Differential responses of physiological parameters, production traits, and blood metabolic profiling between first- and second-parity Holstein cows in the comparison of spring versus summer seasons

Authors: HU, LIRONG - China Agricultural University; BRITO, LUIZ - Purdue University; LUO, HANPENG - China Agricultural University; CHEN, SHAOKAN - Beijing Sunlon Livestock Development Co Ltd; Johnson, Jay; SAMMAD, ABDUL - China Agricultural University; GUO, GANG - Beijing Sunlon Livestock Development Co Ltd; XU, QING - Beijing Jiaotong University; WANG, YACHUN - China Agricultural University

Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2023
Publication Date: 7/25/2023
Citation: Hu, L., Brito, L.F., Luo, H., Chen, S., Johnson, J.S., Sammad, A., Guo, G., Xu, Q., Wang, Y. 2023. Differential responses of physiological parameters, production traits, and blood metabolic profiling between first- and second-parity Holstein cows in the comparison of spring versus summer seasons. Journal of Agriculture and Food Chemistry. https://doi.org/10.1021/acs.jafc.3c00043.
DOI: https://doi.org/10.1021/acs.jafc.3c00043

Interpretive Summary: Parity may impact production and welfare outcomes in dairy cattle. and this may be further influenced by environmental conditions. Therefore, the study objective was to gain a better understanding of how both parity and season impact physiological and molecular responses of lactating first and second parity Holstein cows. It was determined that physiological and molecular responses of cows differed by seasonal replicate (Spring versus Summer), with several biomarkers identified as potential indicators of heat stress in cows. Furthermore, factors including body temperature response, activity levels, and milk production were impacted by parity. Taken together, data from this study provide new information that will assist researchers and producers in the development of heat stress mitigation protocols based upon cow parity.

Technical Abstract: Background: Heat stress (HS) negatively influences cows’ welfare and productivity. Therefore, a better understanding of the physiological and molecular mechanisms involved in HS responses of cows from multiple parities is paramount for the development of effective management and breeding strategies. In this context, we aimed to comprehensively evaluate the impact of seasonal HS on five physiological parameters, 10 production traits, and 44 blood metabolites of first- and second-parity cows and to investigate the differences in thermoregulation between the first two parities. Results: HS influenced physiological parameters and decreased the productive performance of all experimental cows. First-parity cows significantly influenced rectal temperature, respiration rate, daily rumination, daily activity, seven-day average milk yield, and milk yield on sampling day in comparison to second-parity cows. However, second-parity cows had a much greater decline in fat percentage. In total, 18 and 17 metabolites were differentially involved in the HS response of first- and second-parity cows, respectively, in which nine metabolites were shared between both parities. The pathway analyses suggested that HS inhibited the tricarboxylic acid cycle, elevated the utilization of lipolysis, and disrupted the balance of the gut microbiome. The metabolites exclusively identified for each parity are specific to microbial metabolism and amino acid metabolism. Moreover, glucose, ethanol, and citrate were identified as potential biomarkers for diagnosing HS in first-parity cows while ethanol and acetone were better predictors for second-parity cows. Conclusions: The present study demonstrated the impact of HS on physiological parameters, production traits, and blood metabolome of Holstein cows. Furthermore, there are different biological responses and regulation mechanisms between first- and second-parity Holstein cows, in which the biomarkers identified could be used as additional phenotypes in future selection programs.