Relationships between breeding soundness and sex drive classifications in beef bulls

Chenoweth, Peter J.; Farin, P.W.; Mateos, E.; Rupp, Gary P.; Pexton, J.E.

doi:10.1016/0093-691x(88)90172-0

Cited by 13 publications

(4 citation statements)

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“…Houve aumento de touros nas categorias A e B do CAP ao longo do tempo, fato semelhante aos relatos que utilizaram esta metodologia como seleção de touros ao longo do tempo (4) . Possivelmente devido ao descarte de touros inadequados e à compra de touros jovens com maior perímetro escrotal, as porcentagens de touros nas categorias A e B, na avaliação do ano 1997, foram semelhantes às de estudos anteriores sobre raças taurinas (23,(25)(26)(27) e maiores que os observados por Kennedy et al (28) com dez grupos zootécnicos de raças europeias e seus mestiços. Neste último caso, os animais foram avaliados ao sobreano.…”

Section: Resultsunclassified

“…Na Tabela 4 encontram-se as características reprodutivas referentes aos grupos por tipo de fêmeas e a média das propriedades que integraram a estação de acasalamento. Os valores do CAP nos touros do presente estudo foram superiores aos relatados em outros estudos com raças taurinas (8,22,24,25) , para touros taurinos adaptados aos trópicos e zebuínos (9,11,15,28) ; contudo, os touros deste estudo foram selecionados de um grupo maior de touros o que não foi relatado nos trabalhos citados. A diferença encontrada nas idades dos touros entre os grupos de fêmeas (Tabela 4) e a correlação observada nesta característica (CAP) com a prenhez (r =-0,26; p<0,001) levam a refletir sobre a prática rotineira de manejo de se colocarem touros de maior idade nas categorias de fêmeas de menor fertilidade potencial, o que, neste estudo, não foi estabelecido.…”

Section: Resultsunclassified

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Evolução Após Quatro Anos De Aplicação Da Capacidade Andrológica Por Pontos (Cap) Em Touros Nelore E Estudo Da Relação Com a Prenhez Em Estação De Acasalamento

Freneau

Puoli

2017

Ciênc. anim. bras.

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Resumo Estudou-se a evolução da capacidade andrológica por pontos (CAP) de 1092 touros Nelore, mantidos a pasto, durante quatro anos, e sua relação com a porcentagem de prenhez após uma estação reprodutiva. A cada ano, realizaram-se avaliações clínico-andrológicas em que mediu-se o perímetro escrotal (PE) e se coleou sêmen por eletroejaculação, para avaliação dos aspectos físicos e morfológicos dos ejaculados. A partir dos pontos obtidos pelo PE (PEP), motilidade progressiva (MOT) e morfologia espermática (MORF), computaram-se os CAP. Na estação de monta foram utilizadas 4319 fêmeas e 256 touros Nelore, em regime de pasto, para avaliação da fertilidade do rebanho. Após a escolha de 157 touros dentro das faixas A-C do CAP, foram estabelecidos, aleatoriamente, 15 grupos de touros para diferentes categorias e quantidade de fêmeas. Nos quatro anos de estudo houve aumento significativo do CAP, de 59,5 a 79,0. A PEP, MOT e MORF aumentaram no mesmo período de 17,5, 12,7 e 29,3 para 30,1, 14,8 e 34,4, respectivamente (P<0,05). Foram observadas correlações entre o CAP com os seus componentes, o ano e as características reprodutivas estudadas. Houve aumento significativo de touros enquadrados nas categorias A e B do CAP de 9,0% e 46,9% vs. 43,5% e 44,8%, respectivamente. O CAP e a porcentagem de prenhez das fêmeas foram de 82,0 ± 13,2 pontos e 83,1 ± 8,4 %, respectivamente. Houve correlação (P<0,001) entre o CAP e a taxa de prenhez (r=0,25). A utilização de grupos de touros das faixas A e B do CAP favoreceu o aumento da percentagem de prenhez no rebanho. A relação touro:fêmea observada sub-utiliza o potencial reprodutivo dos touros. A técnica empregada foi importante para avaliar a fertilidade potencial e modificar as características reprodutivas da população de touros estudada.

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Section: Resultsunclassified

Evolução Após Quatro Anos De Aplicação Da Capacidade Andrológica Por Pontos (Cap) Em Touros Nelore E Estudo Da Relação Com a Prenhez Em Estação De Acasalamento

Freneau

Puoli

2017

Ciênc. anim. bras.

