Soft or very hard testes indicate degeneration or scar tissue and rams with these defects should not be used for breeding. Supplementary feeding The testes are very sensitive to nutrition and respond rapidly to changes in the diet. Testes are smallest in autumn, when the quality and quantity of feed in paddocks are invariably at their poorest. Feeding supplements to rams grazing poor pastures before the start of joining can increase the size of the testes. A ewe must receive between 50 and 100 million sperm deposited in her vagina to have a good chance of conception.
Rams are very active at the start of joining and mate frequently.
There is a marked drop in the number of sperm in each ejaculate soon after the start of joining. Ewes which receive more than one service during an oestrus have a better chance of conceiving than ewes which receive only one service, because they will be inseminated with more sperm. Rams have a large capacity to produce sperm and a strong desire to mate continually with ewes. With flocks grazing highly oestrogenic subterranean clover pastures, it is suggested that a higher percentage of rams be joined with the ewes, that is, at least 2 per cent of mature rams. In the agricultural areas, mature rams often dominate younger rams and prevent them from mating ewes.