The start of the fall breeding season is upon us.  Proper management of both rams and ewes prior to, during, and after the breeding season is critical for a successful subsequent lambing season.

Ram Management

Most often, newly purchased ram lambs are coming off a high plane of nutrition heading into their first breeding season (completing a structured performance test, or managed on the farm for high growth rates to optimize maturity).  To prepare ram lambs for the breeding season, rams should be “hardened up” prior to introduction with ewes.  This can be accomplished through limit feeding grain while on pasture.  The amount of supplementation will vary according to the ram’s body condition and pasture quality, but as a guideline 1-2% of body weight will suffice to achieve a moderate body condition at the start of the breeding season (not excessively fat or thin).  Be certain that housing and facilities provides adequate shade and ventilation so that rams can stay cool.  These principles also apply to mature rams, which may be new to the flock or been in use for several years.  Exposure to high temperatures can compromise the reproductive soundness of rams.

Newly acquired ram lambs should not be commingled with older, mature rams either prior to or during the breeding season.  Particular care should be taken if rams from different sources (of similar age) need to be commingled, and all commingling should take place prior to the breeding season.

Prior to the start of the breeding season, all rams should be subjected to a breeding soundness exam by a veterinarian.  The breeding soundness exam assess the physical fitness of the ram, and most importantly the ram’s reproductive soundness and capability of settling ewes.  Plan ahead to allow adequate time to find a replacement ram should an existing sire be found to be a non-breeder.

Many factors influence the breeding capacity of rams, including age, breed, nutrition, management, and environment.  As a general guideline, ram lambs are capable of breeding 15 to 25 ewes during their first breeding season, and most mature rams can service 50 or more ewes.  All rams, and particularly ram lambs, should be observed closely to monitor their breeding behavior and libido to ensure they are servicing and settling ewes.  The use of a marking harness, rotating colors every 17 days, is an excellent management tool for this purpose.  The breeding season should be kept to a maximum of 60 days for young rams.  This will prevent over-use, severe weight loss and reduced libido.  Severe weight loss may impair future growth and development of the young ram and reduce his lifetime usefulness.  When practical, supplementing ram lambs with grain during the breeding season will reduce excessive weight loss (feeding rate of 2% bodyweight daily).  Rams used together in multiple-sire breeding pastures should be of similar age and size.  Ram lambs cannot compete with mature rams in the same breeding pasture.  A sound management practice is to rotate rams among different breeding pastures every 17-34 days.  This practice decreases the breeding pressure on a single ram.

Ewe Management

Some advance planning and simple management practices will assist in having a successful breeding season.  Vaccination of the ewe flock for Campylobacter (vibrio) and Chlamydia are important for abortion disease control.  For ewe lambs and ewes not previously vaccinated, these products typically require an initial injection prior to the breeding season followed by a second vaccination during gestation.  In subsequent years, a single booster vaccination is required.  Follow product label directions when administering any vaccine.  A month prior to the breeding season is also an opportune time to trim and inspect feet on the ewe flock, and perform preventative foot care.  This is also a good time to make final culling decisions, and sell poor producing and thin ewes.

Flushing is the practice of increasing energy intake, and therefore body condition, during the 10-14 days prior to breeding.  This practice has been shown to be effective in increasing ovulation rates, and thereby increasing lambing percentage by 10-20%.  The response to flushing is affected by several factors, including the body condition of the ewe and time of the breeding season.  Ewes that are in poor body condition will respond most favorably to the increase in energy, whereas fat ewes will show little if any response.  Flushing can be accomplished by moving ewes to high quality pastures or through providing .75 to 1.25 lb. corn or barley per head per day from 2 weeks pre-breeding through 4 weeks into the breeding season.  Provide a high-selenium, sheep mineral free choice.

Like rams, ewes are also prone to heat stress during the breeding seasons.  Prolonged exposure to high temperatures can have an effect on ewe fertility and embryo survival.  To help reduce these embryo losses and resulting decrease in lamb crop, minimize handling during the heat of the day and allow the flock access to a cool, shaded area.

Ram Management After the Breeding Season

Young rams require a relatively high plane of nutrition following the breeding season to replenish body condition and meet demands for continued growth.  Body condition and projected mature size of the ram will determine his nutrient requirements during the months following the breeding season.  Rams should be kept away from ewes in an isolated facility or pasture after the breeding season.  In the winter months, provide cover from extreme weather that may cause frostbite to the scrotum resulting in decreased fertility.

This Issue:

• Livestock Update - August 2009

Other resources in:

• Beef Cattle

Other resources by:

• Scott P. Greiner

Other resources from:

• Animal and Poultry Sciences