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The impact of selecting for increased ewe fat level on reproduction and its potential to reduce supplementary feeding in a commercial composite flock
- Source :
- Animal Production Science. 56:698
- Publication Year :
- 2016
- Publisher :
- CSIRO Publishing, 2016.
-
Abstract
- In southern Australian grazing systems, energy availability typically exceeds energy requirements. Grazing systems are likely to have higher profitability if ewes can utilise this relatively cheap feed by gaining more condition (muscle and fat) and then mobilising it when feed is expensive. The present paper focusses on the importance of genetic merit for fat on the lifetime productivity of the ewe within a commercial operation. The analysis was carried out on a maternal composite stud flock in Holbrook, New South Wales. Ultrasound fat and muscle depth were measured on 2796 ewes as lambs at post-weaning and as adult ewes, to determine the genetic relationship between young and adult body composition. The hypothesis of the paper is that selection for increased fat at young age will improve body condition of adult ewes, which will lead to improved reproduction and potentially reduced requirements for supplementary feeding. Given that the difference in feed cost between times of abundance and shortage is likely to be larger, the system may become more profitable despite being less efficient (owing to increased feed intake). Our results indicated that selection for scanned post-weaning fat and muscle depth in lambs should lead to increased fat muscle and body condition in the breeding ewe because of strong genetic correlation estimates between the post-weaning and adult traits of 0.68–0.99. The influence of body composition traits on reproduction (number of lambs weaned) within the stud flock was weak. However, it is hypothesised that by genetically increasing post-weaning fat depth in ewes, producers could improve profitability by reducing the demands for supplementary feeding.
- Subjects :
- 0301 basic medicine
Integrated pest management
media_common.quotation_subject
Drought tolerance
0402 animal and dairy science
04 agricultural and veterinary sciences
Biology
040201 dairy & animal science
Genetic correlation
03 medical and health sciences
030104 developmental biology
Animal science
Agronomy
Grazing
Environmental management system
Animal Science and Zoology
Flock
Reproduction
Genetic merit
Food Science
media_common
Subjects
Details
- ISSN :
- 18360939
- Volume :
- 56
- Database :
- OpenAIRE
- Journal :
- Animal Production Science
- Accession number :
- edsair.doi...........6962f4a71c2dd0c2e9742d4ea64a1473
- Full Text :
- https://doi.org/10.1071/an14579