Both sheep and goats originated in the drier regions of the world and to this day are best adapted to thrive in dry areas. To successfully manage sheep and goats in humid areas, it is necessary to under stand how these animals react with their environment. Both sheep and goats are selective grazers rather than mass grazers like cattle or bison. They are physiologically adapted to consuming small amounts of high quality feed rather than large amounts of low quality feed. If possible, they will select only the young leaves and tender growing points of a wide variety of plants. Both species are equipped to metabolize plant toxins such as tannins to a much greater extent than are cattle and routinely select plants that mass grazers find repugnant. This adaptation is illustrated by the fact that goats have thirty percent more liver, measured as percent of body weight, than do cattle. Sheep and goats are adapted to utilizing plants different from those used by cattle and this trait gives them great value in grazing management. It must be remembered, however, that they like all grazing animals require forage that is digestible and with a proper blend of protein, energy and minerals. Far from the popular belief that “goats can live on anything” is the fact that goats are the most nutritionally demanding of all domestic animals. Goats and hair sheep can utilize and need large amounts of browse, the leaves, buds and tender growing points of woody plants, but this does not mean that they can thrive or even exist on a diet made up solely of mature oak leaves. Forage quality is primarily a function of age and goats can no more utilize senescent tree leaves then cattle can thrive on wheat straw. Attempting to hold goats on brush long enough to kill the brush is a guaranteed recipe for disaster and has been proven so by several ill-considered university sponsored research projects. It is quite possible to kill the species of quality browse plants by grazing the plants on a rotational basis using too short a recovery period but a more logical approach would be to consider the browse to be a resource and graze it correctly so that the desired balance of vegetation is achieved.
Pasture composed mainly of grass that would be very high quality for cattle is less than adequate for sheep and totally unsuitable for goats. These species need the additional minerals and unique plant compounds found in the tap rooted forbs and browse that is their preferred feed. Sheep and goats may exist on a diet of Bermuda or fescue grass but they will be nutritionally deprived and under constant stress from parasites and disease. They will also be very hard to keep home because they are smart enough to know that they are not receiving what they need and will make every attempt to go somewhere to find the needed nutrition. Stocking the land with a mixture of species in proportion with the vegetation available for each species is a proven technique to improve the productivity and stability of the land and the profitability of the operation. When all portions of the available vegetation are being utilized correctly, the amounts of nutrients being cycled is greater, the rate of cycling is faster and much more energy flows through the entire system. On an area of mixed grass, forbs and browse it is quite possible to double the amount of protein produced per acre by stocking a mix of cattle, sheep and goats as opposed to only cattle or sheep or goats.
Vegetation is sparse in dry regions so animals dependent upon the vegetation must range over larger areas then would be required in a lusher environment. Sheep and goats evolved in situations where internal parasites were at a disadvantage, dry conditions and low animal concentration, and neither sheep nor goats developed a high degree of genetic resistance to internal parasites. At the same time, many of the internal parasites that infect sheep and goats developed traits to allow them to survive with these disadvantages. Most of these parasites produce very large numbers of offspring so that even if only a small percentage survives the harsh conditions, the species will survive. The parasites also developed the ability to enter a state of reduced metabolic activity in order to survive longer outside the body of their host animal thus having a better chance of obtaining a host. When sheep and goats are moved into a humid area, the abundant forage allows for greatly increased concentration of animals and also of their parasites. This concentration along with the more favorable conditions for parasite survival brings about tremendous increases in parasite infestation. Internal parasites and the resulting loss of vigor are the number one problem of sheep and goats in humid regions. Heavily parasitized animals are much more susceptible to predators and to disease, which rank as the second and third largest problems in sheep and goat husbandry.
