Review of Canadian, Outaouais and Rideau Arcott breeds of sheep: 1. Development and characterization

In the 1970s a multi-disciplinary research program was initiated at the Centre for Food and Animal Research (formerly Animal Research Institute) by introducing newly developed technologies in quantitative genetics, reproductive physiology, nutrition and housing, which had not previously been applied to the management of sheep production. The East Friesian, Finnish Landrace and Ile de France breeds from continental Europe with inherent potential for increasing productivity were imported and assembled with established breeds in North America to develop multi-breed synthetic populations. In 1972, the genetic base of the newly formed populations were closed to any further introduction of new breeding animals. Thereafter, these populations were selected for growth and reproductive performance to develop one specialized synthetic sire and two dam strains. Correspondingly, the Suffolk and Finnish Landrace breeds were maintained as random bred populations to monitor genetic response in the selected sire and dam strains, respectively. The three newly developed strains housed indoors year-round in a controlled environment were divided into two flocks. Concurrently, the use of artificial lighting regimens and exogenous hormones to synchronize estrus in ewes followed by exposure to rams in January, May and September, at the end of a period of short days initiated lambings in February, June and October, at 4-month intervals in 8-month breeding cycles. Growing lambs were raised from birth artificially on milk replacer and high energy diets, to allow maximum expression of their genetic potential, while adult sheep were fed diets to meet nutrient requirements according to stage of production. Genetic parameters estimated for growth and reproduction from the sheep raised in a controlled environment were in the favourable direction. Annual genetic response over 20 years of selection for early growth traits was approximately 1% of the mean realized. As well, there was a reduction in lamb mortality and an increase in fecundity. The morphological characteristics and production performance of the sire and dam strains have been described and compared with the reference breeds, Suffolk and Finnish Landrace. The newly developed synthetic sire strain (Canadian Arcott) demonstrated potential merit for use as a meat-type terminal breed, while the two synthetic dam strains (Outaouais and Rideau Arcotts) had outstanding productivity for use as fecund-type dam breeds.