Cattle Grazing Preference among Tetraploid and Diploid Annual Ryegrass Cultivars

Abstract

Determination of animal preference in the early stages of the evaluation process of new forages may provide insights into potential animal performance as well as plant responses to grazing. A 2‐yr study was conducted at Raymond, MS, to determine grazing preference of cattle between tetraploid and diploid annual ryegrass (Lolium multiflorum Lam.) cultivars and its relationship with morphological and chemical characteristics. Treatments were two tetraploid cultivars, Maximus and Nelson, and two diploid cultivars, Marshall and Gulf, arranged in a 4 × 4 Latin square design experiment. Eight Angus crossbred yearling steers (Bos taurus) (initial body weight of 320 ± 19 kg) were used to determine grazing preference based on herbage disappearance, the Chesson–Manly (CM) index, and amount of time spent grazing. In both years, herbage disappearance was greater for the tetraploid (1380 kg ha−1) than diploid cultivars (895 kg ha−1), with greater CM index for the tetraploid than for the diploid cultivars (8.1 vs. 5.8% in Year 1 and 6.9 vs. 5.5% in Year 2). Also, animals spent about 10% greater time grazing the tetraploid than diploid cultivars during both years. During the first year, the tetraploid cultivars had less neutral detergent fiber (NDF) (556 vs. 589 g kg−1) and less acid detergent fiber (ADF) (341 vs. 359 vs. g kg−1) than the diploid cultivars and Nelson had greater water‐soluble carbohydrate (WSC) concentration (184 g kg−1) than the other three cultivars (152 g kg−1). In the second year, NDF, ADF, and WSC were not different among cultivars. Tetraploid cultivars had a greater proportion of leaf than diploid cultivars. The results indicate that cattle showed greater preference for tetraploid cultivars, which appeared to be linked mainly with pregraze herbage mass and the proportion of leaf.

Morphology and nutritive value of perennial ryegrass cultivars at different phenological stages

“…Generally, at the pre-heading vegetative and reproductive stages, the intermediate-heading cultivars, Kamo and Commando, had greater ADF and NDF concentrations and a lower DOMD than the late-heading cultivars (p < .05). These findings confirmed that high-sugar cultivars (Lee et al, 2002;Miller et al, 2001;Moorby, Evans, Scollan, MacRae, & Theodorou, 2006), tetraploid cultivars (Solomon, Macoon, Lang, Vann, & Ward, 2014;Wims, McEvoy, Delaby, Boland, & O'Donovan, 2013) and late-heading cultivars (Gowen et al, 2003) had a higher nutritive value and the potential to increase milk production, compared with their counterparts.…”

Animal and forage responses on Maximus, a tetraploid cultivar vs Marshall, a diploid cultivar of annual ryegrass

“…Hafley () reported no cultivar effect on ADG between Marshall (1.42 kg/d) and Surrey (1.50 kg/d; S x̅ = 0.08) annual ryegrasses and suggested that if herbage mass and nutritive value are not different between cultivars, then animal response will be the same. An associated study conducted at an adjacent site showed that cattle had greater preference (based on herbage disappearance and time spent grazing) for tetraploid than diploid annual ryegrass cultivars (Solomon, Macoon, Lang, Vann, & Ward, ). This, however, did not express itself into differences in animal performance in the current study.…”

A fungal endophyte of a palatable grass affects preference of large herbivores

“…The frequency of visits was measured by recording the position of each of the three animals within the block every 2 min and for a total period of 1 h (Laca 1998;Solomon et al 2014). The frequency of visits was measured by recording the position of each of the three animals within the block every 2 min and for a total period of 1 h (Laca 1998;Solomon et al 2014).…”

“…In October 2013, forage was offered in one feeding trial to three steers to evaluate whether the endophyte affected preference. The frequency of visits was measured by recording the position of each of the three animals within the block every 2 min and for a total period of 1 h (Laca 1998;Solomon et al 2014). Therefore, the frequency of visits of a given treatment was the proportion of the records on that treatment over the total number or records.…”