ABSTRACT
The Texas A & M Cattle Production Systems Model was used to study herd productivity under several management plans open to cow-calf producers in the southeastern United States. An east Texas farm herd was simulated as a self-contained unit where all hay fed in the winter months was harvested from hay pastures or as surplus forage from grazed pastures. Management options examined involved (1) variation in the amount of forage fed as hay, and (2) spring vs fall calving. All forage was produced on well fertilized, intensively managed Coastal bermudagrass pastures. The winter feed options consisted of hay fed (1) ad libitum, and at (2) 80, (3) 60 and (4) 40% of the ad libitum level. The hay feeding period was November 15 through April 15. Overall herd productivity decreased as level of winter feeding decreased. Higher levels of hay feeding resulted in fewer cattle/unit land area but higher production/breeding cow. Herd size increased by 2.9, 11.9 and 32.5% as winter hay levels were reduced from ad libitum to 80, 60 and 40% of ad libitum, respectively, under spring calving management, whereas herd productivity measured as total live weight sold/herd (fixed land area) declined by 2.2, 9.4 and 10.3% with the respective feed levels. Spring-calving herds were approximately 3.2% larger in number than corresponding fall-calving herds on the same land area, but fall-calving herds produced an average of 3.6% more live weight sales.
