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ARS Home » Pacific West Area » Dubois, Idaho » Range Sheep Production Efficiency Research » Research » Publications at this Location » Publication #374503

Research Project: Enhancing Sheep Enterprises and Developing Rangeland Management Strategies to Improve Rangeland Health and Conserve Ecology

Location: Range Sheep Production Efficiency Research

Title: PSXI-7 Comparison of range-based and irrigated cow-calf systems – grazing season performance

item HALL, JOHN - University Of Idaho
item SPRINKLE, JAMES - University Of Idaho
item ELLISON, MELINDA - University Of Idaho
item GODDARD, SANDRA - University Of Idaho
item Taylor, Joshua - Bret
item GLAZE, BENTON - University Of Idaho

Submitted to: Translational Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2020
Publication Date: 11/30/2020
Citation: Hall, J., Sprinkle, J., Ellison, M., Goddard, S., Taylor, J.B., Glaze, B. 2020. PSXI-7 Comparison of range-based and irrigated cow-calf systems – grazing season performance. Translational Animal Science. 98(Suppl. 4):385-386.

Interpretive Summary:

Technical Abstract: The objectives of this study were to compare: 1) cow performance, 2) cow fertility, and 3) calf performance in a range-based (RAN) or irrigated (IRR) management system over 4 yr. Crossbred beef cows were assigned with respect to age, BW, BCS (1 - emaciated to 9 - obese), and most probable producing ability (MPPA) to either IRR or RAN. Cows and calves remained in their assigned management system throughout the trial. Replacement heifers for each system came from dams within the same system. Cows in IRR (n = 170/yr) grazed irrigated cool season perennial pastures (May-October) then grazed hay aftermath or crop residues (October-December). Cows in RAN (n = 160/yr) grazed sagebrush steppe (May-December). All cows were maintained in their assigned systems and provided hay and supplement (January-mid-March) to achieve average BCS 5 by calving. Calves remained with their dams from birth (February-March) through weaning (September). All cows were provided ad libitum access to water and mineral supplements. All cows were artificially inseminated (AI) using a fixed-timed protocol in May. Donor bulls were distributed across IRR and RAN. Natural-service bulls were introduced on d 8 to 14 after AI. Cows were weighed and BCS recorded at branding (April), each pregnancy diagnosis date, and at beginning of the third trimester (December). Pregnancy diagnosis was conducted at 60, 100, and 120 d after AI. Calves were weighed at birth, mid-summer (July), pre-weaning (August) and weaning (September). All data were analyzed using mixed models. Year (n = 4) was the experimental unit. Models included the main effects of system. Cows from the IRR (n = 674) and RAN (n = 638) had similar (P = 0.13) BW at branding but RAN BCS was 0.4 BCS less (P < 0.05). By the end of the grazing season, IRR cows were 96 kg heavier (P < 0.001) and 1.8 BCS greater (P < 0.001) than RAN cows. Similarly, system did not affect calf birth weight (P = 0.30); however, calves in the IRR system were 20.7 kg heavier (P < 0.003) compared with RAN calves at weaning. System did not affect (P = 0.64) pregnancy rate which averaged 94.7% and 93.6% for IRR and RAN cows, respectively. Gross returns per cow were $60.50 less in the RAN systems compared with IRR system. The range environment resulted in reduced calf BW and return per cow compared with the irrigated environment. In conclusion, producers using sagebrush steppe range will need to operate at a lower cost per cow than irrigated ranches.