Cow-Calf Commentary for Iowa Cattleman Magazine

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By Beth Reynolds, Extension Beef Specialist and Erika Lundy-Woolfolk, Extension Beef Specialist

July 2021

ISU Research Update: Relationship between creep feed administration and cow-calf performance

There’s a thick stack of research studies done with the goal of evaluating the benefits, costs, and effectiveness of providing a creep feed supplement to calves for short or extended time periods. Feed conversions vary greatly, ranging from 3.1 to 20.1 pounds of creep feed to achieve 1 pound of gain, averaging somewhere between 8.1 and 10.1 pounds of feed to achieve 1 pound of gain. The bulk of the variation can be attributed to creep feed type (protein or energy) and the forage quality and availability.

In each of these studies, feed conversions are reported as an average in the group. However, we know and understand that cattle are not consistent in behavior and intake, especially on pasture. Recently the ISU beef team acquired new technology, a mobile feeder (Super SmartFeed™ by C-Lock Inc., Rapid City, SD) to help us evaluate individual animal intake while on pasture. At the McNay Research Farm, the first study using this feeder was done with a creep feed supplement, and we saw some interesting behavior differences during the trial.

Our goals of the study included:

  1. Monitoring individual calf creep feed consumption relative to their dam’s Milk EPD
  2. Track individual performance differences of calves offered ad libitum, limit-fed, or no creep feed
  3. Determine if creep feed consumption is influencing Milk EPD

Calves were split into two groups based on their dam’s milk EPD (low milk EPD {LM} or high milk EPD {HM}). Within each milk EPD classification, calves were then split into three creep feeding strategies (n = 13/treatment): 1) no creep feed, 2) limited creep feed access (up to 2 lbs. per calf per day), or 3) ad libitum creep feed access (up to 15 lbs. per calf per day). Calves had access to the feeder while cow-calf pairs rotationally grazed cool-season, fescue-based pastures for 75 days.

Of the calves that had access to creep feed, 73% from the HM group visited the feeder and consumed feed while only 48% of the LM group visited. While the feeder offers the ability to monitor individual animal intake, the feed designer only allows one calf per stall while consuming feed, likely hindering ‘traditional’ creep feeding behavior.

By design, the LM and HM ad libitum groups had the greatest daily creep feed intake (5.86 and 5.96 lbs. for LM and HM, respectively). On average, the LM limit fed calves consumed 1.27 lbs. of feed per day while the HM limit fed calves consumed 1.37 lbs.  This small difference in intake and limitations on animal numbers in this study make picking up a statistical difference difficult. However, considering that weaning weight is the predominant performance trait used to calculate Milk EPD, the possibility of a trend for HM calves to consume more creep feed begs the question as to whether intake behavior could inadvertently be selected for if selecting for high or low Milk EPD in breeding decisions.

Large variation across groups existed for visit frequency and feed intake.  For example, 40% of calves only skipped going to the feeder less than 10 days out of the 62 days with feeder access (ie - frequent visitors!). Over 90% of the calves visited the feeder at least every other day.  Regardless of treatment, the average creep feed intake was 4.28 lbs. per day. Intake ranged from 0.69 to 8.90 lbs. per day, with the median being 4.46 lbs.  Unfortunately, analyzing feed conversion becomes challenging, since calf gain from milk intake, creep feed, and forage cannot be separated.
 
To estimate milk production, calves were removed from their dams for 12 hours, weighed, allowed to suckle, and then weighed again. The calf weight difference (estimated milk production) was then adjusted to estimate 24-hour milk production. Unsurprisingly, the data agreed with previous research indicating that Milk EPD is a rather poor indicator of actual milk production with the low milk cows having a higher 24-hour milk production than the high milk group. In this study, the poorest milking cows were actually designated as HM cows based on EPD with calves given ad libitum access to creep feed.
 
Male calves from this study were transferred to the ISU Armstrong Research Farm to evaluate how former creep feed treatment impacted feed intake and performance during the receiving phase in the feedyard utilizing the FIMS feed bunks (collects individual animal intake). While there was no apparent correlation between gain during the two periods, dry matter intake was moderately correlated, explaining 25% of the variation, between the creep feeding period and the receiving period. This confirmed our hypothesis that if allowed to consume more creep feed while on the cow, calves are likely programmed to start the finishing phase with greater intakes, and potentially reduced feed conversion.

This research was funded by the Illinois Beef Association Checkoff Division. Additional Iowa Beef Center extension staff involved include Patrick Wall, project PI, and Denise Schwab.

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