Wednesday, July 15, 2020

17 Days Into the Study

Katahdin ram lambs were delivered to the research site on June 15. On June 26, the lambs (n=79) were allocated to treatment groups based on weight, age, type of rearing, and fecal egg count:  PASTURE (n=40) vs. SUPPLEMENTED (n=39). The first weighing was July 6. Due to poor performance and wide variations in gain/loss, the lambs were re-assessed on July 13. The next working will be on July 27.

Each group is grazing 4 paddocks (5 acres)
For the first 10 days of the study, PASTURE lambs (n=40) lost an average of 0.034 lbs. per day. The median ADG was only 0.040 lbs. per day. Forty percent of the lambs; (n=16) lost weight. The large standard deviation (0.401 lbs.) is indicative of a wide variation in performance. The SUPPLEMENTED lambs (n=39) gained an average of 0.189 lbs. per day, but also had a large standard deviation (0.376 lbs.). Thirty-one percent (n=12) of the supplemented lambs lost weight.

We attribute the weight loss/poor performance to lack of acclimation. While the lambs had been grazing, the composition of their  pasture was considerably different than the pastures being used in the study: mostly grass vs. a lot of clover. On July 6, almost 37 percent of the lambs (n=29) had positive dag scores; some, high. A dag score (0-5) refers to the quantity of fecal material on the back side (tail, breach, and legs) of the animal. The younger lambs were most likely to have positive dag scores. There were more positive dag scores in the PASTURE group than the SUPPLEMENTED group: 19 vs. 10.

When the lambs were assessed again on July 13, considerable improvements were observed, especially in the PASTURE group (n=37) , which responded with robust gains. Since the last weighing, the lambs in the PASTURE group gained an average of; 0.929 ± 0.315 lbs. per day. The median ADG was 0.914 lbs. per day. No lamb  lost weight. Lambs in the SUPPLEMENTED group (n=38) gained less: 0.509 ± 0.331 lbs. per day. The median was 0.486 lbs. per day. Only one lamb in the study lost weight between July 6 and 13.

Supplemented lambs (n=38)
For the first 17 days of the study, ADG has ranged from -0.071 to 0.824 lbs. per day and averaged 0.362 ± 0.202 lbs. per day. The median gain is 0.376 lbs. per day. As a result of the recent weight gains, the lambs in the PASTURE group are out-gaining the SUPPLEMENTED lambs:  0.400 ± 0.191 lbs. per day vs. 0.325 ± 0.209 lbs. per day.

So far, internal parasites have not been a problem. No FAMACHA© scores above 3 have been observed. A couple of lambs with FAMACHA© scores of 3 have been dewormed. Body condition scores declined during the first 10 days of the study, but have since improved. The average BCS is 2.9 ± 0.4. Dag scores improved between July 6 and July 13.

Each group of lambs is being rotationally-grazed among four paddocks with similar forage quality and quantity. Forage samples are being collected. The lambs are currently grazing the 3rd paddock in their respective 5-acre systems. The supplemented lambs are currently receiving approximately 0.65 lbs. of barley per head per day. This represents less than 1% of their average body weight. The barley is being gradually increased until it reaches 1 lb. per head per day (slightly more than 1% of body weight.

Both groups have access to the central laneway. There is a roof structure that provides shelter/shade. It also covers the handling system. Water troughs and mineral feeders (n=2) are available to each group. High temperatures may also have contributed to the poor performance of the lambs in the first 10 days of the study.

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Katahdin Day in Western Maryland