Genetic parameters of calf morbidity and stayability for US organic Holstein calves

Abstract

The objectives of this study were to estimate genetic parameters of calf health in organic US Holstein calves. Calves were born on farms across the United States from 2006 to 2019. Three calf health traits were evaluated in the study: calf respiratory disease until 365 d of age, calf scours until 60 d of age, and heifer stayability until 365 d of age. For respiratory disease and scours, animals were assigned a phenotype of 0 if they were healthy and a phenotype of 1 if they were diseased. For stayability, animals were assigned a phenotype of 0 if they were removed from the herd by 365 d of age and 1 if they remained in the herd at 365 d of age. Genetic parameters were estimated from threshold models that included the fixed effects of mean, year-season of birth, and dam age (respiratory disease and scours only) as well as the random effects of herd-year of birth and additive genetics. Heritability estimates were 0.100, 0.075, and 0.085 for respiratory disease, scours, and stayability, respectively. Solutions for estimated breeding values for respiratory disease and scours were transformed from disease risk to disease resistance by reversing the signs before calculating genetic correlations such that higher values of scours, respiratory disease, and stayability were favored. There was a moderate favorable genetic correlation estimate between respiratory disease resistance and stayability of 0.675. However, genetic correlation estimates between respiratory disease resistance and scours resistance (0.148) and between scours resistance and stayability (0.165) were low. Estimated breeding value correlations between calf health traits and other traits evaluated nationally were generally low in magnitude. The strongest correlation estimates were with longevity, particularly between stayability and heifer livability (0.217) and between stayability and cow livability (0.288); respiratory disease resistance was also favorably correlated with heifer (0.190) and cow (0.178) livability. Correlations with cow health traits were generally low and unfavorable. Linear models including the random effect of herd-by-sire indicated that herd-by-sire accounted for approximately 2% of phenotypic variance for scours and stayability, which may indicate a genotype by environment interaction effect for these traits. In conclusion, there is significant genetic variation in organic calf health, and there was evidence of genotype by environment interaction.

Genetic parameters for dairy calf and replacement heifer wellness traits and their association with cow longevity and health indicators in Holstein cattle

“…Both DIA and PNE have low heritability in Chinese Holstein cattle. Previous studies reported heritabilities for DIA and PNE (or RESP) of less than 0.10 (0.012-0.084 for DIA and 0.042-0.090 for PNE or RESP) in US Jersey (Gonzalez-Peña et al, 2020) and Holstein (Henderson et al, 2011;Mc-Corquodale et al, 2013;Gonzalez-Peña et al, 2019;Haagen et al, 2021b), German Holstein (Mahmoud et al, 2017), and French Charolais beef cattle (Vinet et al, 2018), which are in agreement with the findings of the present study.…”

“…Since the 1970s, genetic parameters of replacement survival traits have been estimated in various dairy cattle populations over time (Bar-Anan et al, 1976;Erf et al, 1990;Hansen et al, 2003;Haagen et al, 2021b;Neupane et al, 2021;Weller et al, 2021), with a large variability in the estimates, ranging from 0.001 in Danish Holstein (Hansen et al, 2003) to 0.120 in Indian Jersey crossbred animals (Pathak et al, 2018). The heritability estimates for Sur1 and Sur3 are within the literature range (0.001-0.120), whereas Sur2 has a higher estimate than the other 2 traits.…”

Benchmarking calf health: Assessment tools for dairy herd health consultancy based on reference values from 730 German dairies with respect to seasonal, farm type, and herd size effects

“…In this study, the incidences for D (44.4%) and RD (11.5%) were significantly higher than the prevalence reported in the current study. Possible reasons for these differences may be that the farms in the US study were not randomly selected, and that the disease recording was not done by veterinarians but by farm personnel (26). To our knowledge, ours is the first representative cross-sectional study reporting the prevalence of disorders in preweaned dairy calves on organic farms.…”

“…On smaller farms, calves were more often kept in smaller groups (≤7 calves), which could have reduced the occurrence of RD (37,53). In Germany, on farms with up to 120 dairy cows, it is more common to use old buildings for calf rearing and, in some cases, prophylactic measures are not implemented (26). In unventilated barns, the climatic conditions are often poor.…”

“…There is also a lack of reference values on herd-level for prevalence data on diseases in preweaned dairy calves based on a large study population. The scarce available literature on calf health on organic farms does not yet provide representative data that can be made applicable to all organic farms (26). Furthermore, most studies focus on conventional farms.…”