Our Breeding Philosophy

Our breeding philosophy is relatively simple and consists of three basic tenants. First is to define the needs of the sheep industry we wish to fill, second identify the genetics that will achieve our goals and finally shorten the generation interval.

Understanding our place in the industry... We know that not every sheep functions well under all enviroments and management systems. A seed stock producer must define the roll he wishes to play within the industry and focus all of his efforts into achieving it. At Bunker Hill Farm our objective is to breed black faced terminal sires for the heavy, lean lamb market. These rams must be hardy and tough and sire vigorous, heavy muscled, fast growing lambs that function well in both grass and feed lot scenarios.

Evaluating our sheep... The more accurate we are in defining the actual DNA that affects the traits we are looking for the faster we can make progress towards our goals. That is why we are so excited about the NSIP (National Sheep Improvement Program). This program helps us establish EBVs (Estimated Breeding Values). A "Breeding Value" describes all of the genes that affect a trait such as loin eye size or post weaning growth. We collect data on litter size, growth, loin eye and fat which are submitted to NSIP for analysis. They return estimates of the true breeding values which we call EBVs. The more accurate the estimates the faster we can make genetic change which is the main reason we take such great care when collecting  our data.

Our most Valuable asset...one and two year old breeding stock. To us the best well-kept secret within the seed stock industry is the value of shortening the generation interval. In other words how quickly can we get our newest and best genetics disbursed though out our entire flock. To us that means using our best ram lambs and breeding and retaining a high percentage of our ewe lambs each year. Getting our best genetics into production quickly is a practice we are committed to and it shows with the average age of our ewes exposed this fall at 2.6 years. Our 2014 fall breeding also consisted of using 5 ram lambs and one yearling. Using all progeny untested rams is not ideal but  using our top two or three rams lambs each year is. The challenge of using young stock in our breeding program is correctly identiflying superior genetics. Again this leads us back to the value of having accurate and extensive records which create high accuracy Estimated Breeding Values (EBVs).

susanSusan at work imputing data to NSIPManaging our Data
Over the past ten years we have collected growth data on nearly 1500 Suffolk lambs. NSIP started analyzing carcass data in 2007 and we have scanned and recorded loin eye and fat data on almost 800 Suffolk lambs in those eight years. With this amount of data we are feeling more and more confident that the judgments we make about growth and muscle are accurate predictions of true genetic value.

Growth Trait EBVs:

These are the most economical important traits offered by Suffolk terminal sires.
Birth Weight (BW): Too small = weak lambs; Too big = lambing problems; we try to stay in the middle.
Weaning Weights (WW): A great indicator of early growth. We take these weights at about 60 days of age.
Post Weaning Weights (PWW): A great indicator of overall growth. PWW EBVs are influenced by both BW and WW. We use it as our main selection criteria when selecting for growth. We  normally take these weights at 120 days of age.

Carcass Trait EBVs
The increase in direct marketing and producers selling on the grid has drastically increased the economic importance of these traits for Suffolk Terminal sires.
Eye Muscle Depth (EMD): A substitute measurement for loin eye area. EMD is the world standard for loin eye size and overall muscling. EMD EBVs are increasing becoming a larger factor in our selection criteria.
FAT: Over finished lambs have been a traditional challenge to the U.S. sheep industry. Fat EBVs give us an opportunity to match desired slaughter weights and management practices to yield grades.

maternalSuffolk ewes are relatively prolific, with breed lamb drop average at 200%Maternal Trait EBVs
While we do not put major emphasis on maternal traits we do monitor them and try to keep them above Suffolk breed average.
Number of Lambs Born (NLB): As implied in the name, NLB is an indication of ewe's twining ability.
Number of Lambs Weaned (NLW): It is one thing to drop lambs and another to keep them alive to weaning. NLW is an indication of a ewe's ability to accomplish just that.
Maternal Weaning Weight: (MWWT): Is an indication of a ewe's milking ability. The higher the EBV the more milk a ewe is capable of producing.

Carcass Plus Index
We believe in the value of indexes where several individual EBVs are blended into one economically balanced index. Carcass Plus was designed for Suffolk terminal sires and incorporates birth weights, weaning weights, post weaning weights, eye muscle depth and fat. We think that the Carcass Plus index balances those individual EBV's in a fashion that optimizes profitability to commercial producers. The Carcass Plus index has become our primary performance selection tool in our Suffolk flock.

Frequently Asked Questions:
What is the difference between Estimated Breeding Values "EBVs" and Expected Progeny Difference "EPDs"?

Many from the cattle industry and those from early sheep records are used to seeing production data expressed in EPDs. NSIP now uses EBVs as its standard. An EPD is just ½ of an EBV, as indicated in the name an EPD is concerned with the "progeny". An EBV deals only with a parent genes and only ½ of those are passed on to its progeny. Thus a post weaning wt EBV 10 = a post weaning wt EPD of 5. This web site uses only EBVs unless otherwise noted.