Changing Supplementation Frequency May Impact Cow Weight and Body Condition Score
This article is a summary of the 2016 Kansas Agricultural Experimentation Station Research Reports: Vol. 2: Iss.1. “Effects of Altering Supplementation Frequency During the Pre-Partum Period of Beef Cows Grazing Dormant Native Range.” C.J. McMullen, J.R. Jaeger, J.W. Waggoner, K.R. Harmoney and K.C. Olsen were collaborators on this research study and report. The report is summarized by Aaron Berger, Nebraska Extension Beef Educator.
Dried distillers grains with solubles (DDGS) is a common protein supplement for cows that are grazing dormant low quality forages. Previous research studies have shown no difference in cow body weight or body condition score by supplementing the same total amount either daily, once every three days or once every six days. Reducing the frequency of feeding from every day to once every three or six days can reduce feeding expenses.
Prior research of supplementing cows consuming hay with DDGS once every six days indicated that on the day cows were fed supplement there was a lower number of cows consuming hay during the 60 minutes after the supplement was fed as compared to hay fed cows that were fed DDGS supplement daily. If cows are consuming less total forage during the day following a delivery of a large amount of supplementation, this could be impacting total organic matter intake. From these observations, it was decided to study the effect of changing the frequency of supplementation being fed to cows during the last 28 days prior to calving to determine if this would impact cow performance. It was hypothesized that more frequent daily supplementation during the last month of gestation may increase the total amount of organic matter intake and thus improve cow performance.
A total of 238 pregnant Angus cows were used in the study over a two year period. Cows were grazing dormant native range for 88 days prior to calving. For the 88 days prior to calving, the cows were stratified by age, weight and body condition score randomly into four groups.
- The first group (D1) consisted of cows that were fed 2.60 lbs. per head per day on a dry matter basis of DDGS daily throughout the 88 day trial.
- The second group (D6) consisted of cows that were fed 15.6 lbs. per head of DDGS every six days on a dry matter basis throughout the 88 day trial.
- The third group (D1-D6) consisted of cows that were fed 2.60 lbs. per head per day on a dry matter basis of DDGS daily from day 1 through day 60 of the trial. Day 61 through day 88 the cows went from being fed daily to being fed 15.6 lbs. of DDGS once every 6 days.
- The fourth group (D6-D1) consisted of cows that were fed 15.6 lbs. per head of DDGS every sixth day on a dry matter basis from day 1 through day 60 of the trial. Day 61 through day 88, the cows were then fed 2.6 lbs. per head per day of DDGS on a daily basis.
When results from the two year study were analyzed, there were no significant differences between body weight gain or body condition score for the first, second and third groups. However, for the fourth group (D6-D1), which was the cows fed DDGS every sixth day from day 1 through day 60 and then fed DDGS daily for the last 28 days, there was a difference in cow body weight and a tendency for a difference in cow body condition score. The first three groups of cows gained on average 106 lbs. while the D6-D1 group only gained 81.2 pounds. The first three groups had an average body condition score on day 88 of the study of 5.8. The D6-D1 group of cows had an average body condition score of 5.6
In summary, supplying the same amount of DDGS supplement to cows as infrequently as once every sixth day resulted in similar cow performance during the 88 day study. These results are consistent with prior studies that demonstrated protein supplement can be feed as infrequent as once a week without negatively impacting cow performance. However, switching the frequency from every sixth day to daily during the last 28 days of gestation in this study decreased body weight gain and body condition score when compared to their contemporaries. It is important to point out that cows were still gaining body weight and were in good body condition at the time of calving. Producers delivering fiber based protein supplements to cows grazing low quality forages may be able to reduce the frequency of supplementation to as infrequent as once very sixth day without impacting cow performance.
Interviews with the authors of BeefWatch newsletter articles become available throughout the month of publication and are accessible at https://go.unl.edu/podcast.