Need to Know How to adjust sheep feed requirements Things you need to know about livestock production practices. LINK The information on this Need to Know card is from Virtual Apprentice 2040: Livestock1. Apply this information to the learning tasks in this inquiry topic. Nutrition exerts a huge influence on flock reproduction, milk production and lamb and kid growth. {A number of conditions require adjustments to basic feed requirements for sheep. Body condition, stages of growth and environmental conditions, such as hot or cold temperatures, can all affect nutrient and energy needs. Body condition scoring is a skill that can help you determine the nutrition levels of a feeding program for sheep. Research at different universities has shown that visual evaluation of body condition can be an accurate assessment of body fat reserves. Training and practice can help sheep owners and producers accurately evaluate body condition and make it easier to sort sheep into groups that are fed at appropriate levels. This can help save money and keep sheep in proper condition for maintenance, production and reproduction. DO YOU KNOW enough about body condition scoring? If you think you need to find out more, check out the information in Animal Health & Welfare on the Virtual Apprentice 2020: Animal Husbandry & Welfare website at www.ctsanimals.ca/va2020/ farmq2.html. LINK Watch the About feed requirements video on the Virtual Apprentice 2040: Livestock1 website at www.ctsanimals.ca/va2040/production.html for more information. KNOW HOW THE ENVIRONMENT AND COLD AND HOT WEATHER AFFECTS FEED REQUIREMENTS The maintenance requirements of sheep increase when their activity levels increase. For example, sheep traveling farther distances for feed and water will have higher maintenance requirements than those in a feedlot. Sheep grazing very hilly pastures will have higher nutritional requirements than sheep on level pastures of the same quality because they expend more energy gathering feed on difficult terrain. Weather conditions also affect maintenance requirements. In cold and severe weather, sheep require more feed to maintain their body heat. This is especially true for shorn ewes. Winter rations should be increased to compensate for the energy sheep expend to keep themselves warm. Alberta SPCA 2014 albertaspca.org Permission granted to duplicate for classroom use 1
As a general rule, increase the amount fed by one percent for each degree of coldness below zero degrees Celsius. Remember to consider wind chill when determining how much to increase the feed. Although sheep can be affected by heat stress that may result from heat waves short term hot weather patterns they tend to be less susceptible to it than cattle. Heat waves that occur late in the summer season cause fewer animal deaths because animals become acclimatized to high temperatures. Therefore, heat waves early in the summer season can have a stronger effect on health. A supply of cool, good quality water is essential to minimize heat stress. Sheep may decrease their grazing time and spend more time in the shade, especially during the hottest times of the day. They should be allowed to graze in the evening and early morning hours and rest when temperatures are at their highest. KNOW HOW FEED SHOULD BE ADJUSTED FOR SHEEP Sheep require nutrients for body maintenance, growth, reproduction, pregnancy, and production of products such as meat, milk and hair. The groups of nutrients that are essential for these small ruminants are water, energy, protein, minerals and vitamins. Specific amounts of these nutrients are required for maintenance of the body, to keep sheep warm and maintain body weight. For example, a mature wether requires the correct amount of feed for maintenance. {Growth, pregnancy, lactation and meat, milk and hair production demand additional nutritional requirements above those needed for maintenance. As the productivity of sheep is increased through selection and crossbreeding, nutritional requirements may also increase. DO YOU KNOW enough about basic nutritional needs of sheep? If you think you need to know more about dry matter intake and other nutritional terms, go to Sheep requirements for feed & water in this inquiry topic. Gestation, or the period of pregnancy, affects the ewe s nutrient demands. Feed rations must be adjusted to ensure healthy fetal growth and good milk production. In the last four to six weeks of the pregnancy, protein intake should be increased as about two-thirds of fetal growth occurs during this time. Ewes may need up to 50 percent more energy those with twins may need up to 75 percent more energy. Increased protein intake ensures that the ewe is in good condition when it gives birth. Losses of body condition, lower birth weight of lambs and decrease in milk production can occur in late pregnancy if increased daily protein or energy needs are not met. 2 Alberta SPCA 2014 albertaspca.org Permission granted to duplicate for classroom use
