Production, physiological, and hormonal responses of Holstein and Brown Swiss heat-stressed dairy cows to two different cooling systems

Persistent Link:
http://hdl.handle.net/10150/282866
Title:
Production, physiological, and hormonal responses of Holstein and Brown Swiss heat-stressed dairy cows to two different cooling systems
Author:
Correa-Calderon, Abelardo
Issue Date:
1999
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
To evaluate the effect of two different cooling systems on production, physiological, and hormonal responses, 37 Holstein and 26 Brown Swiss dairy cows were allotted to three treatments. A control group of cows had access to only shade (C). A second group was cooled with spray and fan (S/F) and the third group was under an evaporative cooling system called Korral Kool&circR; (KK). The trial lasted from May to September with a daily maximum temperature-humidity index from 73 to 85. Milk production differences in Holstein cows were significantly increased by KK and S/F. No treatment differences in milk production were observed in Brown Swiss cows. Protein percentages were higher in C group compared to Korral Kool group only in Brown Swiss cows, while fat percentage were similar among treatments in Holstein cows. Rectal temperatures and respiration rates of the C group were higher than S/F and KK in both Holstein and Brown Swiss cows. Triiodothyronine levels in milk were significantly higher in KK group compared to S/F and C groups, while cortisol levels were lower in C group than S/F and KK. Similar differences were observed in body weight and body condition score changes between treatments in Holstein or Brown Swiss cows. Pregnancy rate was increased in the groups under the cooling systems in Holstein cows, however this effect was not observed in Brown Swiss cows where C group had a higher pregnancy rate than cooled groups. The cows under cooling systems spend more time eating and outside of the shade in the early afternoon (12:00 to 15:00) than control group. Cows injected with bST (bovine somatotropin) increased milk yield significantly only in Brown Swiss cows, whereas respiration rates were increased in both breeds by bST but rectal temperatures were similar between bST and non-bST cows. These results demonstrate that both cooling systems are an alternative to increase productive and reproductive performance and comfort of Holstein cows during summer in hot-dry climates. The physiological responses of Brown Swiss cows indicated a better adaptation to a hot climate, however their milk production was lower than in Holstein cows.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Biology, Animal Physiology.; Agriculture, Animal Culture and Nutrition.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Animal Sciences
Degree Grantor:
University of Arizona
Advisor:
Ray, Donald E.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleProduction, physiological, and hormonal responses of Holstein and Brown Swiss heat-stressed dairy cows to two different cooling systemsen_US
dc.creatorCorrea-Calderon, Abelardoen_US
dc.contributor.authorCorrea-Calderon, Abelardoen_US
dc.date.issued1999en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractTo evaluate the effect of two different cooling systems on production, physiological, and hormonal responses, 37 Holstein and 26 Brown Swiss dairy cows were allotted to three treatments. A control group of cows had access to only shade (C). A second group was cooled with spray and fan (S/F) and the third group was under an evaporative cooling system called Korral Kool&circR; (KK). The trial lasted from May to September with a daily maximum temperature-humidity index from 73 to 85. Milk production differences in Holstein cows were significantly increased by KK and S/F. No treatment differences in milk production were observed in Brown Swiss cows. Protein percentages were higher in C group compared to Korral Kool group only in Brown Swiss cows, while fat percentage were similar among treatments in Holstein cows. Rectal temperatures and respiration rates of the C group were higher than S/F and KK in both Holstein and Brown Swiss cows. Triiodothyronine levels in milk were significantly higher in KK group compared to S/F and C groups, while cortisol levels were lower in C group than S/F and KK. Similar differences were observed in body weight and body condition score changes between treatments in Holstein or Brown Swiss cows. Pregnancy rate was increased in the groups under the cooling systems in Holstein cows, however this effect was not observed in Brown Swiss cows where C group had a higher pregnancy rate than cooled groups. The cows under cooling systems spend more time eating and outside of the shade in the early afternoon (12:00 to 15:00) than control group. Cows injected with bST (bovine somatotropin) increased milk yield significantly only in Brown Swiss cows, whereas respiration rates were increased in both breeds by bST but rectal temperatures were similar between bST and non-bST cows. These results demonstrate that both cooling systems are an alternative to increase productive and reproductive performance and comfort of Holstein cows during summer in hot-dry climates. The physiological responses of Brown Swiss cows indicated a better adaptation to a hot climate, however their milk production was lower than in Holstein cows.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBiology, Animal Physiology.en_US
dc.subjectAgriculture, Animal Culture and Nutrition.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAnimal Sciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRay, Donald E.en_US
dc.identifier.proquest9923144en_US
dc.identifier.bibrecord.b39470696en_US
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