Cattle preference in Paspalum atratum and its relationship with morphological and anatomical leaf characteristics

New atra paspalum (Paspalum atratum Swallen) accessions were found to be differentially grazed by cattle, without differences in herbage accumulation and nutritive value. This study aimed to evaluate cattle preference, morphological and anatomical leaf traits, and their relationships at four sampling events. Five new atra paspalum accessions and the cultivar Camba were used. The experimental unit was a 2 m x 2 m plot. Treatments were replicated four times in a completely randomized design. Cattle preference was determined in spring (December 2016 and 2017), summer (March 2017), and autumn (May 2017) using six steers Bos spp. that grazed the plots for 4 h on two consecutive days. Plant height, leaf-blade length, leaf-blade width, and the proportions of five leaf tissues at three leaf regions were measured at each date. The proportion of the leaf that is curved was measured in December 2017. Cattle preference was variable among accessions and sampling events. Some accessions were shorter, with shorter and more flexible leaves than Camba (p < 0.05). The proportion of lignified tissues was greater during the spring (2016 and 2017) and summer (7%-23%) than in the autumn. One accession had the lowest proportion of lignified tissue in the warm season (8%-12%) but the highest during the fall (around 15%). The same accession had the fewest primary vascular bundles in the warm season. Cattle preference was negatively correlated with the proportion of lignified tissues, the number of primary vascular bundles, plant height, and leaf-blade length. Cattle preference was affected by the growing season and reduced by greater presence of leaf structural tissue.

Automated summary

This study investigated the differential grazing behavior, morphological and anatomical leaf traits of new accessions of atra paspalum. The results showed that cattle preference varied among different accessions and sampling events. Some accessions had shorter height, shorter and more flexible leaves compared to the cultivar Camba. Cattle preference was influenced by the growing season and the presence of leaf structural tissue.