Phenotypic, genetic, and single nucleotide polymorphism marker associations between calf diseases and subsequent performance and disease occurrences of first-lactation German Holstein cows

Abstract

A total of 31,396 females born from 2010 to 2013 in 43 large-scale Holstein-Friesian herds were phenotyped for calf and cow disease traits using a veterinarian diagnosis key. Calf diseases were general disease status (cGDS), calf diarrhea (cDIA), and calf respiratory disease (cRD) recorded from birth to 2 mo of age. Incidences were 0.48 for cGDS, 0.28 for cRD, and 0.21 for cDIA. Cow disease trait recording focused on the early period directly after calving in first parity, including the interval from 10 d before calving to 200 d in lactation. For cows, at least one entry for the respective disease implied a score = 1 (sick); otherwise, score = 0 (healthy). Corresponding cow diseases were first-lactation general disease status (flGDS), first-lactation diarrhea (flDIA), and first-lactation respiratory disease (flRD). Additional cow disease categories included mastitis (flMAST), claw disorders (flCLAW), female fertility disorders (flFF), and metabolic disorders (flMET). A further cow trait category considered first-lactation test-day production traits from official test-days 1 and 2 after calving. The genotype data set included 41,256 single nucleotide polymorphisms (SNP) from 9,388 females with phenotypes. Linear and generalized linear mixed models with a logit link-function were applied to Gaussian and categorical cow traits, respectively, considering the calf disease as a fixed effect. Most of the calf diseases were not significantly associated with the occurrence of any cow disease. By trend, increasing risks for the occurrence of cow diseases were observed for healthy calves, indicating mechanisms of disease resistance with aging. Also by trend, occurrence of calf diseases was associated with decreasing milk, protein, and fat yields. Univariate linear and threshold animal models were used to estimate heritabilities and breeding values (EBV) for all calf and cow traits. Heritabilities for cGDS and cRD were 0.06 and 0.07 for cDIA. Genetic correlations among all traits were estimated using linear-linear animal models in a series of bivariate runs. The genetic correlation between cDIA and cRD was 0.29. Apart from the genetic correlation between flRD with cGDS (-0.38), EBV correlations and genetic correlations between calf diseases with all cow traits were close to zero. Genome-wide association studies were applied to estimate SNP effects for cRD and cDIA, and for the corresponding traits observed in cows (flRD and flDIA). Different significant SNP markers contributed to cDIA and flDIA, or to cRD and flRD. The average correlation coefficient between cRD and flRD considering SNP effects from all chromosomes was 0.01, and between cDIA and flDIA was -0.04. In conclusion, calf diseases are not appropriate early predictors for cow traits during the early lactation stage in parity 1.

Genetic parameters for body weight from birth to calving and associations between weights with test-day, health, and female fertility traits

“…Heritabilities for disease traits as well as genetic and phenotypic correlations between health traits with CABW and IBW are shown in Table 7. Heritabilities for health traits are in agreement with estimates from previous studies, that is, with Mahmoud et al (2017) for cow respiratory diseases, with Harder et al (2006) for metabolic disorders, with König et al (2005) or Ger- Table 5. Heritabilities for test-day traits, and genetic (r g ) and phenotypic (r p ) correlations between test-day traits with calf birth weight (CABW) and BW at first insemination (IBW) et al (2006) for clinical mastitis.…”

“…The heritabilities for the same trait were identical from 2 runs including either CABW or IBW. In agreement with Mahmoud et al (2017), heritabilities in same traits were larger at the second official test-day compared with estimates from the first official test-day. Generally, genetic and phenotypic correlations between CABW with productivity and SCS were close to zero.…”

“…However, it is a long time span from the calf toward the milking cow stage. Similarly, only weak associations were identified between the calf health status and milking cow production traits (Mahmoud et al, 2017). The time point for measuring IBW is closer to the lactation stage, and accordingly, a stronger effect of IBW on cow test-day traits was identified ( Table 5).…”

“…Production and health traits were available from first-lactation cows. Analogous to Mahmoud et al (2017), the production traits included records from the first and second official test-day after calving for milk yield (MY1 and MY2), fat percentage (FP1 and FP2), protein percentage (PP1 and PP2), fat yield (FY1 and FY2), protein yield (PY1 and PY2), fat to protein ratio (FPR1 and FPR2), and SCS (SCS1 and SCS2).…”

“…Health traits of first-lactation cows were recorded according to the hierarchical diagnosis key as considered in the official ICAR guidelines (Stock et al, 2013). For the present analyses, the same overall disease categories as introduced by Mahmoud et al (2017) were used. These were the general disease status (GDS), diarrhea (DIA), respiratory diseases (RD), mastitis (MAST), claw disorders (CL), female fertility disorders (FF), and metabolic disorders (MET).…”