Increased Pasture Profits through South African Dorper Sheep

PROJECT BACKGROUND
We operate a family farm consisting of 140 acres of pasture and woodland (40 acres of cleared pasture) in the rolling hills of west central Minnesota. For the past 2 years we have rotationally grazed sheep on our pasture and worked with the Minnesota Department of Natural Resources on managing the woodland acres of our farm as a renewable timber resource and wildlife habitat. Additionally we also have a half acre vineyard planted with ~280 vinifera grape vines and sell these grapes for wine production. The vineyard was in part funded by a previous Minnesota State Sustainable Agriculture grant (1993).

PROJECT DESCRIPTION AND RESULTS
The goal of this grant is to determine the economic effect and feasibility of introducing South African Dorper Sheep genetics into a pasture based farm flock.

Due to the prohibitive cost of Dorper Rams (~$5,000/ram), we chose to utilize Laparoscopic Artificial Insemination (LAI) of our ewes with Dorper Rams semen as an alternative means of introducing Dorper genetics into our flock. Ten polypay ewes were synchronized with synchromate B implants which were introduced subcutaneously into the ears of the sheep at our farm. The ewes were then transported to Elite Genetics, Waukon, Iowa where the implants were removed after a period of ten days by individuals at Elite Genetics. Estrus was detected using a vasectomized ram and the ewes bred by LAI on 11/21/97. At the same time at our farm in Minnesota, ten additional ewes were bred to our own foundation ram who is 75% Polypay/ 25% East Freisland. Out of the LAI group, 8 of 10 ewes lambed between 4/10/98 and 4/16/98 producing 18 live lambs (one ewe had 3 very small deformed lambs that were euthanized). The Polypay-bred group lambed from 4/12/98 to 4/25/98 producing 18 lambs.

Lactating ewes in both groups were fed again and an alfalfa/grass hay mix for about 2 weeks until they went on pasture. Once the ewes were on pasture, no further grain supplement was given except for free choice mineral. Lambs were weaned early (July 25th) due to lack of rain and slow pasture re growth in July and August. Normally we leave the lambs on the ewe until approximately September 1st. After weaning, the lambs were confined in a feed lot and fed ad lib alfalfa/grass hay mix until November 1st. from November 1st through January 4th lambs also were fed ½ pounds of grain per head along with ad lib hay. This departure from out original grant proposal criteria of only feeding grass/hay to the lambs was necessitated by a need to get the lambs to slaughter weight as soon as possible.

Lambs were slaughtered (5 cross bred Dorper and 5 polypay lambs) on January 6th, 1998 at North Dakota State University, Fargo, ND, and carcasses were evaluated by Dr. Paul Berg on January 7th, 1998.

Results:
The first notable difference between the two groups of lambs was that the ½ dorper lambs are more vigorous at birth. They seem to have a much stronger “nursing stimulus”. They are much more active and aggressive when they want to nurse. The poor ewes with triplets were swarmed. Birth weight comparison between the two groups demonstrated no significant advantage with regards to the Dorper crosses. Weaning weights of the ½ dorper lambs appear to be about 10 lbs heavier except for the triplet lambs. The ½ dorper lambs also appear to grow faster after weaning as well and yielded a better carcass.

Discussion:
We were pleased with the results of the Dorper cross lambs. Due to the lamb vigor at birth, increased growth rates, and an improved carcass, we think the Dorper has a place as a terminal sire in our flock. It will be interesting to see how the Dorper cross ewes perform this coming season.

Our future plans include the LAI of the 50% Dorper ewes next season and to continue to upgrade the % Dorper in these Dorper crossed ewes in subsequent seasons until we reach 87-95% Dorper from which a ram lamb will be chosen for a terminal sire. While this particular tract will take 2-3 years to reach the desired genetic make up, it will reduce the cost of attaining this type of animal and will produce a small nucleus of dorper ewes from which future rams can be attained once the flock is closed.

OUTREACH
We advertised our farm field day in two of the local papers (The Pelican Press-Pelican Rapids and The Daily Journal of Fergus Falls) for two weeks prior to the field day. The day of the open house (February 27th) dawned rainy and cold which may, in part, be due to the poor (nonexistent) attendance. Additionally, many of the local producers of sheep undoubtedly involved with lambing out their own flocks during this time of year as well. For whatever reasons, no one showed up for the field day and he roast lamb which was prepared for taste testing was enjoyed by our family for the next few days. There was no discernable difference in taste between dorper cross and polypay lamb they were both delicious.

We plan on submitting a short article for publication in one or two of the local papers for publication in the near future and a copy of this report will also be forwarded to the local Extension Service office in Fergus Falls.