Page 23 - WCA Ketch Pen August 2020

Cow BW and BCS for the winter supple- mentation study are presented in Tables 2 and 3. We found that winter BW and BCS score changes were similar to those observed in our previous protein supplementation studies and those conducted by other researchers. The cows that were weaned early were heavier at the start of winter grazing. Cumulative BW losses from the start of winter grazing until calving tended to be greater for the cows that had their calves weaned at 115 day of age. Interestingly, the cows that had calves weaned early had greater final BW. These results in- dicate that when cows have their spring-born calves weaned at the traditional time in the fall, feeding to meet the NRC requirements results in performance comparable to cows with the calves weaned early. When we com- pared the HIGH vs LOW supplementation levels, cows on the HIGH treatments gained more BW during the period from Novem-
ber 14 to January 7. They also tended to
lose less BW than the LOW treatments
from November 14 to calving. We really focused in on the possibility that the BW
and BCS gained during the summer from early weaning could result in protein supplement savings. We compared the NWHIGH cows (calves weaned at 220
days of age) to the EWLOW cows to determine if the increase in weight gained from early weaning would allow producers
to reduce the amount of protein supple-
ment required to support cows in adequate BW and BCS during the winter through calving. In the first period of the winter grazing season, NWHIGH had greater BW gains than EWLOW. The cumulative BW losses from the start of winter grazing to calving were about 44 lbs greater for the EWLOW cows than the NWHIGH cows. When we looked at final BW at calving, we noted that there were no differences between NWHIGH and EWLOW, which indicates that cows with early weaned calves that started winter grazing with greater BW were able to use the weight they had gained to their advan- tage and have good body weight at calving.
Winter BCS changes were also similar
to previous studies. Cows with early weaned calves had approximately 0.9 greater BCS than the normal weaned cows. The early weaned cows lost more BCS than the normal weaned cows during the winter until calving.
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Ketch Pen
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August 2020