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Rhizoma peanut (RP, Arachis glabrata) hay has the potential to meet horses’ crude protein requirements with less nitrogen excretion than other legumes. This study aimed to evaluate nutrient intake, apparent digestibility, and nitrogen balance of RP ‘Florigraze’ hay compared to alfalfa (ALF, Medicago sativa L. ‘Legendary XHD’) and bermudagrass (BG, Cynodon dactylon L. ‘Coastal’) hays when fed to maintenance horses at 2% BW/d on a dry matter (DM) basis. We hypothesized that nutrient intake would be comparable between the legume hays and lesser for BG, and that RP would result in reduced nitrogen excretion compared to alfalfa. Six mature Quarter Horse geldings (593 ± 40 kg; mean ± SD) were randomly assigned to one of the hays in a replicated 3 x 3 Latin square with 21-d periods. A 14-d adaptation phase was followed by a 3-d total fecal and urine collection. Days 18 to 21 were used for a companion study. Intake of nutrients is reported on a DM basis. Digestible energy (DE) intakes from ALF (29.91 Mcal/d) and RP (29.37 Mcal/d) were greater (P < 0.0001) than BG (20.78 Mcal/d). Crude protein (CP) intake was greater (P < 0.0001) for ALF (2.5 kg/d), followed by RP (1.9 kg/d), and BG (1.5 kg/d). All hays exceeded maintenance requirements for DE, CP, Ca, and P. Apparent digestibility of DM and CP were greatest (P < 0.0001) for ALF (69 and 84%), intermediate for RP (61 and 72%), and least for BG (46 and 64%). Apparent digestibility of neutral detergent fiber did not differ (P = 0.2228) among hays, while digestibility of acid detergent fiber (P = 0.0054) was least for RP but similar for ALF and BG. Water intake (kg/d) for ALF (57) was greater (P=0.0068) than RP (45) and BG (41). Greater (P = 0.0271) water retention (kg/d) was observed for ALF (13.5), followed by RP (10.8) and BG (7.5). There was a difference in nitrogen excretion, with greatest urinary nitrogen excretion for ALF (P < 0.0001) and greatest fecal nitrogen excretion for BG (P = 0.0001). Total nitrogen excretion was greater (P < 0.0001) for ALF (278 g/d), followed by RP (211 g/d), and BG (179 g/d). Nitrogen retention was greater (P = 0.0005) for ALF when represented as g/d (ALF: 129, RP: 86, and BG: 57 g/d), but similar (P = 0.0377) to RP when presented as percent of nitrogen intake (ALF: 32, RP: 29, and BG: 24%). Results indicate that rhizoma peanut hay is a suitable legume for horses by meeting DE and CP requirements and having a significant reduction in nitrogen compared to alfalfa.

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The incorporation of alfalfa (Medicago sativa L.) into bermudagrass [Cynodon dactylon (L.) Pers.] forage systems in the southern United States has increased. Stockpiling this mixture may extend the grazing season into the fall and winter months with high‐quality forage. The objective of this 2‐year study was to evaluate agronomic and structural responses of alfalfa–bermudagrass mixtures managed under five stockpiling periods (6, 8, 10, 12, or 14 weeks) in two locations (Shorter, AL, and Tifton, GA). Across locations, stockpiling mixtures for 8 weeks or longer (2400 lb DM ac−1, on average) resulted in greater (P = 0.001) herbage accumulation than 6 weeks (3185 lb DM ac−1). The alfalfa proportion was similar among stockpiling periods in Shorter but greater (P = 0.043) at 10 and 14 weeks than 6, 8, and 12 weeks in Tifton. A location × year × stockpiling interaction was observed for crude protein (CP, P < 0.001) and in vitro true dry matter digestibility over 48 h (IVTDMD48, P < 0.001). Crude protein concentrations were similar among stockpiling periods in 2020 in both locations. In 2019, however, CP concentrations reduced with increasing stockpiling period length in Shorter and were similar among treatments in Tifton, except for the lesser CP at 8 than at 10, 12, and 14, weeks. Forage IVTDMD48 concentrations declined with increasing stockpiling period length at both locations, with a more pronounced decline in Shorter in 2019. Results suggest that stockpiling alfalfa–bermudagrass mixtures for up to 8 weeks is a viable option to supply high nutritive value forage and lower lodging losses into the early winter months.