Milk production, or lactation, increases nutrient needs for sheep. Milk contains a high concentration of protein. Therefore, lactating sheep, particularly during early lactation, require nearly twice the daily protein of dry sheep. If milk production in the ewe is affected, the health and growth of lambs can be at risk. Most ewes will lose weight during lactation. Weight loss during lactation affects protein requirements. The more weight ewes lose, the higher their protein requirement will be. The health of lambs depends significantly on the nutrition their mothers get during the last 90 to 100 days before lambing. Inadequate energy levels during this critical period can decrease the strength of both the ewes and the unborn lambs. Inadequate nutrition can affect the ability of lambs to nurse. It also affects the natural protection provided by colostrum, or the first milk. During their first weeks, growth and development of lambs is dependent on the ewe s milk production. Lambs that do not receive adequate milk are more prone to disease and poor overall growth. Ewes that are in a maintenance period between the time lambs are weaned and about 23 weeks before breeding can be kept in good condition with pasture grazing. If ewes are kept in a confined environment, a mixture of hay and straw can provide sufficient nutrition. The ewe s body condition score at weaning can determine the amount of feed she will need. Ewes should have a body condition score of 3, three weeks before breeding begins. Weaning refers to the process of gradually introducing an infant to its adult diet and withdrawing the supply of its mother s milk. KNOW ABOUT FEED CHOICES There are a number of choices that help sheep owners and producers manage feed sources and rations. Of all the factors that affect hay quality, stage of maturity when harvested is the most important. As legumes and grasses advance from the vegetative to reproductive, or seed stage, they become higher in fibre and lower in protein content, digestibility and acceptability to livestock. It is better to alternate a day of grazing low quality pasture with a day of grazing higher quality pasture. Grazing ewes on forage that is better than their minimal needs will result in higher weights. This can affect their ability to give birth to more and larger lambs that gain weight faster. However, it can also be associated with lambing difficulties. Be careful that ewes are not kept on poor quality forage for too long, or a reduced number of lambs may be born the next spring. Winter grazing should ensure sheep have access to enough forage and be kept out of mud and standing water during wet fall or winter melt periods. Stockpiled pasture can be used for winter grazing. Stockpiling is the practice of saving certain hay or pasture fields for grazing in the fall and winter, after forage growth has stopped. Stockpiled pasture is also referred to as fallsaved pasture or deferred grazing and is one of several extended grazing techniques. The most important management factor in determining how much forage will be available for fall grazing is the summer resting date. This is the date in the summer when the animals are removed from the pasture so that it can re-grow and be stockpiled for use in the fall and winter. Alberta SPCA 2014 albertaspca.org Permission granted to duplicate for classroom use 3
Feed a minimum amount of forage to ensure a healthy rumen. A common recommendation is to feed ruminants at least one and a half percent of their body weight in forage. Never change rations too abruptly. Sheep digestive systems need time to adjust to a new diet, usually a one to two week period. This is especially true if you are changing from a forage-based diet to one which contains more concentrate, or grains that provide nutrients not available in forage. Feed grains whole. Cracking grain increases the rate of digestion and may increase the risk of acidosis. Also, it is not necessary to process concentrates in sheep and goat rations. Since forage forms the bulk of the diet by volume, weight and feeding time, efficient delivery of the forage component should be a primary goal. Decisions about forage include choosing bales or bulk hay and silage (preserved) or dry hay. Bales can be large or small and round or square. These decisions will impact feeder choices and designs as well as delivery method. Walk-though or drive-through feeders are the most time and labour efficient. KNOW ABOUT NUTRIENT