Genetic parameters for rectal temperature, respiration rate, and drooling score in Holstein cattle and their relationships with various fertility, production, body conformation, and health traits

Abstract

Genetic selection for improved climatic resilience is paramount to increase the long-term sustainability of high-producing dairy cattle, especially in face of climate change. Various physiological indicators, such as rectal temperature (RT), respiration rate score (RR), and drooling score (DS), can be used to genetically identify animals with more effective coping mechanisms in response to heat stress events. In this study, we investigated genetic parameters for RT, RR (score from 1-3), and DS (score from 1-3). Furthermore, we assessed the genetic relationship among these indicators and other economically important traits for the dairy cattle industry. After data editing, 59,265 (RT), 30,290 (RR), and 30,421 (DS) records from 13,592 lactating Holstein cows were used for the analyses. Variance components were estimated based on a multiple-trait repeatability animal model. The heritability ± standard error estimate for RT, RR, and DS was 0.06 ± 0.01, 0.04 ± 0.01, and 0.02 ± 0.01, respectively, whereas their repeatability was 0.19, 0.14, and 0.14, respectively. Moderate genetic correlations of RR with RT and DS (0.26 ± 0.11 and 0.25 ± 0.16) and nonsignificant correlation between RT and DS (−0.11 ± 0.14) were observed. Furthermore, the approximate genetic correlations between RT, RR, and DS with 12 production, 29 conformation, 5 fertility and reproduction, 5 health, and 9 longevity-indicator traits were assessed. In general, the approximate genetic correlations calculated were low to moderate. In summary, 3 physiological indicators of heat stress response were measured in a large number of animals and shown to be lowly heritable. There is a value in developing a selection index including all the 3 indicators to improve heat tolerance in dairy cattle. All the unfavorable genetic relationships observed between heat tolerance and other economically important traits can be accounted for in a selection index to enable improved climatic resilience while also maintaining or increasing productivity in Holstein cattle.

The Genetics of Thermoregulation in Pigs: A Review

“…In contrast to production traits, the inheritance of traits associated to thermoregulation has been poorly described in the literature. In species such as cattle ( 75 – 77 ), rectal temperature is the main thermoregulation trait for which heritability was accurately estimated ( Table 2 ). In pigs, estimation of genetic parameters of thermoregulation traits rarely exist.…”

Comprehensive RNA-Seq Profiling Reveals Temporal and Tissue-Specific Changes in Gene Expression in Sprague–Dawley Rats as Response to Heat Stress Challenges

“…In another of our recent studies, a multiple-trait animal model was used to estimate genetic parameters using 59,265 RT, 30,290 RR, and 30,421 DS records from 13,592 lactating Holstein cows (Luo et al, 2020). A total of 2,627 cows were genotyped using the Illumina 150K Bovine Bead chip (Illumina, San Diego, CA, USA).…”

“…A total of 2,627 cows were genotyped using the Illumina 150K Bovine Bead chip (Illumina, San Diego, CA, USA). After quality control of the chip data, a total of 116,594 singlenucleotide polymorphisms (SNPs) were used in the analysis (Luo et al, 2020). Subsequently, the LiftOver software (https://genome.…”

Fecal microbiota and their association with heat stress in Bos taurus

“…All the heat stress phenotypes were measured as it was described by Luo and colleagues [15]. In order to correct for the environmental effects that may affect phenotype values, cows’ response to heat was expressed by breeding values for rectal temperature (RT), drooling (DS), and respiratory scores (RS) estimated using the following model: where y ijklqno refers to phenotype (RS, DS or RT), µ is the population mean, fym i is the fixed effect for farm-year, p j is the fixed effect of parity, s k is the fixed effect of lactation stage, m l is the fixed effect of the indication if the animal is before or after milking, t q is the fixed effect of testing time (morning or afternoon), thi is the fixed effect of temperature-humidity index, a n is the animal additive genetic effect, pe n is the permanent environmental effect, and E ijklqno is the random residual.…”