Daily intake and the selection of feeding sites by horses in heterogeneous wet grasslands

Abstract

-In spite of the importance of grazed forage in horse nutrition, little information is available on their daily intake at pasture. We determined the intake of 4 non-breeding mares of a heavy breed (average body weight = 674 kg), grazing during the summer in heterogeneous natural grasslands of the Marais Poitevin (France), an internationally important wetland where grazing is an essential process which maintains biodiversity. The mares ate large quantities of forage (21.9 ± 2.4 kg of organic matter per day, i.e. 166.2 ± 20.8 g of organic matter per kg LW 0.75 per day) in comparison with previous published values and with the estimated requirements of these horses. The use of the vegetation was very selective, the mares spent about 70% of their feeding time on short grass lawns (sward surface ≤ 4 cm, biomass < 100 g . m -2 ), that represented only 10% of the area. This behaviour maintained the plants at young growing stages which are of better quality than ungrazed plants. These results are discussed in relation to the dynamics of the plant communities.horse / intake /grassland / heterogeneity / wetland Résumé -Quantités ingérées et sélection alimentaire réalisées par des chevaux en prairies humides hétérogènes. Malgré l'importance de l'herbe dans l'alimentation du cheval, peu de données sont disponibles concernant les quantités ingérées au pâturage. En juillet-août 1997, nous avons déterminé les niveaux d'ingestion de 4 juments de race lourde à l'entretien (poids moyen : 674 kg) pâturant au sein de prairies naturelles hétérogènes du Marais Poitevin (France), un marais d'importance internationale où le pâturage est un processus essentiel au maintien de la biodiversité. Les juments ingéraient d'importantes quantités d'herbe (21,9 ± 2,4 kg de matière organique par jour, i.e. 166,2 ± 20,8 g de matière organique par kg PV 0,75 par jour) en comparaison des résultats publiés antérieurement et des besoins estimés pour ces animaux. Les juments utilisaient la végétation de manière très sélective, passant environ 70 % de leur temps d'alimentation sur des zones d'herbes rases (hauteur ≤ 4 cm, biomasse < 100 g . m -2 ) qui couvraient 10 % de la surface totale. Ce comportement G. Fleurance et al. 150

Selection of feeding sites by horses at pasture: Testing the anti-parasite theory

“…The horses used the taller grass (>16 cm) much less than expected, whatever the risk of consumption of infective larvae, which is typical for horses in temperate grasslands (Ö dberg and Francis-Smith, 1977;Edwards and Hollis, 1982;Putman, 1986;Fleurance et al, 2001;Ménard et al, 2002). This is consistent with the Forage Maturation Hypothesis (Fryxell, 1991) which argues that herbivores should select swards of intermediate, not high, biomass to maximise the daily intake of digestible nutrients because of the inverse relationship between the abundance and the quality of plant tissues.…”

Horse Welfare and Natural Values on Semi-Natural and Extensive Pastures in Finland: Synergies and Trade-Offs

“…Dry matter intake also increases with herbal mass of the pasture [67], which is at its largest in cool-season grasses during the summer months [29]. However, performance of the horses is affected by the botanical composition and nutritional value rather than the mass [24,66].…”

How does the suppression of energy supplementation affect herbage intake, performance and parasitism in lactating saddle mares?

“…We therefore used the method of total faecal collection which has been considered as the reference method in the Herbage Intake Handbook (Penning, 2004). This method was used in a large number of horse studies (Duncan, 1992;Mésochina et al, 2000;Fleurance et al, 2001;Grace et al, 2002a and2002b;Edouard et al, 2009 andFleurance et al, 2010). Estimation of FO required collecting the total amount of faeces produced daily over 4 successive days after the paddock had been cleaned of faeces.…”