Genetic relationships of alternative somatic cell count traits with milk yield, composition and udder type traits in Italian Jersey cows

Abstract

The aim of this study was to estimate genetic associations between alternative somatic cell count (SCC) traits and milk yield, composition and udder type traits in Italian Jersey cows. Alternative SCC traits were test‐day (TD) somatic cell score (SCS) averaged over early lactation (SCS_150), standard deviation of SCS of the entire lactation (SCS_SD), a binary trait indicating absence or presence of at least one TD SCC >400,000 cells/ml in the lactation (Infection) and the ratio of the number of TD SCC >400,000 cells/ml to total number of TD in the lactation (Severity). Heritabilities of SCC traits, including lactation‐mean SCS (SCS_LM), ranged from 0.038 to 0.136. Genetic correlations between SCC traits were moderate to strong, with very few exceptions. Unfavourable genetic associations between milk yield and SCS_SD and Infection indicated that high‐producing cows were more susceptible to variation in SCC than low‐producing animals. Cows with deep udders, loose attachments, weak ligaments and long teats were more susceptible to an increase of SCC in milk. Overall, results suggest that alternative SCC traits can be exploited to improve cow's resistance to mastitis in Italian Jersey breed.

Re-assessing the importance of linear type traits in predicting genetic merit for survival in an aging Holstein-Friesian dairy cow population

“…The motivation for the present study was to determine whether the genetic correlations between linear type traits and survival from one parity to the next change with advancing parity, as no previous study had assessed whether the relationships between linear type traits and survival change as dairy cows age. As expected, in the present study as dairy cows aged, some linear type traits associated with the genetic merit for mastitis and SCC (Seykora and McDaniel, 1986;Němcová et al, 2007;Bobbo et al, 2019) become more important genetic determinants of survival. Nonetheless, the genetic correlations between feet and leg-related linear type traits and survival that were expected to strengthen as cows aged were, in fact, not good determinants of the genetic merit of survival in older dairy cows.…”

“…The linear type traits (udder depth, teat length, and rear udder height) that strengthened in genetic correlation with survival as cows aged in the present study have all previously been associated with genetic merit for mastitis or SCC in dairy cows (Seykora and McDaniel, 1986;Němcová et al, 2007;Bobbo et al, 2019). The combination of a deterioration in the intramammary and anatomical defense mechanisms in aging cows (Jamali et al, 2018) along with poor udder characteristics may put older cows at a greater risk of developing intramammary infections, and therefore, being culled.…”

“…The combination of a deterioration in the intramammary and anatomical defense mechanisms in aging cows (Jamali et al, 2018) along with poor udder characteristics may put older cows at a greater risk of developing intramammary infections, and therefore, being culled. Deeper udders and longer teats are closer to the ground contributing to an increased tendency for the udder and teats to become contaminated with mastitis-inducing environmental pathogens (Bharti et al 2015;Bobbo et al, 2019). As with shallower udders and shorter teats, the association between having a smaller distance between the vulva and the top of the rear udder may result in an increased risk of mastitis, due to the udder becoming more susceptible to coming in contact with, and thus contaminated with, pathogens from feces.…”

Genetic analysis of milk urea concentration and its genetic relationship with selected traits of interest in dairy cows

“…In addition, to reduce potential unfavorable correlated responses, correlations of MU and traits included in the breeding goal have to be considered. Previous research showed that MU (or MUN) is correlated with yield traits (e.g., milk, protein, and fat yields; Yin et al, 2012;Beatson et al, 2019;Ariyarathne et al, 2021), type traits (Satoła et al, 2017b), BW (Hojman et al, 2005), SCC (Bobbo et al, 2019), and reproductive performance (Siatka et al, 2020;Kananub et al, 2020). However, results were not all indicating similar direction and strength of correlations.…”

Ingestion of Gouda Cheese Ameliorates the Chronic Unpredictable Mild Stress in Mice

“…However, the milk yield is reported to be higher in Holstein than in Jersey cows (White et al, 2001). With respect to this, Jersey is regarded as a dairy breed, characterized by lower milk production than the Holstein, but with optimal milk composition and coagulation ability (Bobbo et al, 2019). Therefore, its milk production serves as a major disadvantage in the dairy industry.…”