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Responses to Heat Stress in Slick vs. Normal-Haired Holstein Cows

Permanent Link: http://ufdc.ufl.edu/UFE0025100/00001

Material Information

Title: Responses to Heat Stress in Slick vs. Normal-Haired Holstein Cows
Physical Description: 1 online resource (72 p.)
Language: english
Creator: Alava, Eduardo
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: heat, holstein, respiration, slick, sweating
Animal Sciences -- Dissertations, Academic -- UF
Genre: Animal Sciences thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: RESPONSES TO HEAT STRESS SLICK vs. NORMAL-HAIRED HOLSTEIN COWS Heat stress plays a significant role in cattle performance and likely will be of even greater importance in the future. Selection of cattle adapted to warm environments represents one strategy to mitigate the effects of heat stress. The objectives of this study were to determine the physical, metabolic and production responses of slick (n=11) and normal-haired (n=10), lactating Holstein cows under heat stress conditions and was conducted at the Dairy Research Unit in Hague, FL. The slick-haired phenotype is produced in animals with the Slick hair gene which have very short, sleek, and, sometimes, glossy coats. Cows were maintained in a barn containing fans and sprinklers and equipped with Calanregistered trademark gates. Animals were offered a total mixed ration (TMR) that contained corn silage, alfalfa hay and concentrate mixed at 35, 10 and 55% of the dietary DM respectively. Rectal temperature, respiration rate, and sweating rate were recorded weekly in the morning at 0800 h and in the afternoon at 1430 h each Saturday and Sunday for a four week period beginning in late August. Sweating rate was measured on a clipped and unclipped area of the right shoulder of each cow. Vaginal temperature was recorded continuously for a five day period during two different periods of the study. The first vaginal temperature measurements were taken from September 5 - 10, 2007 at the beginning of the trial, and the second measurement period was from September 28 - October 3, 2007 at the end of the trial. An apparent digestibility trial was also conducted using chromic oxide (Cr2O3) as an external marker. Intake and milk production were recorded daily for subsequent dry matter intake, feed efficiency and energy balance determinations. Slick-haired Holstein cows had lower (P < 0.01) rectal temperatures 38.6 vs. 39.0degreeC, and averaged 0.4degreeC less than those of the normal-haired ones throughout the study. In addition, slick-haired cows had a lower (P < 0.01) respiration rate than the normal-haired cows while under heat stress, 61 vs.72 breath per minute, respectively. There were no differences in sweating rates between slick and normal-haired Holstein for both clipped (P = 0.16) and unclipped (P = 0.43) areas (28.08 vs. 25.3 g/m2h; and 27.9 vs. 26.2 g/m2h, respectively). Slick-haired Holsteins had lower vaginal temperatures (P = 0.04) than the normal-haired ones during week one averaging 39.3 vs. 39.6degreeC, respectively. In contrast, vaginal temperature did not differ (P = 0.56) between slick and normal-haired Holsteins, averaging 39.1 vs. 39.2degreeC, respectively as the weather became cooler at the end of the trial. During both weeks, vaginal temperature showed a hair type by day by time of day (P < 0.01) interaction. In week one, slick-haired Holsteins had lower vaginal temperatures compared to those of normal-haired ones during the day as the ambient temperature rose throughout the day and similarly, during the night time, as body temperature increased as part of the normal circadian rhythm presented during the trial. Slick-haired Holsteins were able to resist increases in vaginal temperatures throughout week one as ambient temperature varied among days. A similar phenomena occurred during week five to a lesser extent as the weather conditions were cooler than in week one. Slick-haired Holsteins were able to control their vaginal temperature similarly to that of week one, but the differences were smaller in magnitude due to the improving weather conditions. Dry matter intake between the slick-haired lactating cows and the normal-haired ones did not differ (P = 0.41) slick = 21.5, normal = 22.3 kg DM/day. However, during the experiment normal-haired Holstein cows had a tendency (P = 0.07) to produce more milk than the slick-haired ones, 28.8 vs. 24.7 kg/day, respectively. Measurements of vaginal temperatures in this study also indicated that slick-haired cows maintained lower core body temperatures than normal-haired cows exposed to elevated ambient temperatures for a four day period of time. The improved thermotolerance of the slick-haired cows indicates that slick-haired Holstein cows are able to regulate body temperature more effectively than normal-haired ones under heat stress, but results in this study show that slick-haired cows did not achieve higher dry matter intake under heat stress. It seems that slick-haired cows have more efficient heat dissipation mechanisms than normal-haired cows.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Eduardo Alava.
Thesis: Thesis (M.S.)--University of Florida, 2009.
Local: Adviser: Olson, Timothy A.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0025100:00001

