22 Incorporating Crabgrass in Southern Pasture Systems to Improve Animal Performance

Bahiagrass (Paspalum notatum L.) is a perennial warm-season forage commonly grown in the Coastal Plains of the Southeastern US, but the nutritive value may not be sufficient for a cow-calf pair. The inclusion of a warm-season annual, such as crabgrass (Digitaria sanguinalis) may improve the forage base when interseeded into bahiagrass monocultures. A three-year summer grazing evaluation was conducted at the University of Georgia Range Cattle Research Station in Alapaha, GA from 2019-2021 to compare concurring production of bahiagrass interseeded with an improved crabgrass (BCG) with bahiagrass monoculture (BG) pastures and animal performance. The experimental design was a randomized complete block with four replications. All paddocks were evaluated on a biweekly basis for herbage availability, botanical composition, and nutritive value. Paddocks (2.6 ha) were continuously grazed using the put-and-take method of stocking with cow-calf pairs, 4 tester pairs per treatment. Pairs were weighed at initiation and on a 28d interval for calculation of calf ADG, cow BCS, and gain/ha. Statistical analyses were conducted using the PROC MIXED procedure of SAS. Average daily gains were analyzed within year and treatment differences were only significant in Y1 (P = 0.05). Forage yield was never limiting in this experiment but CP and TDN were greater (P < 0.001) for BCG when compared to BG for Y1 and Y2. Rainfall was 27cm below average in Y1, therefore these data suggest that during a drought, crabgrass interseeded into bahiagrass can improve the forage nutritive value, and subsequent calf gain, as compared to bahiagrass alone.