J.C. Clay*, S. Moore+, R. Moore+,
R. Wheeler+, and W.P. Shulaw++
*Department of Animal Sciences,
+Eastern Ohio Resource Development Center, and
++Department of Veterinary Preventive Medicine
In an attempt to lower certain input costs, both fixed and variable, outside lambing starting on April 15 was compared with inside lambing starting on January 1 at the Eastern Ohio Resource Development Center for three years beginning in 1989. This paper has to do with integrating those data with experiences and observations of investigators and shepherds, some of whom are individual farmers who are trying the practice. Input costs that were specifically targeted include labor, buildings, and concentrate feed. The commencement date of outside lambing should be specific to each farm. Site of lambing is critical, as well as ewe preparation prior to lambing; the amount of shepherd intervention at lambing; and the timing and methods of tagging, docking, and castration.
Definitions suggest that buildings and inside lambing equipment can be eliminated in terms of investment costs, taxes, and repairs. Depending on the amount of shepherd intervention at lambing, we experienced much less labor. Ewes were allowed to do what many say they do best. In fact, we suggest that when shepherds are thinking about designing an outside lambing management plan, they should be cognizant of hours of labor per ewe per year. Another way to view this plan might be dollars generated per hour of labor and management. In either case, eliminate unnecessary tasks!
We have observed that when given a good outside lambing environment (more on what that is later), one of the major benefits is that it promotes a reliance of ewes' natural instincts of selecting a specific lambing site and executing mother/offspring acquaintance and bonding. Also, when there is a low stocking rate, lambing on pasture offers a clean environment for the newborn. At EORDC, there was a tendency to have a higher drop rate by spring lambing ewes than by winter lambing ewes. Also in this study, a greater percentage of spring lambing ewes had successful pregnancies than did winter lambing ewes.
Disadvantages of outside lambing include less shepherd control. For anyone with vast barn lambing experiences, this can be stressful. If a ewe truly needs help, then catching or corralling her can be difficult. Drastic weather conditions can cause increased lamb mortality. At EORDC, outside spring lambing resulted in a higher lamb mortality rate than inside lambing during winter. April or May lambing could compete with critical times for other farm enterprises.
Lambing dates must be farm-specific, but generally, earlier (April 10 or so) lambing results in:
In the Mid-Appalachian region, somewhere between April 10 and May 15 should be considered for initiation of the lambing season, depending on each farm's lambing site and elevation. Over the years, you may test, learn, and adjust these dates accordingly.
In selecting a lambing site, the site should possess 1) a heavy, well established, multi-specie sod that is on well-drained soils, 2) natural breaks from various wind directions, 3) natural and man- developed predator discouragements, such as electric fence or easy visibility of open areas, 4) access for easy observation of the entire flock, 5) as square or round as possible, 6) sufficient pasture to set stock for 20 days at the proper stocking rate, 7) a good water supply, 8) easy access to a handling facility, and 9) sufficient shade, if any (limited shade promotes piling up of sheep and accumulation of feces and urine).
The proper site is extremely important. When the role of the shepherd in outside lambing is considered, it may be as simple as providing the proper environment for the ewe flock to be successful at lambing time.
Ewes should be in good to excellent body condition. If an appropriate date to start lambing is selected and the pastures are properly prepared (fertility, sod density, and proper plant species), then it is almost impossible for a ewe to be in poor condition. A good health program that includes internal parasite control, as well as a breeding program that considers easy fleshing ability, are important.
Ewes should be shorn prior to lambing so that they more easily can right themselves, especially during late gestation with multiple lambs. Also, they can be more mobile, and shearing will encourage ewes to seek shelter when lambing in harsh rainstorms or wind conditions. Shearing should occur about 2 weeks prior to the start of lambing. Depending on the lambing date, a quarter inch "stubble" might be left on the body.
