Feed Program

Feeding ruminants must take into account rumen health. As the saying goes, “feed the rumen to feed the sheep”. This is critically important, as sheep have evolved to consume relatively poor quality, forage based feeds. Getting nutrients out of forage feeds hinges on a healthy rumen microbiota to be able to digest the components of feed that the sheep itself cannot. An unhealthy rumen can have trickle-down effects to the whole production cycle, and can severely limit nutrient digestibility.

Competition at the bunk or feeding area can compromise plane of nutrition for timid sheep. If bunk space is limited, dominant sheep will take first pick of the feed, which can leave a lower quality of feed available for timid sheep.

Sheep are fantastic at sorting rations, selecting the most palatable parts of feed. Typically, the most palatable parts of feed are the high energy density components. These components will be consumed preferentially over fibrous components of feed. Managing chop length of forages is one strategy to ensure the feed placed in front of sheep is the feed that is actually consumed.

Water is the single most important nutrient. While water does not directly provide any nutrients, all metabolic processes happen in an aqueous environment. Compromising on water availability can drastically affect all aspects of production. Ensure water is readily available and clean.

Late gestation and lambing is a stressful time for ewes, and presents some unique nutrition challenges. Energy and protein requirements increase in late gestation, and diets should be changed to reflect that. This is a time where high quality stored forages should be used.

Late gestation is when most fetal growth occurs. As such, ewe requirements for energy and protein increase, and diets should be adjusted accordingly. Late gestation is also when mammary tissue is developed for lactation post-lambing. Ensuring proper late gestation nutrition can help ewes to birth healthy lambs and provide the nutrients necessary for mammary growth to improve milk production. Mammary development becomes especially important for multiple lamb births; more lambs means more milk required to maintain lamb growth.

Pregnancy toxemia, or twin lamb disease, is a common metabolic condition affecting ewes in late gestation, particularly ewes carrying two or more lambs. Because lambs are relatively large in proportion to ewes, the digestive organs have to move around to make space for the lambs. This largely affects the rumen, by artificially making it smaller. This presents as reduced feed intake. Ewes work hard to grow lambs, and late gestation is a period of high energy and protein demand. High energy demand coupled with reduced feed intake can reduce the total nutrients available to the ewe. As such, late gestation diets should be highly concentrated in energy and protein to ensure delivered nutrients to the ewe are sufficient to carry the pregnancy to term and deliver healthy lambs.

Lambing is a complex process that continues after the lamb has been born. Ewes need to pass the placenta, have their uterus return to a pre-pregnant state, and begin lactating all at the same time. Mineral and vitamin status is critical during this period, as deficiencies in trace minerals can create a host of problems including retained placenta, milk fever, and magnesimic tetany, among others. Feeding a high quality mineral during this period can help prevent metabolic disorders.

Breeding is where the production cycle begins, and a successful breeding season can set producers up for a profitable finishing period. There are multiple techniques that can help improve breeding success.

Proper body condition score (BCS) is one of the most important factors for breeding success. BCS measures energy reserves (mainly backfat thickness) in the ewe, and indicates their plane of nutrition. Ewes should be fit, not fat during breeding season. On a 5 point scale, target between 3.0 and 3.5 during the breeding season. Over conditioned ewes will have trouble becoming pregnant, increasing second and third cycle pregnancies thereby extending the lambing phase. Body condition scoring is a subjective measure, and to maintain consistency a scoring chart should be used. A BCS scoring guide available from Alberta Agriculture can be found at https://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex9622/$FILE/bcs-sheep.pdf

Nutritional flushing is a technique that elevates plane of nutrition during breeding season to improve ovulation. Ewes are fed excess energy to ‘prime the system’ approximately 2 weeks prior and 3-4 weeks after ram turn-out. Energy status is one of the most critical factors in reproductive success. Using a flushing program can help with overall conception rates, as well as conception at first service, meaning lambs are born earlier and have more time prior to slaughter to put on body weight. Flushing is more effective with older ewes, and can present a significant increase in lambing rates.

Minerals (particularly trace minerals) play an important role in fertilization and embryo implantation. A good mineral program should be used year-round. Trace minerals are heavily involved in successful breeding and one of the most cost-effective ways to improve production outcomes.

Rams are 50% of the breeding process, ensuring ram breeding soundness can improve conception rates. Rams should be fit, not fat. It is normal for rams to lose condition over the breeding period. Rams starting the breeding period too thin will only get thinner. Target 3.0 – 3.5 BCS for rams.

The grow/finishing phase of lambs consists of 2 main objectives: develop frame, and deposit muscle and fat mass. This requires high energy, so grow/finishing rations typically have increased levels of grain/starch to provide energy for growth. Rations will depend on desired gains; ensure growth targets are being met through the grow/finishing phase so lambs are at weight when marketed.

High grain, high energy rations take time for the rumen to adapt to. Switching directly from a high\ forage diet to a high grain diet can cause digestive upsets and reduce feed intake, reducing gains and potentially causing health issues. As such, a gradual increase in the grain portion of the ration should be used to give time for rumen microbiota to adapt to the change in feed source.

Processing grain exists to reduce particle size, and to increase energy availability from fed grains. However, lambs will typically chew their cud sufficiently to break up any grains present in the ration, reducing the necessity to process grain for lambs. A good method to evaluate grain digestibility is to look at the manure; whole kernels present in the manure indicate incomplete digestion. That being said, grains can also be digested, and only have the hull pass through the digestive system. If grains are seen in the manure, be sure to check if they are empty hulls or whole undigested grains.

Urinary calculi are a common issue seen in finishing sheep, particularly ram lambs. Urinary calculi (or kidney stones) are accumulation of calcium in the bladder of sheep caused by excess calcium and phosphorus in the diet. One method to help prevent urinary calculi is to include a dietary acidifier in the grow/finishing ration. Dietary acidifiers (such as ammonium chloride) decrease the pH of urine, helping to prevent formation of urinary calculi and can be an effective strategy to prevent problems with urinary calculi.