Variations in and Relationships Between Reproductive Performance and Growth Parameters in Yearling Beef Bulls in Single-Sire Mating at Pasture

Farid, A.; Makarechian, M.; Berg, R. T.; Price, M. A.

doi:10.4141/cjas89-006

Cited by 1 publication

(3 citation statements)

References 7 publications

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“…The average weights of bulls for each year at the start of mating (given earlier) bore no relation to the mean calving rates for the 3 years. Our findings confirm the conclusions by Farid et al (1986) that variation in fertility among Hereford bulls was much more important than variation among years.…”

Section: Possible Explanationssupporting

confidence: 92%

“…Unfortunately, there were not the resources to experimentally test a yearling against a 2-year-old Hereford bull system. Farid et al (1986) found a lower proportion of early calves from cows mated to yearling than to 2-year-old Hereford bulls (difference = 0.07), but no difference in overall calving rate.…”

Section: Other Solutions?mentioning

confidence: 78%

“…Thus, the two breeds were similar in the overall proportion calving early. Data from Alberta by Farid et al (1986) showed 0.55 born in the first 4 weeks in 42 Hereford yearling sire groups. The overall loss rate of apparent pregnancies found at Waikite was consistent with results from experiments at Goudies Station (C. A. Morris unpublished data).…”

Section: Discussionmentioning

confidence: 99%

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On-farm monitoring of mating performance of single yearling Hereford bulls

Morris¹,

Hunter²,

Bedford³

1988

New Zealand Journal of Agricultural Research

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The reproductive performance of 18 yearling Hereford bulls was monitored in detail to relate mating marks (from chinball harnesses) to subsequent pregnancy and calving results and calving dates. Single-sire mating groups with Hereford yearling heifers and cows at pasture (average 27 females per group) were monitored over 8 -lO-week mating periods in the springs of 1983 -85. The herd was of interest because of a suspected problem with bull fertility. Over the 3 years, 520,10 of females put to the bull were marked in the first 3 weeks; 36% of those put to the bull calved in the first 3 weeks of calving. Over the whole calving period, 71 % of females calved, including those put to five bulls of low reproductive performance. Two of these were identified during mating, one with few mating marks (first 3 weeks) and one with a high return rate (Weeks 4 -5). However, under the commercial beef farming conditions prevailing, the other three were not identified until pregnancy diagnosis. There was greater variation in reproductive performance among yearling bulls within a year than among years. About one-fifth of each mating group consisted of yearling heifers, which had been monitored for puberty using vasectomised bulls before the entire matings began. More heifers (+ 21 %) subsequently became pregnant to entire bulls in the 8-week mating period if heifers had reached puberty by the start of mating than if they had not.