Journalartikel
Genetic analyzes of physiological traits in relation to climatic stresses in German Black Pied cattle
Autorenliste: Kipp, Cordula; Al-Kanaan, A.; Bruegemann, Kerstin; Koenig, S.
Jahr der Veröffentlichung: 2021
Seiten: 81-98
Zeitschrift: ZUCHTUNGSKUNDE
Bandnummer: 93
Heftnummer: 2
ISSN: 0044-5401
eISSN: 1867-4518
Verlag: EUGEN ULMER GMBH CO
Abstract:
Breeding on improved heat tolerance in dairy cattle is a topic of increasing importance due to the climatic challenges, even in Germany. Attempts in this regard, i.e., the development of genetic evaluations, are under progress in some states of North America. Consequently, the aim of the present study was to estimating genetic parameters and variance components for novel physiological cow traits in dependency of a continuous temperature-humidity-index (THI). Genetic correlations in same traits across THI were evaluated as indicators for possible genotype by environment (heat stress) interactions. Own trait recording during several years considered 838 cows of the local breed Deutsches Schwarzbuntes Niederungsrind (DSN) and their genetic upgrades with HF, which were kept in eight different herds reflecting a pasture based production system. Repeated trait recording considered more than 7000 observations. The recorded physiological traits included respiration rate (RESPR, in number of breaths per minute), pulse frequency (PULSF, in number of heartbeats per minute), body temperature (KT, in C degrees), vaginal temperature (VT, in C degrees) and surface temperature recorded via infrared thermography for different segments of the cow body (free-form polygon covering the whole surface (OTG), rectangle along the spine (OTWI), line along the spine (OTR) circle at withers (OTW)). Barn temperature and humidities from intervals in one minute were used for the calculation of hourly THI, which were merged with the corresponding point in time for cow trait recording. Phenotypically, trait variations were more pronounced under heat stress (THI > 65) in comparison to trait reactions under temperate climatic conditions (THI <= 65). The estimation of variance components for physiological traits was conducted with repeatability models considering distinct THI classes (THI > 65 und THI = 65), as well as via random regression methodology on a continuous THI scale. From both modelling approaches, additive genetic variances and heritabilities increased with increasing THI, implying improved genetic differentiations under stress conditions. Genetic correlations in same traits recorded at THI > 65 and THI <= 65 were close to 0.80 or even smaller, indicating obvious genotype by environment interactions. Especially for THI in greater distance, genetic correlations substantially declined, e.g. 0.31 for OTG. Genetic (co)variance components indicated environmental sensitivity for a local breed, which should be adapted to heterogeneous climatic impact. The longitudinal physiological trait data allows ongoing studies to enhance genetic evaluations towards improved heat tolerance and robustness.
Zitierstile
Harvard-Zitierstil: Kipp, C., Al-Kanaan, A., Bruegemann, K. and Koenig, S. (2021) Genetic analyzes of physiological traits in relation to climatic stresses in German Black Pied cattle, ZUCHTUNGSKUNDE, 93(2), pp. 81-98
APA-Zitierstil: Kipp, C., Al-Kanaan, A., Bruegemann, K., & Koenig, S. (2021). Genetic analyzes of physiological traits in relation to climatic stresses in German Black Pied cattle. ZUCHTUNGSKUNDE. 93(2), 81-98.
Schlagwörter
Dairy cows; FEED-EFFICIENCY; genetic parameters; HEAT-STRESS; LACTATING DAIRY-COWS; RANDOM REGRESSION-MODELS; THERMOTOLERANCE