It requires effort on several fronts to keep parasite loads to acceptable levels anywhere but a multi facetted approach is an absolute necessary in humid regions. The conventional method of dealing with internal parasites has been, for many years, to dose the animals with some sort of toxin to kill the parasites after they have become established. A lot of different compounds have been used over the years from a copper sulfate and nicotine sulfate mixture to phenothiazine to the made for the purpose chemicals in common use today. The effectiveness of these materials varies widely as does their toxicity to man, beast and the environment. Such things as tetrachlorethylene, carbon tetrachloride, phenothiazine and nicotine sulfate are no longer used because of their toxicity. The made for the purpose vermifuges are generally less overtly toxic and are effective in killing parasites at least until they have been in use long enough for parasites to develop genetic resistance to them. In some parts of the world the economically important internal parasites are resistant to all commercially available antihelmintics and there are no effective materials available to kill parasites in sheep or goats. Even when effective low toxicity compounds are available it is not possible to control internal parasites solely by the use of antihelmintics in any but the most arid areas. When an effective de-worming agent kills all or nearly all of the parasites in an animal, antibody production stops or greatly decreases and the level of protective antibodies in the animal drops. When the animal is again exposed to infective parasite larvae the reduced antibody level allows most of the larvae to become established and the animal suffers a severe parasite infection. Another downside of most chemical wormers is their deleterious effect on dung beetles, earthworms and other beneficial organisms that play vital roles in nutrient cycling and in the reduction of parasite levels. Control of internal parasites can be achieved without toxins by adopting a management regimen that attacks the problem on a number of different fronts. An effective program for dealing with internal parasites will consist of three main parts; promotion of animal health and thus healthy immune systems, selection for genetic resistance and reduction of parasite levels in the environment. Intervention with antihelmintics should be practiced only in crisis situations and not as a routine part of animal husbandry.
The key to producing healthy animals with vigorous immune systems is to make certain that all of their needs physical, nutritional and psychological are met. The vast majority of the disease and parasite problems that afflict our animals are caused by mismanagement on our parts. It is not possible to maintain livestock in an environment that is totally free of pest organisms; infective agents are always present but healthy animals are able to resist most infection. Stress in any form weakens an animal's ability to combat the organisms that cause disease and parasitism. The source of stress can be overt as with being forced to live in their own filth, rough handling, severe climatic conditions, lack of feed, poor quality water or dusty conditions but it can also be caused by more subtle factors such as nutritional deficiencies due to the wrong type of feed, disruption of the social order or by requiring animals to behave in ways foreign to their nature. Goats and sheep are able to survive under poor feed conditions because they have the ability to selectively gather the very high quality small leaves and growing points that are not available to mass grazers such as cattle. This ability is the source of their reputation as destroyers of rangeland and they are very destructive when kept in one area for too long. In this situation, the animals will be in nutritional stress and subject to disease and parasites long before they seriously impact the vegetation. Both sheep and goats are selective grazers that take in relatively small amounts of feed and require a diet that is higher in quality than that required by cattle. In the proper conditions, both species satisfy this need by selectively grazing the growing points of mainly forbs and shrubs with some use of immature grasses. If they are forced to subsist on grass with its' lower nutrient content or mature shrub leaves, they soon become nutritionally deprived and lose vigor. In an effort to gain the needed nutrition they will graze closer to the ground and thus pick up heavier loads of parasites. To thrive both sheep and goats need access to a diverse and healthy mixture of plants, forbs, shrubs and grasses, from which to select their preferred diet. Supplementation with proper amounts of minerals, protein and energy can help but there is no substitute for quality pasturage. Recent research has shown that adding kelp to the mineral mixture has real benefits in stimulating immune system health and some producers feel that adding garlic powder, unprocessed diatomaceous earth and dried apple cider vinegar also serves the same purpose.
Stress from psychological factors can be just as damaging as stress from physical sources. Both sheep and goats have very highly developed herding instincts and become stressed when separated from the flock. This trait is so strong that mothers will often leave their newborn offspring rather than be left behind when the flock moves. No herd animal should ever be isolated from other animals and managing these animals so that the herd remains the social unit provides real health benefits. This is particularly important at lambing or kidding time and the grazing should be planned so that the animals have access to the quantity and quality of feed required without the stress of frequent moves or supplemental feeding. If animals can be kept content and stress free, many of the maladies that afflict them will disappear. An excellent practice is to set aside an area with enough quality forage to maintain the females for at least the major portion of the lambing/kidding season and to not graze this area with sheep or goats except this one time a year; it can and should be included in the grazing rotation for other species such as cattle, horses or bison during the rest of the year.
Selection pressure is one of the most powerful tools available to the livestock breeder. It is fairly easy to breed animals with higher weaning weights, more or less wool, smaller mature size or anyone of many different traits simply by mating “the best to the best”. To do this it is necessary to be able to determine to what extant various animals demonstrate the desired trait. If calves are creep fed from the time they are old enough to eat, it will be very hard to determine which cows are deficient in milk production. The same is true of parasite resistance in sheep or goats that are managed under a routine worming program. If routine worming is stopped, it will be very apparent, which animals have genetic resistance to parasites and which do not. If those animals showing signs of parasitism are culled and breeding stock is selected from those not showing damage, in a few generations it is possible to greatly increase the amount of genetic resistance in a flock. The same technique works on other traits such as foot rot, balloon teat and long toes. Even traits that show low estimates of hereditability improve dramatically in a population that is subjected to intense selection pressure for or against these traits. The advent of antibiotics and chemical antihelmintics has made it possible to save and even breed animals that in earlier times would not have survived due to genetic weakness. Good husbandry dictates that we use the materials necessary to prevent death in these animals but that we do not perpetuate the poor genetics by allowing these animals to reproduce.