DEFICIENCIES Energy is the most important nutritional factor for sheep, and can be the nutritional factor most commonly lacking due to shortage of forage. Low energy intakes can result in deficiencies that include: Maturation rates and growth Loss of body weight Lowered resistance to disease and parasites Poor conception rates. Protein can be lacking in summer and fall diets when green forage is not always available. Low protein intake can result in deficiencies that include: Reduced appetites Reduced growth rate in fetuses and lambs Loss of weight Inadequate intake of other nutrients Poor conception rates Reduced milk production in ewes. Information adapted from Sheep and Goat Management in Alberta Nutrition: Alberta Lamb Producers and "Nutrition" Virtual Tool Box: Canadian Sheep Federation. www.ablamb.ca/documents/ management-modules/sgma/sgma_nutrition_module.pdf and www.cansheep.ca/user/docs/vtbox/nutrition%20section%205.pdf 4 Alberta SPCA 2014 albertaspca.org Permission granted to duplicate for classroom use
A number of different minerals are required for growth, bone formation, reproduction and many other body functions. Those that are required in fairly large amounts are called macro-minerals. They include sodium chloride (salt), calcium, phosphorous, magnesium and potassium. Those that are required in very small amounts are called micro, or trace, minerals and include iodine, copper, zinc, sulphur and selenium. Mineral content is affected by the type and quality of the feedstuff. The addition of supplementary minerals to the ration can sometimes be necessary to make sure that adequate amounts of these minerals are provided. The type of supplementary minerals is determined by the feeds in the ration and the animal's requirements. DO YOU KNOW how nutritional deficiencies can lead to nutritional disorders and disease? If you think you need to know more, go to How to deal with pests, ailments & disease in sheep in this inquiry topic. Some Symptoms of Mineral Def iciencies Mineral Calcium Phosphorous Magnesium Sodium chloride (salt) Selenium Molybdenum Iodine Deficiency Symptoms Poor growth and abnormal bone development Staggering, nervousness Poor growth Decreased appetite Listlessness Poor conception rates Muscle tremors Staggering, convulsions, grass staggers Nervousness, excitement Poor growth Chewing or licking various objects Lack of coordination Weakness Weakness Inability to stand Copper deficiency Lameness Loss of weight Enlarged thyroid gland Weakness Alberta SPCA 2014 albertaspca.org Permission granted to duplicate for classroom use 5
Necessary vitamins for good sheep nutrition include vitamins A, D and E. Fresh forage is a good source of these vitamins. The vitamin content of well-preserved hay is initially high, but declines over time. Silages usually contain low amounts, since the fermentation process destroys most of the vitamins. Grains usually contain relatively low amounts of these vitamins. Insufficient vitamins can result in a number of different deficiencies and require adjustments to feed sources and supplements. Vitamin A is essential for normal growth and for the formation of strong bones and teeth, normal vision and cell structure, protecting the linings of the respiratory, digestive, and urinary tracts and for healthy skin. Young animals with coccidiosis, a parasitic disease of the intestinal tract, need more vitamin A because of impaired absorption. Vitamins A and E are made from compounds found in green forage. Vitamin A can be stored in the liver for two or three months after sheep have been eating green forage for several months. Therefore, when animals are eating fresh pasture, or fresh or well-made hay, no supplemental vitamins are needed. Similarly, vitamin E can be stored in fatty tissue for short periods of time. When sheep eat forage that is old, weathered, mature or low in vitamin A, this vitamin should be added to the mineral mixture. Other feeds that will result in inadequate vitamin A levels are corn silage, corn stalks and straw. Vitamin D is required for proper development of bone. Vitamin D deficiency in lambs can result in bowing of the leg bones, called rickets. In older animals, bones become weak and easily fractured. Animals that are housed indoors for more than two to four weeks, such as lambs being finished in confinement, need vitamin D in the diet. Vitamin E, along with selenium, is required for proper development of muscle tissue. Lack of vitamin E and/or selenium causes nutritional muscular dystrophy, commonly called white muscle disease. Too much vitamin E can also cause problems. Vitamin E and selenium are closely interrelated. 6 Alberta SPCA 2014 albertaspca.org Permission granted to duplicate for classroom use