Mating Conditions and Management Practices Influence Pregnancy Scanning Outcomes Differently between Ewe Breeds

Bates, Amy L.; McGrath, Shawn; Robertson, Susan; Refshauge, Gordon

doi:10.3390/ani12212908

Cited by 4 publications

(2 citation statements)

References 52 publications

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“…In a survey of Victorian farms, Armstrong, et al 7 found variation between breeds and seasons of mating for reproduction rate, ranging between 116% and 144%. Most recently, Bates, et al 27 reported on 29,157 naturally mated ewes, including four breeds, three seasons and located across 58 farms across southern Australia. In that study, the average pregnancy rate was 90% and reproduction rate was 140%.…”

Section: Discussionmentioning

confidence: 99%

Fertility and fecundity in the Australian sheep flock

Refshauge

Golledge

Rickard

et al. 2023

Preprint

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After decades of decline, the Australian sheep flock aspires to rebuild its population of breeding ewes. A successful, rapid rebuild will rely on high pregnancy rates and number of lambs born and reared. To examine this potential, historical pregnancy scanning records were collated from two experienced sheep pregnancy scanning businesses (years 2006 to 2019) from 15,397 mobs of ewes, totalling 7,443,314 ewes. Client details were de-identified and excluded from analyses, but when available details describing the mobs were retained, such as season of mating, production zone, ewe age, and breed. The key finding was a mean pregnancy rate (ewes pregnant per ewe scanned) of 0.76 ± 0.24, with a median of 0.83. Mobs scanned for litter size had a higher mean (0.84 ± 0.15) and median (0.89) pregnancy rate. The mean reproduction rate (fetuses per ewe scanned) was 1.21 ± 0.27 and the median was 1.25. None of the factors including age, breed, season, year or production zone explained the low overall mean pregnancy rate. The unexpected findings imply a problem exists with the fertility of many Australian sheep flocks and that pregnancy rate is a clear constraint on flock rebuilding aspirations.

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Section: Discussionmentioning

confidence: 99%

Fertility and fecundity in the Australian sheep flock

Refshauge

Golledge

Rickard

et al. 2023

Preprint

View full text Add to dashboard Cite

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“…Sheep producers were recruited through professional networks by the New South Wales (NSW) Department of Primary Industries (DPI) for a broader study [18] in accordance with the Charles Sturt University Human Ethics Committee (protocol number H21037). The producers managing these sheep flocks were the target population and participants/respondents of the cross-sectional study.…”

Section: Study Area Participants and Survey Designmentioning

confidence: 99%

A Cross-Sectional Study of Commercial Ewe Management Practices for Different Sheep Breeds across Southern Australia

Bates

McGrath

Allworth

et al. 2023

Animals

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The management of ewes across southern Australia may vary with breed and can change over time and, as such, a greater understanding of producer management practices and the motivations that influence these practices is required. A cross-sectional study was performed by telephone interview with sheep producers managing Composite, Maternal, Merino or shedding ewe breeds mated in either spring, summer, or autumn. The surveyed producers were a unique subset of southern Australian producers. A large proportion of the surveyed producers followed current best practice guidelines for ewe mating and lambing nutritional management; however, some producers did not align with these targets. Further, some producers did not see the value in attaining the current recommendations. Pregnancy scanning was widely practiced, likely an artefact of the recruitment process; however, a few producers did not utilize this information for nutritional management at lambing time. Finally, most producers were active in their search for new information, seeking information regularly from a wide range of sources and reported making management changes within the last five years. Further work is required to understand why some producers are not adopting best practice where possible and to understand current barriers for adoption. Management guidelines for all sheep breeds are required to best manage sheep across southern Australia.

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An analysis of fertility and fecundity in the Australian sheep flock between 2006 and 2019

Refshauge,

Golledge,

Rickard

et al. 2024

Sci Rep

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After decades of decline, the Australian sheep flock aspires to rebuild its population of breeding ewes. A successful, rebuild will rely on high pregnancy rates and number of lambs born and reared. To examine this potential, a cross-sectional study of historical ultrasound pregnancy scanning records was undertaken using records collated from two experienced sheep pregnancy scanning businesses (years 2006 to 2019) from 15,397 mobs of ewes, totalling 7,443,314 ewes. Client details were de-identified and excluded from analyses, but details describing the mobs were retained when available, such as season of mating, production zone, ewe age, and breed. The key finding was a mean pregnancy rate (ewes pregnant per ewe scanned) of 0.76 ± 0.24, with a median of 0.83. Mobs scanned to identify fetal number had a higher mean (0.84 ± 0.15) and median (0.89) pregnancy rate. The mean reproduction rate (fetuses per ewe scanned) was 1.21 ± 0.27 and the median was 1.25. Differences were observed between the factors including age, breed, season, year or production zone but all results were lower than anticipated. The unexpected findings imply a problem exists with the fertility of many Australian sheep flocks.

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Mating Conditions and Management Practices Influence Pregnancy Scanning Outcomes Differently between Ewe Breeds

Cited by 4 publications

References 52 publications

Fertility and fecundity in the Australian sheep flock

Fertility and fecundity in the Australian sheep flock

A Cross-Sectional Study of Commercial Ewe Management Practices for Different Sheep Breeds across Southern Australia

An analysis of fertility and fecundity in the Australian sheep flock between 2006 and 2019

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