG的遗传力与零无显著差异。这个低值且标准误较大，可能是由于样本量有限以及可能未考虑到的较大环境变异性。特别是，我们无法对羔羊摄入的IgG量进行校正，而这可能对血清IgG以及可能对遗传力估计有显著影响。初乳性状的遗传力适中，IgG浓度、IgG质量和初乳体积的估计值分别为0.25（±0.16）、0.35（±0.16）和0.25（±0.16）。由于数量较少，与产奶量的遗传相关性显示出较高的标准误。然而，估计表明产奶量与初乳中IgG浓度之间存在负遗传关联（遗传相关性 = -0.44 ± 0.33），这可能与与初乳总体积的正相关有关。首次估计的显著遗传力证明了山羊初乳质量存在遗传控制，并为该物种的选育开辟了机会。
