SciELO - Scientific Electronic Library Online

vol.10 issue4Productive and economic response to concentrate supplementation by grazing dairy cows at high stockingStress indicators in cattle in response to loading, transport and unloading practices author indexsubject indexsearch form
Home Pagealphabetic serial listing  

Services on Demand




Related links

  • Have no similar articlesSimilars in SciELO


Revista mexicana de ciencias pecuarias

On-line version ISSN 2448-6698Print version ISSN 2007-1124

Rev. mex. de cienc. pecuarias vol.10 n.4 Mérida Oct./Dec. 2019  Epub Apr 30, 2020 


Productive and ingestive behavior in growing hair sheep in silvopastoral and stabled weight-gain systems

Carlos Ricardo Villanueva-Partidaa 

Víctor Francisco Díaz-Echeverríaa  * 

Alfonso Juventino Chay-Canulb 

Luis Ramírez-Avilésc 

Fernando Casanova-Lugoa 

Iván Oros-Ortegaa 

a Tecnológico Nacional de México, Instituto Tecnológico de la Zona Maya, División de Estudios de Posgrado e Investigación, Km 21.5 carretera Chetumal a Escárcega, Ejido Juan Sarabia Quintana Roo, México.

b Universidad Juárez Autónoma de Tabasco, División Académica de Ciencias Agropecuarias, Villahermosa Tabasco, México.

c Universidad Autónoma de Yucatán, Facultad de Medicina Veterinaria, Xmatkuil Yucatán, México.


In sheep silvopastoral systems, forage legumes are promising alternatives to commercial feed since they can lower costs. An evaluation was done comparing productive and ingestive behavior parameters in hair sheep in silvopastoral and stabled systems for four months. Nine variables were evaluated: dry matter intake (DMI); organic matter intake (OMI); crude protein intake (CPI); neutral detergent fiber intake (NDFI); daily weight gain (DWG); feeding time (FT); rumination (RT); walking (WT); and other activities time (OAT). Experimental animals were eighteen sheep (initial weight= 16.83 x 2.57 kg) distributed in a completely random design, with three treatments: a silvopastoral system (SPS) including the legume Leucaena leucocephala and the grass Cynodon plectostachyus (L+E); another SPS including L. leucocephala and the grass Panicum maximum (L+M); and a stabled weight-gain system (SWS). Orthogonal contrasts were applied to compare the SWS vs SPSs and the two SPSs. Compared to the two SPSs, all intakes (DMI= 1246.2 g; OMI= 1073.0 g; CPI= 157.1 g; and NDFI= 364.0 g animal d-1) and DWG (195 g animal d-1) were higher (P<0.001) in the SWS. Daily weight gain did not differ between the SPSs (102 and 114 g animal d-1), but all intakes were higher (P<0.001) in L+M (DMI= 772.2 g; OMI= 662.7 g; CPI= 124.0 g; and NDFI= 334.2 g animal d-1) than in L+E (DMI= 548.9 g; OMI= 86.20 g; CPI= 483.0 g; NDFI= 252.3 g animal d-1). Feeding time (FT) was shortest (P<0.001) in the SWS (148.33 min). Between the SPSs, FT was shortest (P<0.05) in the L+E (318.3 min) than in the L+M (344.6 min). Time dedicated to other activities was longer (P<0.001) in the SWS (247.9 min) than in the SPSs. Silvopastoral systems combining legumes and grasses provided sufficient growth in hair sheep although the stabled weight gain system produced faster growth in the studied time period.

