Animal Science: Today and Tomorrow
Dr. Tom Troxel Dr. Michael L. Looper
So you can graze 300 days in Arkansas!
The 300 day grazing demonstration was a statewide educational effort demonstrating how to plan and manage forage production in seasonal blocks of summer, fall, winter, and spring to match the nutrient demands for livestock. The statewide education was complemented with a 300 day grazing discovery farm established at the Livestock and Forestry Research Station near Batesville, AR. The goals of the discovery farm were to 1) demonstrate rotational and strip-grazing management to improve the utilization of complimentary cool- and warm-season forages, 2) demonstrate targeted fertilizer use and reduction of fertilizer through legume establishment, 3) reduce hay feeding to 60 d or less, 4) manage for a 90% net calf crop 5) manage for an average weaning weight of 550 lbs. and 6) to implement management practices that are common and available to all cattle producers. The objective of this case study was to describe the adopted management practices and report production outcomes measured at the 300 day grazing discovery farm from 2008 through 2014.
Here are some results from the 6 year project:
-The time frame of the demonstration was July 1 to June 30 for the following years:
Year 1 = 2008 to 2009
Year 2 = 2009 to 2010
Year 3 = 2010 to 2011
Year 4 = 2011 to 2012
Year 5 = 2012 to 2013
Year 6 = 2013 to 2014
–Forage base was 45 acres of toxic endophyte-infected Kentucky-31 tall fescue, 22 acres of Ark-Plus tall fescue, 22 acres of Ark-Plus fescue/annual grass mix and 40 acres bermudagrass.
-Year 1 the cow herd was 38 predominately Balancer females bred to Balancer bulls with a fall calving season. Thirty-eight cows were chosen because that is the average herd size in Arkansas.
-The breeding season for all 6 years was approximately November 28 to January 28. After year 1, 2 horned Hereford bulls were fertility tested before each breeding season and in years 4, 5 and 6, also were tested for trichomoniasis. The calving season averaged 60 days.
-Calf crop percentages for the cows ranged from 84% (year 1) to 100% (year 3) with an overall average of 91%. Only one year (year 3) was a 100% calf crop achieved because a cow had twins that compensated for a cow that lost a calf.
-The cow percent diagnosed pregnant ranged from 79% (year 1) to 100% (year 2). The improvement beyond year 1 may be attributed to initially culling cows with poor reproductive performance and improving body condition score over the course of the demonstration. The average percent diagnosed pregnant across all 6 yr was 94%.
-One goal of the program was a 90% net calf crop. The cow net calf crop percentages for yr 1, 2, 3, 4 and 5 was 66%, 95%, 97%, 89% and 79%, respectively. Net calf crop was determined by multiplying the calf crop and percent diagnosed pregnant times 100. If year 1 was considered the benchmark year, a 90% net calf crop was obtained in yr 2 (95%) and 3 (97%) and almost obtained in yr 4 (89%). The average cow net calf crop for yr 2, 3, 4 and 5 was 90% which was 24 percentage points better than year 1. The cows for year 6 are now calving, therefore, are not included in this dataset.
-The overall adj. 205-day weight increased from year 1 (419 lbs.) to years 3, 4, and 5 (496, 490, and 514, respectively). The greatest steer adj. 205-day weight was in year 5 (549 lbs.). The heifer adj. 205-day weight increased from year 1 (406 lbs.) and was not different in yr 3, 4, and 5. The improvement in adj. 205-day weight was due to heterosis and improved grazing management.
-The weaning weight of year 1 was 470 lbs. The average weaning weight goal was achieved for yr 2, 3 and 5 and was 562, 602 and 571 lbs., respectively.
-For all 6 years, it was decided to retain the calves for a short grazing period. The grazing period ranged from 42 (year 3) to 71 (year 2) days with an average of 60 days. The factors determining the length of the post-weaning grazing were weather, pasture condition, and market trends. The calves and cows were grazed in a leader-follower grazing program with the calves grazing the higher quality bermudagrass and the cows followed to uniformly graze the bermudagrass. All 6 years the post-weaning grazing resulted in a positive return. The greatest and least return came in year 6 ($378 per head) and 4 ($30 per head), respectively, with an average return per calf of $118.
Weaned 300 day grazing calves in July 2014
-By using a seasonal forage plan, grazing seasons exceeding 300 days were achieved for 5 of the 6 years. Grazing seasons for year 1, 2, 3, 4, 5 and 6 were 337, 311, 326, 323, 279 and 308 days, respectively. As a result, the number of days hay was fed for year 1, 2, 3, 4, 5 and 6 were 28, 54, 39, 42, 86 and 57 days, respectively.
Cow-calf producers will continue to face increasing production costs for feed, fuel and fertilizer. As a result, the input cost of harvested forage (hay) will continue to climb and erode producer’s profits. The 300 day grazing demonstrated the value in using science based management practices to utilize existing forages, strategic fertilization (based on soil testing) and proper grazing principles (rotational grazing and/or strip grazing) to extend the grazing season. In addition, science based cattle management practices were implemented to improved cow reproduction, calf performance and economic return. By using these sound management practices both pasture and cattle production goals were achieved with a systems approach while strengthening farm sustainability.