Effects of Bedding Feedlot Cattle During the Winter on Performance, Carcass Quality, and Nutrients in Manure

V.L. Anderson, R. J. Wiederholt, and J. P. Schoonmaker

 

Introduction

Feeding cattle in North Dakota poses some environmental challenges with wind, snow and cold.  Crop residues used as bedding can make animals more comfortable, improve performance and net return. (Anderson et al., 2005)  Ammonia volatilization from animal manure is considered a major pollution source in the environment.  This paper reviews two research projects that explore the effects of bedding and different bedding materials for feedlot cattle fed during the winter in North Dakota.

 

Experiment 1

This study compared levels of bedding with wheat straw for finishing steer calves during the winter.  The bedding treatments were no bedding, modest bedding, and generous bedding (2x modest bedding).  Dry matter intake was not affected by bedding level (P<.05).  Bedded cattle gained faster (P<.05) as generously-bedded steers gained 3.53 lbs. per day, modestly-bedded steers gained 3.69, and steers without bedding gained 2.83.  Gain per feed improved significantly (P=.06) in one period and overall for bedded steers (P=.09). Most carcass quality traits were also positively affected by bedding (P<.05).  Marbling scores improved with bedding as did the percent of carcasses grading choice.   Twenty-three percent of carcasses from steers without bedding graded choice, vs. 45% and 63% for bedded steers.

 

Table 1 shows a trend of increasing N sequestration in composted manure with an increase in the amount of bedding used per pen.  This makes sense since the higher level of total N in the fresh manure carried through to the compost results.

 

Experiment 2

This study was conducted to compare different crop residues as bedding materials for feedlot cattle.  The bedding treatments were: 1) No bedding (pens were scraped two times per month), 2)  bedding with wheat straw, 3) corn stover, or 4) soybean residue.  Steers were assigned to one of eight pens with 14-15 head per pen, and two replicates per treatment.

 

  Steers bedded with wheat straw.

 

 Steers bedded with corn stover.

 

  Steers bedded with soybean residue.

 

Results

Feedlot performance

Dry matter intake tended to be lower (P<.12) overall for the calves bedded with corn stover vs. all other treatments.  The palatability of stover is well known and calves tend to eat the leaves and husks if available.  Dry matter intake was equal for all other treatments.  Calves bedded with straw gained the fastest (P<.01) followed by soybean residue, stover, and the calves in the scraped control pen.  Differences in weight gain over several months led to significantly heavier (P<.05) calves in the straw treatment followed by soybean residue, corn stover, and last, no bedding.  Feed efficiency was greater for the bedded calves (P=.03 to .11) during the coldest part of the winter.  Yield grade and fat thickness appear to be affected by treatment (P<.02) and patterned after live weight with increased fat deposition in straw-bedded calves followed by soybean residue, control, and corn stover.  Ribeye area and kidney-pelvic-heart fat were not affected by treatment.

 

Manure Nutrient Analysis and Composition

According to Table 2, there are definite trends associated with the amount of NH4-N, Total N and P when comparing fresh or composted manure from pens that used bedding vs. no bedding.  The numbers show that these nutrients are more highly sequestered when any bedding is used vs. no bedding either when analyzed fresh or composted.

 

 

When bedding is utilized, more of the urine is retained in the pack and the bedding is an enhanced substrate for retaining NH4-N.   The reason for higher NH4-N levels in corn stover vs. the other bedding materials from the composted manure analysis is due to the nature of the composting process.  When you compare the C:N ratio of corn stover (65) to wheat (80) and soybean (40) straw, it is in the middle. The C:N ratio of beef manure is 15.  For optimum composting a C:N ratio of 30:1 to 40:1 is required.  The corn stover bedding mixed with the beef manure probably resulted in a near optimum C:N ratio.  With an optimum compost process, there should be less loss of NH4-N added to the fact that there was nearly twice as much NH4-N in the fresh corn-stover bedded manure means that a higher amount of NH4-N should remain in the material after composting.

 

Economics

Based on Experiment 1 results, if steers are sold on a realtime grid with a $10/cwt break from choice to select cattle, the advantage for modest bedding is $61.76 per head and $81.61 for generous bedding.   Several other factors can affect carcass value with different marketing grids and time of the year including Yield Grade, USDA Grade, premium programs, carcass weight, and other traits.  Additional value is captured from the extra nutrients in the manure which is used for fertilizer, either in the raw or composted state.  If the cost of N is $0.30/lb and the use of generous bedding can sequester 7 more lbs. of N per ton of fresh manure then a producer can realize $2.10 more N fertilizer value per ton of manure.