Flexible reproduction still has a seasonal pattern

A June 1995 USDA Agricultural Research Service report describes a three-year experiment begun in 1989, in which groups of St. Croix ewes were bred at different times of year. The researchers investigated whether the breed’s reproductive flexibility could support sheep production in the southern United States.

Results were not uniform throughout the calendar. The report describes substantially lower lambing percentages after April and May breeding than after several other breeding periods. Therefore, calling a breed less seasonal does not mean that every month gives an identical reproductive outcome. Place, weather, animal condition and management remain relevant.

The same report summarizes earlier comparisons showing greater resistance to nematode parasites than Dorset sheep under the studied conditions. Those specific comparisons are evidence about the experiments, not an assurance that all St. Croix sheep are parasite-free. Its discussion of the shedding hair coat also explains a practical distinction from wool breeds: fleece shearing is not the same regular production task. Historical research is most useful when its conditions and limits travel with its results.