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Inclusion of legumes into grass pastures improves pasture quality while significantly decreasing the use of nitrogen (N) fertilizer. Changes in nutritive value of the pasture can affect gut microbiome and health. This study aimed to determine the effects of bahiagrass (Paspalum notatum) pasture intercropped with rhizoma peanut (RP, Arachis glabrata) on forage nutrient composition and fecal variables. Unfertilized bahiagrass (UNF) with no N fertilizer, bahiagrass with 120 kg N.ha-1 (FER), and bahiagrass intercropped with RP and 30 kg N.ha-1 (RP) pastures were evaluated using twelve mature Quarter Horses continuously stocked for 84 days in a randomized block design. Forage and fecal samples were collected every 28 days. Pasture samples were analyzed for nutrient composition by NIR, and fecal samples were analyzed for dry matter (DM), fecal fluid pH and volatile fatty acids (VFA). Data were analyzed using a repeated measure mixed model ANOVA and associations between variables were tested using Pearson’s correlations. Pasture starch was higher (P &lt; 0.01) and non-fiber carbohydrates tended to be higher (P &lt; 0.1) in RP. Hemicellulose and aNDF tended (P &lt; 0.1) to be higher in UNF than in RP. Horses grazing RP tended (P &lt; 0.1) to have greater fecal fluid propionic acid concentration and lower proportion of butyric acid. Proportion of acetic acid was lower (P &lt; 0.05) in FER. Propionic acid concentration was negatively correlated with aNDF (r = -0.55) and ADF (r = -0.52), and positively correlated with ethanol-soluble carbohydrates (ESC, r = 0.55). Butyric acid proportion was negatively correlated with nonstructural carbohydrates (r = -0.70). Horses grazing FER pasture tended to have lower (P &lt; 0.1) fecal DM when compared to RP. Fecal DM was negatively correlated with hemicellulose (r = -0.51), and positively correlated with water-soluble carbohydrates (r = 0.68) and ESC (r = 0.64). Intercropping RP provides pasture nutrient composition superior to UNF and similar to FER with decreased N fertilizer rate, and stimulates positive fermentation outcomes.

Intercropping legume into grass pastures improves pasture quality and decreases the need for nitrogen (N) fertilizer, while providing a more heterogenic grazing environment. This study aimed to evaluate the effect of rhizoma peanut (RP, Arachis glabrata) intercropped into bahiagrass (Paspalum notatum) pasture on horse grazing performance. Unfertilized bahiagrass (UNF) with no N fertilizer, bahiagrass with 120 kg N ha-1 (FER), and bahiagrass with RP and 30 kg N ha-1 (RP) pastures were evaluated using twelve mature Quarter Horses continuously stocked for 84 days in a randomized block design with two blocks. Grazing, activity and leisure behaviors were recorded every 10 minutes for 24 hours on day 35 and 70 using scan sampling. Chew (CR, chew/min) and bite (BR, bite/min) rates were counted for five consecutive 1-min intervals on days 36 and 71. Data were analyzed using a repeated measure mixed model ANOVA. Pasture did not affect (P &gt; 0.05) total time spent on grazing (13.57 ± 1.81 h, mean ± SD), leisure (9.64 ± 1.64 h), and activity (0.79 ± 0.60 h). Pasture x time of day interaction (P &lt; 0.05) was significant for grazing, leisure and activity. Horses grazing FER spent more time grazing between 1100 and 1700 h, whereas horses grazing RP spent more time grazing between 2300 and 500 h when compared to horses grazing FER. Horses grazing FER spent more time in leisure between 2300 and 700 h. No day or pasture effects were observed for BR (30.8 ± 6.3 bites/min, mean ± SD), but a pasture x day interaction was observed for CR. On day 36, CR of horses grazing FER was similar to RP (50.8 and 53.8 chews/min), but lower than RP on day 71 (41.4 and 61.3 chews/min). Intercropping RP into bahiagrass pastures does not affect total grazing, leisure and activity time of horses.