Key words Grazing; stabled; productive and ingestive parameters


El objetivo fue comparar los parámetros de comportamiento productivo e ingestivo de ovinos alimentados en sistemas silvopastoriles y confinamiento. Se evaluaron los consumos de materia seca (CMS), de materia orgánica (CMO), de proteína cruda (PC) y de fibra detergente neutro (CFDN), la ganancia diaria de peso (GDP), el tiempo dedicado al consumo (TPC), a la rumia (TPR), a caminar (TPCM) y otras actividades (TPOA), en 18 ovinos con peso inicial de 16.83 ± 2.57 kg, distribuidos en un diseño completamente al azar, con tres tratamientos: dos tipos de sistemas silvopastoriles (SSP): 1) Leucaena leucocephala y Cynodon plectostachyus (L+E); 2) L. leucocephala y Panicum maximum (L+M); 3) Sistema de engorda en confinamiento (SEC). Se realizaron contrastes ortogonales para comparar el SEC vs los SSP y entre los SSP. Se encontró un mayor (P<0.001) CMS, CMO, CPC, CFDN y GDP en el SEC (1246.2, 1073.0, 157.1, 364.0 y 195 g animal día-1, respectivamente) comparado con los tipos de SSP. Los CMS, CMO, CPC y CFDN fueron mayores (P<0.001) en el L+M (772.2, 662.7, 124.0, 334.2 g animal día-1, respectivamente) que en L+E (548.9, 86.20, 483.0, 252.3 g, respectivamente); aunque la GDP fue similar en ambos SSP (102 y 114 g). El SEC resultó con un menor (P<0.001) TPC (148.33 min) que los SSP. Animales en L+E invirtieron menos (P<0.05) TPC (318.3 min) que en L+M (344.6 min). Animales en SEC utilizan mayor (P<0.001) TPOA (247.9 min) que en los SSP. Sin embargo, el TPOA fue similar entre los SSP.

Palabras clave Pastoreo; Estabulado; Parámetros productivos e ingestivos


Sheep production in the tropics of Mexico has been growing in response to increasing demand and attractive market prices. However, productivity in grazing sheep is limited mainly by low pasture availability and quality during the dry season. This affects lamb growth and development and consequently the time required for finishing animals for sale1.

An alternative for addressing problems of low fodder availability and quality is the use of forage trees and shrubs which have higher nitrogen content than grasses, a compound that promotes proper rumen functioning2. Forage trees and shrubs are also an excellent source of digestible energy and can provide bypass protein, which is required to ensure a productive response in grazing animals under tropical conditions3.

Integration of forage trees and bushes into sheep production systems in the tropics has grown as silvopastoral systems (SPSs) are implemented as an alternative in livestock production. These systems associate trees and shrubs with traditional elements (i.e. grasses and animals) within a comprehensive management system that provides high fodder availability and quality for animal feed year-round as well as providing environmental benefits4. However, it is important to understand sheep ingestive behavior in these systems. For example, animals with limited grazing in SPS use most of their time for feeding, with minimal time dedicated to walking or extended rest and ruminating periods5.

Most studies show positive effects on voluntary intake and animal weight gain when controlled quantities of forage tree species are included in diets6,7. However, these studies have been done under controlled conditions with stabled animals and may not express the actual potential of forage tree species since grazing animals have greater energy expenditure, which may limit maximum productive expression of this feed alternative2.

The leguminous forage tree Leucaena leucocephala has been widely studied and is commonly used for establishing SPS in the tropics. In Mexico little is known about this legume’s potential when used in SPS and how it affects weight gain in ruminants8 in comparison to stabled conditions. More knowledge is needed on the use of alternative forage plants to replace commercial feeds, which increase production costs. Although SPSs have been extensively studied in other countries, in southeast Mexico further evaluation is needed of these systems when animals are directly involved in the system through grazing, and to assess if their use is feasible for weight gain and finishing of animals intended for market. The present study objective was to evaluate productive and ingestive parameters in hair sheep grazing two SPSs based on L. leucocephala and compare them to a stabled weight gain system (SWS).

Material and methods

Study area

The study was done at the Instituto Tecnológico de la Zona Maya (18°31’ N; 88° 29’ W), in the state of Quintana Roo, Mexico. Regional climate is warm sub-humid (Aw1), with annual mean temperatures ranging from 24.5 to 25.8 °C9. Based on the IUSS classification system, soils are predominantly haplic greysols10. The study was done during the rainy season, from September to December 2016.

