CONSUMPTION AND CHEMICAL COMPOSITION OF SHRUB AND HERBACEOUS SPECIES WITH POTENTIAL TO FEED SMALL RUMINANTS UNDER GRAZING CONDITION

Macchiavelli, Raúl

Ramos-Santana, Rafael

Valencia-Chin, Elide

English

Portal de Revistas Académicas Universidad de Puerto Rico

Research Note 
CONSUMPTION AND CHEMICAL COMPOSITION OF SHRUB AND 
HERBACEOUS SPECIES WITH POTENTIAL TO FEED SMALL RUMINANTS 
UNDER GRAZING CONDITIONS'-2 
Rafael Ramos-Santana3, Elide Valencia-Chin4 and Raúl Macchiavelli6 
J . Agrie. Univ. RR. 94(3-4):275-278 (2010) 
Small ruminant production is a growing newcomer industry in Puerto Rico Most of 
our small ruminant farmers are presently dedicated to the production of meat.The main 
sheep breeds in use are Dorper, Saint Cross, and Cathadine. As to goat breeds, the Boar 
and local genotypes are among the best known. Meat from both sheep and goats com-
mands the highest prices in the local market of about $9 to $11 per kilogram. However, 
even though it is growing this is still a small industry on the islandwith an annual gross 
production of only 136,000 kilograms . At present, one of the industry' s most difficult 
problems is the high cost of concentrate feeds, about $20 per 23 kilogram bag. The intro-
duction of woody forage species sue h as the shrubs Morus alba (Morera) and Hibiscus 
rosa-sinensis in small ruminant production systems could be a possible alternative for re-
ducing the high cost of concentrate feeds used on Puerto Rican farmsAt the Tropical Ag-
ricultural Research and Higher Education Center (CATIE) in Turrialba, Costa Rica, high 
digestibility of these shrubs was demonstrated in studies with lactating goats An in vivo 
digestibility of 79% w as found for Morera, and 64.2% for Amapola (Malvabiscus ar-
bóreas). The in vitro digestibility (89%) of Morera w as also higher than that of seven 
other shrub species native to Costa Rica (Jegou et al., 1994). Rhizoma perennial peanut 
has demonstrated a nutritive value higher than that of tropical grasses in Puerto Rico . 
Mean in vivo digestibility of Florigraze peanut was between 61.7 and 64.4% when fed to 
Holstein heifers (Ruiz et al., 2007). 
More research is needed on the possible use of the above mentioned plant material^ 
because of the high nutritional potential of these forages for ruminants. The objective of 
this study was to evaluate the effects of adding Morus alba leaves and soft twigs (MA), 
Hibiscus rosa-sinensis leaves and soft twigs (HB) andArachis glabrata (AG) chopped fo-
liage to the diet of young lambs grazing on Guinea grass (Panicum maximum) pastures, 
and to evaluate these forages in terms of quality and of dry matter consumption. 
The study was conducted at the CorozalAgricultural Experiment Station of the Uni-
versity of Puerto Rico, where the facilities included a small ruminant stable divided into 
six cages, each provided with salt and water for free choice consumption and a feeder for 
forage placement. Next to these facilities , in an area of 0.6 ha, there were nine fenced 
plots of Guinea grass available for grazing. Additional areas of 0.18, 0.14 and 0.12 ha of 
Morus alba, Hibiscus rosa-sinensis and Arachis glabrata, respectively, were used for har-
'Manuscript submitted to Editorial Board 24 June 2010. 
2This material is based on local research funded by the Agricultural Experiment Sta-
tion, Project SP-421. 
3Professor, Department of Crops and Agroenvironmental Sciences, Agricultural Ex-
periment Station at Corozal. 
4Professor, Department of Crops and Agroenvironmental Sciences. 
6Professor, Department of Crops and Agroenvironmental Sciences. 
275 
2 7 6 RAMOS-SANTANA ET AL./SMALL RUMINANT DIETS 
vesting the supplemental forages offered during stable confinement after Guinea grass 
