Author: Dr. Susan Kerr, WSU-Klickitat County Extension Director
Publish Date: Winter 2013Pregnant animals have a few very i
The start of care for a pregnant animal should begin well before gestation even starts. Animals need to have an acceptable body condition score (neither too fat nor too thin) to be able to cycle, conceive and support a fetus. This means that producers must have an appropriate nutritional program in place for their breeding herd.
Small ruminant producers typically “flush” their animals by increasing the plane of nutrition for two to four weeks before and after breeding to encourage the production and release of multiple eggs, which produces more twins and triplets. Providing grain, feeding higher quality hay or turning animals into a reserved lush pasture are all effective approaches to flushing.
After animals are bred and confirmed pregnant, few management changes are needed until the last third of pregnancy. In the first two-thirds of pregnancy, animals should be encouraged to exercise and graze to help them stay healthy, wear down their hooves and prevent obesity. Animals can be sorted into groups and fed accordingly if changes in body condition scores are needed during this time.
During the last third of pregnancy, the fetus(es) finally make(s) an impact on the mother’s nutritional requirements. Pregnant animals need more protein and energy to support the growth of a normal, healthy fetus. In some cases, a pregnant animal’s additional nutritional requirements can be met by simply feeding more of the current ration.
If animals are already consuming their maximum amount of dry matter possible each day, however, a more nutritionally-dense feedstuff will have to be added to or substituted for the current ration. Examples of more nutritionally-dense feedstuffs include high-quality hay, protein concentrates or energy concentrates. Remember to make all ration changes gradually.
Dr. Rodney Kott, Montana State University Extension Sheep Specialist, reports that ewes carrying singles in late gestation need 50% more nutrition than in early pregnancy and 75% more if they are carrying twins. The National Research Council’s current recommendations for a 1,172-pound beef cow in late pregnancy include 13.9 megacalories of net energy per day and 672 grams of metabolizable protein per day. Compare these figures to daily recommendations for non-lactating, first trimester pregnant cows of 8.9 megacalories of net energy and 436 grams of metabolizable protein and you will note a 55% increase in requirements in late gestation for beef cattle.
Energy requirements also go up as the thermometer goes down. For every one degree drop in temperature below a critical temperature (20°F is often used), an animal’s energy demands increase by 1%. This is because additional energy is required to maintain normal body temperature. If this energy isn’t provided through feed, animals will need to call on their body fat reserves.
If pregnant animals are underfed, they will be in poor body condition when they give birth and begin lactating; milk production will be significantly reduced. They will also be slow to start cycling again. Underfed animals may also give birth to lightweight and/or weak offspring. In small ruminants, the dam may be unable to support twins or triplets and one or more may die in utero.
Special attention should be paid to pregnant immature animals. Pregnant doelings, ewe lambs, heifers, etc. must be fed for maintenance, growth and pregnancy. For example, Table 1 depicts the minimum nutrient requirements during winter for spring-calving pregnant beef cows vs. heifers. Grouping and feeding pregnant youngstock separately will help managers remember to pay special attention to these animals.
Overfeeding pregnant animals can also cause undesirable outcomes: fetuses may grow too large and dams may have fat deposits and poor muscle condition that interfere with giving birth. Overconditioning also puts animals at risk of pregnancy ketosis and/or fatty liver syndrome. Fat youngstock may have reduced milk production due to the deposition of fat in the udder.
Milk fever primarily affects dairy cattle, but it can be seen in any lactating animal. This condition strikes because of the sudden demand for calcium after an animal gives birth and begins to lactate. If a pregnant animal has been on a high-calcium diet during pregnancy, her body is not ready to mobilize calcium from her bones—a process that is necessary during lactation. The sudden drain of calcium through milk makes blood calcium levels fall, which causes weakness, trembling, collapse and even death. To prevent milk fever, avoid feeding high calcium sources (e.g. alfalfa, dairy grain, dairy minerals) in the last month or so of pregnancy.
A few important tasks need to be done in the last month or so before birthing. Your veterinarian may recommend you give vitamin E/Selenium and/or other vitamin injections to pregnant animals in the last two to four weeks of pregnancy. This action helps prevent White Muscle Disease in the developing fetus and Selenium deficiency in the dam. Your veterinarian may also recommend deworming pregnant animals. Follow your veterinarian’s recommendations about which products to use because some are not recommended for use in pregnant animals. Use low-stress handling techniques as well.
Booster vaccinations are often given about two weeks before birthing to protect pregnant animals from disease and encourage the production of high-quality colostrum. Ask your veterinarian about what vaccinations to give your pregnant animals in late gestation—some vaccines are specifically developed for use in pregnant animals and others should be avoided.
Other requirements of pregnant animals include providing shelter from wind and precipitation, space and time to exercise and good ventilation. Transportation, handling and any other sources of stress should be minimized. Care should be taken when routine procedures such as hoof trimming, shearing, crutching, etc. are performed on pregnant animals; alternative handling techniques may be needed.
Prepare a clean and dry area in which animals will give birth. Remove dirty bedding and, if possible, disinfect the premises between births. Make sure the birthing area is free from drafts and doesn’t contain anything that could hurt the mother or her offspring.
As with all livestock production practices, time spent planning and preparing will reap large dividends through all the problems that will be avoided. Pay particular attention to caring for your pregnant animals—after all, you are caring for two (or more)!
For More information:
http://extension.psu.edu/courses/meat-goat/reproduction/ body-condition-scoring (goats)
www.animalrangeextension.montana.edu/articles/sheep/ Flock%20Handbook/Nutrition-1.htm (sheep)
www.vetmed.ucdavis.edu/vetext/INF-SW_CarePrax. html (swine)
www.vetmed.ucdavis.edu/vetext/INF-SH_CarePrax. pdf#search=%22care%20of%20pregnant%20sheep%22 (sheep)
www.vetmed.ucdavis.edu/vetext/INF-GO_ CarePrax2000.pdf#search=%22goat%20care%20 practices%22 (goats)