Altering supplementation frequency of dried distillers grains
Effects of feeding pregnant beef cows prior to calving
By Justin Waggoner and Jason Warner
Supplementing pregnant cows grazing dormant forages with protein is a well-established management practice that is recommend to decrease body weight loss and maintain cow body condition. However, supplement delivery is one the largest expenditures for forage-based beef cattle operations. Decreasing the frequency of supplementation has the potential to reduce the costs of labor and fuel associated with supplementing cows.
Previous research has shown no difference in body weights or body condition scores of cows supplemented with dried distiller’s grains daily, once every three days, or once every six days. Cattle producers often increase supplementation frequency to daily immediately prior to calving, to make locating newly born calves easier. Are there any additional benefits to increasing supplementation frequency prior to calving? What is the effect of altering supplementation frequency immediately prior to calving?
These questions were addressed in a Kansas State University study conducted at the Agriculture Research Center in Hays, Kansas. McMullen and colleagues (2016) evaluated the effects of altering supplementation frequency of dried distiller’s grains during the last 28 days of gestation on performance of spring-calving beef cows consuming low-quality dormant native range.
Experimental proceduresPregnant Angus crossbred cows (n = 238; age = 6 ± 2.5 years; initial body weight = 1362 ± 123.9 lb; initial body condition score = 5.7 ± 0.03) were maintained on dormant shortgrass native range (sideoats grama, western wheatgrass, blue grama, Japanese brome, and buffalograss) for 88 days until the onset of calving.
Cows were stratified by age, weight and body condition score, and assigned randomly to one of four treatments:
Dried distiller’s grains fed daily (D1)
Dried distiller’s grains fed once every 6 days (D6)
Dried distiller’s grains fed daily for the first 60 days and then once every 6 days for the remaining 28-day period (D1-D6)
Dried distiller’s grains fed every 6 days for the first 60 days then daily for the remaining 28-day period (D6-D1)
Treatments were initiated 100 days prior to expected onset of calving. Dried distiller’s grains with solubles were delivered and stored in bulk for use throughout the duration of the study.
Cows were sorted daily into treatment groups and supplement was delivered at 8:30 a.m. into a bunk for consumption. Only one set of bunks was available; therefore, on days when multiple supplement treatments were fed, each group was given one hour to consume the supplement before being moved out of the feeding area. Cows were allotted 28 linear inches of bunk space each.
Supplement intake was prorated to supply 0.79 lb crude protein per cow daily (2.58 lb dried distiller’s grains in year 1 and 2.60 lb dried distiller’s grains in year 2, dry matter basis). At the onset of calving, treatments were discontinued and cows were fed forage sorghum hay at 2% of body weight and supplemented 1.43 lb dried distiller’s grains (dry matter basis) daily in a common pasture.
Cow body weights and body condition scores were measured every 28 days at 9 a.m. Supplement was withheld the morning of data collection and fed immediately after all cows had been weighed.
Two independent, trained observers assigned body condition scores using a 9-point scale (1= extremely emaciated, 9=extremely obese; Wagner et al., 1988) on each respective weigh date. Cows that calved before the final weigh day were excluded from the analysis, resulting in a total of 232 observations in the experiment.
ResultsThe authors hypothesized that increasing supplementation frequency for the 28 days prior to onset of calving from once every six days to daily would increase dry matter intake, thus resulting in greater nutrient intake and more favorable performance. In contrast, increasing supplementation frequency had the opposite of its intended effect (Table 2).
Cows in the D6-D1 group had lighter body weights (P=0.04) and less body weight gain at the end of the 88-day supplementation period compared to cows in the D1, D6 and D1-D6 groups. Likewise, body condition scores of D6-D1 cows tended (P =0.09) to be lower than those of cows in the D1, D6 or D1-D6 supplementation groups.
Increasing supplementation frequency from once every six days to daily during the final 28 days prior to calving resulted in less body weight gain and poorer body condition scores for pregnant beef cows supplemented with dried distiller’s grains. We found no differences between groups of cows supplemented daily or at 6-day intervals (Table 2) and no adverse effects of reducing supplementation frequency to once every 6 days were observed in pregnant beef cows fed dried distiller’s grains.
Reducing supplementation frequency may be a viable means of reducing supplementation costs when dried distiller’s grains are used as supplement.
ReferencesMcMullen, C. J.; Jaeger, J. R.; Waggoner, J. W.; Harmoney, K. R.; and Olson, K C. 2016. Effects of Altering Supplementation Frequency During the Pre-Partum Period of Beef Cows Grazing Dormant Native Range Kansas State University Cattlemen’s Day 2016. Kansas Agriculture Experiment Station Research Report. Vol. 2. https://doi.org/10.4148/2378-5977.1172
Waggoner is an Extension beef cattle specialist and Warner is an Extension cow-calf specialist, both with Kansas State University.
