Abstract:
Animal Production in Australia 1998 Vol. 22 CHANGES IN SOURCES OF GENETIC INFLUENCE IN THE QUEENSLAND MERINO INDUSTRY MARY ROSE Sheep and Wool Institute, Department of Primary Industries, Yeerongpilly, Qld 4105 SUMMARY A study of ram sources in Queensland Merino studs was made for the period 1981 to 1992. There were very few studs in Queensland; only 72 in 1992, of which 31 were Poll studs. Twenty-four studs sold more than 1500 rams in the period and were considered influential. Their sales represented 75.2% of the total ram sales. The studs selling the largest number of rams were a Merino and a Poll stud with one owner which together sold 16.6% of all rams sold. Eight of the influential studs were Poll studs and this reflected a greater demand for Poll rams; 40.6% of rams sold in the period were Poll. It was estimated that the sale of rams by Queensland studs in 1992 provided 63% of the rams which were required by commercial flocks in Queensland. Although interstate studs may not have a large genetic influence through their sales of rams and semen to Queensland studs, they do have a major influence in supplying a large proportion of the flock rams used by commercial sheepbreeders. Keywords: Merino sheep, studs, rams, semen. INTRODUCTION Buying locally bred rams has often been recommended to commercial woolgrowers as a sensible practice and the Queensland Merino Stud Sheepbreeders Associations promotion has long been Buy Queensland bred rams. The reasons given are manifold but the main reason with a basis genetic would be the belief that rams bred for a long time in a particular environment are better adapted to that locality. If rams are selected in the environment in which they are to produce, any adverse effects of genotype x environment interactions resulting from the use of rams purchased in a different environment are thus avoided. Many of Queenslands studs are large and long-established, eight being over 100 years old, and of the 24 influential studs identified by Rose (1987) seven were listed as daughter studs by Roberts et al.(1975). Rose (1988) reported that for the period 1965 to 80, interstate rams purchased were less than 1% of sires used for most of the influential studs. In only two studs which are still in existence was this proportion significant (the first with a proportion of 7.6% purchased rams from 11 different studs, and the other with 12.4% purchased, with all but one ram from one parent stud). She concluded that interstate studs did not have a big influence on the Queensland stud rams supplied to commercial flocks. However since Queensland studs supplied only 54% of Queensland commercial flock rams, the other major influence on the Queensland industry was that of interstate studs which sold directly to commercial woolgrowers. However there is a perception held by many in the industry, that Queensland studs are largely influenced by interstate studs through purchases of interstate rams. Therefore this study was undertaken to determine any changes since 1980 in the genetic influences in the Queensland Merino industry; whether Queensland studs were largely using locally-bred rams, or were buying a larger proportion of interstate rams bred in different environments and for breeding objectives which did not necessarily suit their clients. MATERIAL AND METHODS Data for sires in use, rams and semen purchased and source of rams and semen for the period 1981 to 1992 were obtained from the Australian Stud Merino Flock Register Volumes 59 to 65 (1982 to 93). RESULTS AND DISCUSSION Number of studs Sheep numbers in Queensland rose from 10.6 million in 1980 to a peak of 17.8 million in 1991, falling to 15.5 million in 1992 (ABS 1996). A total of 102 Queensland studs were registered in the period of this study. In 1981 there were 66 registered studs in Queensland and in 1992 seventy-two, 31 of which were Poll studs. Seventeen studbreeders owned a Poll stud and a Merino stud, and in all but one case they ran both studs on the same property. 265 Animal Production in Australia 1998 Vol. 22 Annual ram sales Table 1 shows the number of studs by rams sold during the period 1981 to 1992. The mean annual number of rams sold by Queensland studs in this period was 102 (range 0 to 916). This compares with a mean of 198 (range 0 to 1696) reported by Rose (1984) for the period 1960 to19 80. Influential studs Rose (1984) defined influential studs as those which had sold more than 5000 rams (1.2% of the total rams sold by all studs) in the period 1960 to 80. Twenty-four studs sold over 1500 rams (1.2% of the total rams sold by all studs) between 1981 and 1992, representing 75.2% of all rams sold. There were five studs which sold over 5000 rams in the period. The most influential studs were a Poll stud selling 8.8% of rams sold and a Merino stud selling 7.8% which have the same owner. These two studs sold 16.6% of all rams sold. The next most influential studs were three Merino studs which sold 6.3%, 5.0% and 4.1% of