by Frederick Harper, Extension Horse Specialist, University of Tennessee
In the fall, Broodmares are often relegated to the back 40 acres. At this time, foals have been weaned, and it is too late in the year to get non-pregnant mares bred again. An exception to this situation is the Tennessee Walking Horse breed that registers foals born in October, November and December as foals of the following year.
Mares are not the major emphasis in the fall since they have performed their task of foaling, lactating and being re-bred. They will not be center-stage again until foaling and re-breeding next spring.
After foals are weaned, most breeders tend to focus on weanlings and yearlings that are being prepared for shows, sales and/or performance in the case of long yearlings.
Fall management of broodmares is far more critical than some breeders realize and can directly impact foaling and re-breeding successes next year.
Weaning. Most foals are weaned between four and six months of age. Depending on foaling date, weaning can occur in late summer or early fall. If there are several foals, owners may wait until the younger foals are at least four months old to wean all foals at the same time. On large breeding farms, weaning may occur over several weeks to accommodate the difference in ages of the foals.
Weaning has been shown to be stressful to foals. Foals average daily gain decreases after weaning. Foals rebound from the stress of weaning in 10-14 days. Mares are also stressed at weaning but to a lesser extent than their foals.
A major management factor after weaning is getting lactating broodmares dried-up as rapidly as possible. Mastitis is not a big problem in mares, but a few mares do have mastitis.
It is not advisable to milk out mares after weaning. Milking out a mare only stimulates her udder to continue producing milk and prolongs the drying-up process. By not milking out mares, the natural process will result in mares drying up more rapidly and being less stressed.
Mares’ udders will be swollen, hot and feverish. If mares are uncomfortable, owners can use camphorated oil or udder balm, commonly applied to cows’ udders, to relieve their hot, swollen udders.
It is advisable not to feed grain to mares during the drying-up process. Eliminating grain feeding of mares a week before weaning may also be helpful. Even if mares are thin, (See: Body Condition Score), there is adequate time to properly condition these mares before they will foal and be re-bred next spring.
Exercise is also important in helping the mare dry-up properly and rapidly. Mares should not be kept in stalls after their foals are weaned. Mares can be placed on lower quality pasture that requires more time to graze. Mares not fed grain or hay will spend more time grazing, thus exercising more, which aids in the drying-up process.
Pregnancy Checking. Owners can more properly manage mares by pregnancy checking them in the fall. Even mares that were pregnant at 14-18 days and at 40 days post-breeding should be reexamined now. If mares were not pregnancy tested previously, it is imperative that they are checked in the fall. Fall pregnancy checking is a wise investment and pays extra dividends in saving feed and labor cost and results in healthier foals next year. While fall pregnancy testing is always important, it is critical when fall pasture is poor, there is a shortage of good quality hay for winter feeding or feed prices are higher than normal.
Classification of mares as pregnant and non-pregnant allows owners to fine-tune their management. Pregnant and non-pregnant mares need to be managed differently in the fall and winter. Feeding is one key area. There often is a tendency to feed all mares the same type and amount of feed. Barren mares require only a maintenance ration; whereas, pregnant mares need precision-managed feeding during their second and third trimesters.
One of the major advantages of fall pregnancy checking is the identification of mares that were previously pregnant and are now barren. Barren mares are often not given proper attention until late winter or spring just before being bred. This is too late to correct some problems and get mares pregnant in the breeding season. Fall is the time to make specific management decisions and actions regarding barren mares.
Barren mares selected to remain in the breeding herd may benefit from a uterine biopsy. A uterine biopsy of the mare’s endometrium, lining of the uterus, will indicate the probability of her conceiving and maintaining a pregnancy. Mares with a Grade III biopsy are not likely to maintain a pregnancy. The best time for a uterine biopsy is in the fall after the breeding season and before mares begin transition into winter anestrus. Do not biopsy pregnant mares.
Breeders must decide whether they are going to keep or cull barren mares. Mares, 16 years of age and older decline in their ability to maintain a pregnancy. Older mares become pregnant at about the same rate as younger mares, but fewer will be pregnant at 40 days post-breeding and in the fall.
Two key factors help breeders make this decision. Is the mare an economical producer; in other words, are her foals profitable, and is she a genetically superior producer? Any mare that is not an economical producer certainly must be considered for culling. Those that produce below-average-quality foals will not contribute to a breeder’s success.
Fall pregnancy checking is important in mares that grazed endophyte-infected fescue pastures during breeding and were not pregnancy tested earlier. Mares grazing endophyte-infected fescue pastures in the breeding season have a tendency for early embryonic death.
Artificial Lights. Barren mares with high probability of maintaining a pregnancy need to be managed to have the greater possibility of becoming pregnant next year. This includes proper nutrition, body condition, health and reproductive management. It is advisable to place these mares under artificial lights in November or at least by the first of December. Artificial lights will cause these mares to come into estrus and ovulate about six to eight weeks after being placed under them. The advantage of this process is the barren mare can be mated earlier and more often during the breeding season which enhances her chance of becoming pregnant. Mares placed under light in November have one or two estrous cycles to combat infections and eliminate difficult problems before being bred.
Placing pregnant mares due to foal in March and April under artificial lights will shorten the length of their gestation by 10 days. By foaling earlier, they can be re-bred sooner in the breeding season.
Body Condition Score. Another management tool is to body condition score all broodmares in the fall. Owners cannot only separate mares into pregnant and non-pregnant groups, but also place them into groups based on their body condition score. For example, pregnant mares could be grouped as thin (BCS 4 or below), moderate (5-7) or fat (8 & 9) for proper management.
Body condition is stored body fat. Stored body fat is used later by the broodmare as an energy source for the rapidly growing fetus in late pregnancy and for milk production in early lactation. Because of the large size of the fetus, it is difficult for pregnant mares to consume adequate feed to meet both the nutritional needs of the fetus and the mare herself. The fetus has first priority over feed nutrients. The fetus makes 75 percent of its growth in the last trimester. Early lactation has a greater nutritional demand than late pregnancy.
Mares will store body fat until about 270 days of pregnancy. After which, their BCS will decline slightly as the stored fat is used for fetal growth. This decline continues into lactation, especially if the mare is a good milker. Lactating mares tend to lose body condition during the first 120 days of milk production.