Bull selection and use in northern Australia

Bertram, J. D.; Fordyce, Geoffry; McGowan, Michael; Jayawardhana, G. A.; Fitzpatrick, L.A.; Doogan, V. J.; Faveri, J. De; Holroyd, R. G.

doi:10.1016/s0378-4320(02)00025-8

Cited by 24 publications

(11 citation statements)

References 10 publications

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“…The proportion of calves that were assigned an unambiguous sire in the NRH1 population was very close to the predicted level of 85%. A similar value was found in a large study of multi‐sire Bos indicus herds in Australia (Bertram et al. 2002).…”

Section: Discussionsupporting

confidence: 88%

Impact of candidate sire number and sire relatedness on DNA polymorphism‐based measures of exclusion probability and probability of unambiguous parentage

Sherman¹,

Kachman

Hungerford³

et al. 2004

Animal Genetics

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Genetic paternity testing can provide sire identity data for offspring when females have been exposed to multiple males. However, correct paternity assignment can be influenced by factors determined in the laboratory and by size and genetic composition of breeding groups. In the present study, DNA samples from 26 commingled beef bulls and their calves from the Nebraska Reference Herd-1 (NRH1), along with previously reported Illinois Reference/Resource Families data, were used to estimate the impact of sire number and sire relatedness on microsatellite-based paternity testing. Assay performance was measured by exclusion probabilities and probabilities of unambiguous parentage (PUP) were derived. Proportion of calves with unambiguous parentage (PCUP) was also calculated to provide a readily understandable whole-herd measure of unambiguous paternity assignment. For NRH1, theoretical and observed PCUP values were in close agreement (85.3 and 85.8%, respectively) indicating good predictive value. While the qualitative effects on PUP values of altering sire number and sire relatedness were generally predictable, we demonstrate that the impacts of these variables, and their interaction effects, can be large, are non-linear, and are quantitatively distinct for different combinations of sire number and degree of sire relatedness. In view of the potentially complex dynamics and practical consequences of these relationships in both research and animal production settings, we suggest that a priori estimation of the quantitative impact of a given set of interacting breeding group-specific and assay-specific parameters on PUP may be indicated, particularly when candidate sire pools are large, sire relatedness may be high, and/or loci numbers or heterozygosity values may be limiting.

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Section: Discussionsupporting

confidence: 88%

Impact of candidate sire number and sire relatedness on DNA polymorphism‐based measures of exclusion probability and probability of unambiguous parentage

Sherman¹,

Kachman

Hungerford³

et al. 2004

Animal Genetics

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“…Some researchers claim that the relationship between measures of libido and fertility is inconspicuous. However, other reports showed positive (Crichton and Lishman, 1988;Blockey, 1989) or contradictory or negative correlations (Boyd et al, 1989;Bertram et al, 2002;Holroyd et al, 2002). Albeit, several Brazilian reports indicate no correlation between libido and seminal traits in Nellore bulls (Pineda et al,.…”

Section: Resultsmentioning

confidence: 93%

“…Whilst Galal et al (1978) with seasonal studying on Merino, Ossimi and their crosses stated that relationship between semen quality and libido is not clear across breeding groups. This incoherence in results of different probers may be due to various methods of testing libido, such as the latency for males to copulate, or reaction time (Chenoweth, 1981;Landaeta-Hernandez et al, 2001) counts and durations of interest, such as sniffing at the vulva and time spent with females ) the number of mounts and/or serves during a specified period of time (Landaeta-Hernandez et al, 2001;Bertram et al, 2002), and scores assigned according to various combinations of these measures (Chenoweth, 1981;LandaetaHernandez et al 2001). On the other hand, sexual activity of males is influenced by the test conditions and the methods applied in tests can vary considerably, even within the same experiment.…”

Section: Resultsmentioning

confidence: 99%

Study of correlation between reaction time and refractory period (as indices of libido) with semen characteristics in ArkharMerino×Moghani and Baluchi×Moghani rams

Moghaddam

Pourseif

Rahimi

2012

Italian Journal of Animal Science

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This study was conducted on 10 crossbred rams consisted of 5 ArkharMerino×Moghani (AM×MG) and 5 Baluchi×Moghani (BL×MG), to analyze correlation between semen characteristics and libido activity. The semen samples were evaluated for semen volume, total sperm per ejaculate (TSE), spermatozoa concentration (SC), color, wave motion, spermatozoa progressive motility, percentage of live and abnormal spermatozoa, pH, rate of metabolic activity of spermatozoa and semen index. The libido of rams was measured by two indices including reaction time (RT) and refractory period (RP). While RT only had a negative and significant correlation with semen volume (r=-0.15, P=0.04), but RP had a significant correlation with seminal traits except for TSE. Moreover, libido test scores between two genetic groups did not have a significant difference (P<0.05). Considering the observed significant correlation between RP and semen characteristics, we suggest that a reliable monitoring with the aim of detecting rams of poor semen quality and libido seems worth making an effort for the future of the herd. In summary, the reported correlation between libido and seminal traits will confirm the importance of simultaneous selection for both libido and semen quality in the herd. Finally, the importance of performing an individual evaluation of semen and libido for each male and for using a ram in breeding programs is highlighted, due to the existence of differences among rams as well as a low correlation between semen characteristics and libido indices.

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“…In behavior tests, virgin bulls tend to perform worse than experienced bulls because they engage in more disoriented and oriented mounts, their reaction time is longer, and they perform fewer services than a mature bull (Coulter & Kozub, 1989;Godfrey & Lunstra, 1989). One study (Bertram et al, 2002) confirmed the effect of sexual experience in improving the serving capacity of young bulls:…”

Section: Age/sexual Experiencementioning

confidence: 91%

The Importance of Reproductive Behavior Tests in Bull Breeding Soundness Evaluation

García-Paloma¹,

Fernandez-Novo²,

Perez-Villalobos³

2022

CCBR

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In extensive beef cattle farms, fertility is one of the factors that determines the number of calves born each year and is therefore essential for maintaining a farm's competitiveness and sustainability. In farms where natural breeding is the usual reproductive management strategy, bull reproductive soundness should be assessed to exclude animals that may compromise productivity. The standard method of evaluation, known as bull breeding soundness evaluation, comprises health, physical, seminal, and behavior assessment. However, veterinarians in many countries often omit the behavior assessment from bull breeding soundness evaluation because of its complexity and resource requirements. Instead, farmers closely observe bulls during the first weeks of the mating period to detect problems with libido or mating ability. We believe that detecting "problematic bulls" before mating period through reproductive behavior tests should be considered. To develop tests that may prove more affordable and easier to perform, we examined fundamentals of serving capacity, libido, and mating ability as main reproductive behavior tests. This approach may turn the reproductive behavior tests more affordable so they can be included in the bull breeding soundness evaluation performed at medium-sized cattle farms.

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Bull selection and use in northern Australia

Cited by 24 publications

References 10 publications

Impact of candidate sire number and sire relatedness on DNA polymorphism‐based measures of exclusion probability and probability of unambiguous parentage

Impact of candidate sire number and sire relatedness on DNA polymorphism‐based measures of exclusion probability and probability of unambiguous parentage

Study of correlation between reaction time and refractory period (as indices of libido) with semen characteristics in ArkharMerino×Moghani and Baluchi×Moghani rams

The Importance of Reproductive Behavior Tests in Bull Breeding Soundness Evaluation

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