the rams. Ten of the influential studs in this study were among the 24 influential studs of 1960 to 1980 described by Rose (1987) as well as two others which were registered in the last five years of the previous study and were becoming important because of large annual ram sales. It is interesting to note that in the period 1960 to 80 only three Poll studs were among the most influential. The most influential in the current study was one of these. From 1981 to 1992 there were eight influential Poll studs reflecting a greater demand for Poll rams by commercial woolgrowers. In this period 40.6% of the total rams sold were from Poll studs. Supply of flock rams to commercial flock It was estimated, using the formula of Rose (1984), that in 1992 Queensland studs supplied 63% of the flock rams estimated to be required by commercial flocks. Almost all the remaining rams are purchased from interstate studs, chiefly in New South Wales and South Australia. Sources of rams purchased by Queensland studs Table 2 shows the number of rams purchased by Queensland studs in the period 1981 to 1992 and the locality of their source stud. Of the 938 interstate rams purchased, New South Wales rams made up the majority (82.5%). There were no records available for the number of sires used by studs in 1986, 1987 or 1989 so the number of sires used for those years was assumed to be the same as in 1985. The total number of sires used in the total period was then estimated to be 31,675. This meant that 1659 rams purchased represented 5% of sires used, while interstate rams represented only 3% of all sires used in Queensland studs. Number of rams purchased by influential studs Table 3 shows the number of rams purchased by influential studs expressed as a percentage of sires used. In the majority of studs these rams represented less than 5% of sires and in only one stud was a significant number of sires purchased (33.2%) which represented a purchase of 80 rams from a New South Wales stud in one year. Table 1. Number of rams sold by Queensland Merino studs in the period 1981 to 1992 Number of rams sold >10000 5001-10000 2001-5000 1001-2000 501-1000 101- 500 1- 100 0 Total 125230 Number of studs 1 4 7 3 5 3 8 1 1 1 1 2 1 1 Total 102 266 Animal Production in Australia 1998 Vol. 22 Table 2. Number of rams pur chased by Queensland Merino studs and their source in the period 1981 to 1992 Number of rams purchased 774 79 77 8 721 Total 1659 * Includes a single purchase of 624 rams from one stud Locality of source stud New South Wales South Australia Western Australia Victoria Queensland * Table 3. Number of rams (as % of sires) purchased by influential Queensland Merino studs in the period 1981 to 1992 Purchased rams (% of sires) Number of studs 0 <1 1-3 3-5 5-10 >10 3 7 4 7 2 1 Semen purchases In addition to the ram purchases, 27 Queensland studs purchased semen in the period 1981 to 1992. The number of influential studs purchasing semen from interstate studs was 13 (54.2% of influential studs). Two Poll studs purchased over 1000 doses in the period (one purchased a total of 1590 from Western Australia and New South Wales over eight years, and the other 1717 doses from Western Australia in two years). Four studs purchased 500 to 600 doses over two to five years, four 200 to 400 over one to three years, three more than 100 doses in one to two years. It is difficult to ascertain the influence of such purchases but their selected use and the success rate of the AI program would largely determine this. CONCLUSIONS Queensland has relatively few Merino studs and the influential studs are large and long established. There has been a rise in the number of influential Poll studs since 1980 but many of the studs designated as influential by Rose (1984) remain so. A few studs play a very important role in supplying flock rams to Queensland commercial flocks but there is still a significant number of flock rams purchased from interstate studs. There was little change in policy among Queensland studs in the purchase of interstate rams and in most of the influential studs the influence of interstate purchases would have been small even if they were given preferential use. Semen purchases in this period were a feature in a few influential studs although their impact is difficult to quantify without further study of their use in the breeding program of the individual studs. The breeding objectives of a small number of Queensland studs and the efficiency with which a small number of studbreeders select their sires will largely determine the genetic improvement in a large proportion of Queenslands Merino industry. However the large genetic influence of interstate studs is still a major factor through direct sales of rams to Queensland commercial flocks. REFERENCES ROBERTS, E.M., JACKSON, N., and PHILLIPS, J.M. (1975). Wool Technol. Sheep Breed. 22, 6-9. ROSE, MARY (1984). Proc. Aust. Soc. Anim. Prod. 15, 561-4. ROSE, MARY (1987). PhD Thesis, University of Queensland. 267