The effect of dam age on ewe offspring productive performance and efficiency

摘要

The objective of this study was to determine if dam age (i.e., being born to a ewe-lamb vs. mature adult ewe) affected the productive performance and efficiency of singleton ewe offspring to four years of age. Live weight was recorded every two monthsfrom birth to four years of age for singleton ewe progeny born to either ewe-lamb dams or adult ewes (ewe-lamb progeny: ELP, n = 20; adult-ewe progeny: AEP, n = 25). The number of lambs born and weaned, and weight (kg) of lamb born and weaned were determined for each ewe for each productive year and as a combined total. Ewe production efficiency was calculated for each year and as a combined total. Results show that AEP were heavier at birth and remained heavier until one year of age (P<0.05). Live weight was again greater (PO.05) for AEP in mid-pregnancy in 2010 and at weaning in 2011. The number of lambs born and weaned and the weight of lamb born and weaned per ewe did not differ in any of the three productive years or for the combined total. Ewe production efficiency was not affected by dam age, with similar efficiencies reported for ELP and AEP. The results from this study show that despite experiencing a weight penalty, the productive performance and efficiency of singleton ewe progeny born toewe-lamb dams, if conventionally bred themselves as 18 months of age, appears to be similar to that of singleton ewe progeny born to mature adult ewes.