The relationship of libido and serving capacity test scores in rams on conception rates and lambing percentage in the ewe

Mickelsen, W. Duane; Paisley, Larry G.; Dahmen, J. J.

doi:10.1016/0093-691x(82)90051-6

Cited by 19 publications

(12 citation statements)

References 15 publications

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“…Many factors affect sex drive and sexual performance, including season of year, genetics, breed differences, hormonal influence, postweaning management, temperature and nutrition (Mickelsen et al, 1982). In the present study, the frequency of pre-copulatory sexual behaviour was similar among breed groups.…”

Section: Discussionsupporting

confidence: 49%

Sexual behaviour of yearling Awassi, Charollais × Awassi and Romanov × Awassi rams exposed to oestrousAwassi ewes

Kridli

Shaker

Abdullah

et al. 2007

Trop Anim Health Prod

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This study was conducted to evaluate the sexual performance of 10-month-old, ram lambs of different breed groups. Eight ram lambs each of Awassi (A), F1 CharollaisxAwassi (CA) and F1 RomanovxAwassi (RA) breed types were subjected to sexual performance tests by being individually exposed to two oestrous Awassi ewe lambs for four 20-min periods. Bouts of leg kicking and anogenital sniffing were similar among breed groups. Mounting frequency was greater (p<0.05) in RA than in A and CA ram lambs. Tail-raising was greater (p<0.05) and mating rate tended to be greater (p<0.10) in A than in RA and CA ram lambs. The number of mounts per tail-raising (efficiency) was influenced by breed group and test day (p<0.05). Awassi ram lambs maintained the best efficiency throughout the experiment. Efficiency in RA and CA ram lambs improved with each test day. Results of the present study indicate that RA ram lambs have greater mounting frequency than A and CA, while Awassi are more capable of mating with fat-tailed females than the CA and RA ram lambs.

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Section: Discussionsupporting

confidence: 49%

Sexual behaviour of yearling Awassi, Charollais × Awassi and Romanov × Awassi rams exposed to oestrousAwassi ewes

Kridli

Shaker

Abdullah

et al. 2007

Trop Anim Health Prod

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“…As highlighted by the authors, the reduced pregnancy rate was likely linked to the high number of ewes in oestrus at the same time as oestrus was synchronised in the ewes. Other studies have failed to link ram mating libido to reduced flock fertility when oestrus had not been synchronised and relatively low ewe to ram ratios were used (Kelly et al, 1975;Mickelsen et al, 1982). Thus, use of rams with low libido may not affect Note that information regarding the number of sires and mate groups is the same as provided in Table 2. 1 Value fixed at 0 as trending negative; NS (P > 0.05).…”

Section: Discussionmentioning

confidence: 99%

Heritability of ram mating success in multi-sire breeding situations

Juengel

Hickey

Clarke

et al. 2019

Animal

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Multi-sire mating of a mob of ewes is commonly used in commercial sheep production systems. However, ram mating success (defined as the number of lambs sired by an individual) can vary between rams in the mating group. If this trait was repeatable and heritable, selection of rams capable of siring larger numbers of lambs could reduce the number of rams required for mating and ultimately lead to increased genetic gain. However, genetic correlations with other productive traits, such as growth and female fertility, could influence the potential for ram mating success to be used as a selection trait. In order to investigate this trait, parentage records (including accuracy of sire assignment) from 15 commercial ram breeding flocks of various breeds were utilised to examine the repeatability and heritability of ram mating success in multi-sire mating groups. In addition, genetic and phenotypic correlations with growth and female fertility traits were estimated using ASReml. The final model used for the ram mating success traits included age of the ram and mating group as fixed effects. Older rams (3+years old) had 15% to 20% greater mating success than younger rams (1 or 2 years of age). Increasing the stringency of the criteria for inclusion of both an individual lamb, based on accuracy of sire assignment, or a whole mating group, based on how many lambs had an assigned sire, increased repeatability and heritability estimates of the ram mating success traits examined. With the most stringent criteria employed, where assignment of sire accuracy was >0.95 and the total number of lambs in the progeny group that failed to have a sire assigned was<0.05, repeatability and heritability for loge(number of lambs) was 0.40±0.09 and 0.26±0.12, respectively. For proportion of lambs sired, repeatability and heritability were both 0.30±0.09. The two ram mating traits (loge(nlamb) and proportion) were highly correlated, both phenotypically and genetically (0.88±0.01 and 0.94±0.06, respectively). Both phenotypic and genetic correlations between ram mating success and growth and other female fertility traits were low and non-significant. In conclusion, there is scope to select rams capable of producing high numbers of progeny and thus increase selection pressure on rams to increase genetic gain.

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“…Positive associations between rams with high scores for sexual performance and ewe fertility have been reported (Mattner et al, 1971;. In contrast, some studies found little relationship between sexual performance scores of rams and flock fertility (Kelly et al, 1975;Kilgour and Wilkins, 1980;Mickelsen et al, 1982).…”

Section: Introductionmentioning

confidence: 99%

Heritability and repeatability of sexual performance scores of rams

Snowder¹,

Stellflug²,

Vleck³

2002

Journal of Animal Science

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Sexual performance has been subjectively measured with a libido test during screening of rams before public sale and breeding at the U.S. Sheep Experiment Station from 1990 to 2000. The objective of this study was to determine whether sexual performance was genetically influenced. Sexual performance scores ranged from 1 to 6 with scores increasing from sexually inactive to highly sexually active in the presence of estrous ewes. The overall average score was 3.5+/-0.02. Records from four breeds (Columbia, n = 807; Polypay, n = 1,668; Rambouillet, n = 1,208; and Targhee, n = 1,002) were combined into one analysis because breeds had similar phenotypic variances. Total number of records was 4,685, which included a second sexual performance test on 1,212 rams in the following year. Variance components were estimated using a REML algorithm. Fixed effects were breed of ram, selection line within breed, and year by breed. A permanent environmental effect for ram was included to account for repeated observations on individual animals. Age and weight of the rams at time of the libido test were linear covariates and were breed-specific. Adjusted means for sexual performance scores did not differ among breeds (P > 0.05). Age was a significant effect (P < 0.01), with sexual performance score increasing 0.05 units for each month of age. The additive genetic variance was estimated as 0.54. The estimate of variance due to ram permanent environmental effects was 1.19. The residual variance was estimated to be 0.67. The heritability estimate was moderate (0.22+/-0.04) and repeatability was high (0.72). These results imply that one screening for sexual performance provides a reliable measure of sexual performance and that favorable response to selection for ram serving capacity may be expected.

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The relationship of libido and serving capacity test scores in rams on conception rates and lambing percentage in the ewe

Cited by 19 publications

References 15 publications

Sexual behaviour of yearling Awassi, Charollais × Awassi and Romanov × Awassi rams exposed to oestrousAwassi ewes

Sexual behaviour of yearling Awassi, Charollais × Awassi and Romanov × Awassi rams exposed to oestrousAwassi ewes

Heritability of ram mating success in multi-sire breeding situations

Heritability and repeatability of sexual performance scores of rams

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