AVERAGE DAILY GAIN: EVALUATING ITS USE IN GOATS
Average Daily Gain (ADG) is a significant factor in assessing growth rates in most food animal species. Why is ADG important? The producer wants faster growth so that the animals achieve market weights in the shortest amount of time using the least amount of input/cost so that the highest price can be received. In most livestock species, the most cost-efficient (optimal) feed conversion and the highest average daily gain are the primary factors determining efficiency of production.
As a measure of production, ADG is less important in meat goats at this point in the industry's development than it is in other livestock species for reasons cited and analyzed in this article. The factors described below have more impact on goats and their ability to gain weight rapidly than they do on cattle or sheep.
Goats are primarily foragers/browsers, instinctively eating as high off the ground as possible to avoid parasitic worms. When forage/browse is poor, production factors such as weight gain are equally poor. Goats cannot be successfully feedlotted in the same manner as cattle and sheep because (1) pushing them on grain products often results in grain-induced illnesses such as ruminal acidosis, enterotoxemia, bloat, laminitis/founder, and urinary calculi, (2) goats cannot handle the stress that crowding in feedlots produces, frequently becoming ill or dying, resulting in economic loss, and (3) weight gain beyond that which goats can readily convert to muscle (meat) goes to produce fat that layers under the skin and around internal organs (like deer) rather than marbling fat as cattle do. Feedlotting as it presently exists was developed for cattle and sheep to provide uniform products year-round and focuses on consumers' preference for grain-fed rather than grass-fed meat; the seasonal demand for goat meat is one of several factors that negatively impacts current feedlot programs.
Goats inherit the ability to gain weight from their dams and sires. From a genetic point of view, the heritability for weight gain, although high, is somewhat less in goats than in other food animal species. The ability of goats to efficiently convert forage material to meat is
important because most goats have not been genetically selected for efficient conversion of forage/browse into muscle/meat as have cattle and sheep. Instead goats have been selected on other primarily body appearance (phenotypic) traits. To be successful, feedlot conditions for goats must be different from that provided for other ruminants. Careful management is required to prevent the conditions and illnesses mentioned above.
Producers raising goats to sell for meat cannot routinely afford to feed processed grains at the present time. This is because feedlot conditions for goats are not common enough to make it worthwhile for producers to pursue genetic selection of goats for efficient grain conversion to meat. Fat deposits in cattle and sheep are desirable in those markets, but fatty goats are not what today's markets demand.
Goats need to feed themselves on forage/browse except during periods of bad weather conditions in order to be profitable meat animals. This is as true of breeding stock as of their slaughter offspring, because these traits transmit from sires and dams to their kids.
Commercial herd sires should always be top-quality producers so that maximum production traits are transferred to their offspring. Because many does are kept as replacement breeding stock and few bucks are retained, over time the collective sires contribute much more than one-half of the gene pool, making the buck significantly more than one-half of the entire herd.
Consumers of goat meat are largely ethnic groups whose demand changes at different times of the year and is often based upon religious beliefs and traditions. Beef, pork, and poultry producers have successfully introduced value-added items such as prepared dishes, lunch meats, weiners, jerky, and sausage to create year-round demand for their products. Ethnics who eat goat meat prefer
fresh but they will buy frozen if fresh is not available or is deemed too expensive to purchase. They do not eat any value-added products. This is a very price-sensitive and culturally-based market. The price obtained for goat meat is seasonal and dependent mostly on supply and demand throughout the year. Complicating this situation is the fact that seasonal demand for goat meat does not correlate positively with the time that live goats are most plentiful to sell for meat consumption.
Most goat breeds cycle into heat when the days begin to shorten -- third week of June to third week of December in the northern hemisphere. (The Myotonic breed -- which is normally aseasonal -- breeding throughout the year -- may experience cycling-into-heat limitations in some locations under unique conditions.) The highest prices for goats occur when demand is greatest between
Thanksgiving and Christmas and prior to Easter (roughly November through April) compared with the supply of goats of the desired size and type. Producers must get their does to cycle into heat no later than March to produce offspring to sell at the peak pricing of the Fall market (allowing five months' gestation and three months until weaning). This timeframe is completely counter to the
months when most female goats normally cycle into heat. In the south, southeast, and southern Atlantic seaboard parts of the United States where many goats are currently being raised, the summers are too hot and too wet to permit pregnant and lactating does to remain healthy and newborn and young kids to grow well. Parasites are a life-threatening problem, the dams' milk production may be diminished, and kids have difficulty maintaining their body temperatures. It takes excellent management to select for genetically-adapted female goats that will cycle in the spring and kid in the fall so that the producer can take advantage of the higher fall/winter prices. Further, it is difficult to utilize winter forage/browse to make sure that does produce enough milk so that their kids grow well. Late-summer forage often lacks enough nutrients to promote growth in the kids.
