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Journal of Animal Science and Technology
Korean Society of Animal Science and Technology

J Anim Sci Technol

pISSN: 2055-0391, eISSN: 2672-0191

DOI: https://doi.org/10.5187/jast.2022.e104

Article

Effects of dry period length on milk production, physiological responses and metabolic status of dairy cows exposed to heat stress during the transition period

Dong-Hyun Lim1, Da Jin Sol Jung1, Kwang-Seok Ki1, Dong-Hyeon Kim1, Manhye Han1, Younghoon Kim2,*
1Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Chungcheongnam-do, Cheonan 31000, Korea.
2Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Science, Seoul National University, Seoul 08826, Korea.
*Corresponding Author: Younghoon Kim, Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Science, Seoul National University, Seoul 08826, Korea, Republic of. Phone: 028804808. E-mail: ykeys2584@snu.ac.kr.

© Copyright 2022 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Oct 17, 2022; Revised: Nov 12, 2022; Accepted: Nov 14, 2022

Published Online: Dec 20, 2022

Abstract

The objective of this study was to investigate the effects of a traditional dry period (60 d) versus a no dry period (0 d) on the milk production, physiological response, and metabolic status of dairy cows exposed to heat stress during the transition period. Holstein dairy cows (n = 15) with similar expected calving dates were randomly assigned to two different dry period lengths: (1) no dry period (n = 7) and (2) a traditional dry period of 60 days (n = 8). All cows were studied from 8 weeks before expected calving to 10 weeks after calving and experienced heat stress during the transition period. The results showed that cows with no dry period decreased their milk yield in subsequent lactation, but compensated for the loss of milk yield accounted for by additional milk yield before calving. The energy balance at postpartum was improved in cows with no dry period compared to cows with a traditional dry period. There were no significant differences in the physiological response and blood metabolites at postpartum between the dry period lengths of dairy cows exposed to heat stress during the transition period. Taken together, our results showed that omitting the dry period improved the milk production and metabolic status of dairy cows exposed to heat stress during the transition period.

Keywords: Dairy cows; heat stress; dry period length; milk production; blood metabolites