Animals, handling and feeding

Experimental animals were 18 males (Pelibuey × Blackbelly) with a 16.83 ± 2.57 kg initial weight. These were randomly divided into three groups of six animals each, corresponding to three treatments. The animals were weighed at the beginning of the trial and deparasitized with 1% ivermectin at 1 ml / 50 kg live weight (LW) (Iverfull®, ArandaLab®) and 5% closantel at 1 ml / 10 kg LW (Closantel-Panavet® 5%). They were administered two vitamin supplements: 2 ml per animal of a multivitamin containing retinol (Vit. A), colecalcipherol (Vit. D3) and tocopherol acetate (Vit. E) (Vigantol ADE-Bayer); and 5 ml per animal of a B complex (Complejo-B, Virbac). They were allowed 15 d adaptation before the treatments were begun. Disease treatment was done following established national animal welfare and health guidelines (NOM-062-ZOO-1999).

Three treatments were evaluated: SWS, based on a commercial feed concentrate and fresh grass; L+E, based on L. leucocephala and Cynodom plectostachyus; and L+M, based on L. leucocephala and Panicum maximum.

Evaluated variables

Nine variables were evaluated. Five were productive variables (g animal-1 d-1): daily weight gain (g animal-1 d-1; DWG); dry matter intake (DMI); crude protein intake (CPI); organic matter intake (OMI); and neutral detergent fiber intake (g animal-1 d-1; NDFI). Another four addressed ingestive behavior (minutes): feeding time (FT); ruminating time (RT); walking time (WT); and other activities time (OAT).

Available forage estimation

Before the grazing treatments, random samples were collected of forage in each area following an established technique11. Briefly, a one square-meter frame was placed over an area containing grass and this cut to 10 to 15 cm above soil surface, approximating the height at which the animals were observed to graze it. Leucaena leucocephala was cut at 40 cm above soil surface. Samples were weighed fresh. A subsample was dried in a forced air stove for 72 h at 60 °C to constant weight and weighed. These data were used to calculate dry matter content per hectare. All the samples were ground for later chemical composition analyses.

Pens and feeding

In the SWS, animals were housed in individual pens divided by sheep fencing in a building with concrete walls and floors, and a sheet metal roof. Each pen was equipped with feeders and water bottles, and feed and water were freely available. The commercial feed (Maltacleyton Premium) was adjusted according to production stage (15% CP in months 1 and 2, and 13% CP in months 3 and 4). Chopped fresh grass (P. maximum cv. Mombaza) was provided separately. Throughout the experimental period the feed ratio was 70 % feed concentrate and 30 % grass.

In the SPSs the animals were grazed in pastures containing 36,000 L. leucocephala plants with grass between the rows. These plots were established in 2014 under seasonal conditions and without application of fertilizers. Electric fence was used to divide each SPS pasture (1 ha) into four 2,500 m2 paddocks. These were trimmed every 60 d at a height of 40 cm for L. leucocephala and 10 to 20 cm for the associated grasses. The daily area used per animal lot inside the paddocks averaged 178 ± 29.54 m2. This was calculated based on average dry matter intake (DMI) per animal (3 to 4.5 % LW) and adjusted every fourteen days. Rotational grazing was used with polywire fence from 0700 to 1600 h; a container of clean water was provided during this time. After grazing the animals were stabled in individual pens like those used in the SWS treatment, where they were provided with a portion equivalent to 20 % commercial feed concentrate based on the quantity offered animals in the SWS (70 % of total diet). Grazing time and feed in all three treatments were adjusted every 14 d.

Voluntary intake (VI)

Voluntary intake (VI) in the SWS was determined using the difference between the feed offered and that rejected during 24 h. Values for DMI, OMI, CPI and NDFI were estimated using VI and the chemical composition of the feed concentrate and grass.

In the SPSs, VI was estimated individually with the external marker technique12, using chromium oxide (Cr2O3) as a marker. This was administered the animals for eleven days during the second and fourth months of testing. Stool samples were collected directly from the rectum over three days, dried in a forced air stove at 60 °C to constant weight, and ground.

Daily weight gain (DWG)

Daily weight gain was measured by weighing animals on a digital scale, after a 15-hour fast, at 0, 14, 28, 42, 56, 75, 84, 98, 112 and 140 d. Weight was measured before feeding, and DWG estimated as the slope of the linear regression between VI and days.