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“…Consequently, an early in life indicator trait would be beneficial to collect if it were relatively easy to garner and reasonably genetically correlated to prolificacy. Bulls with high libido have a higher servicing capacity ( Chenoweth et al, 1988 ), but libido is not evaluated in routine breeding soundness exams. Of the traits tested during physical examinations, scrotal circumference is one of the closest correlated traits to bull fertility ( Parkinson, 2004 ).…”

Section: Introductionmentioning

confidence: 99%

Genetic parameter estimates for bull prolificacy and its relationship with scrotal circumference in a commercial beef cattle population

Russell

Pollak

Spangler

2021

Translational Animal Science

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The commercial beef cattle industry relies heavily on the use of natural service sires. When artificial insemination is deemed difficult to implement, multi-sire breeding pastures are used to increase reproductive rates in large breeding herds or to safe-guard against bull injury during the breeding season. Although each bull might be given an equal opportunity to produce offspring, evidence suggest that there is substantial variation in the number of calves sired by each bull in a breeding pasture. With the use of DNA-based paternity testing, correctly assigning calves to their respective sires in multi-sire pastures is possible and presents an opportunity to investigate the degree to which this trait complex is under genetic control. Field data from a large commercial ranch was used to estimate genetic parameters for calf count (CC; 574 records from 443 sires) and yearling scrotal circumference (SC; n=1961) using univariate and bivariate animal models. Calf counts averaged 12.2±10.7 and SC averaged 35.4±2.30 cm. Bulls had an average of 1.30 records and there were 23.9±11.1 bulls per contemporary group. The model for CC included fixed effects of age during the breeding season (in years) and contemporary group (concatenation of breeding pasture and year). Random effects included additive genetic and permanent environmental effects, and a residual. The model for SC included fixed effects of age (in days) and contemporary group (concatenation of month and year of measurement). Random effects included an additive genetic effect and a residual. Univariate model heritability estimates for CC and SC were 0.178±0.142 and 0.455±0.072, respectively. Similarly, the bivariate model resulted in heritability estimates for CC and SC of 0.184±0.142 and 0.457±0.072, respectively. Repeatability estimates for CC from univariate and bivariate models were 0.315±0.080 and 0.317±0.080, respectively. The estimate of genetic correlation between CC and SC was 0.268±0.274. Heritability estimates suggest that both CC and SC would respond favorably to selection. Moreover, CC is lowly repeatable and although favorably correlated, SC appears to be weakly associated with CC.

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“…An overall score was allocated to the bull, which was derived from individual values for SC, sperm motility and morphology. Final categorisation of bulls as exceptional, acceptable and unsatisfactory potential breeders were dependent on this score (Chenoweth et al, 1988).…”

Section: Methodsmentioning

confidence: 99%

Relationship between production characteristics and breeding potential of 25-month old extensively managed Bonsmara bulls

2010

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________________________________________________________________________________ AbstractThe aim of the study was to determine if the breeding potential of 25-month old Bonsmara beef bulls could be predicted from production characteristics. Forty-one Bonsmara bulls were included in an on-farm performance test (also known as the Phase D growth test) for a period of 180 days. At an average age of 24.7 months the bulls were subjected to a libido test and overall breeding soundness evaluation (OBE). The bulls were categorised into independent breeding potential categories according to the scores they obtained for the measured reproductive traits. The categories included sperm morphology and motility. One-way ANOVA revealed that none of the production traits measured had a significant effect on the different breeding potential categories. A positive correlation (r = 0.33) was recorded between pre-weaning growth rate and percentage morphologically normal sperm, while a negative correlation (r = -0.36) was recorded between total acrosomal-and flagellar sperm defects and pre-weaning growth. A positive correlation was demonstrated between sperm motility and pre-weaning growth (r = 0.36), and a consequent negative correlation (r = -0.38) between the percentage aberrant sperm movement and pre-weaning growth. The correlation between the percentage morphologically normal sperm and percentage progressively moving sperm was r = 0.50, while the correlation between percentage morphologically normal sperm and aberrant and immotile sperm was r = 0.48 for both variables. The number of total defects correlated highly significantly with flagellar and acrosomal defects (r = 0.72 and r = 0.93, respectively) and correlated poorly with the total number of nuclear defects (r = 0.32). These results suggest that total sperm defects were mainly due to acrosomal and flagellar defects, rather than nuclear defects and as the percentage morphologically normal sperm decreased, the motility also decreased. High growth rates before weaning may have a positive effect, while high growth rates after weaning may have a negative effect on the breeding potential of a bull. None of the measured reproductive and production traits had a significant effect on libido score and thus, cannot be used to predict the libido of young extensively maintained bulls. ________________________________________________________________________________

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Relationships between breeding soundness and sex drive classifications in beef bulls

Cited by 13 publications

References 8 publications

Evolução Após Quatro Anos De Aplicação Da Capacidade Andrológica Por Pontos (Cap) Em Touros Nelore E Estudo Da Relação Com a Prenhez Em Estação De Acasalamento

Evolução Após Quatro Anos De Aplicação Da Capacidade Andrológica Por Pontos (Cap) Em Touros Nelore E Estudo Da Relação Com a Prenhez Em Estação De Acasalamento

Genetic parameter estimates for bull prolificacy and its relationship with scrotal circumference in a commercial beef cattle population

Relationship between production characteristics and breeding potential of 25-month old extensively managed Bonsmara bulls

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