Supplementation: When, What, & Why?
Have you ever heard the saying, “Ignorance is Bliss!” For me, that statement is quite accurate for supplementing sheep and goats on pasture. If you are comfortable with your supplementation strategy or lack thereof and don’t want to confuse things, stick with what you’re doing. But if you are looking to refine your supplementation strategy, the answer will not come easily.
There is an abundance of research on dietary needs of sheep and goats at various stages of production. Plus, there is an abundance of research and information on diet quality of feedstuffs. Therefore, we can strategically design diets for animals in a pen and on full feed. But, when we attempt to feed animals on pasture, it is difficult for a rancher to accurately know what the pasture diet quality and daily intake is. Consequently, it is almost impossible to strategically design a supplement that is exactly what the animal needs.
Okay, lets back-up for a minute. We can be more certain about when and why to supplement. We know that diet quality in the pasture is poor when grasses, weed, and browse are dormant. So during the winter or after periods of drought, supplementation is more likely to be needed.
Plus, we know that when the flock/herd is in late gestation or lactation or animals are young and growing, their demands for dietary energy and protein are much higher than during maintenance and early pregnancy. So these periods are when we need to pay more attention to animal health and pasture conditions.
And we know that we can use body condition scores of the livestock as a guide to know if they need supplementation. Animals in good to great condition can afford to lose a little weight without major losses in performance; whereas, low body condition animals are at much greater risk of having health issues.
Okay, we have evaluated the situation and have decided that the animals need some supplementation. Now what do we use as a feedstuff to supplement? In beef cattle, the most common supplement is cottonseed cake. It is high in protein, which is often the limiting factor for cattle. Supplementing with cake will increase dietary protein, which will increase the digestibility of low quality grass and the amount eaten.
Sheep and goats are different from cattle because they are more selective about what they eat. Sheep do not consume large quantities of low quality grass as cows do and goats eat even less grass than a sheep. Sheep will spend a lot time seeking out weeds and other higher quality feed in the pasture. Goats are browsers and will consume more brush than sheep. In both cases, the diet of sheep and goats in the pasture is likely going to be higher in protein than that of cattle. So it is less likely that protein supplementation will increase pasture utilization in sheep and goats as it may cattle.
This is not to say protein may not be needed. Sheep and goats have higher protein requirements during lactation than beef cattle, when they are nursing two or more offspring. However, this requirement is for only a short period of time (60 days or less). If the ewe or doe is in good body condition they can mobilize protein from muscle. Some lean tissue weight loss isn’t a bad thing, as long as they don’t lose too much weight. I am comfortable with 1 condition score loss from birth to weaning, which equates to around 15 pounds for the average ewe.
If they don’t need supplemental protein, what do they need? From my experience, the most likely limiting factor is energy. Dietary energy can come from a wide variety of feedstuffs. Ruminants are designed to generate energy from the fibrous component of plants. Highly digestible fiber sources, such as wheat middlings, are good energy supplements; whereas, lowly digestible fiber sources, such as cottonseed hulls, are poor energy supplements. Grains, such as corn and oats, are good energy supplements; however, they must be fed carefully. Too much grain can cause an imbalance in the rumen and create digestive upsets. Supplements high in protein, such as cottonseed meal, are good supplements but expensive compared to energy supplements. Supplements high in fat, such as whole cottonseed, are good supplements, though they can cause digestive upsets if total diet exceeds 8 percent fat. Most pelleted feeds have a combination of all of the above. Plus, pelleted supplements typically have added vitamins and minerals.
Logically, the most economical energy supplement is going to be the least-cost supplement. To calculate, divide the cost per pound of the feed by its energy content. Unfortunately energy content is not included on the feed labels. It must be estimated based on the feed ingredients or sent off for testing.
Most often, grains are the cheapest source of energy. Currently, whole corn ($150 per ton) is going to cost 7.5 cents per pound; whereas, pelleted protein supplements at $300 per ton are going to cost 15 cents per pound. Switching to corn can cut supplemental feed costs. But not everyone can get access to corn at this price. Note that “deer corn” is often sold at much higher prices than commodity corn, which could negate the cost savings. Corn is also lower in protein and may not be the best supplement during lactation or to growing animals.
Whole cottonseed is another feedstuff that is a relatively cheap energy supplement. Currently, it is priced at $200 per ton, which equates to 10 cents per pound. Cottonseed is high in protein, fat, and fiber. The high fat content can cause digestive issues but shouldn’t be an issue if fed at a rate of ½ pound per day. The biggest disadvantage of whole cottonseed is transportation. You normally have to get a truckload of it and it is bulky to deliver to your livestock.
Supplementation is a complicated topic. Too complicated to cover in one article. Next month, I’ll discuss more about supplementation of sheep and goats.
To provide feedback on this article or request topics for future articles, contact me at reid.redden@ag.tamu.edu or 325-653-4576.