Ingestive behavior

The activities involved in ingestive behavior were documented following an established methodology13 in which three sheep were randomly selected per treatment and one observer assigned each animal. Animal activities were recorded every 5 min during a 9-hour period (equivalent to grazing time) over four consecutive days every month from October to December. The total time allotted each activity by the animal was calculated based on behavioral activity times in five-minute intervals.

Laboratory analysis and calculations

Samples were taken of the commercial feed, grasses, legumes and weeds eaten by the animals to measure DM, OM and CP contents with AOAC techniques14, while NDF content was measured according to Van Soest et al15.

Feces Cr2O3 content was measured with a microwave plasma atomic emission spectroscope (MP-AES 4200, Agilent) coupled to a nitrogen generator (Genius 5200, Peak). In vitro dry matter digestibility (IVDMD) was quantified in forage samples from each SPS16. Feces production and DMI were estimated using published formulas17, and adding DMI corresponding to the feed concentrate provided in the pens:

Feces Prod. (g DM/day) =Marker Dose (mg/day)Marker concentration in feces (mg/g DM)

Voluntary intake (g/day)=Feces production (g DM/day)[1 - (IVDMD/100)]

Estimates of DMI, CPI, OMI, and NDFI were made using VI values and chemical composition for the grasses, weeds, L. leucocephala and feed concentrate.

Experimental design and statistical analysis

Response variables were compared with an orthogonal contrast test in a completely random design with three treatments and six replicates. Calculation of differences between SWS vs L+E and L+M, as well as L+E vs L+M were done with the PROC GLM in the SAS statistics program18.

Results and discussion

Forage availability and chemical composition

The L+M system provided more (P<0.05) dry matter than the L+E system, which is unexpected since C. plectostachyus had higher DM, NDF and OM contents than P. maximum.

Table 1 Chemical composition of forage species and feed concentrate, and forage availability in the silvopastoral systems.  

Content L. leucocephala C. plectostachyus P. maximum Feed concentrate
DM, % 25.08 ± 3.71 28.5 ± 5.52 21.30 ± 3.96 89.05 ± 2.70
CP, % 21.38 ± 1.17 8.21 ± 1.68 8.36 ± 1.38 13.33 ± 0.43
NDF, % 37.58 ± 1.97 57.50 ± 1.31 55.15 ± 1.88 12.25 ± 0.75
OM, % 86.46 ± 0.92 89.37 ± 0.49 84.42 ± 1.24 85.51 ± 0.11
Forage availability (t DM ha-1):
System Total
L+E 3.56 ± 0.71 3.73 ± 0.77 7.30 ± 1.49 b
L+M 2.01 ±0.19 8.64 ±0.09 10.65 ±0.28 a
P value 0.012

L+E = Leucaena leucocephala + Cynodon plectostachyus; L+M = Leucaena leucocephala + Panicum maximum.

ab Different letter superscripts in the same column indicate significant difference (P<0.05).

Weight gain

Daily weight gain (DWG) was higher in the SWS (P<0.001) than in the SPSs, which did not differ (P>0.05). Animals in the SWS had higher DMI, PCI, OMI and NDFI (P<0.001), than in the SPSs, and those in the L+M had higher values (P<0.001) than those in the L+E (Table 2).

Table 2: Daily weight gain and nutrient intake in hair sheep in a stabled weight gain system (SWS) and two silvopastoral systems (g animal-1d-1)  

Treatments Contrasts
Parameters SWS L+E L+M SE Cont. 1 Cont. 2
DWG 195 102 114 8.7 ** NS
DMI 1246.2 548.9 772.2 22.6 ** **
CPI 157.1 86.2 124.0 3.4 ** **
OMI 1073.0 483.0 662.7 19.7 ** **
NDFI 364.0 252.3 334.2 11.5 ** **

DWG = daily weight gain; DMI = dry matter intake; CPI = crude protein intake; OMI = organic matter intake; NDFI = neutral detergent fiber intake; Cont. 1 = SWS vs. SPSs; Cont. 2 = L+E vs. L+M; SE = standard error between means.

