Production records can be used as follows:
Production records point out the large differences in ewe productivity, lamb gains, and adjusted 60-day weights that can exist with a flock (Tables 1, 2, and 3).
Without some sort of production records, it is difficult to determine if progress is being made in flock improvement. Such factors as weaning weights, fleece weights, lambing percentage, and percentage death loss have a direct effect on income and profit from the enterprise.
The importance of production records is very evident from the research carried out at the University of Wyoming. Results indicated that good progress can be made in increasing lambing percentage by selection. The Wyoming study used only western white-faced ewes (with no Finnish Landrace breeding). The primary purpose of the study was to evaluate the progress that can be made toward increasing the proportion of twin births in the more widely used and readily available breeds by selection for an extreme (triplet) birth.
Only triplet-born sires were used in the project from the 1970 breeding season to the end of the project. The results of this study are presented in Table 4.
Records can be very simple or quite complex, depending on the needs and goals of the producer. Some producers say that they do not have time to keep records; but you really cannot afford not to take the time. Why guess about the overall productivity of your flock or of individual ewes when there is a more accurate way of figuring things?
Probably the simplest record system for commercial sheep producers is that of ear-notching lambs at birth, using a coding system for type of birth in one ear and week of birth in the other. This helps evaluate lambs for size and weight on the basis of their approximate age and type of birth. It does not, however, identify lambs with their mothers or with specific sires.
Ideally, all ewes and lambs should be permanently identified so you can evaluate each ewe's production and each ram used in the flock. Lambs should be weighed at weaning time and their weights adjusted to a standard age such as 60, 90, or 120 days. Weaning weights should also be adjusted for sex, age of dam, type of birth, and type of rearing. Recommended adjustment factors are given in Table 5.
After weaning, you may want to feed all the ram lambs together or by sire groups and determine average daily gain for the next 40 to 60 days. If the lambs are fed by sire groups, you could check for differences in feed efficiency as well as in average daily gain among sire groups. The average daily gain for this postweaning period is more highly heritable than gain from birth to weaning, because you have eliminated the influence of the ewe's milk production.
Although very few people obtain yearling weights on rams and ewes, those are important data because yearling weight is a highly heritable trait and strongly related to growth rate from weaning to traditional market weights. If you are breeding ewe lambs or using ram lambs to breed with, or both, then 6- to 8-month weights may be more meaningful to you.
Fleece weights are also part of a total evaluation program and should be obtained for each breeding animal in the flock. You should also obtain carcass information on some of your lambs to determine whether you are producing desirable meat-type lambs.
Copies of three manual production record forms are included in this publication. Permanent records can also be maintained with the use of computers. Producers without their own computers can obtain computerized production records through the National Sheep Improvement Program or from some of the land-grant universities (e.g., North Dakota State University). Producers with access to a personal computer can purchase one of several commercial software packages which have been developed specificially for sheep records.