Summer season is over, winter is here and many of us look forward to warm spring mornings with new foals playing in the green grass. This is a good time of year to evaluate your broodmares for body condition and their feeding program.
Body condition is the single most important clue in determining nutrition when aiming for a successful breeding program. For example, I would much rather deal with an obese broodmare than a thin broodmare. When broodmares are thin, their metabolism makes reproduction a luxury she can not afford. To determine the condition of a mare, understanding and implementing a numerical body-condition scoring program is an absolute necessity. The most common scoring system uses grades of 1 to 9 where 1 represents starvation and 9 indicates extreme obesity. The ideal score for broodmares is 6 to 7. Research has shown that mares with less than a 6 body-condition score require more breedings per conception and have more embryonic loss.
Many colleges and extension offices have brochures that detail body-condition scoring. The Equine Research Centre in Guelph, Ontario, has an excellent Website that also details body-condition scoring (http://www.equiworld.net/uk/horsecare/veterinary/erc/conditionscoring.htm). Weight tapes and scales are also good tools to help monitor body condition.
The first trimester of gestation is the best time to improve body condition. This is challenging, however, because many mares are still in lactation from a previous foal, which means they demand great amounts of calories and yet will still lose weight, sometimes leading to embryonic loss. The use of high fat rations of 8 to 10 percent during lactation in addition to high-quality alfalfa hay can prove to be useful.
For obese mares, the second trimester of gestation is the best time to modify body condition. While studies have shown that obesity in broodmares has few negative effects on pregnancy and does not lead to more difficulty foaling, increased feed costs, increased stress on joints and laminitis should be concerns.
“Body condition is the single most important clue in determining nutrition when aiming for a successful breeding program.”
For many years it was thought that 60 percent of foal growth occurred during the last trimester of pregnancy. Based on this, we thought that nutrients didn’t need to be increased until the last three to four months of gestation. However, recent studies have shown that mares can gain significant weight during the second trimester, presumably due to fetal tissue growth. Because of this, mares with a body-condition score of less than 6.5 should be offered improved nutrition during the second trimester.
The last trimester is the time to prepare the mare for lactation. With a rapidly growing foal in the mare’s abdomen, there is a limited amount of space that can be available for intestinal fill, which is why any forage fed in the last trimester must be of the highest quality. The broodmare can ill afford to be consuming a bulky, poor-quality forage with the difference in nutrients to be made up in grain.
If your forages include endophyte fescue, the last trimester is the time to move the mares to a dry lot and offer alternative forages. Many managers will make this move 90 days prior to foaling, but I have been successful with removing fescue as little as 45 days prior to foaling. The toxic effects of fescue clear very rapidly from the mare.
While protein requirements increase slightly as the foal is growing in the uterus, mineral requirements increase greatly. The last three months is a good time to introduce a balanced broodmare concentrate with improved fortification. Now is the time to slowly increase the amount of grain concentrate fed to acclimate the mares’ gastrointestinal tract to the increased grain that will be needed during lactation. Do not, however, abruptly increase the mare’s grain.
Another thing to take into account is the fact that a mare’s milk is inherently low in trace minerals like copper and zinc, ingredients critical to proper bone and cartilage development. A nursing newborn must rely on copper and zinc stored in his liver, so it is important to feed minerals to the mare during gestation.
Recent interest has turned to organic trace minerals to optimize mineral deposition. Most manufactured feeds are made with mineral salts such as copper sulfate and zinc sulfate. These are called inorganic minerals and do not bind as well to amino acids and peptides and will not be absorbed the way organic minerals are. Because of this, the ingredients of your feed should contain organic minerals such as copper proteinate, zinc proteinate or zinc methionine and investigate products that offer organic minerals sometimes called chelated minerals. These feeds usually cost a little more, but they are a good investment nutritionally.
In some circles, bran mashes are often given to mares late in gestation and after foaling. I am not a proponent of this traditional practice because any abrupt changes in feed of any horse will increase the risk of colic. After a mare has just gone through the stress of labor, why would you want to make a profound dietary change? In my opinion, the best equine laxatives are high-quality hay and water.
“After a mare has just gone through the stress of labor, why would you want to make a profound dietary change?”
For weaning broodmares kicked back out to pasture, finding adequate vitamin and mineral nutrition can be another challenge. While they may be able to maintain their body condition on pasture, what is their mineral status? Offering a free-choice mineral supplement to these mares is an excellent practice. Loose salt and mineral products fed free choice are far superior to trace mineral blocks because blocks are only 2 percent mineral and horses do not lick as well as cattle. While free-choice loose minerals in a pasture require more management, the mares will be able to bridge any forage-based nutritional gaps.
After you’ve scored body conditions and designed a maintenance program for your mares, group your thin mares and feed them accordingly. The same goes with your heavier ones. Evaluate the minerals in your broodmare ration and consider feeding free-choice loose mineral-salt products year-round. Lastly, scout around and purchase the highest quality forages. By providing adequate calories and minerals to your broodmares, you are on your way toward your goal of healthy happy foals romping in spring pastures and mares that are fit for the next season.