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Effect of season and genotype on values for bull semen variables under tropical conditions


Landaeta-Hernández, Antonio J; Gil-Araujo, Marcelo A; Ungerfeld, Rodolfo; Owen Rae, D; Urdaneta-Moyer, Angela; Parra-Núñez, Alexander; Kaske, Martin; Bollwein, Heiner; Chenoweth, Peter J (2020). Effect of season and genotype on values for bull semen variables under tropical conditions. Animal Reproduction Science, 221:106592.

Abstract

To assess the effects of season and genotype on fresh semen quality for freezing and subsequent use for AI, 32 healthy, mature (>4 to <6 years old) and habituated bulls (Bos indicus n = 14, Bos taurus n = 5, Crossbred taurus x indicus n = 6, and tropically adapted Bos taurus composites n = 7) were evaluated at a Venezuelan AI center for 12 months in which four distinct seasons (Hot-dry, Transition, Hot-humid, Cool-rainy) occur. Ejaculates were collected weekly from Bos taurus (n = 260), Bos indicus (n = 669), tropically adapted Bos taurus composites (n = 389), and crossbred Bos taurus x Bos indicus (n = 340) bulls. Routine AI Center assessments were conducted i.e., ejaculate volume (EV), sperm mass-motility (MM), total sperm number/ejaculate (TSE), sperm concentration/mL (SC), pre-freezing (PREF), and post-freezing minimum criteria rate for AI use (POSTF). Genotype affected EV (P < 0.0001), TSE (P < 0.0001), and SC (P < 0.0001) but not MM (P>0.05). Season affected EV (P < 0.001), TSE (P < 0.0001), SC (P < 0.01), and MM (P < 0.05). There were genotype x season interactions for EV, MM, TSE, and SC. The PREF averaged 74.0% during the study, although was less (P < 0.0001) during the hot-humid season than the other seasons. Even though, percent ejaculates considered unsuitable for freezing differed (P < 0.03) among the Hot-dry (20.2%), transition (30.9%), Hot-humid (32.4%), and Cool-rainy (24%) seasons. For POSTF, there were no seasonal differences (P>0.05). It is concluded that in tropical regions, season and genotype can affect bull semen variables, particularly those which affect the success of semen freezing and AI.

Abstract

To assess the effects of season and genotype on fresh semen quality for freezing and subsequent use for AI, 32 healthy, mature (>4 to <6 years old) and habituated bulls (Bos indicus n = 14, Bos taurus n = 5, Crossbred taurus x indicus n = 6, and tropically adapted Bos taurus composites n = 7) were evaluated at a Venezuelan AI center for 12 months in which four distinct seasons (Hot-dry, Transition, Hot-humid, Cool-rainy) occur. Ejaculates were collected weekly from Bos taurus (n = 260), Bos indicus (n = 669), tropically adapted Bos taurus composites (n = 389), and crossbred Bos taurus x Bos indicus (n = 340) bulls. Routine AI Center assessments were conducted i.e., ejaculate volume (EV), sperm mass-motility (MM), total sperm number/ejaculate (TSE), sperm concentration/mL (SC), pre-freezing (PREF), and post-freezing minimum criteria rate for AI use (POSTF). Genotype affected EV (P < 0.0001), TSE (P < 0.0001), and SC (P < 0.0001) but not MM (P>0.05). Season affected EV (P < 0.001), TSE (P < 0.0001), SC (P < 0.01), and MM (P < 0.05). There were genotype x season interactions for EV, MM, TSE, and SC. The PREF averaged 74.0% during the study, although was less (P < 0.0001) during the hot-humid season than the other seasons. Even though, percent ejaculates considered unsuitable for freezing differed (P < 0.03) among the Hot-dry (20.2%), transition (30.9%), Hot-humid (32.4%), and Cool-rainy (24%) seasons. For POSTF, there were no seasonal differences (P>0.05). It is concluded that in tropical regions, season and genotype can affect bull semen variables, particularly those which affect the success of semen freezing and AI.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:05 Vetsuisse Faculty > Veterinary Clinic > Department of Farm Animals
Dewey Decimal Classification:570 Life sciences; biology
630 Agriculture
Scopus Subject Areas:Health Sciences > Food Animals
Life Sciences > Animal Science and Zoology
Life Sciences > Endocrinology
Uncontrolled Keywords:Food Animals, Animal Science and Zoology, Endocrinology, General Medicine
Language:English
Date:1 October 2020
Deposited On:10 Feb 2021 15:41
Last Modified:11 Feb 2021 21:00
Publisher:Elsevier
ISSN:0378-4320
OA Status:Closed
Publisher DOI:https://doi.org/10.1016/j.anireprosci.2020.106592

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