If we wish to manage so as to reduce the number of parasites present in an environment, we must understand the life cycle of the pest and attack it at its' weak points. The majority of parasites are most vulnerable during that period when they are outside the body of the host animal. Most parasite eggs are shed in the spring when temperatures are warm and moisture is most plentiful so it is this period when management can be used to reduce parasite loads. The organisms are limited in the time that they can survive outside a host by the limits of their biological clocks, the amount of their energy reserves, predation by other organisms and by climatic conditions. The number of viable parasites on an area decreases rapidly with every day beyond what is required for the parasite to hatch and grow into the infective stage. One of the most effective means of reducing parasite numbers is to remove all susceptible animals from the area until most parasites have expired. Since most parasites are host specific, this method is even more effective if the area can be grazed with non-susceptible animals during the period it is empty of susceptible animals. If an area is empty of sheep and goats for 60-90 days during warm weather and grazed with cattle during that time, it will have very few if any sheep and goat parasites. The reverse is also true that sheep and goats help to reduce the numbers of cattle parasites. Tillage greatly reduces the number of viable parasites on an area and can be used to prepare a clean area with high quality forage on which to wean lambs or lamb out a set of ewes. The ability to control what areas are grazed at what periods is a necessity in livestock management but it is especially so with sheep and goats. Seven to eight paddocks through which sheep and/or goats can be rotated is a minimum number if parasite control is going to be achieved primarily through good hygiene. Special care should be taken to reduce common areas such as water lots, lanes or any other areas that are used continuously or frequently by the animals as these serve as reservoirs for disease and parasite organisms. With the ability to practice time controlled grazing the height of the forage sward can be managed so that animals are not allowed to graze forage shorter than 3-4 inches before being moved to fresh pasture. This maximizes nutritional quality for the animals while promoting vigor in the forage and also reduces parasite infection since most worm larvae do not crawl higher up than two inches on forage. A secondary benefit to good time controlled grazing is an increase in soil life, which is the basis of soil productivity and also dramatically reduces the population of pest organisms that spend a part of their life cycle in or on the soil. In humid areas, it will be extremely hard to control internal parasites in sheep and goats without the ability to plan the grazing sequence and timing through multiple paddocks and without the ability to practice multiple species grazing.
The grazing techniques, which reduce parasite levels, also help eliminate disease problems such as foot rot, overeating disease, lamb scours and any other malady that can be prevented by good nutrition, healthy immune systems and clean pasture. The same techniques also reduce the incidence of metabolic upsets such as bloat, milk fever and pregnancy toxemia by supplying forage of the proper kind and age. Poisonous plants also become much less of a problem since the animals needs are being met and they are much less likely to eat highly toxic plants. Hygiene is always important but is doubly so in humid areas where disease and parasite organisms can survive for long periods of time. Providing clean water that cannot be contaminated by manure or urine is critical and barnyards, lanes and shelter sheds should be fenced out except when actually in use. Changing the working area where lambs and kids are marked by using portable pens will help prevent diseases such as tetanus, blackleg, polyarthritis and CLA.
Setting the lambing/kidding season to coincide with good pasture and good weather goes a long way to prevent expense and loss of animals. Females that receive green pasture prior to parturition will produce and save more and healthier offspring; there is no feed of any kind that can provide the nutritional quality and balance of green pasture. Setting the breeding season so that young are born in the winter and thus big enough to utilize spring growth and wean off at heavier weights is seldom a good strategy. The females will require supplementation of some sort, death loss and sickness of both dams and young will be high and predation is apt to be high since food for predators is scarce. Loss to eagles in west Texas can be severe with winter lambing but drops to nothing with spring lambing. One ice storm in the midst of lambing season can remove any possible economic advantage for winter lambing for many years. If spring born lambs are too small to meet the market requirements, supplemental feed for them makes more economic sense then winter lambing in most situations. One of the real advantages of humid area production is that the grazing can often be planned so that lambs can be weaned onto high quality pasture and finished for slaughter on pasture alone. The secret to success is planning; humid areas offer advantages that can be exploited and disadvantages that can be over come by a well-designed production program.
Walt Davis © 2005