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A PROGRESS REPORT ON THE DEVELOPMENT OF A MEAT MERINO LINE IN SOUTH AUSTRALIA (THE FIBRE MEAT PLUS)
V.M. Ingham1 and R.W. Ponzoni2
1 Livestock Systems Alliance, Adelaide University, Roseworthy SA 5371
2 SARDI, Livestock Systems Alliance, Roseworthy SA 5371
SUMMARY
A line of Merino sheep (Fibre Meat Plus) with a breeding objective aiming to enhance performance in traits related to meat production (reproductive rate, growth rate, carcase attributes and meat quality) with minimum possible compromise in wool production and fleece characteristics is being assembled in South Australia. The project has been initiated and will be run with significant input from producers. Preliminary results suggest that this line already differs to the existing SA Selection Demonstration Flocks run by SARDI.
Keywords: Merino sheep, selection, sheep meat.
INTRODUCTION
Merino sheep are 'dual purpose' in the sense that they generate income from both the sale of wool and of surplus sheep. Using 1987-88 prices as a basis (100) the corresponding figures in 1997-98 for wool, lambs and mutton are 60, 140 and 151, respectively (ABARE 1998). In many SA Merino flocks this trend has resulted in an increase in the contribution of lambs and mutton to income, relative to that from wool, and greater emphasis placed (or considered) on sheep meat production, relative to that placed on wool.
Traditionally, Merino sheep have been selected mainly for wool traits, with limited attention paid to meat attributes. The objective of this project is the development of a line of Merino sheep with enhanced performance in traits related to meat production (namely, reproductive rate, growth rate and carcase attributes) with minimum possible compromise in wool production and fleece characteristics.
This is being achieved by having a breeding objective emphasising these traits, and carrying out selection using the latest advances in genetic evaluation technology, while not neglecting aspects of structural soundness of the sheep. In creating the Fibre Meat Plus (FM+) line, we are offering Australian woolgrowers the opportunity to stay with Merino sheep, while at the same time capitalising on the trend of increased profit from sheep meat production.
MATERIALS AND METHODS
This project has been designed and will be run with significant producer input. All decisions are made in consultation with the breeders involved. A total of 190 ewes selected according to an agreed breeding objective emphasising meat related traits (high reproductive rate, growth rate and muscling, and low fibre diameter) were assembled at Turretfield Research Centre. A list of producers who have contributed ewes is presented in the Appendix. The first artificial insemination (AI) of these ewes took place in January 2000. Four Merino sires were selected according to the breeding objective using Lambplan records and any other performance information available. One Dohne Merino sire
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was also used. Sires’ identities and stud of origin are shown in Table 1. A breeding objective accommodating the following aims will be used when choosing ewe and ram replacements; maintain a high clean fleece weight and approximately 19µm wool, increase reproductive rate, improve: lamb growth rate, carcase quality, and eating quality.
Table 1. Sires used in the Fibre Meat Plus line for 2000 mating
Sire Breed Stud of origin
White 292 Merino Leachim
Centre Plus 341 Merino Centre Plus
Grange 901 Merino The Grange
Willemenup H8 32/017 Merino Willemenup
GB98.058 Dohne Merino Summerfield Dohne Merinos
The lambs born in 2000 have been fully pedigreed and will be intensely recorded for reproduction, wool and body traits, as is normal practice in SARDI experimental flocks. These lambs have been run in such a way as to enable the comparison with the more conventional Merinos in the SA Selection Demonstration Flocks (Ponzoni et al. 2000). This will allow the monitoring of progress in reproduction, growth, carcase traits, as well as any changes that could occur in wool traits, and will constitute a direct and highly credible means of benchmarking.
Table 2. Number of records available, simple means, standard deviations (s.d.) and range for each trait measured on all flocks
Trait No. of records Simple mean s.d. Range
Weight Birth 901 5.07 0.89 2.3 – 8.4
(kg) Weaning 902 28.3 5.55 10.4 – 44.2
15 weeks 895 30.9 5.97 13.0 – 47.0
21 weeks 885 31.5 5.65 13.0 – 47.0
29 weeks 845 33.1 5.93 16.0 – 54.5
34 weeks 831 36.4 6.25 18.5 – 58.0
Fat depth 15 weeks 890 2.02 0.67 0.5 – 3.5
(mm) 21 weeks 779 1.38 0.49 0.5 – 3.5
29 weeks 833 1.28 0.58 0.5 – 3.5
34 weeks 827 1.30 0.58 0.5 – 4.0
Muscle depth 15 weeks 890 21.4 2.82 10.0 – 29.0
(mm) 21 weeks 779 19.1 2.14 13.0 – 28.0
29 weeks 833 17.3 2.97 9.0 – 25.0
34 weeks 827 20.5 2.80 11.0 – 29.0
Statistical analysis. The data were analysed by restricted maximum likelihood (REML) using SAS (SAS 1999). An animal model was fitted allowing optimal analysis of a finite, selected population.
The flock means were adjusted for effects including type of birth and rearing, age of dam, sex, and
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time of birth (to account for the fact that progeny of AI sires were born earlier than progeny of back up sires). The number of records available, the simple mean, standard deviation and range for each of the traits are shown in Table 2.