grazing. 
The initial experimentation took place between 4 September and 17 December 2007. 
During this period forage consumption and forage quality were evaluated. The animals 
grazed the Guinea grass plots between 7:00 a.m. and 2:30 p .m. daily. Thereafter they 
were placed by pairs in four of the stable cages and supplied cut or c hopped forages ac-
cording to the following treatments: 
MA — Cut Morus alba leaves and soft twigs 
HB — Cut Hibiscus rosa-sinensis leaves and soft twigs 
AG — Chopped Arachis glabrata 
GG — Chopped Guinea grass (control) 
The quantity of supplemental forage provided daily under eac h treatment w as 
equivalent to 1.5% of animal body weight on a dry matter basi^The two young lambs per 
cage (16 to 18 kg body weight) were used to determine the level of forage consumption of 
each treatment during a two-week eye le. After every cycle, the four groups of animals 
were rotated, so that each one was fed twice during a total of eight cycles. 
All forages were harvested at regrowth intervals from the 16th week to the 31st 
week. During the first week of eac h cycle the animals were adapted to the new diet of-
fered. In the second week, daily 200-g samples of the offered forages were taken and com-
bined to produce a 7-day composite per treatment. The forages were air-dried in an oven 
at 65° C for two weeks. The sampling dates chosen as representative of typical forage of-
ferings were 13 to 20 November and 11 to 18 December. 
Laboratory evaluations of forage quality were based on determinations of crude pro-
tein (% CP), percentage acid detergent fiber (% ADF), and neutral detergent fiber (% 
NDF) content, and calculated values of total digestible nutrients (% TDN), and net en-
ergy for lactation (NE1), for maintenance (NEm), and for gain (NEg). 
Daily forage consumption proportional to the amount offered, and expressed as a 
decimal fraction, was determined according to the formula: 
Proportional Forage Intake = offered forage — refused forage 
offered forage 
The statistical evaluation of forage consumption employed an ANOVA with diets 
and cycles as fixed effects, and animals as random effect. A T test (LSD) w as used for 
mean comparisons. For the determination of CP, ADF, NDF, TDN, NE1, NEm, NEg of the 
supplemental forages, an ANOVA with LSD tests was used for mean comparison (SAS, 
1990). 
Figure 1 presents the daily proportional forage consumption by pair of lambs during 
the period between 4 September and 17 December 2007. Significant effects (P<0.01) of 
the cycle were detected throughout the whole experiment. Consumption of lea ves and 
soft twigs of the shrubs MA and HB was significantly (P < 0.01) higher than that of the 
chopped forage of AG and GG in the period between mid October and December The dis-
tribution of forage consumption points in the graph is seen to be more consistent in most 
of the periods with the MA diet rather than with the diets of other forages. 
Table 1 presents the mean Tukey-Kramer least square mean (LSM) of the four for-
age treatments under evaluation over the whole experimental period. We found signifi-
cantly (P < 0.01) higher mean proportional consumption of forage shrubs MA and HR 
(leaves and soft twigs) than of GG and AG as chopped herbage. The high proportion of 
stems observed in GG andAG might have caused the low consumption rates obtained for 
J. Agrie. Univ. P.R. VOL. 94, NO. 3-4, JULY-OCTOBER 2010 277 
1sep07 16aep07 31oct07 17oct07 2nov07 18nov07 3dec07 17dec07 
Date 
Treatments: Arachis Guinea Hibiscus Morus 
FIGURE 1. Daily proportional forage intake under each treatment. 
these forage species. Because the level of plant maturity in both shrub species was high, 
