Heat stress during late pregnancy and postpartum influences genetic parameter estimates for birth weight and weight gain in dual-purpose cattle offspring generations

Abstract

Impact of direct heat stress (HS) on genetic parameter estimates, i.e., HS close to the trait recording date, was verified in several previous studies conducted in dairy and beef cattle populations. The aim of the present study was to analyze the impact of time-lagged HS at different recording periods during late pregnancy (a.p.) and postpartum (p.p.) on genetic parameter estimates for birth weight (BWT) and weight gain traits (200 day- and 365 day-weight gain (200dg, 365dg)) in offspring of the dual-purpose cattle breed ‘Rotes Höhenvieh’ (RHV). Furthermore, we estimated genetic correlations within traits across time-lagged climatic indicators, in order to proof possible genotype by environment interactions (GxE). Trait recording included 5,434 observations for BWT, 3,679 observations for 200dg and 2,998 observations for 365dg. Time-lagged climatic descriptors were classes for the mean temperature humidity index (mTHI) and number of HS days (nHS) from the following periods: 7 d-period a.p. (BWT), 56 d-period a.p. and 56 d-period p.p. (200dg and 365dg). Genetic parameters were estimated via two-trait animal models, i.e., defining the same trait in different climatic environments as different traits. Genetic variances and heritabilities for all traits increased with increasing mTHI- and nHS-classes for all recording periods, indicating pronounced genetic differentiation with regard to time-lagged in-utero HS and HS directly after birth. Similarly, in low mTHI- and nHS-classes indicating cold stress, genetic variances and heritabilities were larger than for temperate climates. Genetic correlations substantially smaller than 0.80 indicating GxE were observed when considering same traits from mTHI- and nHS-classes in greater distance. Estimated breeding values (EBV) of the ten most influential sires with the largest number of offspring records fluctuated across mTHI- and nHS-classes. Correlations between sire EBV for same traits from distant climatic classes confirmed the genetic correlation estimates. Sires displaying stable EBV with climatic alterations were also identified. Selection of those sires might contribute to improved robustness in the RHV outdoor population genetically.

A systematic review of genotype-by-climate interaction studies in cattle, pigs, and chicken

“…All observational studies on pigs and 83.3% of the studies on cattle used reaction norms. The remaining observational studies typically categorized records by the climatic parameter (e.g., into quintiles), and performed a two-trait (e.g., Espasandin et al, 2013;Halli et al, 2021) or multiple-trait (Zwald et al, 2003) analysis. In experimental studies, the statistical model used is largely determined by the experimental design.…”

“…We observed two main approaches to characterize thermal conditions using THI: either a statistic of THI was assigned to a period of pre-defined duration (e.g., mean THI over the last 60 days of gestation in Meneńdez-Buxadera et al, 2020; sum of THI units from birth to 205 days in Santana et al, 2016), or a heat stress limit was predefined and a duration statistic was assigned to it (e.g. number of days with daily mean THI ≥60 in Halli et al, 2021). Nevertheless, there are more physical environmental factors that may affect cold or thermal load.…”

Direct genetic effects, maternal genetic effects, and maternal genetic sensitivity on prenatal heat stress for calf diseases and corresponding genomic loci in German Holsteins

“…The maximum distance between a herd and a weather station was 27.88 km, the minimum distance was 0.74 km, and the average distance was 14.26 km. Hourly temperature (T) and relative humidity (RH) data were used to compute the hourly THI as follows (NRC, 1971): The HS threshold of 60 was chosen according to results from previous studies that evaluated timelagged HS effects for a broad phenotypic trait pattern (Halli et al, 2021;Kipp et al, 2021a,b). The average THI for each week was scaled for the heat load range using the following formula: −1 + 2[(THI − 60)/(74 − 60)], where 60 = minimum THI and 74 = maximum observed THI.…”

“…The late-gestation period plays a crucial role in fetal growth, and carryover effects from dams exposed to HS during late gestation can influence the performance of their offspring (Monteiro et al, 2016). Halli et al (2021) and Kipp et al (2021a) identified alterations of genetic variances for production traits and G×E in young dual-purpose cattle and in first-lactation cattle based on prenatal temperature and humidity. For calf diseases, even larger effects of prenatal HS are expected than with cow traits because calf diseases are expressed in early stages of life (i.e., very soon after prenatal HS occurred).…”

Identification of candidate genes on the basis of SNP by time-lagged heat stress interactions for milk production traits in German Holstein cattle

“…Monteiro et al [ 13 ] studied long-term effects of in-utero HS on female fertility and performance traits recorded in offspring and identified most detrimental impact of HS from the last 6 weeks of gestation. Quantitative-genetically, Halli et al [ 16 ] identified alterations of genetic co(variance) components for weight and growth traits of dual-purpose cattle due to HS impact on their dams during the late pregnancy period.…”