Influence of sward height on bite dimensions of horses

Abstract

The management of pastures used by horses poses various problems: swards are often grazed down rapidly, patches of bare ground and refused areas develop. In order to gain a better understanding of the plant-animal interaction behind this problem the influence of sward height on bite dimensions (bite depth, weight, volume, area) of horses was investigated. Perennial ryegrass (Lolium perenne) microswards were grown on artificial substrate to four different heights (3, 8, 15, 19 cm) but the same plant density. Biomass and bulk density for each sward height was determined. Eight horses (predominantly Thoroughbred ×) were allowed to take six bites of each grass height. Bite depth, weight, volume and bite area were calculated.Bite depth, weight, volume and area were not fixed, but increased with sward height (P < 005). For all sward heights, the horses removed between 51% and 68% of the initial grass length. The horses adjusted their bite dimensions to sward height but did not maximize food intake per bite. The response to sward height might be explained by a preference for easily digested food or the trade-off between energy intake and the cost for food processing.This experiment suggests that grass height has a major influence on bite dimensions of horses. However there may be more complex factors influencing ingestive behaviour of horses (e.g. age, dietary experience and social behaviour) that have to be considered when horses are grazing pasture.

Short-term ingestive behaviour of cattle grazing tropical stoloniferous grasses with contrasting growth forms

“…The observation that the bite dimensions, bite mass and intake rate increase with the sward height in CG and BG (Fig. 1) is in line with the findings of previous studies (Black & Kenney 1984 ;Burlison et al 1991;Laca et al 1992;Gong et al 1996 b;Naujeck & Hill 2003). However, the shapes of the responses differed between the two species.…”

Effects of fire on sward structure and grazing in western Serengeti, Tanzania

“…Herbage height may affect selective feeding behaviour of ruminants (Distel et al. , 1995) as together with bulk density it has influence on bite dimensions (Naujeck & Hill, 2003), and therefore on intake rates. However, the higher quality, in terms of higher ratios of leaf and live phytomass and lower ratio of stem phytomass to total phytomass, is likely to have determined the preference for burnt‐plots in this period.…”

Comportamento ingestivo de equinos e a relação com o aproveitamento das forragens e bem-estar dos animais

“…e Macroptilium spp. para leguminosas (Elphinstone, 1981;Carvalho & Haddad, 1987;Nunes et al, 1990;Webb et al 1990). Especificamente no gênero Cynodon spp., os eqüinos preferem o Tifton 85, Coastcross 1 e Jiggs em relação ao Tifton 68 e ao Tifton 44, enquanto a Estrela Roxa e a Porto Rico são preteridas (Dittrich et al, 2001;Radünz, 2005).…”

“…Os cavalos selvagens, mantém sítios de menor altura e despendem maior tempo em pastejo nos mesmos (Ménard et al, 2002), mas esta estratégia pode estar relacionada a evitar o pastejo em áreas de gramíneas altas contaminadas com fezes (Putman et al, 1987). Em pastagens cultivadas e livres de contaminação prévia por fezes, a escolha dos equinos é por dosséis mais altos e por plantas mais altas, demonstrada pelo maior tempo de pastejo nos dosséis de maior altura e por seleção de plantas mais altas, individualmente, os quais proporcionam maior dimensão de forragem colhida a cada bocado, tanto para gramíneas temperadas (Naujeck & Hill, 2003;Naujeck et al, 2005) quanto para gramíneas tropicais (Dittrich et al, 2005). As duas principais estruturas das plantas (folhas e caules) refletem também a qualidade do alimento colhido pelo cavalo.…”