the use of leaves and soft twigs was more pertinent for this evaluation.If these shrub spe-
cies were used to feed small ruminants under an energy or protein bank of browsing sys-
tem, excellent forage consumption could be expected based on the present results 
Table 2 presents a comparison of the least square means for the different criteria of 
chemical composition and energy values of the supplemental forages No significant (P < 
0.01) differences were observed among the three non-gramineous species MA, HB and 
AG in contents of CP, NDF, TDN, or the three net energy values. The three non-gramin-
TABLE 1.—Mean proportional consumption of Morus alba (MA) and Hibiscus rosa-
sinensis (HB) (leaves and soft twigs) and Arachis glabrata (AG) and Guinea 
grass (GG) (chopped) offered as supplemental forage between 4 September 
2007 and 17 December 2007. 
Treatment (Diet) Consumption 
MA 
HB 
AG 
GG 
0.92 a1 
0.90 a 
0.76 b 
0.78 b 
'Means with different letters are significantly different (P < 0.05). 
2 7 8 R A M O S - S A N T A N A ET AL./SMALL RUMINANT DIETS 
TABLE 2.—Comparison of the Least Square Means of percentage content ofCP, ADF, 
NDF, and TDN, NEl, NEm and NEg values of the supplemental forages on 
the dry basis. 
Forage species 
(Treatment)1 
MA 
HB 
AG 
GG 
Mean 
LSD 
CP% 
25.5 a2 
18.4 a 
17.7 ab 
7.0 b 
17.1 
11.2 
ADF% 
21.5 c 
16.1c 
35.3 b 
48.2 a 
30.3 
9.7 
NDF% 
43.6 b 
33.5 b 
48.0 b 
79.0 a 
51.0 
21.2 
TDN% 
64.0 a 
66.0 a 
62.0 a 
53.5 b 
61.4 
6.3 
NEl 
Mcal/kg 
1.43 a 
1.54 a 
1.36 a 
0.62 b 
1.23 
0.33 
NEm 
Mcal/kg 
1.23 a 
1.96 a 
1.19 a 
0.88 b 
1.14 
0.22 
NEg 
Mcal/kg 
0.73 a 
0.79 a 
0.66 a 
0.37 b 
0.64 
0.20 
'Means of two collection periods: 13 to 20 November, and 11 to 18 December 2007. 
^ e a n s in the same column for each parameter with different letters are significantly 
different (P < 0.01). 
eous species (MA, HB and AG) showed significantly (P < 0.01) higher energy values and 
lower fibrous fractions than GG. 
The present findings of high consumption and forage quality of MA and HB point to 
the desirability of using these forages in the diets of small ruminants in Puerto RicoThe 
high level of acceptance of the shrub species MA and HB , given to young lambs as sup-
plements under grazing conditions, was noteworthy. The significantly (P < 0.01) higher 
mean forage consumption of these two shrubs offered as lea ves and soft twigs was over 
that of AG and GG consumption when offered as chopped forage, thus indicating a pref-
erence in young lambs for leaves and soft twigs. This difference should also be related to 
the lower ADF content of the two shrub species and the higher stem proportions of AG 
and GG. Further research is needed in relation to the use of these forage shrubs under 
more extensive farm conditions , where complex management factors need to be ad-
dressed. 
LITERATURE CITED 
Jegou, D., J. J. Waelput and G. Brunschwig, 1994. Consumo y digestibilidad de la materia 
seca y del nitrógeno del follaje de Morera ( Morus sp.) y Amapola (Malvabiscus ar-
boreus) en cabras lactantes. Informe Técnico 236, CATIE, Vol. 1, P. 155-162. 
Ruiz, T. M., M. de L. Lugo, A. Sotomayor-Ríos, R. Ramos-Santana, E. Valencia and D. So-
tomayor-Ramírez, 2007. Release of 'Henorico' rhizoma perennial peanut ( Arachis 
glabrata Benth.) J. Agrie. Univ.P.R. 91(l-2):81-85. 
SAS Institute, 1990. SAS Users Guide, SAS Institute, Cary, NC. 


CONSUMPTION AND CHEMICAL COMPOSITION OF SHRUB AND HERBACEOUS SPECIES WITH POTENTIAL TO FEED SMALL RUMINANTS UNDER GRAZING CONDITIONS

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CONSUMPTION AND CHEMICAL COMPOSITION OF SHRUB AND HERBACEOUS SPECIES WITH POTENTIAL TO FEED SMALL RUMINANTS UNDER GRAZING CONDITIONS

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