Michael Metzger, Michigan State University Extension Educator (Previously published on MSU Extension, Sheep & Goat: August 6, 2018)
(Image Source: Sheep 101.info)
Increasing the level of nutrition for does and ewes 2-3 weeks prior to and 3 weeks into the breeding season can improve kid/lamb crop in some instances.
When managing a goat/sheep herd farmers are always looking for ways to improve their herd, increase production and raise profitability. One way that a farmer can accomplish this is to implement flushing into their breeding practices. Flushing is a temporary but purposeful increase in the level of nutrition around breeding time. This is done to boost ovulation, conception and embryo implantation rates. Flushing may also increase the proportion of females that exhibit estrus. Flushing can increase lambing and kidding rates by 10-20 percent. This is important because a flock’s lambing/kidding rate is one of the primary factors influencing profitability. Flushing works best in mature females, at the beginning and end of the breeding season and in out-of-season breeding programs. After the first month of gestation, the level of nutrition fed to bred ewes and does can then return to maintenance levels until late gestation, when fetal development begins to place significant demands on the dam.
No benefit is seen in animals with excessive Body Condition Scores (BCS’s) or during the height of the normal breeding season. Overly thin animals also do not respond to flushing. Does and ewes that are maintained in very good condition on relatively high levels of nutrition throughout the year are less likely to respond to flushing.
To flush, producers supplement breeding animals with good quality hay, fresh pasture or grain for two weeks before and two to four weeks after breeding. Most literature pertaining to ewes recommends starting to flush two weeks before breeding; whereas literature pertaining to does recommends starting three to four weeks before breeding. During flushing, producers should focus on increasing the amount of energy fed to ewes and does. Typically, producers feed one-half to one pound of grain per head per day, during the flushing process, grain should be added gradually to the diet. A key component in this practice is making sure that adequate bunk space is available for the herd. If this is not done there is a potential for some animals getting too much grain and others not getting enough, which will negate any effort that has been put into flushing.
As farmers are evaluating the practice of flushing they need to look at the make-up of their herd and resources available to them. Farmers can start by identifying animals that may be the most suitable for flushing by looking at the BSC. BCS at breeding should be between 3.0 and 3.5 on a scale from 1 to 5. It should be noted that it takes three weeks on an increased level of nutrition to increase a BCS by one half-score. When looking at the resources available, if farmers do not want to increase their feed costs by adding grain to the diets, pasture can be set aside in advance so that it can be used for flushing. It is best not to use legume pasture for flushing as fresh alfalfa, clovers, birdsfoot trefoil and other legumes contain estrogen-like compounds that can interfere with estrous cycles.
When used correctly flushing can help a producer increase the production of their herd and in-turn expand their profit margin. The expectation from implementing this practice is an increase the kid/lamb crop by 10-20 percent. When this happens, the first lamb or kid can help a producer break even and each additional lamb or kid can help the farmer turn a bigger profit. Utilizing the flushing practice when managing your herd can make a positive impact in the size of the kid/lamb crop and assist with growing the herd size.