Why rams should not be over-fed

Australian vet and Charollais breeder, Ian McDougall, described the negative effects of giving rams too much creep or cereals, advising breeders to ‘practice cool testicle management’ instead.

Temporary infertility
Over-feeding rams causes them to lay fat down, including in their scrotum, so testicles become hotter than the required 4-5degC below the ram’s core body temperature. This destroys semen-producing cells, causing testicles to become soft and small.

Testicle temperature does not have to be raised much, or for very long, for significant damage to semen production and quality to occur

Fat rams are also unfit, so any minor physical exertion raises their body temperature and increases their inability to keep testicles at a lower temperature. This is exacerbated indoors because there is less air movement around the scrotum.

Inability to serve many ewes
Fat rams are less able to detect oestrus and, when they do, find it difficult to actually mount the ewe. This will prevent them serving the same ewe several times, while smaller ewes will not let them mount at all because of their size and weight.

Ewe lambs have a shorter standing oestrus period, so need rapid serving, which is a challenge for fat rams.

Rapid weight loss or ‘melting’

Shedding weight means tissue is lost from all areas of the body, including the testicles. This means the smaller volume of semen produced will have a higher percentage of abnormal sperm.

Newly-purchased rams will ‘melt’ on commercial farms because the microbes in their gut are adapted to the cereal diet they have been reared on and not grass. It will take three weeks for grass-digesting microbes to dominate, during which time the ram will lose weight.

If he is placed with ewes immediately, there will be a ‘double whammy’ effect because what little energy the ram has will be spent chasing ewes.

Long-term problems

Some rams reared on a concentrate-based diet and sold to a grass-based system never adapt, reducing longevity or causing serious health problems (such as chronic lameness) which mean they are culled young. They may never have the ability to serve many ewes.

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