Mossy Dell Farm

Breeding Objectives

Top ram lambs are sold as breeding stock in the fall

“We need to much more strenuously select for adaptability and increased fitness/self sufficiency, such that the number of man hours per ewe per year can be reduced and the number of ewes per person thereby be increased.”—Kelley O’Neill, 2004 Spooner sheep day, on managing a 1,900-ewe flock

In our breeding program we measure performance, exerting selection pressure for biological fitness and economically important traits. Our ewe lambs are selected to become efficient, maternal ewes. Our rams are bred to lift the quality and profitability of a flock by increasing milking ability, lamb survivability, and lamb growing ability while retaining prolificacy and enhancing maternal temperament. These genetically balanced qualities result in larger and heavier litters at weaning.

A National Sheep Improvement Program Flock
In 2003 we submitted two years of data (pedigree, birth dates and weights, 60- and 120-day weights), to the National Sheep Improvement Program and have submitted yearly since. The analysis by NSIP has given us EPDs (Expected Progeny Differences) that have helped us balance matings and stack milking and growing ability. Sheep with known breeding values earned in an unbiased performance program like NSIP will move your flock forward in economically important traits. Genetically balanced sheep make shepherds more money by weaning more pounds of lamb with less hassle and fewer inputs.

Using our own records and NSIP data our Katahdin sheep are selected for three primary goals, in this order:

Ewe Productivity
We select for twins plus, mothering ability on pasture, milk production, lamb survival, and growth on forage. The traditional way to gauge the success of such maternal goals was by totaling adjusted litter weights at 60 days. While still an indication of maternal performance, there is a more effective way.

In 2004 the Katahdin breed made history by being the first breed being evaluated by the National Sheep Improvement Program to have an EPD for pounds of lamb weaned. This biological index of reproductive efficiency contains more adjustment factors for the farm’s biological environment—pasture-based, in our case. It includes the ewe’s previous records and incorporates the performance of daughters and siblings on the farm, as well as relatives on other farms.

The pounds-of-lamb weaned EPD identifies ewes that are most successful at producing the most pounds of lamb in a particular environment and production system. Highly ranked ewes could be successful triplet-bearing ewes, or they could be consistent twinners with high lamb survival and growth.

This composite EPD rewards successful mothering behavior that is coupled with optimum growth and milk production. Higher prolificacy (triplets) or lower (mostly twins) can easily be selected for with other EPDs, but the ewe productivity EPD provides genetic balance that lessens the issue of “I want only twins,” or “I want lots of triplets”—and even “My ewes need more milk”—by identifying maternal success with twins or triplets. In this way, the complex traits associated with mothering ability can be identified and rewarded in balance with other important traits. It penalizes ewes that reject or lose lambs, or that lack prolificacy, milking ability, growth, and maternal behavior.

We are making fast progress in increasing our pounds of lamb weaned per ewe by identifying the most productive ewes, buying the most productive rams to go with them, and by using the superior-peforming sons of such matings in our flock.

Parasite resistance
The Katahdin is 50 percent more parasite resistant, on average, than wooled sheep. This ability to resist attack by internal parasites must be increased for reasons of economics, labor, animal health, and lamb performance.

We are among several NSIP flocks involved in the effort to identify superior rams that pass on greater parasite resistance to their offspring. This initiative involves strategic fecal collection, laboratory examination, and data submission. NSIP analysis provided preliminary, on-farm results in early 2006 that helped participants rank their rams for transmitting resistance to parasites. This project is expected to result in a cross-flock EPD as early as 2007. Very soon, this EPD will be the most powerful selection tool available in breeding Katahdins for greater and more consistent parasite resistance.

In the past three years, FAMACHA eyelid scoring has greatly reduced our traditional deworming. Soon, our breeding for more resistant sheep will reduce naturally the number of parasite larvae on pasture. In the meantime, we are managing for higher levels of larvae (by deworming very few adult sheep) to select for resistant sheep and in order to avoid the expensive and unsustainable practice of trying to kill every worm. Gastrointestinal parasites quickly adapt to wormers. Past worming practices have bred resistant worms on farms across the country, and this is becoming a serious problem.

Growth, muscling, and conformation
A lamb’s genetic ability to grow is bred in. It is an important trait and varies widely. Sixty-day growth rates are the most relevant measure in a maternal breed like the Katahdin.

Enhanced 120-day growth rates can help achieve heavier market weight faster and can maintain or increase mature size as needed. It is important to keep in mind that 120-day weights and 120-day EPDs are correlated with mature size must be used carefully in a practical, maternal breed. For some years, Katahdin NSIP flocks will be achieving "selection movement" by stacking 120-day growth—that is, lambs that grow as desired at all stages without undue influence on mature size. Eventually, we should select for average 120-day weights in order to avoid creating large, inefficient ewes.

We want ewes that have the ability and body capacity to raise twins and triplets unassisted on pasture. An efficient size for our forage-based system is 145- to 165-pound ewes, with 150- to 160-pound ewes probably an ideal size. Such ewes can produce rams of 200 to 250 pounds, depending upon the sire used.

Muscling must be selected for separately from production. It is an area that generally needs improvement in the Katahdin, but not at the expense of maternal performance or even growth rate. Maternal traits tend to be negatively correlated with large mature size and extremely heavy muscling. If needed, Katahdins can be crossed with a terminal sire breed like the Texel, Dorper, or Suffolk to produce customized market lambs.

Mossy Dell Farm is seeking moderate-framed Katahdins that thrive on pasture. We favor early maturing sheep that will lamb as yearlings in a forage-based system. On conformation, we like straight toplines, width, and shedding coats. These qualities are desirable but must not compromise ewe maternal ability. Rams are held to a higher standard on conformation than are ewes.