Performance and rumimal metabolism are not changed in lactating dairy cows offered spring available annual forage crops during a short-term grazing experiment

• Published in: Journal of animal science Vol. 94; pp. 294 - 295
• Main Authors: Juntwait, K A, Brito, A F, O'Connor, K S, Smith, R G, Aragona, K M, Ghedini, C P, Pereira, A B D
• Format: Journal Article
• Language: English
• Published: Champaign Oxford University Press 01-10-2016
• Subjects: Animal lactation; Barley; Biomass; Cattle; Chromium; Chromium oxides; Composition; Crops; Dairy cattle; Dairy farms; Esophagus; Forage crops; Grasses; Grazing; Legumes; Metabolism; Milking; Pasture; Proteins; Rye; Sampling; Spring; Strip; Studies; Total mixed rations; Triticale; Urea; Wheat; United States > US
• ISSN: 0021-8812; 1525-3163

Spring available annual forage crops (AFC) can potentially be used to extend the grazing season by increasing pasture production. We aimed to determine the impact of spring available AFC on pasture production and animal performance during a short-term grazing experiment. Fourteen multiparous and 2 primiparous lactating organically certified Jersey cows were randomly assigned to either a traditional legume-grass pasture mix (control treatment; n = 8 cows) or a spring AFC mix of wheat, triticale, barley, cereal rye, and hairy vetch strip-tilled into a traditional pasture (SpAFC treatment; n = 8 cows). The botanical composition (DM basis) for the control averaged 70% grasses, 17% legumes, and 13% other (broadleaf, weeds, and dead), whereas that for SpAFC averaged 60% grasses, 14% legumes, 13% AFC grasses, 4% AFC legumes, and 9% other. Cows averaged 433 ± 48 kg of BW and 83 ± 50 DIM for the control group and 416 ± 46 kg of BW and 86 ± 43 DIM for the SpAFC group. A 14-d adaptation period was followed by a 7-d sampling period. Pasture nutrient composition during the sampling period averaged 16.0 and 15.1% CP, 53.3 and 56% NDF, and 34.6 and 32.1% ADF for the control and the SpAFC, respectively. Pasture biomass averaged 3,038 ± 303 and 4,052 ± 353 kg of DM/ha for the control and SpAFC, respectively. Cows were fed a total mixed ration (TMR) and milked twice daily and had access to a new strip of pasture after the afternoon milking. Pasture intake was estimated using chromium oxide and IVDMD. Ruminal fluid was sampled using an esophageal tube immediately after the morning milking with samples analyzed for VFA. Results are shown in Table 1. There were no significant differences in pasture and TMR intake comparing the control with SpAFC, but a trend (P = 0.08) was observed for increased total DMI (+0.8 kg/d) in cows fed the control treatment. Contents and yields of milk and milk fat and protein and ADG did not differ between treatments. A trend (P = 0.06) for greater MUN was observed with feeding the SpAFC rather than the control treatment. No significant differences were observed in the plasma concentrations of urea N and NEFA or in the ruminal concentration of total VFA. Strip-tilling spring available AFC into a perennial grass-legume pasture mix increased herbage biomass production and did not affect animal performance of lactating Jersey cows in the Northeastern United States.