Heritability of phenotypic udder traits to improve resilience to mastitis in Texel ewes

Abstract

There are no estimates of the heritability of phenotypic udder traits in suckler sheep, which produce meat lambs, and whether these are associated with resilience to mastitis. Mastitis is a common disease which damages the mammary gland and reduces productivity. The aims of this study were to investigate the feasibility of collecting udder phenotypes, their heritability and their association with mastitis in suckler ewes. Udder and teat conformation, teat lesions, intramammary masses (IMM) and litter size were recorded from 10 Texel flocks in Great Britain between 2012 and 2014; 968 records were collected. Pedigree data were obtained from an online pedigree recording system. Univariate quantitative genetic parameters were estimated using animal and sire models. Linear mixed models were used to analyse continuous traits and generalised linear mixed models were used to analyse binary traits. Continuous traits had higher heritabilities than binary with teat placement and teat length heritability (h2) highest at 0.35 (SD 0.04) and 0.42 (SD 0.04), respectively. Udder width, drop and separation heritabilities were lower and varied with udder volume. The heritabilities of IMM and teat lesions (sire model) were 0.18 (SD 0.12) and 0.17 (SD 0.11), respectively. All heritabilities were sufficiently high to be in a selection programme to increase resilience to mastitis in the population of Texel sheep. Further studies are required to investigate genetic relationships between traits and to determine whether udder traits predict IMM, and the potential benefits from including traits in a selection programme to increase resilience to chronic mastitis.

Udder Measurements and Their Relationship with Milk Yield in Pelibuey Ewes

“…In addition, Capote et al [34] indicated a greater importance on the balance between the horizontal and vertical diameters of udder compared with length parameters. Other authors [12,16,18,[32][33][34] have suggested that the predictive capacity of udder measurements have important practical implications for breeding programmes to increase resilience to mastitis in the population [35]. In addition, Milerski et al [36] reported that the linear scores for udder depth, cistern depth, teat position and teat size would permit prediction of future correlated responses in milk-oriented selection schemes in the Tsigai, Improved Walachian and Lacaune breeds.…”

Udder Morphometry and Its Relationship with Intramammary Infections and Somatic Cell Count in Serrana Goats

“…The measurable parameter, UP, despite presenting significant differences between the different groups of SCC, did not show differences between the lowest cell count group, associated with healthy animals, and the group with the highest SCC, associated with bacterial infection. The significant differences found between SCC groups may be due to the influence of lactation stage and udder fullness [25], revealing that UP may not be a good indicator of udder inflammation.…”

Size of supernumerary teats in sheep correlates with complexity of the anatomy and microenvironment

“…Indeed, supernumerary teat removal correlates with a reduced incidence of subclinical mastitis in Dutch dairy heifers, although this observation could point to wider management differences between farms implementing different removal policies, rather than necessarily reflecting a direct effect (Santman‐Berends et al ). In small ruminants, as in cattle, bacterial mastitis is a major health issue with welfare implications (Hughes & Watson, ), in both dairy sheep (Bramis et al ) and those used for meat production (Phythian et al ; Crump et al ; Phythian et al ). It has been suggested that poor udder conformation, including the presence of supernumerary teats, may also constitute a minor, but notable, risk factor for acquisition of new intramammary infections (Vasileiou et al ), potentially as an indirect effect due to impairment of lamb sucking and consequent inefficient removal of milk (Menzies & Ramanoon, ).…”