Breeding strategies within a terminal sire line for meat production

Transcription

1 Breeding strategies within a terminal sire line for meat production LAMBINNOVATION Hamar 2005 Turi Kvame UMB/GILDE Norwegian Meat

2 Introduction Demand for lamb meat -lean meat from the higher valued parts of the carcass (Gilde Norwegian Meat, 2003) To maintain or increase the request for lamb a greater emphasis on carcass traits is needed

3 Terminal Sire: Emphasis on production traits Selection in a terminal sire breed is an effective method for improvement in lean meat production, as selection can be concentrated on a numerically small group of animals that have a large genetic contribution to the market product (Kempster et al. 1987; Leymaster and Jenkins, 1993; Wolf et al. 1981) Breed differences in carcass composition, i.e Texel is found to have a high muscle:bone ratio compared to other breeds (Hopkins et al., 1997; Kempster et al., 1987; Kirton et al., 1997) But, with moderate growth rate (Leymaster and Jenkins, 1993)

4 Recording and selection for carcass traits Carcass traits are measured accurately by CT (Sehested, 1986) and are moderate to highly heritable (Jones et al., 2004; Kvame and Vangen, 2004). Jopson et al. (2004): two-step selection procedure based on ultrasound and CT, and selection for composition in cuts can be more beneficial than selection based on progeny testing

5 Overview Overview Sheep production in Norway and development of a meat line (ML) of sheep Breeding plan for the ML Results from recent research: selection for lean in the higher valued parts of the carcass related to carcass classification, payment for lamb cut and the demand for lamb meat Discussion and conclusion

6 Sheep production in Norway Breeding goal for Norwegian sheep breeds: - 2 lamb weaned/ewe - High growth rate - High muscularity; mid-region, leg - Good maternal traits - growth rate of the progenies - low rate of birth difficulties - More, and better quality of wool - Functional animal Spring Autumn

7 Overview Development of a meat line (ML) of sheep 1. Selection experiment for ultrasound muscle depth (UMD) (Larsgard and Kolstad, 2003) 2. Introduction of Texel into the selected line (ML) from 1998 Selection criteria : UMD (BLUP value) + phenotype/functional traits 3. Use of CT in the selection of sires for use in the ML from 2001 Selection criteria: LEAN weight (BLUP value) + phenotype/functional traits 4. Rams evaluated for AI after one year of use in the ML Selection criteria: as for 3. + progeny mean for UMD

8 Selection of breeding animals within the ML AI rams ~6/year Lambs used as sire in the ML ~7 mth (~12 sires/year) CT scanning of the beste (n=30) male lambs LEAN Ultrasound scanning of all lambs n~100 ML male lambs ULTRASOUND MUSCLE DEPTH

9 Breeding programme for the ML Nucleus flock, Ås Breeding herds - production of terminal sires IMPORT OF SEMEN/EMBRYO AI CENTRE Commercial sheep flocks - production of lamb for slaughter

10 Challenges Size of the sire line (ML) compared to the maternal line (NWS/Spel ) - 30% ML vs 70% NWS/Spel..? (Vangen, 2005) Breeding scheme for NWS be modified when used as a maternal line mated to terminal sires? Possibilities for different production system, i.e. intensive low-land grazing vs. hill/mountain grazing Potential for a more intensive and larger variation in the lambing season and less seasonal variation in the production of slaughter lamb? Essential to maintain a sustainable hill sheep with good maternal traits as for NWS at present (Olesen et al., 1995)

11 Further improvement in carcass traits Selection for weight of lean and a negative weighting for fat in the carcass does not correspond completely with the real economical value of the carcass as different parts of the carcass are priced differently when sold in the marked The most economical valued parts of the carcass (NZ marked) (1>2>3): LOIN/RACK (1) HINDLEG 2 (2) FOREQUARTER (3) Include estimates of composition (LEAN) in the higher valued cuts in the selection of terminal sires?

12 Prediction of Cuts Hindleg HINDLEG CA2 S3 Accuracy of prediction for lean (R 2 ): Cut Weight (kg) R 2 R 2 TR Hindleg Loin Loin L6 LOIN L1 Rack Forequarter Rack T9 RACK T13 Forquarter T5 CV7

13 EUROP classification system Weight kg Fat -2 to +2 Confirmation High score for the leg, the mid-region and the shoulder (each region currently valued 1/3 each) E+ P-

14 Prediction of LEAN in carcass regions in agreement with the EUROP classification system R 2 for prediction of lean Leg: 0.93 Mid-region: 0.89 Shoulder: 0.93

15 VIAscan and composition of cut Higher net benefits when selection was for weight of cuts and fat than for weight of LEAN and against FAT in the carcass (Kvame et al., 2004) Hopkins et al. (2004) and Standford et al. (1998) showed that the VIAscan technology recently introduced to several abattoirs in New Zealand and in Australia offers significant potential for automatically predicting meat yield in three primal cuts (hindleg, saddle, and forequarter) in lambs

16 Discussion and conclusions, 1 Improvement in carcass traits of lamb should be emphasised on within a terminal sire line mated to ewes of a maternal line Traits Carcass traits selected on within the sire line should be measured accurately by ultrasound (and CT) Reproduction and functional traits should be the main emphasis in the selection of breeding females in order to maintain a high producing and sustainable sheep capable to utilize hill and mountain pasture Further work should be done to evaluate the effect of introducing a meat line to the Norwegian sheep industry including the number required for each of the two lines and the effect on the national sheep breeding schemes of NWS using a such system

17 If selection for composition of carcass regions will be an alternative in Norway or else were in the future, it should be practised within a terminal sire line mated to ewes of a maternal line where the emphasis is for reproduction and maternal traits Though, high mature weight or too large emphasis on muscling in i.e the leg should be avoided in order to minimize birth difficulties. Emphasis on slaughter quality traits in the selection of breeding animals will be most efficient if there is a high agreement with the valuing and payment system of carcasses, the economical value of the products when sold in the market and consumers request for meat

18 Thank you for your attention Department of Animal and Aquacultural Sciences