Very few ewes will be observed having their lambs, and it has been our experience that dystocia has been very low. One caution: A breech presentation can go unnoticed until it is too late. As discussed earlier, you should protect your ewes from severe winds by selecting proper lambing sites and protection from predators. Also, allow them space and time to "mother-up" and bond. You should intervene only when there is a problem, such as a breech presentation, or if other serious lambing problems exist. Observe lambs' body conditions after a few days. If there are twins or triplets that are poor, then pulling one lamb to raise as an orphan will help. It is difficult to have sufficient nutrient density in forages for ewes to yield sufficient milk for triplet lambs while maintaining her body condition. When lambs are restricted on nutrients, they have less body condition and are more susceptible to severe weather conditions and disease. Over time the sheep management system must strike a proper balance among forage quality, milk yield, easy fleshing abilities, and drop rate.
If a ewe needs to be caught, a lariat may help. It has been our experience that by riding a horse, the shepherd can move through the flock quietly and place the lariat over the ewe's head more easily than without a horse.
Check the ewes as often as needed, but make sure that your presence or help does not have a negative result. Young ewes will need closer and more careful observation. Weather conditions will influence the frequency of observations but remember ewes prefer to be left alone during lambing.
Tagging at or near birth has the potential to cause abandonment of lambs, especially by ewes with multiple births; therefore, the shepherd's ability to handle this situation is critical. If exact parentage is not paramount, consider tagging at birth only those lambs whose exact parentage will result in a positive result for the flock, such as in the selection of ram or ewe replacements. Does exact parentage knowledge of lambs to be slaughtered have returns sufficiently above the costs? Each shepherd will need to answer this question for his operation.
When has a great deal to do with how! With outside lambing, labor savings are possible, should be a goal, and must be considered in developing a strategy for these operations. Reducing human intervention during ewe/lamb acquaintances and bonding periods should be kept at a minimum. If these operations are going to be done in the field, then they must be done shortly after birth during the acquaintance/bonding process, because lambs become very difficult to catch later. In some cases, this time period may be as short as 6 hours. Any kind of intervention this soon after lambing can be viewed by the ewe as an attempt to predate.
Data from the 3 years at EORDC suggest that when ewes are bred during the short-day season of December, they "breed-up" very quickly. This trait was measured in terms of the number of days of ram exposure before the ewes were bred. Assuming a 17-day estrous cycle, a 145-day gestation period, the ram introduction date, and the lambing date of each ewe, we found the ram days to be around 10.5 for the 3-year period. If all ewes had bred within the first 17 days and the above assumptions were true, then that number would have been 8.5 ram days (winter lambing ewes without prior introduction of a teaser ram was around 22 days). Almost 90% of the lambs were dropped after 20 days into the lambing season.
From these data and experiences, we suggest moving ewes and lambs to a working facility for processing 20 days into the lambing season. If there were lambs dropped that day, be careful! Some ewes will prefer to stay in the pasture, so allow them to do so. Some ewes will be so gregarious they will choose to go along with or without their lambs. These ewes must be handled with great care, and their lambs must be brought with them in some manner. Be aware of the amount of time ewes are separated from their lambs.
Some hints in moving and handling ewes and lambs for this process are:
You will need to repeat this operation 20 days later after the remaining lambs are born and another dose of dewormer is scheduled to be administered.
If all lambs are to be slaughtered, is it really necessary to tag them? The only benefit of tagging is to identify ewes that are not performing. But we have found that barren ewes and ewes with extremely low milk yield can be identified easily and culled without tagging lambs. Tagging increases costs, labor, and stress on lambs and only can be done successfully shortly after birth.
It is a different case with lambs from mothers of replacement rams and ewes where parental identification is important to the breeding program and consequently to the flock. If parental identification is necessary, it must be done quickly after birth when lambs can be caught. However, be careful in intervening with the acquaintance/bonding process. Keep this group of elite ewes to a minimum. Low ewe replacement rate aids in reducing the percentage of elite ewes.
Ear notching to indicate year of birth might be a good strategy to employ on ewe or ram replacements so age can be determined at a quick glance while sheep are coming up the single file run in the handling facility.
Outside lambing offers an excellent opportunity to Mid-Appalachian shepherds for reducing costs of lamb production. Outside lambing can be successful if 1) lambing season is timely for your farm, 2) lambing site provides ewes with a good lambing environment, 3) ewes are in good condition, and 4) shepherd intervention is done with care.