Many producers kid in the spring when forage/browse is plentiful to eat and winter is over. Weaning takes place in early summer when the supply of goats is highest and goat-meat prices are lowest. Even kids with high average daily gain (ADG) who are born in this timeframe will be ready for market in the early part of the lowest price cycle or the producer will have to hold them over until the beginning of peak pricing time in November, hoping that they have not gained too much weight. Either scenario costs the producer extra money and lowers his profit margin.
Kids are the referenced market in this article because kid goats are a huge part of goat meat sold for human consumption. Historically the best prices for goats have been received for weaned kids weighing 25 to 60 pounds liveweight. A kid with high average daily gain (ADG) is worth more than a low or moderate ADG kid only if it can be sold before it gets too heavy. If a high or moderate
ADG kid reaches more than 60 pounds at an undesirable marketing time, that kid is worth less -- not more -- at meat sale. The successful producer will breed later and grow the kids for a shorter period of time. Knowledge of the average prices paid throughout the year is essential for calculating if, when, and how to alter normal breeding seasons. Example: If the maximum price paid for a
60-pound kid is $1.20/lb., then the gross income would be $72.00 per kid. If the kid is grown to 70 pounds and the price per pound drops to $1.05/lb., then the gross return is $73.50 per kid. In this example, while growing the heavier kid is not a loss of gross income, it will likely result in a net loss to the producer when he takes into account how much additional forage/browse or supplemental grain was needed to add that extra ten pounds to the kid.
Goats are not efficient converters of processed grain to weight gain. Seven pounds of grain produces one pound of weight gain. Determining average daily gain on a diet of forage/browse is how most producers measure the ability to grow fast. This does not factor in the cost of that gain, so the producer needs to determine the amount of consumable digestible nutrients available on the land,
compute the cost of producing these plant materials, figure out how to measure the amount of forage/browse consumed per goat, and calculate the cost of the average daily gain at the same time as calculating the ADG.
Forage/browse and land costs must be factored into cost of gain in a forage-based system. Any type of grain supplement, even creep feeding provided prior to weaning, skewers the results obtained when using average daily gain (ADG) to determine or predict growth in a goat and its ability to pass that trait to its offspring. Different breed types and crossbred goats will perform differently on different blends of forage/browse/grain supplements in different locations under differing environmental conditions. Refer to my article on Adaptability and its importance in successfully raising meat goats on the Articles page at www.tennesseemeatgoats.com. Results will be more favorable when market time coincides with historically highest market prices if the producer has been able to get the does to cycle off-season.
Even though growth rate is highly heritable (0.4) in goats, for ADG to have any significant effect, both sire and dam must have very high ADG numbers or transmit a genetic tendency to gain weight to the offspring. Genetically speaking, the offspring will receive from its parents only the average of the sire's and the dam's ADG. The odds of inheriting the tendency to gain more than this average are the same as inheriting a tendency to gain less. Genetics can be very much as "crap shoot."
Fertility, body conformation, muscling, sound body structure, tolerance of internal parasites, hooves that aren't prone to hoof rot/hoof scald, and an easy-going nature are arguably as or more important than average daily gain in goats for specific producers, depending upon their location and marketing circumstances. Although goat producers would like to distill down to a single trait the definition of a fast-growing quality meat goat, these complex and unique animals currently defy such categorization. Goats are not "little cattle" and their similarity to sheep ends with the word "ruminant." Goats behave more like deer in how they eat, live, and react to stress. Relying solely on average daily gain doesn't work with meat goats at the present time. The cost of gain per day is the more significant number for the producer.
This writer thanks Dr. Ken McMillin, Meat Scientist at Louisiana State University-Baton Rouge, for providing the data that supported this writer's analysis of ADG in goats and for reviewing this article for accuracy. Additional thanks go to Dr. Lou Nuti, Reproductive Biologist at Prairie View A&M University near Houston, Texas, for reviewing this article and for coining the phrase "cost of gain per day."
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