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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Livestock Nutrient Management Research » Research » Publications at this Location » Publication #412680
Research Project: Strategies to Manage Feed Nutrients, Reduce Gas Emissions, and Promote Soil Health for Beef and Dairy Cattle Production Systems of the Southern Great Plains

Location: Livestock Nutrient Management Research

Title: Optimization of limestone and calcium inclusion levels in diets fed to growing and finishing cattle

Author
item LONG, NATHAN - Texas A&M University
item PROCTOR, JARRET - Texas A&M University
item FOSTER, RYAN - Texas A&M University
item GOUVÊA, VINICIUS - Texas A&M Agrilife
item Beck, Matthew
item SMITH, JASON - Texas A&M Agrilife

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/14/2024
Publication Date: 8/14/2024
Citation: Long, N.S., Proctor, J.A., Foster, R.C., Gouvêa, V.N., Beck, M.R., Smith, J.K. 2024. Optimization of limestone and calcium inclusion levels in diets fed to growing and finishing cattle [abstract]. Plains Nutrition Council Spring Conference Proceedings, April 10-12, 2024, San Antonio, Texas. 2024:136.

Interpretive Summary:

Technical Abstract: Methane (CH4) is a primary greenhouse gas that is produced as a byproduct of ruminal fermentation. Reducing CH4 production in beef animals represents a longstanding goal within all sectors of the industry as it is often associated with atmospheric warming and also represents an energetic loss to the animal. Thus, the objective of experiment 1 was to determine if dietary inclusion of limestone is an effective CH4 mitigant. Steers (n = 16) were sorted into 2 treatment groups based on BW and offered isocaloric and isonitrogenous diets over 35 d with 1 of 2 limestone inclusion levels (1.3 and 2.6% of diet dry matter) using an automated cattle feeder (SmartFeed Pro; C-Lock Inc.; Rapid City, SD). Statistical analyses were conducted using JMP Pro v. 17 with a fixed effect of treatment and individual animal serving as the experimental unit. Statistical significance was defined as P = 0.05 with a tendency set at 0.05 < P = 0.10. Results from experiment 1 indicated there was no difference in dry matter intake (DMI), daily CH4 emissions (g/d), or CH4 yield (g/kg DMI) when additional limestone was added to the diet (P = 0.68). However, there was a 12.5% increase in average daily gain (ADG; P = 0.02), 11.0% decrease in feed to gain ratio (F:G; P = 0.03), and CH4 emission intensity (g/kg ADG) tended to decrease 9.1% (P = 0.09) when limestone was included at 2.6% of diet dry matter compared to 1.3%. Because results from experiment 1 indicated additional dietary limestone may increase animal performance, a meta-analysis was conducted to determine the optimal concentration of limestone in beef cattle growing and finishing diets. A database was constructed containing 17 manuscripts where limestone or calcium inclusion via limestone represented experimental treatments. Using the database models were generated for predicting DMI, ADG, and F:G based on limestone inclusion level. Models for each variable were then incorporated into an economic sensitivity analysis to determine optimum inclusion from a least cost perspective. The optimum inclusion for limestone as a percentage of diet dry matter was determined to be 2%.