**= P<0.001; NS= P>0.05.

The higher DWG in the SWS was associated with the increased DMI, PCI, OMI and NDFI in this treatment. Similar results have been reported in sheep fed diets containing high proportions of concentrate (14% CP and 8.36 MJ/kg DM) in which higher concentrate consumption may have led to greater DM ruminal degradability and ruminal flow rate, and consequently more weight gain19. In another study the production parameters in goats fed diets supplemented with peanut cake were directly linked to nutrient intake which influences dietary fiber digestibility and weight gain during growth20, similar to the present results.

The lack of significant difference in DWG between L+E and L+M may indicate that the higher DMI (223.24 g animal-1 d-1), OMI (179.66 g animal-1 d-1) and CPI (37.80 g animal-1 d-1) values in L+M were insufficient to digest the higher NDFI (81.94 g animal-1 d-1) present in both SPSs. This coincides with a previous report suggesting that consumption of higher amounts of cellulose and lignin in ruminants fed tropical grasses and legumes reduced forage transit rate, leading to longer rumen retention times, and consequently modifying DWG21.

In the SWS, the DWG values (195 g animal-1 d-1) were slightly higher than those reported for sheep fed different proportions of grain silage (maize, sorghum and millet) plus 50 % commercial feed concentrate (120 to 180 g animal-1 d-1)22. In contrast, the DWG values for L+E (102 g animal-1 d-1) and L+M (114 g animal-1 d-1) were similar to those reported for hair sheep grazed in a SPS containing L. leucocephala (35,000 plants/ha) and P. maximum (106 g animal-1 d-1)23. Weight gain in the two studied SPSs was within DWG ranges reported for lambs fed feed concentrate plus the grass Pennisetum purpureum plus 30 % inclusion of the forage trees Moringa oleifera or Trichanthera gigantea (96 to 155 g animal-1 d-1)24, and for sheep fed the grass C. plectostachyus and different inclusion levels of the forage trees Guázuma ulmifolia, L. leucocephala or Gliricidia sepium (54 to 137 g animal-1 d-1)25.

Intake values in the SWS (DMI, 1,246.24 g; CPI, 157.11 g; OMI, 1073.03 g; and NDFI, 363.99 g animal-1 d-1) are near those for growing Pelibuey lambs fed the grass Cenchrusaris ciliaris Link. and a conventional concentrate including exogenous enzymes (DMI, 1029 to 1120 g; OMI 928 to 976 g; CPI 130 to 137 g; NDFI 447 to 470 g animal-1 d-1)26.

One aspect to consider in the present study is that the animals were allowed to graze for nine hours. Given the season, forage intake can decline between 1100 and 1400 h due to extreme heat, which may have contributed to reducing intake and thus lowering DWG in the SPS treatments. Moreover, feeding of 20 % concentrate in the pens after grazing may have conditioned the animals to wait for this ration, consequently decreasing their feeding time and intake on the pasture.

Feeding behavior

Animals in the SWS spent less time feeding than those in the SPSs (P<0.001). In addition, animals in the L+E spent less time feeding than those in the L+M (P<0.05). Time spent walking (WT) and ruminating (RT) did not differ between the SWS and the SPSs (P>0.05). This is of note since the SWS included less fiber in the diet and would be expected to have had a shorter RT than in the SPSs. Perhaps this is due to the animals in the SPSs choosing young grass and legume leaves, which would lower their fiber intake and result in similar rumination times in the three studied systems. Other activities (OAT) occupied a greater portion of the time in the SWS than in the SPSs (P<0.01), although OAT values did not differ between L+E and L+M (P>0.05) (Table 3).

Table 3 Ingestive behavior in the stabled weight gain system and two silvopastoral systems based on L. leucocephala and associated grasses 

Treatments Contrasts
Activity SWS L+E L+M SE Cont. 1 Cont. 2
Feeding time, min 148.33 318.33 344.58 8.28 ** *
Walking time, min 20.00 24.17 30.00 7.25 NS NS
Ruminating time, min 62.08 53.75 31.67 10.33 NS NS
Other activities, min 247.92 83.75 73.75 12.90 ** NS

SWS = stabled weight gain system; L+E = Leucaena leucocephala + Cynodon plectostachyus; L+M = Leucaena leucocephala + Panicum maximum; SE= standard error between means;

Cont. 1 = SWS vs. SPSs; Cont. 2 = L+E vs. L+M.