Permanent Link: http://ufdc.ufl.edu/UFE0025100/00001

Material Information

Title: Responses to Heat Stress in Slick vs. Normal-Haired Holstein Cows
Physical Description: 1 online resource (72 p.)
Language: english
Creator: Alava, Eduardo
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: heat, holstein, respiration, slick, sweating
Animal Sciences -- Dissertations, Academic -- UF
Genre: Animal Sciences thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: RESPONSES TO HEAT STRESS SLICK vs. NORMAL-HAIRED HOLSTEIN COWS Heat stress plays a significant role in cattle performance and likely will be of even greater importance in the future. Selection of cattle adapted to warm environments represents one strategy to mitigate the effects of heat stress. The objectives of this study were to determine the physical, metabolic and production responses of slick (n=11) and normal-haired (n=10), lactating Holstein cows under heat stress conditions and was conducted at the Dairy Research Unit in Hague, FL. The slick-haired phenotype is produced in animals with the Slick hair gene which have very short, sleek, and, sometimes, glossy coats. Cows were maintained in a barn containing fans and sprinklers and equipped with Calanregistered trademark gates. Animals were offered a total mixed ration (TMR) that contained corn silage, alfalfa hay and concentrate mixed at 35, 10 and 55% of the dietary DM respectively. Rectal temperature, respiration rate, and sweating rate were recorded weekly in the morning at 0800 h and in the afternoon at 1430 h each Saturday and Sunday for a four week period beginning in late August. Sweating rate was measured on a clipped and unclipped area of the right shoulder of each cow. Vaginal temperature was recorded continuously for a five day period during two different periods of the study. The first vaginal temperature measurements were taken from September 5 - 10, 2007 at the beginning of the trial, and the second measurement period was from September 28 - October 3, 2007 at the end of the trial. An apparent digestibility trial was also conducted using chromic oxide (Cr2O3) as an external marker. Intake and milk production were recorded daily for subsequent dry matter intake, feed efficiency and energy balance determinations. Slick-haired Holstein cows had lower (P < 0.01) rectal temperatures 38.6 vs. 39.0degreeC, and averaged 0.4degreeC less than those of the normal-haired ones throughout the study. In addition, slick-haired cows had a lower (P < 0.01) respiration rate than the normal-haired cows while under heat stress, 61 vs.72 breath per minute, respectively. There were no differences in sweating rates between slick and normal-haired Holstein for both clipped (P = 0.16) and unclipped (P = 0.43) areas (28.08 vs. 25.3 g/m2h; and 27.9 vs. 26.2 g/m2h, respectively). Slick-haired Holsteins had lower vaginal temperatures (P = 0.04) than the normal-haired ones during week one averaging 39.3 vs. 39.6degreeC, respectively. In contrast, vaginal temperature did not differ (P = 0.56) between slick and normal-haired Holsteins, averaging 39.1 vs. 39.2degreeC, respectively as the weather became cooler at the end of the trial. During both weeks, vaginal temperature showed a hair type by day by time of day (P < 0.01) interaction. In week one, slick-haired Holsteins had lower vaginal temperatures compared to those of normal-haired ones during the day as the ambient temperature rose throughout the day and similarly, during the night time, as body temperature increased as part of the normal circadian rhythm presented during the trial. Slick-haired Holsteins were able to resist increases in vaginal temperatures throughout week one as ambient temperature varied among days. A similar phenomena occurred during week five to a lesser extent as the weather conditions were cooler than in week one. Slick-haired Holsteins were able to control their vaginal temperature similarly to that of week one, but the differences were smaller in magnitude due to the improving weather conditions. Dry matter intake between the slick-haired lactating cows and the normal-haired ones did not differ (P = 0.41) slick = 21.5, normal = 22.3 kg DM/day. However, during the experiment normal-haired Holstein cows had a tendency (P = 0.07) to produce more milk than the slick-haired ones, 28.8 vs. 24.7 kg/day, respectively. Measurements of vaginal temperatures in this study also indicated that slick-haired cows maintained lower core body temperatures than normal-haired cows exposed to elevated ambient temperatures for a four day period of time. The improved thermotolerance of the slick-haired cows indicates that slick-haired Holstein cows are able to regulate body temperature more effectively than normal-haired ones under heat stress, but results in this study show that slick-haired cows did not achieve higher dry matter intake under heat stress. It seems that slick-haired cows have more efficient heat dissipation mechanisms than normal-haired cows.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Eduardo Alava.
Thesis: Thesis (M.S.)--University of Florida, 2009.
Local: Adviser: Olson, Timothy A.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0025100:00001


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m d

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P P

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ad libitum B taurus

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B indicus B taurus B indicus

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B. taurus Slick hair P

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P Slick

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Slick hair

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Slick gene

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Bos indicus Bos taurus

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