Maataloustieteellinen A ikakauskirja Vol. 60: 523—530, 1988 Many-sided performance testing of Finnsheep rams M.-L. PUNTILA Department of Animal Breeding, Agricultural Research Centre. SF-31600 Jokioinen, Finland Abstract. Central performance testing of youngrams 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 Finn- sheep (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) fort- nightly. 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 test- ed. 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) cm 1 . 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. Index words: Finnsheep, performance testing, ultrasonic, feed intake, feed efficiency, growth rate Introduction In a country like Finland, with very small flocks, within-flock selection cannot be in- tense, and comparison of animals across flocks is difficult. Varying pasture conditions further reduce the reliability of field testing. Fewson (2) emphasized the importance of cen- tral performance tests in increasing the accura- cy of genetic evaluation. Its value in selection for growth rate was confirmed in several studies (25. 17, 16, 20, 26, 12. 23). Selection for meat production in sheep suffers from lack of good measures for 523 JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND https://www.c-info.fi/en/info/?token=SPq-q5FDUv9fv7xh.XQycE6FNrkaINoBZw8pj4A.3vMJN5jNbiwTMhXQ0yQzm7WOJjXF2AOts-VGs-4qABp7OxzSS1X1o8zg0liddlZp3L6l1ZATc5cnUe5PjTDBupcEGO56vomPIPM2tXgrIv0aEPRJkSWMZ-oE825YigfWayKCP3TMsZ3N-_YBiQMwKOfqFfj3rMR5QHEq predicting the carcass composition from live animals. Hence, centralized sib-testing sta- tions are used in selecting rams for carcass traits (15). Ultrasonic measurements are not as com- mon in sheep as in cattle and pigs, in predict- ing carcass traits, due to the poor precision of prediction (11,3, 19). Attempts to use them on lambs have been disappointing, because of the small variation in backfat thickness and muscle area or depth. However, some reports show the measurements to be of some value in predicting carcass composition (13, 1). Finnish results of testing rams with Scano- gram (4) presume it to be useful under inten- sive feeding, but not underpasture conditions. It may also be more advantageous in meat type breeds. Scanning may be a good tool, if the emphasis in evaluation is on lamb cutlets (5). Despite the modest improvement in predicting the carcass lean proportion, Kemp- ster (14) suggests ultrasound to be useful in selection programmes. Using the new real time scanner has also been shown to be justified in circumstances like at central testing stations (15). It is worth mentioning that ultrasonic measurements have been routinely used in per- formance testing of rams of various breeds in Denmark since 1977 (6, 7,8, 9, 10). Station tests give the prerequisites for meas- uring individual feed consumption. There is clearly some interest to include the traits of feed efficiency also as one of the selection criteria (8, 21). Previous performance tests in Finland The first central performance tests were car- ried out in 1975—77 as combined phenotype and progeny test, including comparisons be- tween rearing indoors and on pasture. The results showed the performance tests to be well applicable to evaluating sheep for carcass traits. During 1981—84 the tests were carried out on natural pasture. Low growth rates did not stimulate breeders to buy rams tested in this way, therefore the test in that form was discontinued. 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 fac- tors and to estimate the phenotypic para- meters of the most important traits. Material The performance test data spans three years from 1985 to 1987. There were records from 274 lambs (67 sires, 206 dams). Average num- ber of lamb records per sire was 3.1. The per- formance test station at Jokioinen has the ca- pacity for 100 rams. In addition to Finnsheep some Texel and Rygja rams were tested, they are not included in this study. The perfor- mance test was a combined half-sib test. The object was to have four half-sibs per sire, al- though groups of two and three also existed. The rams came from recorded flocks through- out the country. The pre-selection was made by extension technicians. There were recom- mendations for feeding and weaning of lambs at the farm before the test period. The birth data was restricted to be from late February to early April. Hence there was quite a lot of age variation at the beginning of test. The test period was 90 days, from 60 to 150 days of age. The initial weights were adjusted to 60 days of age. The rams were kept in individu- al pens and fed on concentrate diet to appe- tite, roughage was under restriction. FI was recorded daily, growth rates fortnightly. At the end of test rams were ultrasonically meas- ured behind the last rib. The scanning equip- ment used was a B-model linear real time Hitachi HUB 27 scanner. In the first and third year some linear body measurements were tak- en, too. Fleece and fur characteristics and structural soundness were evaluated. Growth, feed efficiency (FE) and meatiness indices were calculated separately for each ram, utiliz- ing sib information. The best ranked animals were sold at auctions to farmers, few being used for artificial insemination. The rest were slaughtered immediately after the test. Dur- 524 ing the first two years these carcasses were dis- sected for determining carcass composition. Methods