The objectives of this study were to determine 1) the effect of bull:heifer ratio on reproductive performance and associated costs and return on heifers in synchronized estrus and 2) the effect of estrus synchronization on reproductive performance and economic variables, in a multiple-sire, pasture breeding situation. Eight hundred yearling beef heifers and 28 mature, sexually experienced beef bulls were allotted to four treatments (two replicates per treatment) at bull:heifer ratios of 2 per 100 (1:50; Treatment 1), 2 per 100 (1:50; Treatment 2), 4 per 100 (1:25; Treatment 3), and 6 per 100 (1:16; Treatment 4). Treatment 1 (control) used nonsynchronized heifers, whereas heifers in Treatments 2, 3, and 4 were synchronized using the 33-d melengestrol acetate (MGA)-prostaglandin F2 alpha (PGF2 alpha) program. Pregnancy results after a 28-d breeding season indicate that there may be a limit to how many estrus-synchronized heifers bulls can impregnate. Treatment 2 showed a 6% decrease (P < .10) in pregnancy rate (77%) compared with Treatment 3 (83%), indicating that the bulls probably were not able to service all the synchronized heifers. Treatments 3 and 4 had similar pregnancy rates (83 and 84%, respectively). Treatment 4 had a 3-d advantage (P < .01) over Treatment 3 in average day of conception. However, based on economic analysis, Treatment 3 exhibited greater returns. Estrus synchronization failed to provide any advantage in pregnancy rate or day of conception. For unknown reasons, the control, nonsynchronized heifers cycled and conceived as if they were synchronized.(ABSTRACT TRUNCATED AT 250 WORDS)
Dynamic programming was used to obtain optimal management and marketing policies for stocker operations in Southeastern Colorado under different stocking rates, rainfall, and price scenarios. Simulated steer liveweights at low, moderate, and high stocking rates were incorporated with simulated steer prices to masimize the present value of net returns from the sale of 0,50, and 100% of the steer inventory in July, August, September, or October. Two low-risk, 1 moderate-risk, and 2 high-risk scenarios were considered. The 2 low-risk scenarios were favorable rainfall-optimistic price and favorable rainfall-pessimistic price. The moderate-risk scenario was average rainfallaverage price. The 2 high-risk scenarios were unfavorable rainfall-optimistic price and unfavorable rainfall-pessimistic price. The highest net returns from the low-risk and moderate-risk scenarios were obtained at the high stocking rate with sales in September and October. The highest net returns from the highrisk scenarios were obtained at the moderate stocking rate with sales in September and October. Risk-averse operators who are not prepared to handle sales before October will be better off using a low stocking rate. Risk-taker operators will obtain higher net returns than risk-averse operators using a high stocking rate providing they are prepared to sell half of the herd in July if cumulative rainfall up to June is below 149 mm. If this high stocking rate is maintained beyond July, operators should sell in September independently of the amount of rainfall or the level of prices in August.
The San Luis Valley farming systems' project sought to identify improved technologies and better decision-making capabilities for modest-sized and limited-resource farms. Characteristics of limited-resource farms operated by Hispanic and Anglo families, which mayor may not be associated with differential rates of social participation and/or institutional discrimination, were examined. To determine characteristics of client farms, data were collected and stratified on farm resources, farm operations, goal hierarchies, and operational management strategies. Hispanic and Anglo farmers differed significantly in several respects. Key among these differences were crop and livestock enterprise mixes and the importance of off-farm income to households. For many farming parameters, farm size, age of farmer, and full-time/part-time characteristics overshadowed ethnicity as a determinant of decision-making. However, an important subset of the farm population is composed of Hispanic farmers who operate below median farm acreage on a part-time basis and for whom few technological developments or assistance programs are specifically designed or delivered.
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