Increasing Lambing(Conception) Rates
When it comes to lambing, we all know it’s more profitable to have twins than a single. But did you know there’s a method by which the ewes are fed a higher percentage of protein around ovulation that has been proven to increase lambing percentages?
Proper nutrition is essential for optimizing reproductive ewe performance. When ewes are given an elevated intake of nutrition in the weeks before being exposed to a ram it is called flushing. Flushing often increases ovulation, conception, and embryo implantation rates (1). Lambing rates can easily increase by 10%-20% and even higher depending on multiple factors (1).
A New Zealand study on flushing found that feeding 1 kg [2.2 pounds] of grain to ewes for three weeks before breeding resulted in a 25% increase in ovulation (1). By feeding 0.5 kg (1.1 pounds) of grain for 6 weeks before breeding resulted in an ovulation rate of 30% (1). Continuing and increased nutrition intake for four weeks post breeding will help reduce early embryo loss which are often connected to poor nutrition (1).
While the results of this study are promising, it’s important to gradually increase the grain given to the ewes to help prevent acidosis. Acidosis, or grain poisoning, occurs when an animal with a rumen consumes a large quantity of grain which ferments in the rumen due to the release of carbohydrates rather than being digested (3). The overload on volatile fatty acids from the grain consumption lowers the rumen’s PH preventing the rumen from working properly (4). While increasing grain feed, be sure to watch the sheep closely to identify any cases of acidosis. Sheep that have acidosis will be off feed but may pretend to eat, have diarrhea, become dehydrated, look depressed, lie down more than normal or during abnormal times (when other sheep are eating), be bloated, and may die (4). We offer our flock free-choice baking soda (sodium bicarbonate) when feeding grain. The addition of free-choice baking soda to the sheep’s diet allows the flock to balance their rumen as needed.
One factor to consider is the body condition scoring (BCS) of each individual ewe. If you have an average body condition score of 3, they may only need to be flushed for three weeks prior to breeding, whereas ewes with body conditions lower than 3 may benefit from the additional nutrients six weeks prior to breeding. Ewes with a higher body condition score of three or greater may not see as much benefit, as their system is not jumpstarted greatly by the influx of nutrients. The target body condition score of each ewe should be between 3.0 and 3.5 on the 1-5 scale. Greater results are seen when flushing outside of traditional, breeding times. It is also interesting to note that there is no correlation between flushing and ewe lamb lambing rates. As ewes mature, there is a greater ovulation effect from flushing.
How much value does flushing add to an operation and is it worth the cost of feed and time? The traditional breeding months are between October and November (2) when the days start getting shorter. Some ewes regardless of the breed can and are capable of breeding all year or out of season but generally the natural breeding season is in the fall. It may not be worth flushing in fall months, because the benefits are not as high. To determine cost, take the number of ewes (ewes) and multiply it by the number days on feed (days) and multiply that by feed amount (lbs/day).
For example: 10 (ewes)x70 (days)x 1.1(lbs/day)=770 lbs of feed.
Multiply the pounds of feed by the cost of feed and add the labor cost for an estimated time it will take to feed each day. We are able to get a 15% cracked corn, soybean meal, and distillers dried grain mix for $350 a ton. Which comes to $0.175 a pound. When multiplied by our example 770lbs x $0.175 results in $134.75 or $13.47 per ewe.
(Pounds of feed)x(Cost of feed)+(Hours to feed)x (Hourly rate/wage)= Total Cost
The calculation will result in an overall cost figure. Now take the ewes average birth rates and multiply it by 10-25%, I generally stay on the conservative side.
(Number of ewes)x(Rate increase)x(Average sale amount per lamb)= Gross Profit
Example 10 ewes x .25 lambing rate increase x (75 lbs lamb x $2.00 per pound = $150) = $375
Multiply that number (the estimated additional lambs you will have, if you flush) by the average sale amount per lamb. Subtract the total cost of feed and time and you have determined whether it is worthwhile flushing your ewes.
(Gross Profit)-(Total cost)= Total gain or loss
Some factors that come into play here are the amount of time you have to feed every day and to obtain the grain. Do you have a place to feed the ewes, like a trough or some sort of surface they can eat off of? A way to haul the feed and then store it?
Each farm needs to decide whether the outputs justify the inputs. For us, and when we breed, we feel like it is beneficial to flush our ewes. It allows us to optimize our lambing rates while keeping a smaller flock.
References
