Production cow-calf responses from perennial forage-based and integrated beef-cropping systems

Abstract

An experiment was conducted to measure production responses of an alternative cow-calf production system integrated into a cropping system without access to perennial forage compared to a traditional cow-calf system utilizing perennial forage. Multiparous, cross-bred beef cows (n = 160; average age = 6.2 ± 2.8 yr) were utilized in a randomized complete block experimental design and unstructured treatment design. Upon initiation, cows were blocked by age and stratified by source, assigned randomly to one of two production systems, each with four replicates (n = 20 cows/replicate). Once allotted to their treatment groups, cows remained in their experimental units for the duration of the experiment. Treatments were: 1) a traditional system consisting of April to May calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to August calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). There were no differences (P ≥ 0.27) in calving rates (91.8 vs. 86.7 ± 2.92%), pregnancy rates (89.3 vs. 89.9 ± 2.66%), and weaning rates (87.2 vs. 82.3 ± 3.29%) for TRAD vs. ALT, respectively. However, there was an increase (P = 0.04) in the rate of twin offspring in ALT (2.9 vs. 9.4 ± 2.36% for TRAD vs. ALT, respectively). One calf from the set of twins was selected randomly at birth to be removed from the experiment, so the production data are only from single calves. There was no difference (P = 0.47) in calf body weight at birth (40 vs. 39 ± 0.7 kg for TRAD vs. ALT, respectively). At weaning, calves in the ALT system were lighter (P < 0.01) at the same day of age (184 vs. 229 ± 5.5 kg) compared to TRAD calves. Cows from the ALT system had fewer (P < 0.01) kg weaned per cow exposed to bull (150 vs. 199 ± 7.2 kg) compared to TRAD cows. Apart from the twinning rate, no differences in reproductive performance were observed among systems. However, reduced weaning weights and kilogram of weaned calf per cow exposed may negatively impact revenue to the cow-calf enterprise of the ALT system.

Keywords: annual forage; beef cow; drylot; limit-feeding; partial-confinement; systems.

Figure 1.

Annual timeline of feed resources and cow production cycles for two cow-calf production systems. Treatments consisted of a traditional, spring-calving cow-calf system utilizing smooth bromegrass pasture in spring, summer, and fall, and winter corn residue grazing (TRAD) and an alternative fall-calving cow-calf system utilizing partial-drylot, fall grazing of a late-summer planted oat cover crop and corn residue grazing (ALT).

Figure 2.

Smooth bromegrass pre-grazed biomass production quadratically increased (P = 0.05; SE = 0.091) over the grazing season in cycle two for the traditional cow-calf system. There were no differences (P = 0.39; SE = 6.340) for post-grazed biomass measurements. The grazing season for the traditional cow-calf system was Julian days 122 (2 May 2019) to 312 (8 November 2019) for cycle two.

Figure 3.

Smooth bromegrass, collected via diet sample, in vitro organic matter digestibility (IVOMD) was not different (P = 0.94; SE = 0.0195) over the grazing season for the traditional cow-calf system. The grazing season for the traditional cow-calf system was Julian days 127 (7 May 2018) to 319 (15 November 2018) and 122 (2 May 2019) to 312 (8 November 2019) for cycles one and two, respectively.

Figure 4.

Smooth bromegrass, collected via diet sample, crude protein (CP) was not different (P = 0.19; SE = 0.011) over the grazing season for the traditional cow-calf system. The grazing season for the traditional cow-calf system was Julian days 127 (7 May 2018) to 319 (15 November 2018) and 122 (2 May 2019) to 312 (8 November 2019) for cycles one and two, respectively.

Figure 5.

Late-summer planted oat, clipped at ground level, in vitro organic matter digestibility (IVOMD) linearly decreased (P = 0.02; SE = 0.0272) over the grazing season for the alternative cow-calf system. The oats grazing season for the alternative cow-calf system was Julian days 296 (23 October 2018) to 378 (13 January 2019) and 296 (23 October 2019) to 373 (8 January 2020) for cycles one and two, respectively.

Figure 6.

Late-summer planted oats, collected via clipped sample, crude protein quadratically decreased (P = 0.04; SE = 0.0003) over the grazing season for the alternative cow-calf system. The oats grazing season for the alternative cow-calf system was Julian days 296 (23 October 2018) to 378 (13 January 2019) and 296 (23 October 2019) to 373 (8 January 2020) for cycles one and two, respectively.

Figure 7.

Body condition score at the beginning of the breeding season for two cow-calf production systems. Treatments consisted of an alternative fall-calving cow-calf system utilizing partial-drylot, cover crop, and corn residue grazing (ALT) and a traditional, spring-calving cow-calf system utilizing perennial forages and corn residue grazing (TRAD). Body condition distribution was significantly (P < 0.01; SE = 0.82) different among the treatments. There was a shift in the ALT body condition distribution with a greater percentage near a body condition score of 5 compared to the TRAD treatment.

Figure 8.

Body condition score at weaning for two cow-calf production systems. Treatments consisted of an alternative fall-calving cow-calf system utilizing partial-drylot, cover crop, and corn residue grazing (ALT) and a traditional, spring-calving cow-calf system utilizing perennial forages and corn residue grazing (TRAD). Body condition distribution was significantly (P < 0.01; SE = 0.55) different among the treatments. There was a shift in the ALT body condition distribution with a greater percentage of body condition scores of 4 and 5 compared to the TRAD treatment.