The great goat rush slowed last year with numbers in the Midwest reaching a plateau of sorts. In Missouri goat inventory hit about 92,300 head in 2011, down a bit from the year before. Of those, meat goats accounted for some 80,000 head and milk goats, 11,000 head. Throw in a few angora and you match the total. But prices still show demand, and so we should revisit some of the challenges you’ll find in feeding small ruminants.
Abrupt Ration Changes
One recurring cause of health problems in small ruminants is the abrupt change in amounts, ratios or ingredients of rations. By nature, goats consume a wide variety of forages and browse. Goats have faster metabolisms than cattle, and they tend to eat more often than cattle. Therefore, in theory, a large concentrate meal once or twice daily is unnatural and makes smaller ruminants more susceptible to metabolic diseases. However, in practice I see less incidence of bloat and founder in goats than I see with cattle. Any ruminant is sensitive to ration changes—because any ruminant can change intake faster than the rumen microbial population can change. Thus, we need to change rations no faster than the rumen microflora can change.
A rapid shift to a high-grain ration may cause enterotoxemia, cause animals to refuse feed, or induce diarrhea or other digestive upset. As a rough rule, one can increase grain feeding by 5 percent a day.
Enterotoxemia, or overeating disease, is one of the most commonly occurring and most costly diseases. Enterotoxemia is best prevented by making ration changes slowly and gradually. While toxins produced from bacteria that are inherent to the ruminant digestive tract cause the disease, the disease is associated with high concentrate feeding and abrupt dietary changes. Changes in the rumen environment cause type C and D to reproduce rapidly. When this happens, the bugs “bloom”. Often, the faster growing, better-doing, most aggressive eating animals are affected. Hence the name “overeating disease.” In addition to making ration changes slowly, you should follow the vaccination schedule of the herd veterinarian.
While forages often provide the base for small ruminant production systems, hay and pasture quality and quantity will vary greatly from year to year and even from field to field. Forage species, fertilization program, dates of harvest and storage method have a great influence on forage quality. It is nearly always advisable to test conserved forages to determine the nutrient content. Grass samples will range from 4 percent protein to 24 percent. TDN can vary from 25 percent to 75 percent. Given the variability, it is a shot in the dark to develop supplementation programs without forage analyses.
Accumulation occurs in forages when the uptake of soil nitrates continues even as plant photosynthesis, carbohydrate and protein synthesis cease. Factors that contribute to the accumulation of nitrates in plants include drought, frost, low light intensities, low temperatures, soil nutrient deficiencies, excess nitrogen fertilization and some plant diseases. Nitrates will accumulate to varying levels within the plant with the lower stalk containing the highest concentrations. When conditions exist that may lead to accumulations of nitrates in forages, forages should be tested for nitrate concentrations. Testing should be performed before the first use of the forage to avoid potential problems. Plants use the nitrate as a nitrogen source, so plants will always have some nitrates. The goal is to ensure that there are not too many nitrates. Nitrates in the entire diet lower that 0.4 percent are considered safe.
Lack of a proper mineral/vitamin supplementation program is a fundamental challenge. Salt, or sodium chloride, is still offered as the only mineral supplement in countless situations. The mineral content of forages varies greatly by season, by year and area. Forages will always be short of iodine and sodium. They will likely be short in selenium, copper and zinc. In dormant forages, phosphorous will be short, and in early growth forage will be magnesium-short. A complete mineral is a good means of providing vitamins A, D and E. Offering white salt as the only source of mineral supplementation tends to make a herd susceptible to nutritional deficiencies. These nutritional deficiencies are often subclinical; they tend to go unnoticed and unrectified.
Mineral deposits form in the urinary tract and are referred to as uroliths or urinary calculi. These deposits occur in all animals. But, a blockage of urine flow occurs most often in wethers and to a lesser degree, intact males. The blockage and subsequent build up of urine will cause the animal to strain and gaze skyward. The bladder might burst, aside from being unpleasant and fatal for the animal, this dents your profitability. The condition is more common in feedlot conditions where the phosphorous level is high while salt and calcium levels are low. In range conditions, the situation is common where the silica content of the diet is high. Using a balanced ration, ensuring adequate water and using a balanced goat feed will help prevent incidence of urinary calculi.
Providing a continuous supply of fresh, clean water and adequate trough space will help assure performance and productivity. Many factors influence an animal’s water intake: stage of production, environmental temperature, salt consumption and ration moisture content. Figure on 0.75 to 1.5 gallons of water daily per goat as a rough rule. Inadequate water intake will result in decreased dry matter intake, reduced ADG, increased susceptibility to disease and a general lack of thrift.