Nutrition for small ruminants begins before birth – ideally with a properly nourished dam – followed by colostrum shortly after birth. The goal of good nutrition for small ruminants is to establish and maintain a healthy digestive system, especially the rumen, for health and maximum lifetime production.
Dr. Jessica Garcia, large animal internal medicine veterinarian at University of Tennessee College of Veterinary Medicine, explained how the rumen changes over an animal’s lifetime. But before the rumen takes over the primary digestive work, the abomasum is where most nutrient uptake and digestion occurs.
“The esophageal groove is a special adaptation that closes due to suckling and certain chemical stimulations from the milk,” said Garcia. “When those reflexes are stimulated, the groove shunts milk into the abomasum. In the first few weeks of life, the abomasum is where most of the nutrient uptake and digestion occurs. As the animal gets older and develops a rumen, microbes produce VFAs (volatile fatty acids), the number one source of energy for ruminants.”
Rumen development relies on butyrate and propionate, two of the three VFAs, which are important for rumen papillae development. While hay is important, hay alone won’t provide enough of a “scratch” factor to result in a well-developed rumen. Ideally, a young small ruminant consumes milk first, then milk and grain, followed by hay.
Ruminants are considered pre-gastric fermenters, with the abomasum acting as the gastric compartment. “There are advantages and disadvantages to being a pre-gastric fermenter,” Garcia said. “One advantage is the animal develops microflora of microbes and fungi and protozoa, which produce VFAs for energy. Microbes are doing all the work. The animal can also digest protein and nitrogen more efficiently.”
However, stressful events such as illness or grain overload can result in rumen dysbiosis (an imbalance in bacterial metabolic activity). This results in poor nutrient absorption and a variety of health issues.
“The rumen doesn’t absorb oral medications well,” said Garcia, explaining rumen dysbiosis. “Think of the rumen as a big vat of fluid, fiber and microbes, and with anything that goes in, there’s a dilution effect.” Because of the dilution effect, oral medications are not readily absorbed in the rumen. This limits medications suitable for oral administration.
Small ruminants have highly mobile tongues and lips, which allows efficient forage grazing. Sheep are grass and roughage grazers and tend to prefer higher quality portions of the plant. Goats are active foragers and select more highly digestible portions of grasses. Goats also browse woody plants and are willing to explore more challenging grazing locations such as steep, rocky areas.
Forage-based herbivores require about 1.5% to 2% of their body weight in forage throughout the day in a maintenance level diet. Breeding animals require higher energy intake to avoid losing weight and body condition score (BCS). Diet increases should be made gradually to avoid rumen dysbiosis.
Pet and geriatric goats don’t require much, if any, grain. Since wethers have lost the testosterone that helps dilate the urethra, stones resulting from a grain-heavy diet can cause a urinary obstruction.
Ewes and does require adequate energy, especially during last few weeks of gestation when the majority of fetal development occurs. “Seventy percent of fetal growth happens during that period,” said Garcia. “Inadequate nutrition can result in poor colostrum production and contributes to low birth weight and lower energy reserves in newborns.”
Ideally, females should have a good BCS prior to giving birth. Too much grain toward the end of pregnancy can result in pregnancy toxemia. Overfeeding can lead to difficult births. Pregnant females should be on a higher plane of nutrition during the last several weeks of gestation to ensure energy density requirements are met both pre- and post-kidding or lambing.
Making sure kids and lambs receive colostrum – or colostrum replacer – early in life sets them up for success later. Photo by Courtney Llewellyn
For neonates, colostrum is the ideal first feeding. It’s rich in essential nutrients and immune factors such as IgG, which neonates require to jump start their immune system. Toward weaning age, which ideally occurs at eight to 12 weeks, young animals gradually transition from milk to a forage diet. Lambs or kids on pasture will have already started to graze or browse as young as one week.
When possible, young animals should be weighed regularly to check for consistent weight gain. Any decrease in weight can indicate poor mothering, a poor start, an incorrect bite such as parrot mouth or illness.
Nearly everyone who raises sheep or goats has dealt with orphans. Orphan lambs or kids can be hand-reared when necessary, with colostrum for the first feedings. Colostrum replacer can be used to supplement or replace colostrum. Garcia recommended feeding colostrum replacer for newborns for several days.
“It’s nutrient rich,” said Garcia, explaining the importance of colostrum and/or colostrum replacer. “It has vitamin E, which is good for nervous system health, and has higher protein and immunoglobulins. Even though immunoglobulins aren’t being absorbed from the gut to the bloodstream, they’re still actively working in the lumen of the gut. Replacer also has laxative effects.”
While she sees some small ruminant owners feeding milk to orphans at birth, Garcia said any colostrum with IgG is better than no colostrum.
The IgG level in colostrum replacer should be at least 14%. Neonates should receive 10% to 20% of body weight in colostrum (or colostrum replacer) within the first 12 hours of life. When transitioning from colostrum/colostrum replacer to milk replacer, the goal should be feeding 20% to 25% of body weight.
“Start slowly so the gut isn’t overfilled,” said Garcia. “Smaller, more frequent meals are better because that’s closer to their physiological normal and may reduce risk of disease.” She added that protein and fat in milk replacer should each be 20%.
Consult a knowledgeable nutritionist for feed rations, and work with your veterinarian to manage any issues due to nutrition deficits.
by Sally Colby
Leave A Comment