David Brown, Livestock Field Specialist, University of Missouri Extension
(Previously published online with the University of Missouri Extension: October, 2023)
As fall
season approaches, daylight begins to get shorter, and sheep/goats are ready for breeding. The breeding season should be an exciting time for producers because the number of lambs and kids raised and weaned successfully determines the profitability of the operation. Understanding the reproductive system of the animals helps to maximize the breeding season and use resources wisely. This is particularly true for beginning producers who are experiencing their first breeding season. The season of the year is the main determinant for sheep and goat reproduction, with the majority being seasonal breeders that cycle in the fall (their natural mating season) and lamb in the spring. However, some breeds will cycle in the spring and have lambs/kids in the fall.
Peak fertility is from late September through November. Ewes have an average cycle length of 17 days, with most being between 14 and 20 days, while does have an estrus cycle of 18 to 22 days, and they display estrus for 24 to 48 hours. The gestation period ranges between 144 and 152 days. Management practices for producers to ensure profitability during the breeding season are highlighted below.
Reproductive health of the male
Rams and bucks should be in good condition, masculine and legs should be stronger and free from defects. The animal should have both testicles intact in the scrotum and display good libido. Testicle size relates to sperm production and larger scrotal circumference leads to greater semen volume and sperm viability. Producers should conduct the breeding soundness exam (BSE) before the breeding season to reduce risk of breeding failure. The BSE consists of a physical examination, inspection of the reproductive organs, semen collection and sperm evaluation. Animals that do not pass a BSE should be retested 30 to 60 days later. BSE is a worthwhile investment and producers should not consider it as dollar loss. A veterinarian or trained individual should perform the BSE. Contact your local veterinarian or local extension office to schedule and learn more about BSE.
Body condition scoring (BCS)
This is a great tool for monitoring nutritional status of your animals. BCS ensures that does and ewes are not too thin or too fat prior to the breeding season. Females that are excessively fat or thin may have lower conception rates and higher embryonic mortality. Monitoring BCS allows producers to make informed decisions on animal nutritional needs and make adequate adjustments prior to the breeding season. Direct correlation exists between body condition, ovulation rate and number of lambs/kids born. Producers should try to have ewes and does around BCS of 3 on a 5-point scale at breeding and increase slowly to an average body condition of 3.5 at lambing.
Flushing
This is a management strategy to improve the ewe/does condition just before and during the breeding season. Producers may choose to flush the animals by supplementing with a high energy diet or relocating the animals to a high-quality pasture. Care should be taken when flushing with legumes such as clovers and alfalfa. Estrogens present in the legumes may cause problems with estrus and fertility. Animals may be supplemented with ¾ to 1 pound of whole corn/head/day. Flushing should commence three to four weeks before breeding and continue through one estrous cycle. Flushing increases the ovulation and lambing rate and decreases the early embryonic mortality. Producers should only flush lean animals to avoid overfeeding.
Producers should consider the nutrition of the ram/buck, as they tend to lose significant weight during the breeding season. It is possible for producers to neglect the nutritional needs of the breeding male. It is recommended to increase the plane of nutrition to two times their maintenance energy for six to eight weeks prior to mating to reach a target condition score of 3 to 3.5 at mating. This practice increases semen production and quality. The goal of the producer is to condition the rams/buck to be “fit” and not “fat,” as the breeding season approaches. Over-conditioned rams/bucks will have low libido, whereas underfed rams produce lower semen quality. Rams require about 10% increase in dry matter intake and energy and 18% increase in protein prior to the breeding season. In most cases, the nutrient composition of the late-summer and fall-pastures will not meet the ram nutrient requirement. Producers should supply 0.5 to 1.0 pound of grain supplement to stimulate sperm production and improve conception rates.
In addition to good nutrition, body weight management of young ewes is important. Yearlings should weigh at least 80% of their mature body weight before the onset of the breeding season. Improper body condition of ewes will impact embryonic survival. The weight of lamb/kid at parturition will determine survivability of the young ones. Lambs/kids with low birth weight have lower chance of survival, as approximately 70% of lamb/kid mortalities occur during the first 48 hours after birth. Producers should examine breeding stock for internal parasites using the FAMACHA system and five-point check. Overall good management practices before mating will lead to a more successful lambing and kidding season.
Editors Note: Refer to the original publication here for supporting references.