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- Philipsson, Jan, et al.
(författare)
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Estimates of economic values for important traits of two indigenous Ethiopian sheep breeds.
- 2012
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Ingår i: Small Ruminant Research. - : Elsevier BV. - 0921-4488. ; 105, s. 154-160
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Tidskriftsartikel (refereegranskat)abstract
- A bio-economic model was adapted to estimate economic values for important traits of two Ethiopian indigenous sheep breeds, the Menz and Horro breeds. To do so, a meat sheep herd for fattening lambs and rearing young replacement sheep was simulated. Traits included in the analysis were: daily gain (fattening trait), live weight of ewes, length of productive life, lambing interval, litter size, stillbirths and lamb survival (functional traits). To avoid double counting, the economic value for each trait was derived while keeping all other traits constant. Economic values were obtained per ewe place, year, and genetic standard deviation. For the Menz breed, economic values in (sic) per genetic standard deviation were 0.63 (daily gain), -0.77 (mature ewe live weight), -0.97 (length of productive life), 1.57 (lambing interval), 0.98 (litter size), 0.41 (stillbirths) and 2.20 (lamb survival). Economic values (in (sic)) of 1.35 (daily gain), -1.26 (mature ewe live weight). -1.15 (length of productive life), 1.98 (lambing interval), 3.67 (litter size), 0.56 (stillbirth) and 3.25 (lamb survival) were derived for the Horro breed. Negative economic values for length of productive life and mature ewe live weight were estimated for both breeds. After setting the economic values of length of productive life and mature ewe live weight to zero, the economic values (in %) for the ratio of the trait complexes fattening: functional traits were 11:89 and 12.5:87.5 for Menz and Horro, respectively. Economic values for litter size, lambing interval and lamb survival traits were sensitive to changes in price for breeding rams in both breeds. (C) 2012 Elsevier B.V. All rights reserved.
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| 4. |
- Zonabend König, Emelie, et al.
(författare)
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Breeding objectives for Red Maasai and Dorper sheep in Kenya – a participatory approach
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The Red Maasai sheep breed is under threat due to indiscriminate crossbreeding and strategies are needed to conserve and improve the breed. The aim of this study was to understand farmers' preferences for important traits of flocks of Red Maasai, Dorper and crosses in two different areas, Amboseli and Isinya, in Kenya. Farmers identified three ewes that represented the best, average, and poorest within its breed group of each farm and gave reasons for their ranking. The most important traits were body size and growth rate and thereafter milk yield. The Red Maasai was preferred for its better reproduction and tolerance against diseases and drought. In the harshest area, Amboseli, all breed groups had about the same body weight, whereas in Isinya, where conditions are better and farmers are more market oriented, Dorper and crosses had superior weights.
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| 6. |
- Zonabend König, Emelie, et al.
(författare)
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Live weight, conformation, carcass traits and economic values of ram lambs of Red Maasai and Dorper sheep and their crosses
- 2017
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Ingår i: Tropical Animal Health and Production. - : Springer Science and Business Media LLC. - 0049-4747 .- 1573-7438. ; 49, s. 121–129-
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Tidskriftsartikel (refereegranskat)abstract
- Meat production is the most important trait in the breeding objectives of sheep production in East Africa. The aim of this study was to investigate breed differences in live weight, conformation, carcass traits and economic values for meat production among Red Maasai and Dorper sheep and their crosses. In total, 88 ram lambs, which were reared at the ILRI experimental station, Kapiti plains Estate in Central Kenya, were used for the study. The lambs were slaughtered at Kenya Meat Commission (KMC) at about 1 year of age. Prior to slaughter, the lambs were weighed, measured and assessed by experienced evaluators, and at the abattoir carcass traits were recorded. Large breed differences were found for most traits. Dorper lambs were heavier at delivery for slaughter and had better carcass grade but lower dressing percentage and fat levels than Red Maasai. Crossbreds were generally better than the parental breeds. Evaluators were willing to pay more for the Dorper lambs for slaughter although carcass weights later were shown not to be higher than for Red Maasai. Evaluators undervalued Red Maasai lambs by 8-13 % compared to Dorper lambs according to the prices quoted per kilogramme live or carcass weight by KMC. Live weight was better than any other live measure in predicting carcass weight. Due to the overall higher ranking of the crossbred lambs for meat production, Dorper may be useful as a terminal sire breed for crossing with Red Maasai ewes.
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| 7. |
- Zonabend König, Emelie, et al.
(författare)
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Participatory definition of breeding objectives for sheep breeds under pastoral systems -the case of Red Maasai and Dorper sheep in Kenya
- 2016
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Ingår i: Tropical Animal Health and Production. - : Springer Science and Business Media LLC. - 0049-4747 .- 1573-7438. ; 48, s. 9-20
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Tidskriftsartikel (refereegranskat)abstract
- Crossing local breeds with exotic breeds may be an option for increased livestock productivity. However, there is a risk for endangerment of the local breeds. One such case is in Kenya where the imported Dorper breed is used for crossbreeding with Red Maasai sheep. The aim of this study was to investigate farmers' trait preferences as a basis for determination of breeding objectives for Red Maasai and Dorper sheep at two sites, Amboseli and Isinya, in Kenya. Within their own flock, each farmer identified three ewes representing the best, average and poorest within each breed group: Red Maasai, Dorper and Crosses. Farmers gave reasons for their ranking. Body measurements and weights were also taken. At the harshest site, Amboseli, differences between breed groups in body weight were small and breeds were equally preferred. In Isinya, where environmental conditions are better and farmers are more market oriented, Dorper and Crosses had significantly higher body weights and market prices and were thus preferred by the farmers. Red Maasai were preferred for their maternal and adaptive traits. Breeding objectives should emphasize growth traits and milk production in both breeds at both sites. Body condition needs to be specifically considered in the breeding objectives for sheep in Amboseli, whereas adaptive traits need to be generally emphasized in Dorper.
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| 9. |
- Zonabend König, Emelie, et al.
(författare)
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Purebreeding of Red Maasai and crossbreeding with Dorper sheep in different environments in Kenya
- 2017
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Ingår i: Journal of Animal Breeding and Genetics. - : Wiley. - 0931-2668 .- 1439-0388. ; 134, s. 531-544
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this article was to study opportunities for improvement of the indigenous and threatened Red Maasai sheep (RM) in Kenya, by comparing purebreeding with crossbreeding with Dorper sheep (D) as a terminal breed, in two different environments (Env. A and a harsher Env. B), assuming different levels of genotype-by-environment interaction (GxE). Breeding goals differed between environments and breeds. Four scenarios of nucleus breeding schemes were stochastically simulated, with the nucleus in Env. A. Overall, results showed an increase in carcass weight produced per ewe by more than 10% over 15years. Genetic gain in carcass weight was 0.17 genetic SD/year (0.2kg/year) across scenarios for RM in the less harsh Env. A. For survival and milk yield, the gain was lower (0.04-0.05 genetic SD/year). With stronger GxE, the gain in the commercial tier for RM in the harsher Env. B became increasingly lower. Selection of females also within the commercial tier gave slightly higher genetic gain. The scenario with purebreeding of RM and a subnucleus in Env. B gave the highest total income and quantity of meat. However, quantity of meat in Env. A increased slightly from having crossbreeding with D, whereas that in Env. B decreased. A simple and well-designed nucleus breeding programme would increase the genetic potential of RM. Crossbreeding of RM with D is not recommended for harsh environmental conditions due to the large breed differences expected in that environment.
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