Bull selection and use in northern Australia

Fordyce, Geoffry; Fitzpatrick, L.A.; Cooper, Naomi; Doogan, V. J.; Faveri, J. De; Holroyd, R. G.

doi:10.1016/s0378-4320(02)00027-1

Cited by 36 publications

(24 citation statements)

References 14 publications

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“…The bull percentages observed in the current study were generally lower than that reported by O'Rourke et al (1992) and may be due to the adoption of research findings that recommended their reduction such as Fordyce et al (2002). However, the current bull percentages used still remain higher than the 2.5% recommended as being adequate under extensively managed environments, assuming all bulls mated were reproductively sound.…”

Section: Discussioncontrasting

confidence: 77%

Risk factors affecting the reproductive outcome of beef breeding herds in North Australia

McCosker¹

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Approximately half of Australia's beef breeding herds are located in northern Australia with reproductive performance being identified as having a significant impact on the profitability of these businesses. Although many of the risk factors affecting the reproductive performance of beef cattle have been previously identified, the relative contribution of major risk factors to key measures of performance, after partitioning the effects of other confounding variables, is lacking, particularly for extensive tropical rangeland systems typical of northern Australia.The overall objective of the research described in this thesis was to, i) describe the reproductive performance of commercial beef breeding cattle in northern Australia and, ii) determine, and quantify the effect of the major risk factors associated with three key measures of reproductive performance (lactating cows becoming pregnant within 4 months of calving, cows failing to become pregnant within an approximate 12 month reproductive cycle, and foetal/calf loss between confirmed pregnancy and weaning). It was hypothesised that the major risk factors determining the probability of lactating cows becoming pregnant within four months of calving are similar to those determining the probability of foetal/calf loss between confirmed pregnancy and weaning. To address these objectives, a prospective population-based epidemiological study was conducted between 2007 and 2011 involving 78 commercial beef properties located across northern Australia.Attainable and typical levels of reproductive performance for cow-age cohorts were described using a dataset containing 114,154 annual production cycles of performance data that represented approximately 78,000 heifers and cows managed in 142 breeding groups. Properties were assigned to one of four broad country types following a subjective assessment of the production potential of the grazing land and cross-referencing with pasture and vegetation descriptions reported by the herd owners/managers.The typical overall reproductive performance of cows in the Northern Forest (57 live calves at muster per 100 surviving mature cows), was considerably lower than that for the other country types (71-83 live calves at muster per 100 surviving mature cows). This was due to typically much lower percentage of cows becoming pregnant within 4 months of calving, higher foetal and calf loss and higher estimated mortality of pregnant cows in the Northern Forest compared to the other genotypes. These findings are consistent with the generally poorer quantity and quality of pasture, ii harsher environment and higher disease risk of cattle managed in the Northern Forest compared to the other country types.Country type and predicted calving period were top-order determinants of pregnancy within 4 months of calving while lactating. The effect of cow-age class cohort was dependent on country type with the expected occurrence of lactating cows pregnant within 4 months of calving estimated to be 23. 1-53.8, 38.1-61.6, 35.4-56.5 and 38.5...

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Section: Discussioncontrasting

confidence: 77%

Risk factors affecting the reproductive outcome of beef breeding herds in North Australia

McCosker¹

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“…Quando se utilizam touros com valores genético e reprodutivo superiores em um rebanho, pode-se reduzir o número de reprodutores em serviço e acelerar o ganho genético [13]. Entretanto, existem diferenças na capacidade fertilizante entre os touros [14]- [17].…”

Section: Avaliação Da Fertilidade Em Tourosunclassified

Avaliações seminais e novas ferramentas genômicas na estimação da fertilidade em touros

