Abstract
Central performance testing of young rams has been conducted in Finland since 1975, in 1985—87 indoors as combined phenotype and 1/2-sib tests, which are the subject of this study. There were 100 individual boxes available, of which ca. 90 were annually used for Finnsheep (F). The rams were fed on concentrate diet (13.5 % DCP) ad lib. + hay. The test period was from 60 to 150 days of age. Feed intake (FI) was recorded daily, live weights (LW) fortnightly. At the end, MLD-areas were ultrasonically scanned, fleeces weighed, some linear body measurements taken, and fleshiness and wool quality scored. A total of 276 F rams were tested. They were progeny of 85 sires (2—4 half-brothers/sire). The means for all rams (30 selected rams) were: birth type 3.19 (3.18), rearing type 2.93 (3.01), age at start 64.3 (63.7) days, 60-day LW 19.5 (19.5) kg, 150-day LW 45.1 (47.6) kg, ADG 284 (312) g/d, FI 1.28 (1.34) kg/d, FE 4.49 (4.29) kg/kg gain, MLD-area 8.83 (9.63) cm2. There was considerable variation in the important traits (ADG, FI, FE, MLD-area), in spite of preselection. The phenotypic correlations of ADG with 150-d. LW, FI, Fl/kg gain and MLD-area were .61, .57, —.63 and .37, resp. (PC.001). Those of 150-d.LW with the last three traits were .59, —.15 NS and 0.44, resp.(P< .001). Selection for ADG, 150-d. LW, Fl/kg gain and MLD area in the performance test appeared to improve the value of offspring for meat production in F.
Highlights
In a country like Finland, with very small flocks, within-flock selection cannot be intense, and comparison of animals across flocks is difficult
The objectives of the current study were to analyze data recorded for growth rate (ADG), feed intake (FI) and ultrasonic measurements, to describe the influence of non-genetic factors and to estimate the phenotypic parameters of the most important traits
By dividing the rams to three weight groups according to starting weight, the lightest group had significantly better ADG in the test than the heaviest group
Summary
In a country like Finland, with very small flocks, within-flock selection cannot be intense, and comparison of animals across flocks is difficult. Varying pasture conditions further reduce the reliability of field testing. Fewson [2] emphasized the importance of central performance tests in increasing the accuracy of genetic evaluation. Its value in selection for growth rate was confirmed in several studies Selection for meat production in sheep suffers from lack of good measures for predicting the carcass composition from live animals. Centralized sib-testing stations are used in selecting rams for carcass traits [15]
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