Voluntary heat stress abatement system for dairy cows: Does it mitigate the effects of heat stress on physiology and behavior?

L. N. Grinter, G. Mazon, J. H.C. Costa

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Many cooling strategies are used to keep cows in thermal homeostasis; however, most of them are applied to the group level, commonly at the feed bunk or milking parlor. The variance of heat stress effects on animals are well known, but with more individualized management in dairy farms, group cooling opportunities are becoming restricted. It is known that dairy cattle are variable in their responses to an increase in heat load. Thus, the first objective of this study was to investigate the effect of 2 mandatory soakings at the exit of the milking parlor and free access to a voluntary soaking system compared with cows with access to a voluntary soaking system only, with no mandatory soakings. The second objective of this study was to assess the heat abatement capability of voluntary soaking of cows by assessing cow physiology, behavior, and milk production. Last, this study aimed to determine the individual use of the voluntary heat abatement system and its relationship with temperature-humidity index (THI). Fifteen mid-lactation Holstein cows were enrolled in this study and had free access to a motion-activated soaker (Cool Sense, Edstrom) located adjacent to the research pen for an 8-wk data collection period. Cows were paired according to parity, milk production, and body weight, and assigned a treatment with or without mandatory soakings twice per day. In the mandatory soaking treatment (MS), cows were soaked using a motion-activated soaker at the exit of the milking parlor and had free access to the voluntary soaker in the pen. Cows in the treatment without mandatory soakings (NMS) were not soaked at the exit of the milking parlor and had free access to the voluntary soaker in the pen. The effects of soaker treatment were analyzed using mixed linear models. The model included treatment, soaker uses per day, pair, mean daily THI, days in milk, daily milk yield, and interaction of treatment with mean daily THI. Study day was specified as a repeated measure, and cow as the subject, using an autoregressive structure. Also, we assessed the relationship of mean soaker use and THI against all variables. There was great individual variation in voluntary soaker use, ranging from 0 to 227 soakings/d (mean ± standard deviation, 13 ± 30 voluntary soakings/d). Treatment did not affect voluntary soaker use (MS, 12.4 ± 1.4 soakings/d; NMS, 14.8 ± 1.4 soakings/d), respiration rate (MS, 57.3 ± 0.4 breaths/min; NMS, 56.4 ± 0.4 breaths/min), or milk yield (MS, 36.5 ± 0.6 kg/d; NMS, 36.2 ± 0.6 kg/d). However, MS cows spent more time ruminating (MS, 558.6 ± 5.2 min/d; NMS, 543.4 ± 5.4 min/d). Temperature-humidity index had a positive relationship with voluntary soaker use and mean respiration rate. In conclusion, voluntary soaker use related positively to the THI, but no major productive, physiological, or behavioral differences were observed between soaking treatments. Furthermore, we found that voluntary soaker use is highly variable among cows and it was related positively to milk yield, where higher producing cows used the soaker more frequently.

Original languageEnglish
Pages (from-to)519-533
Number of pages15
JournalJournal of Dairy Science
Volume106
Issue number1
DOIs
StatePublished - Jan 2023

Bibliographical note

Funding Information:
We gratefully acknowledge and thank the staff and students of the Coldstream Dairy Research Farm (Lexington, KY) who helped in this experiment, especially Adrien Lebreton, Charlotte Pertuisel, Brittany Core, Amelia Fendley, Joey Clark, and Matt Collins. We also thank Olga Vsevolozhskaya, Michelle Arnold, and Eric Vanzant from the University of Kentucky (Lexington, KY) for their contributions to this project. This project was funded by DairyMaster Co. (Kerry, Ireland) through a research project partnership with the Dairy Science Program at the University of Kentucky. This research was also funded in part by a U.S. Department of Agriculture National Institute of Food and Agriculture Hatch Grant Project (KY007100) at the University of Kentucky. The authors have not stated any conflicts of interest.

Publisher Copyright:
© 2023 American Dairy Science Association

Keywords

  • precision dairy technology
  • shower
  • thermoregulation

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology
  • Genetics

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