Preference of goats (Capra hircus L.) for tanniniferous browse species available in semi‐arid areas in Ethiopia

Abstract

The objectives were to determine browse species preference of goats using dry matter intake (DMI) as a proxy, to compare preference when offered in combination with polyethylene glycol (PEG) and to establish relationships between browse species intake and chemical compositional data. Air-dried leaves of Acacia etbaica, Cadaba farinosa, Capparis tomentosa, Dichrostachys cinerea, Dodonaea angustifolia, Euclea racemosa, Maerua angolensis, Maytenus senegalensis, Rhus natalensis and Senna singueana were used. Two cafeteria trials, each lasting 10 days, were conducted using four local mature male goats of 2-2.5 years receiving a daily ration of grass hay (4% of body weight) and 200 g wheat bran. In trial 1, goats were offered 25 g of each browse species for a total of 30 min with intake, time spent on consumption and the number of visits to specific browse species recorded at 10-min intervals. In trial 2, the same procedure was followed except that 25 g of PEG 4000 was added to the daily wheat bran ration. Crude protein and neutral detergent fibre in browse species ranged from 69.0-245.5 to 159.8-560.6 g/kg dry matter (DM) respectively. Total phenols and total tannins contents ranged between 3.7-70.6 and 2.5-68.1 mg tannic acid equivalent/g DM, respectively, and condensed tannins 1.7-18.4 Abs /g DM. Preference indicators measured in the first 10 min of browse species intake differed significantly among browse species and with PEG (p < 0.0001). Principal components explained 69.9% of the total variation in browse species DMI. Despite the high tannin levels, D. cinerea, R. natalensis and A. etbaica were the most preferred species regardless of PEG presence. Tannin levels at the observed browse species DMI did not determine preference, instead, preference appeared to be based on hemicellulose. Determining browse species preference is essential to exploit them to improve nutrient utilization and control parasites in goats.

The in vitro anthelmintic properties of browse plant species against Haemonchus contortus is determined by the polyphenol content and composition

“…CT from sainfoin exhibited anthelmintic properties against exsheathment of H. contortus in vitro and in vivo in sheep (Brunet et al, 2007). The browse plant species used in the present study have been reported to be voluntarily consumed by goats (Yayneshet et al, 2008;Mengistu et al, 2016) and at optimal intake, may exhibit anthelmintic activity against H. contortus. Anthelmintic properties of the browse plant species, however, have to be examined under practical farming conditions before foreseeable future practical application to control H. contortus to improve productivity and health of goats in the study area and for wider application in similar regions.…”

“…This information allows comparisons of anthelmintic properties of polyphenols from different plant sources and across studies. The browse plant species in the present study grow in semi-arid areas (Bein et al, 1996) and are readily consumed by goats in these areas (Yayneshet et al, 2008;Mengistu et al, 2016). However, their anthelmintic properties against goat nematodes are unknown.…”

Feeding Preferences of Domestic and Wild Ungulates for Forage Trees in the Dry Tropics

“…Bite count is a direct measurement with a long tradition in foraging behaviour research [26,27]. This method has been chosen for its ease of application in the field and because it does not require the estimation of the dry weight that is applied in the determination of preferences based on the difference between intake and rejection.…”

In vitro fermentation of browse species using goat rumen fluid in relation to browse polyphenol content and composition

“…Leaves of Acacia etbaica, Cadaba farinosa, Capparis tomentosa, Dichrostachys cinerea, Dodonaea angustifolia, Euclea racemosa, Maerua angolensis, Maytenus senegalensis, Rhus natalensis and Senna singueana were collected by hand-clipping from two area exclosures (protected areas allowed to rest from human and animal intervention) in the Tigray region of Ethiopia in October 2014. The browse species are voluntarily consumed by goats from the same region (Mengistu et al, 2016). From each exclosure, leaves were collected from 15 phenologically similar plants per species, bulked into one sample per species and air-dried in an open shed.…”

“…Regardless of previous exposure to tannins, the saliva of goats is high in proline-rich proteins (Ventura-Cordero et al, 2015). This adaptation enables goats to voluntarily consume substantial quantities of tannin-containing browse species (Yayneshet et al, 2008;Mengistu et al, 2016) commonly found in semi-arid areas.…”