[Results through Mar-Apr lambing in 2008, prepared on 26 May 2008]

Several changes have been made in management of the Cornell Sheep flock in the past three years. These have included 1) shifting from feeding day-old complete dairy cow feed remainders to the ewes in the barn to a diet of hay and self-fed concentrate; 2) providing a higher protein creep feed; 3) providing a weaned lamb feed that is based on corn and soy hulls, instead of barley; 4) increasing the vitamin E levels of the mineral supplement for hay and of concentrate feeds to the much higher levels recommended by the 2007 NRC; 5) expanding the flock size to make full use of labor resources.

The following table contains data on lambing percentages:

*Note that as of the date of this report, not all of the March-April 2008 lambs have reached 60 days of age.

Survival of lambs in the March-April 2008 lambing season was poor. Part of this was due to an increase in lambs affected with abomasal hemorrhage, a disease first diagnosed in the Cornell flock about 2 years ago. A trial to test vaccination of ewes prior to lambing against Clostridium perfringens type A is underway because it is thought that C. perfringens is the causative agent.

• Ewes lambing: 691 (197 ewes lambed twice during the year) so the annual lambs surviving to weaning per ewe was 1.64.
• Lambings per ewe in the past year: 1.29.
• Current total live lamb loss for all lambs (lamb age varies with lambing season) is 21.9%, the current live lambs of all ages per lambing per year is 1.23, and the current live lambs of all ages per ewe lambing is 1.57.

Lambings per ewe per year is much lower than the expected value of 1.67 in a perfect STAR-manged flock. But, the flock is expanding so many of these ewes lambed for the first time in past year with no opportunity - yet - to lamb again (ewe age distribution). Our flock is now at the 750-ewe size that we are hoping to maintain so it is obvious that even more yearling ewes will lamb for the first time this year.

Many annual-lambing flocks should have much higher lambs per ewe, depending upon which ewes are counted. Many smaller flocks should also have higher survival rates than those shown here. However, death losses in the Cornell flock this past year were relatively low compared with published values (see literature summary and the summary in the April 2007 issue of The Shepherd magazine of crossbred survival rates at the US Meat Animal Research Center where lamb losses of lambs from ewes lambed under intensive management ranged from 17 to 30%). One of the obvious objectives of the Cornell flock is to define management procedures to increase survival rates of lambs in accelerated lambing flocks.