Black oat grown with common vetch improves the chemical composition and degradability rate of forage

Abstract

This study aimed to evaluate the effect of cultivating a combination of common vetch (Vicia sativa L.) with black oats (Avena strigosa Schreb.) on the chemical composition of forage and the grazing behavior of heifers. To accomplish this, two paddocks 2500m2 each from a Voisin Rational Grazing management system were divided into three blocks each and then into thirds (278m²) characterizing a randomized block design. Three different forage compositions were distributed into these thirds: oats grown alone, vetch grown alone, and oats grown with vetch. Forage samples were collected after 65 days through the square method. Right after collection, three groups of four heifers each grazed the plots for two hours in a 3x3 double Latin Square design for behavioral observation, grazing simulation through the hand-plucking method, and biting rate determination. Forage samples collected either by hand-plucking or the square method, were analyzed for chemical composition and “in vitro” degradability. Statistical analyses were performed using the R package lme4. Data were evaluated with linear mixed-effects models. The inclusion of common vetch significantly increased forage production and oat protein content, but decreased the fiber content, which promoted better “in vitro” degradability. Grazing frequency was higher in pasture where oats were grown with vetch, but the biting rate was similar in all the three forage compositions evaluated. Forage collected by the square method did not differ from forage consumed by the heifers, probably meaning low herbage selectivity by heifers. Furthermore, no interaction of investigated variables occurred between forage compositions and the method of collection. The inclusion of common vetch with black oats increased forage chemical composition, “in vitro” degradability, and forage production, thus having positive effects on the time cows spent grazing.

Creating a Design Framework to Diagnose and Enhance Grassland Health under Pastoral Livestock Production Systems

“…For instance, it is well documented that ruminants exhibit a preference for legumes and have a higher intake rate compared to grasses [ 178 ]. Accordingly, they spend more time grazing when the pasture is composed of legumes and grasses rather than only grasses [ 179 ]. Still, ruminants recognize the post-ingestive effects of eating certain foods and adjust their intake at safe levels [ 180 ].…”

Voisin Rational Grazing as a Sustainable Alternative for Livestock Production

“…This optimum recovery period (ORP; Figure 1 ) can be defined as the moment when the acceleration of pasture growth curve is equal to zero; the moment of maximum herbage growth rate [ 21 ], which has been related to the regrowth moment when light interception reaches 95% [ 19 ]. The ORP coincides with the maximum accumulation rate of protein, energy, and organic matter digestibility in herbage [ 20 , 22 , 23 ]. On the other hand, after the plant has reached its ORP, it rapidly redirects nutrients and energy to enter into the reproductive stages, followed by the decline of herbage mass growth rate, drop in leaf to stem ratio, and severe reduction of herbage quality [ 23 , 24 , 25 ].…”