Vega

Maciel

2015

Spei Domus

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Cómo citar este artículo: Ortiz-Vega WH, Maciel-Júnior VL, Quirino CR. Avaliações seminais e novas ferramentas genômicas na estimação da fertilidade em touros. Spei Domus. 2015;11(23) Resumo. Tema e alcance: a estimativa da fertilidade do reprodutor é uma ferramenta importante na escolha do macho, não só porque reflete o estado individual do reprodutor, mas também porque dito resultado influencia o futuro do rebanho. A presente revisão aborda o assunto fertilidade no macho bovino sob a perspectiva da biotecnologia do sêmen. Características: descreve as características seminais que influenciam o potencial reprodutivo e apresenta de forma geral técnicas laboratoriais rotineiras e inovadoras na avaliação de espermatozoides. Documentos base na área de biotecnologia de sêmen assim como artigos das últimas quatro décadas foram utilizados na revisão; além disso, aspectos-chave de manuais e livros de difusão mundial complementam o acervo bibliográfico referenciado. Achados: o amplo número de estudos sobre o tema e a diversidade nos resultados pressupõem vazios no conhecimento que abrem uma oportunidade na utilização de ferramentas genômicas e permitem explicar com maior acurácia os diferentes eventos fisiológicos presentes na expressão das características seminais referentes à fertilidade. Conclusões: a variância genética e as mudanças epigenéticas podem estar influenciando o potencial reprodutivo no macho; fenômenos funcionais ainda pouco conhecidos precisam ser elucidados no intuito de compreender e, talvez, alterar essa variação entre e inter reprodutores.Palavras-chave: espermatozoide, inseminação artificial, marcador molecular, proteômica.

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“…Social dominance influences fear and stress response to handling of goats (Miranda-de la Lama et al, 2013a) and dominancerelated interactions in cattle can cause stress, bruises and physical injuries (Fordyce et al, 2002). In contrast, there are a limited number of studies on the relationships between social dominance and meat quality traits.…”

Section: Introductionmentioning

confidence: 99%

Factors influencing the priority of access to food and their effects on the carcass traits for Japanese Black (Wagyu) cattle

Takanishi

Oishi

Kumagai

et al. 2015

Animal

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The factors influencing the priority of access to food and the effects of the priority of access to food on their carcass traits were analyzed for Japanese Black (Wagyu) cattle in a semi-intensive fattening production system. The records of 96 clinically healthy steers and heifers were analyzed. The calves at ∼ 3 to 4 months of age were allocated to pens with four animals per pen; all four animals in the same pen were of the same sex and of similar body size. The ranking of the animals' priority of access to food (1 st , 2 nd , 3 rd and 4 th ), which was determined by the farm manager, was used as an indicator of social dominance in the present study. Four models including sire line, maternal grandsire line and the difference in the animals' birth dates as fixed effects were used to analyze factors influencing the priority of access to food. Ranking was represented by ordinal scores (highest = 4, lowest = 1) in Model 1, and the binary scores were assigned in Model 2 (highest = 1; 2 nd , 3 rd and 4 th = 0), Model 3 (1 st and 2 nd = 1; 3 rd and 4 th = 0) and Model 4 (1 st , 2 nd and 3 rd = 1; lowest = 0). The results showed that the difference in the animals' birth dates had a significant effect on the establishment of the priority of access to food in Model 3 ( P < 0.05), suggesting that animals born earlier may become more dominant in the pen. The maternal grandsire line tended to affect the social rank score in Models 2 and 3 ( P < 0.10). Our results indicated that the maternal grandsire line may affect the temperament of calves through their mothers' genetic performance and thereby more aggressive calves may be more dominant and have higher priority of access to food. On the other hand, there was a significant effect of the priority of access to food on beef marbling score (BMS; P < 0.05), and the priority of access to food also tended to influence the carcass weight ( P = 0.09). The highest BMS was observed for animals with the first rank of the priority of access to food ( P < 0.05), and the higher-ranking animals had the tendency to be heavier carcass than the lower-ranking animals. Our findings emphasized the importance of information about the priority of access to food determined by farmers' own observation on implementing best management practices in small-scaled semi-intensive beef cattle production systems.

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Bull selection and use in northern Australia

Cited by 36 publications

References 14 publications

Risk factors affecting the reproductive outcome of beef breeding herds in North Australia

Risk factors affecting the reproductive outcome of beef breeding herds in North Australia

Avaliações seminais e novas ferramentas genômicas na estimação da fertilidade em touros

Factors influencing the priority of access to food and their effects on the carcass traits for Japanese Black (Wagyu) cattle

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