What determines grazing preference for Mediterranean woody species? Perevolotsky A. Systèmes sylvopastoraux. Pour un environnement, une agriculture et une économie durables Zaragoza : CIHEAM Cahiers Options Méditerranéennes; n. 12 1995

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Zaragoza : CIHEAM

Cahiers Options Méditerranéennes; n. 12 1995

pages 221-224

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--- Perevolotsky A. Wh at determin es grazin g preferen ce for Mediterran ean woody species?.

Systèmes sylvopastoraux. Pour un environnement, une agriculture et une économie durables . Zaragoza : CIHEAM, 1995. p. 221-224 (Cahiers Options Méditerranéennes; n. 12)

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woody species ?

Perevolotsky Avi

-

Summary: This the of the value vs. the of

that minimizing tannin ingestion is

the since goats must

1.5-2.0 kg diet is of abundance,

low content of

to

to of

woody 'plants but not as an its

of in

et al., selectivity is obviously affected, to

- -

The objective of this study was to in detennining

3lo40'N, longitude 34*55'E, elevation

-

350 m,

-

400 mm). The woody vegetation in the

dominated by Cistus lentiscus and

lycioides) and low Quercus calliprinos and

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in the goat diet (equivalent of r in

-

- -

the of'a given

food item in (r) to of

(p)

-

was used quantifying plant selectivity.

the most common species in the goats' diet:

Cistus sp., latfolia, and of

lentiscus

of the dominant species by the

the the common species in the study

to any

avoidence of 2 by

Quercus

calliprinos Cistus and is chosen in

of the in

Table 1.

to the it

compounds

(fig.3). the

'Table 1. The nutritional and tannin content in,foliage of dominant species

I I I I I 1

( Y O )

Herbaceous vegetation **

** -

^the ⁽³^months)

* -

in of weight.

47.00 8.00

11.50

40.00 8.00

45.00 0.70

40.00 7.50

35.60 2.20

Quercus calliprinos

52.00 9.50

44.40 5.40

Cistus spp.

70.00 15.00

70.00 0.20

This study suggests that a combination of attempting to of

l'maxi-minil' in

222

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Fig. 1. Grazing time (%) of most commón species 3

Species

veg. Cistus sp. Quercus cal. PhiUyrea Pistacia lent.

Fig 2. Species

n.5 'I

veg. EI

Ø r=p Cistus

o

0.0 0.2

Species presence in the field (p) (%) ^0.4

Fig. 3. The relationships between species preference

4

and tannin content / nutritional value

3

Nut-index 2

y (tannins)= 1.4521

+

= 0.766

y (nut.)= - 0.46548

+

0.33087~

1

2 4 6 8 1 0 1 2

Nutritional value or tannin content

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et al., in 'menu.'

in the of to low value, it

is efficient to consume them on an availability basis and thus obtaining the the

diet in to the diet quality, goats also selective

While doing so, the level of ingested tannins (as well as chemicals) may induce

a diet switch once effects 'with the

continuous need to sample the vegetative community and the limited

the the goat diet selectivity in the

The these not

as much as selective mixed the

of a minimum amount of digestive maintenance

within a limited of time, while avoiding the ingestion of too compounds.

Bryant J.P., Provenza Pastor J., T.P,, du Toit J.T., 1991.

and Systematics

1986. Effects of plant spinescence on Oecologia 68:446-455.

A.E., Butler 1978. quantitative of tannins.

Journal 26:809-812.

1982. of the XXY,

Con$ on Goat pp. 398-403

1961. Ecology of the Feeding of Fishes. New Conn., Yale

1988. and diet selection of goats. 1:205-216.

Perevolotsky A., Y., 1991. The effect of thinning and goat on the and

Perevolotsky A., Y., 1992. of woodland species to

1990. of woody plant in an Acacia

development of woodland in 49:61-74.

evidence of defense Botany 40:305-313.

Senegal savanna of East 3:211-225.

224