RESULTS AND DISCUSSION
All results presented are preliminary, as the FM+ flock has only very recently been assembled and only one drop (2000) of lambs is currently available for evaluation. However, the values presented in the table that follows may serve the purpose of assessing the extent to which we are succeeding in differentiating a line of Merinos with enhanced growth and meat attributes.
Table 3. Least squares means for growth traits at different ages (2000 drop) of SDF’s
Trait FlockA Birth Weaning 15 Weeks 21 Weeks 29 Weeks 34 Weeks
Control 4.8a 27.0a 30.5ab 32.4a 32.5a 36.2a
Weight
(kg) MPR 5.0a 28.5b 31.2a 31.8ab 31.7ab 35.9ab
PCA 5.0a 26.7a 29.6b 30.7b 30.6b 35.0a
EWF 4.9a 26.6a 30.1ab 30.5b 30.8b 34.3b
FM+ 5.3b 28.4b 30.7ab 32.5a 35.5c 38.7c
Overall 5.00 27.5 30.4 31.6 32.2 36.0
Control 2.0 1.5 1.4a 1.4a
MPR 1.9 1.2b 1.2b 1.2b
Fat depth
(mm) PCA 1.9 1.3 1.1b 1.3ab
EWF 1.9 1.3b 1.1b 1.2b
FM+ 1.9 1.3b 1.3b 1.3ab
Overall 1.92 1.30 1.24 1.26
Control 21.5a 19.2a 17.8a 21.4a
MPR 21.2ab 18.7ab 17.2ab 20.4ab
Muscle depth
(mm) PCA 20.4b 18.2b 16.3b 19.8b
EWF 20.9ab 18.3b 16.0b 19.6b
FM+ 21.2ab 18.8ab 17.7a 21.1a
Overall 21.0 18.7 17.0 20.4
A Selection Demonstration Flocks. MPR = Measured Performance Recording, PCA = Professional Classer Assessment, EWF = Elite Wool Flock, FM+ = Fibre Meat Plus. See Ponzoni et al. (2000) for further explanation of flocks. Means with no superscript or with a common superscript do not differ significantly (P > 0.05) from each other within age group.
Least squares means for weights and fat and muscle depths at different ages are presented in Table 3.
The FM+ were significantly heavier than the other flocks at birth and in the later measurements (29 and 34 weeks). At 15 weeks there are no differences among the flocks in fat depth. However, the Control flock was consistently, and for the 21, 29 and 34 weeks measurements significantly fatter than the other flocks. The FM+ was not significantly different from the other selection flocks, but it increased fat depth steadily after the early reduction between 15 and 21 weeks. The poor live weight gains and the reduction in fat and muscle depth between 15 and 29 weeks of age was due to
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unforeseen problems with the quality of the water available to the lambs. At the beginning of measurement of muscle depth (15 weeks) the control flock was significantly different from the PCA flock. With an increase in age the muscle depth of the Control and FM+ flocks became significantly greater than for the other selection flocks.
Apart from selection strategies used there is a difference in bloodlines used in the selection lines and the Control. The Control flock is pure South Australian Merino whereas the selection flocks have Victorian and New South Wales (and Western Australian for the FM+) Merino blood.
These results suggest that the FM+ has a faster growth rate than all other flocks (including the Control) and has greater fat and muscle depth than the other selection lines in the SA Selection Demonstration Flocks (but not the Control). Therefore we may say that the selection carried out to establish the FM+ line has resulted in improved growth and carcase characteristics relative to the other SDF lines.
The future. Intensive measurement of both growth and wool characteristics will continue for the 2000 drop lambs and will start for the 2001 drop lambs. For mating in January 2001 a combination of sires selected according to the same selection criteria as 2000 were chosen from external sources, and some ram lambs from the FM+ flock were used. Encouraged by the performance of the 2000 drop lambs, two Dohne Merino sires were used. For the 2002 mating we are hoping to use a combination of outside and ‘home-bred’ sires. Reproductive technology (AI, Multiple Ovulation and Embryo Transfer and possibly Juvenile InVitro Embryo Transfer) will be used to introduce genes from outstanding individuals identified in the FM+ flock into the flocks of participating breeders.
REFERENCES
ABARE (1998) “Australian Commodity Statistics 1998” Commonwealth of Australia, Canberra.
Ponzoni, R.W., Jaensch, K.S., Grimson, R.J., Smith, D.L. and Ingham, V.M. (2000) Wool Tech.
Sheep Breed. 48: 166.
SAS Institute Inc. (1999) “SAS/STAT User’s Guide” Release 8 Edition. SAS Inst. Inc., Cary, NC.
APPENDIX Merino Breeders
Name Property Contact Person(s) and Phone Numbers Anama Pastoral Co. Anama S.A. Ryves &Tom Hawker Ph +61 8 8842 2158 EM Davidson & Co. Moorundie Park S.A. Geoff & Russel Davidson Ph +61 8 8662 6269 Merinotech. Baderloo S.A. Phil & Anne Hammat Ph +61 8 8665 4019 DJ & MB Pocock Panlatinga Poll S.A. Jim & Michael Pocock Ph +61 8 8757 8287 Grass Merinos Pty Ltd. Grass Merinos N.S.W. Graham Peart Ph +61 2 6884 5544 Old Ashrose Pty Ltd Old Ashrose SA Rob Ashby Ph +61 8 8894 2015 RJ Garnett & Son. Willemenup W.A. Dick & Collyn Garnett Ph +61 8 9827 1304