Data were analyzed by the GLM procedure in SAS. The general statistical model includ- ed fixed effects due to year, rearing type (I—s), age of dam (2—7 years or more) and birth flock, and the age of lambs at the be- ginning of test as a covariate. Only phenotypic correlations were possible to calculate. Pedi- gree indices were based on half sibs with the heritabilities for daily gain, feed efficiency and meatiness (ultrasonic muscle area) .4, .3 and .3 respectively. The average relationship in sire progeny groups was estimated according to Osborne (1957). Results and discussion Overall means and coefficients of variation for weights and daily gain (ADG) in differ- ent periods are given in Table 1. The CV for age at start was about 8 %, the same over the years, the mean being 64 days. Starting weight is the most variable trait due to both genetic and environmental factors. The CV for weight at different periods were B—l 48—14 % in each year, while periodic gains varied markedly be- tween years. The growth pattern was typical for each year. In the first year the rams gained most during 6 first weeks in the test and in the year 1987the situation was reversed. In gener- al, the ADG was at its maximum on the third fortnight period. Mean ADG from 60 to 150 days was similar during all tests, varying with- in year from 172 to 370 g. The results were in agreement with the previous performance test data where the rams were fed on concen- trates (25). 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. Con- sequently the major part of the rams fully uti- lizes growth potential during the test period. The average FI varied from 0.7 to 1.4 kg DM/d, FE from 3.2 to 5.7 kg DM/kg gain. Figure 1 describes the increase of FI on the group of immediate start weight during suc- cessive growth periods. The analyses of variance are given in Table 2. The (non-genetic) factors included in the model had a significant or almost significant Table 1. Overall means (x) and coefficients of variation for daily gain (g/d) recorded fortnightly from 60 to 150 days of age in different years. 1985 1986 1987 Trait x CV. x CV. x CV. Age at start 63.5 7.7 64.9 7.8 64.5 8.6 Initial weight 19.1 16.9 20.4 18.6 22.2 13.2 Adjusted 60 day weight 18.0 16.6 19.4 19.4 21.1 12.2 Weight at period 1 23.4 13.9 24.1 14.9 25.9 12.4 II 27.8 11.9 28.3 13.6 29.7 11.7 111 32.0 10.4 32.8 11.8 34.3 10.5 IV 35.9 9.8 37.3 10.4 38.5 9.5 V 39.5 9.3 41.4 10.2 42.7 9.7 VI 42.6 8.9 43.8 8.3 45.7 7.9 Final weight (150 d) 43.3 8.5 44.9 9.1 46.9 8.8 Gain at period 1 315 24.6 258 46.4 260 28.7 II 312 24.6 304 27.7 276 31.3 111 301 31.4 322 24.9 326 28.3 IV 277 32.5 320 28.0 305 27.4 V 259 36.9 297 28.1 299 29.3 VI 247 43.7 245 44.7 274 33.4 ADG 281 11.9 284 12.5 286 11.4 525 effect on the differences in the traits studied. The year of birth had a significant influence on all main traits except ADG. Age at begin- ning had a highly significant effect on the start weight as expected. The influence lasted until the final weight and overall ADG. Rearing type had a significant influence on the start weight as well as on 150 day weight. This is in agreement with the results of Olson et al. (17). The previous Finnish data indicated the rearing type to have an effect mainly on the weaning weight, not on the final weight (11). In this study the rams came from the litters averaging 3.2 (range 2—6) and rearing type 2.9. Depending on the preselection the flocks had a fairly constant litter size. Age of dam has usually been shown to have significant influence on ADG and body weight of lambs. Adjustment of the weaning weight to dam’s age in the performance test has been considered necessary (17). In this study there was no significant effect of dam’s age, prob- ably due to the fairly constant age of dams, 70 % of them were 3—6 years old. The phenotypic correlations are presented in Table 3. The correlations between ADG, FI and final weight varied around .60. As mentioned earlier, during the first two years the rest of the rams were slaughtered and dissected after the test period to evaluate the usefulness of ultrasonic muscle measurements in predicting carcass composition. The meas- urements were adjusted to the same live weight according to the recommendations of Fortin et al. (3) even if there was some small varia- tion in the live weight. Table 4 shows the results from the dissecting data (year 1986). The muscle area measurements seem to give slightly better association with carcass traits than muscle depth. The correlations between the real-time ultrasound live animal muscle measurements and dressing percentage as well conformation were around 0.50 (pcO.OOl) but between lean meat percentage and lean- Fig. I. Feed intake in different test years 526 6 Table 2. Analysis of variance for the effects of non-genetic factors on the most important traits in performance test. Ultrasonic Source of Initial variation weight Final FI FE MLD- MuscleADG intake efficiency area depthweight Year 109.21*** 2786.97 ns 73.88*** o.3o*** 2.l6*** 2.39* 13.58** Flock 1228.46*** 94163.47*** 1973.79*** I.ll*** 15.89*** 75.61" 358.51** Rearing type 225.34*** 3264.21 ns 160.82** 0.04 ns 0.50 ns 3.08 ns 20.48 ns Age of dam 37.62 ns 2293.08 ns 16.12 ns 0.02 ns 0.20 ns 1.38 ns 13.11ns Age at beginning 304.73*** 6452.73** 72.25** 0.00 ns 1.35** 0.03 ns 2.47 ns R 2 0.707 0.375 0.583 0.437 0.433 0.313 0.314 ns =P>o.lo, * =P<0.05, ** =Po.lo, * =p<0.05, �• =p •*» = p