Beef bulls mated to estrus synchronized heifers: Single- vs multi-sire breeding groups

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

doi:10.1016/0093-691x(82)90016-4

Cited by 35 publications

(16 citation statements)

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“…After a variable number of copulations (range: 0 to 7) females usually refused to stand for any additional mounts. Farin, Chenoweth, Mateos, and Pexton (1982) observed female cattle copulating 0 to 13 times (mean 5 S.E. = 3.1 2 0.3) with 16-month-old bulls.…”

Section: Discussionmentioning

confidence: 93%

The role of penile stimulation and ejaculatory experience on the development and maintenance of reproductive behavior in the bull (Bos taurus)

Katz

Price

1986

Developmental Psychobiology

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To determine the role of afferent input from the penis and copulatory experience on the ontogeny of reproductive behavior, 49 bulls were randomly assigned to the following groups: control; surgical penile deflection (penis deviation), which prevents intromission; penile neurectomy; or penis deviation plus neurectomy. Sexual performance tests were conducted at 3-month intervals from 9 to 24 months of age. Bulls deviated but not neurectomized mounted more frequently than bulls in the other groups. The low mount frequency for control bulls in tests in which copulation occurred was due to the sexually quiescent postejaculatory refractory period. Preventing control bulls from copulating by affixing cloth patches to females' perinea increased mount frequency to the level of deviated bulls. It is concluded that copulatory experience is not essential to the development and maintenance of normal mounting activity. However, sensory stimulation from the penis facilitates the expression of sexual behaviors.

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Section: Discussionmentioning

confidence: 93%

The role of penile stimulation and ejaculatory experience on the development and maintenance of reproductive behavior in the bull (Bos taurus)

Katz

Price

1986

Developmental Psychobiology

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“…Overall, the pregnancy rate was low and did not differ (P > .20) between SC groups (Table 4). Farin et al (1982) single-sire mated yearling bulls to 20 estrus-synchronized heifers for 30 h and found that HSC bulls tended to have a higher number of services and service a higher percentage of heifers in estrus compared with bulls of lower SC. Differences in pregnancy rates were not stated by the authors, although the overall pregnancy rate was similar at 29%.…”

Section: Bebavior and Fertility During Heavymentioning

confidence: 99%

Serving Capacity of Crossbred Yearling Beef Bulls. I. Single-Sire Mating Behavior and Fertility during Average and Heavy Mating Loads at Pasture

Boyd

Lunstra

Corah

1989

Journal of Animal Science

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Eighty crossbred, virgin, yearling beef bulls were subjected to three serving capacity (SC) tests. Ten low SC (LSC) and 10 high SC (HSC) bulls similar in weight (avg wt = 452 kg), testicular size and seminal traits but differing in average services were selected. Objectives were to evaluate the mating behavior and fertility of LSC and HSC bulls at pasture when exposed to an average and a heavy mating load and to determine the effect of sexual activity on body weight and testicular characteristics. One LSC and one HSC bull per block were exposed single-sire to 25 naturally cyclic (N) cows for 3 d and to 9 estrus-synchronized (S) cows for 1 d in a randomized complete block design consisting of 10, 4-d blocks. Bulls were fitted with pedometers to record distance travelled. Behavioral data were collected by periodic visual observation. During the N cow treatment, LSC bulls had fewer (P less than .05) services per cow, total services and a higher mount to service ratio than HSC bulls. During the S cow treatment, LSC bulls showed increased sexual activity, though they achieved fewer (P less than .09) services per cow. Pregnancy rates for LSC and HSC bulls did not differ (P greater than .20) and across SC groups averaged 53.6% for N cows and 31.9% for S cows. Distance travelled also was similar (P greater than .20) between SC groups for both treatments. Sexual activity during pasture exposure had no effect (P greater than .20) on testicular characteristics but resulted in an average decline in body weight of 25.7 kg across SC groups during the 4-d period. Post-exposure SC tests found that LSC bulls had increased (P less than .05) services, decreased mounts and mount to service ratio compared to pre-exposure measurements, but LSC were still lower (P = .06) than HSC bulls for average services. These results suggest that LSC virgin, yearling bulls should be offered sexual experience and retested before their inherent SC can be determined.

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“…Research has determined that natural mating can be an effective alternative to artificial insemination in estrus synchronization programs (Farin et al, 1982Pexton et al, 1989;Plugge et al, 1990). However, estrus synchronization will increase breeding pressure on bulls and may exceed the limits of some bulls' breeding capabilities; therefore, there may need to be an adjustment in mating loads in order to achieve desired pregnancy rates.…”

Section: Introductionmentioning

confidence: 99%

Investigating optimal bull:heifer ratios required for estrus-synchronized heifers1

Healy

Boyd

Gutierrez

et al. 1993

Journal of Animal Science

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The objectives of this study were to determine 1) the effect of bull:heifer ratio on reproductive performance and associated costs and return on heifers in synchronized estrus and 2) the effect of estrus synchronization on reproductive performance and economic variables, in a multiple-sire, pasture breeding situation. Eight hundred yearling beef heifers and 28 mature, sexually experienced beef bulls were allotted to four treatments (two replicates per treatment) at bull:heifer ratios of 2 per 100 (1:50; Treatment 1), 2 per 100 (1:50; Treatment 2), 4 per 100 (1:25; Treatment 3), and 6 per 100 (1:16; Treatment 4). Treatment 1 (control) used nonsynchronized heifers, whereas heifers in Treatments 2, 3, and 4 were synchronized using the 33-d melengestrol acetate (MGA)-prostaglandin F2 alpha (PGF2 alpha) program. Pregnancy results after a 28-d breeding season indicate that there may be a limit to how many estrus-synchronized heifers bulls can impregnate. Treatment 2 showed a 6% decrease (P < .10) in pregnancy rate (77%) compared with Treatment 3 (83%), indicating that the bulls probably were not able to service all the synchronized heifers. Treatments 3 and 4 had similar pregnancy rates (83 and 84%, respectively). Treatment 4 had a 3-d advantage (P < .01) over Treatment 3 in average day of conception. However, based on economic analysis, Treatment 3 exhibited greater returns. Estrus synchronization failed to provide any advantage in pregnancy rate or day of conception. For unknown reasons, the control, nonsynchronized heifers cycled and conceived as if they were synchronized.(ABSTRACT TRUNCATED AT 250 WORDS)

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Beef bulls mated to estrus synchronized heifers: Single- vs multi-sire breeding groups

Cited by 35 publications

References 4 publications

The role of penile stimulation and ejaculatory experience on the development and maintenance of reproductive behavior in the bull (Bos taurus)

The role of penile stimulation and ejaculatory experience on the development and maintenance of reproductive behavior in the bull (Bos taurus)

Serving Capacity of Crossbred Yearling Beef Bulls. I. Single-Sire Mating Behavior and Fertility during Average and Heavy Mating Loads at Pasture

Investigating optimal bull:heifer ratios required for estrus-synchronized heifers1

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