Plant Persistence and Animal Performance for Continuously Stocked Alfalfa Pastures at Three Forage Allowances

Abstract

Alfalfa (Medicago sativa L.) has not been well suited for pasture because of its intolerance to grazing. ‘Alfagraze’, a cultivar bred for grazing tolerance, offers potential to use alfalfa as pasture. A 3‐yr grazing study was initiated in central Georgia to investigate persistence and animal performance of ‘Apollo’ and Alfagraze alfalfa at low, medium, and high forage allowance (FA). The FA for this study were targeted at 1000, 2000, and 3000 lb dry matter (DM)/1100 lb animal unit for low, medium, and high FA, respectively. Low FA reduced stand of both cultivars (P < 0.05) after only 1 yr (low = 6.8, medium = 8.2, high = 8.8 plants/sq ft). After 2 yr, high FA paddocks averaged 8.6 plants/sq ft, while medium and low FA had decreased to 5.4 and 4.4 plants/sq ft, respectively. The difference in grazing tolerance between cultivars became evident after 2 yr of grazing, when, averaged across FA, Alfagraze had 7.3 plants/sq ft and Apollo had 5.0 plants/sq ft. After an additional year of continuous stocking, Alfagraze had approximately 150% more plants than Apollo. Persistence differences between cultivars were most evident at low FA. After 2 yr of low FA, Alfagraze had 5.5 and Apollo had 3.3 plants/sq ft. After 3 yr, Alfagraze maintained stands of 5.5 plants/sq ft, while Apollo stands decreased to 1.5 plants/sq ft. Lower FA resulted in greater bermudagrass [Cynodon dactylon (L.) Pers.] encroachment. Lower FA decreased average daily gain (ADG) in yr 1. At low FA, improved persistence of Alfagraze resulted in 0.45 lb/d higher ADG than Apollo in yr 2. The better grazing‐tolerance of Alfagraze alfalfa resulted in longer stand persistence and better animal performance. Research Question Alfalfa is a high quality forage that can produce good animal gains. Little acreage of alfalfa in the USA is grazed because of poor persistence of hay‐type cultivars. ‘Alfagraze’, a grazing‐tolerant cultivar, offers livestock producers extended productivity of alfalfa used for pastures. This study investigated persistence differences between Alfagraze and ‘Apollo’ alfalfa, as well as the effect of forage allowance (FA) on stand persistence and animal performance of steers continuously stocked on alfalfa pasture. Literature Summary High quality forage is important for profitable stockering of weaned calves. Various forages can provide this during fall, winter, and spring in the southeastern USA, but a forage is needed that will produce high animal gains in summer. Alfalfa is a high quality forage for the late spring and summer, but its use as a grazing crop has been limited because of poor persistence when grazed. Rotational stocking has been recommended for alfalfa, but even then stand life is limited because of periodic overgrazing. ‘Alfagraze’, a grazing‐tolerant cultivar with high yield potential, should provide excellent animal gains during summer and good stand persistence. Study Description A 3‐yr grazing study was conducted at the Central Georgia Branch Experiment Station near Eatonton. Alfagraze and Apollo alfalfa were planted in fall...

Development and evaluation of grazing-tolerant alfalfa cultivars: A review

“…Animal performance trials at the University of Georgia showed that maintaining alfalfa stand density provided higher animal gains under continuous grazing at high stocking rates (Table 4) Bates et al 1996). These data are extremely important because they show that a grazing-tolerant cultivar can result in more saleable animal product for the producer.…”

Persistence of Alfalfa Sod‐Seeded into Bermudagrass Pastures on Coastal Plain Soils

“…Butler et al (2012) evaluated four alfalfa varieties under stocking and reported that excessive stand loss (>50%) of alfalfa occurred between the end of the third year and beginning of the fourth year for both grazing systems. Cultivars such as Alfagraze that were selected for grazing tolerance have increased the use of alfalfa due to its nutritive value, persistence under continuous stocking, and potential profits (Smith et al, 1989;Smith and Bouton, 1993;Bates et al, 1996;Bouton et al, 1998;Bouton and Gates, 2003). Grazing could potentially shift the mixture toward bermudagrass because of its sod forming nature, deep rooting abilities, and the susceptibility of alfalfa to frequent defoliation.…”

Responses of Medicago sativa and M. falcata type alfalfas to different defoliation times and grass competition

“…Developing proper defoliation management is critical in gaining acceptance and use of alfalfa as a grazing resource (Bates et al 1996). Medicago falcata alfalfa may have different responses to grass competition and defoliation management than M. sativa.…”

“…For instance, alfalfa survival was lower in treatments with a single yearly defoliation of alfalfa in Conservation Reserve Program than in treatments that had three to four cuttings per year (Sheaffer et al 1997). A lower frequency of defoliation in mixed alfalfa-grass stands improved yield (Bittman et al 1991;Hoveland et al 1996) and decreased grass encroachment (Comstock and Law 1948;Bates et al 1996;Hoveland et al 1996).…”