*= P<0.05; **= P<0.001; NS= P>0.05.

Feeding times (FT) in the present results were higher than those reported in sheep fed ammoniated C. ciliaris L. in which this variable accounted for 38.4 % of daily activities27; these differences are probably due to use of a 9 h daily observation period in the present study compared to a 24-h period in the previous study. However, the present results are similar to those reported for other ruminants (bovines) in a restricted grazing regime including Bracharia humidicola and P. maximum infested with legume creepers28, and another regime involving Cynodon nlemfuensis supplemented with corn distillers grains in the dry season29.

The present ingestive behavior results also coincide with those reported for goats in an SPS using P. maximum, L. leucocephala, native legumes and natural pastures5, in which the animals spent most of their time walking and feeding (152 min and 36.28 % during 8 h observation). In another study goat kids grazing C. nlemfuensis were found to prefer grazing pasture in the daytime, spending from 82 to 83 % of their time doing it30. The fact that FT in the present results was shortest (15.44 min) and least frequent (31.34 %) in the SWS treatment may be associated with several factors such as feed supplementation. This has been reported elsewhere in ruminants grazing C. nlemfuensis supplemented with 1.5 or 2.5 kg corn distillers grains in which feeding time was shorter and thus allowed more time for other activities or resting29.

Differences in FT between the SWS and the SPSs, as well as between the two SPS treatments, may be due to variations in diet NDF content. For example, in a report on sheep fed ammoniated C. ciliaris L. hay higher dietary fiber content was related to longer rumination time, suggesting that the time spent on feeding and ruminating was influenced by diet composition and was probably proportional to cell wall content27. This does not coincide with the rumination times and frequencies in the SPSs studied here which had shorter rumination times and frequencies than previous reports26; worth noting is that after grazing the animals did engage in rumination once penned. However, the previous results are similar to the rumination time and frequency in the SWS, perhaps due to lower grass (and therefore fiber) content in the diet.

More research is needed to corroborate hair sheep productive and ingestive behavior year-round. The number of observations used in the present study was limited due to the difficulty of observation during the rainy season. Despite some limitations, the present results provide an encouraging picture of the use of silvopastoral systems in sheep production in southern Quintana Roo.

Conclusions and implications

Hair sheep in the stabled weight-gain system exhibited greater weight gain than the silvopastoral systems due to higher dry matter, crude protein, organic matter and neutral detergent fiber intake, and they required less time to feed. Weight gain in the two tested silvopastoral systems did not differ despite higher intake levels in the L. leucocephala-Mombaza grass association, probably due to longer feeding time. Walking and ruminating times did not differ between the three production systems. Silvopastoral systems are promising alternative production systems in the tropics because they incorporate tree legumes such as L. leucocephala. These are rich in nutrients, particularly protein, and promote higher feed intake in ruminants consequently increasing livestock production under grazing conditions and reducing dependence on external inputs.


The research reported here formed part of the Master’s degree of Carlos Ricardo Villanueva-Partida, and was financed by the Programa para el Desarrollo Profesional Docente (superior), Tecnológico Nacional de México (proyecto: ITLZM-CA-1) and the Consejo Nacional de Ciencia y Tecnología (proyecto: 270666).


1. González-Garduño R, Blardony-Ricardez K, Ramos-Juárez JA, Ramírez-Hernández B, Sosa R, Gaona-Ponce M. Rentabilidad de la producción de carne de ovinos Katahdin x Pelibuey con tres tipos de alimentación. Avan Inv Agrop 2013;17(1):135-148. [ Links ]

2. Chay-Canul A, Magaña-Monforte J, Chizzotti M, Piñeiro-Vázquez A, Canul-Solís J, Ayala-Burgos A et al. Requerimientos energéticos de ovinos de pelo en las regiones tropicales de Latinoamérica. Rev Mex Cienc Pecu 2016;7(1):105-125. [ Links ]

3. Pedraza RM, Orskov ER. Sistemas silvopastoriles: papel en la nutrición y la alimentación de los rumiantes. V Congreso Latinoamericano de Agroforestería para la Producción Pecuaria Sostenible. Maracay, Venezuela. [CD ROM]. 2008. [ Links ]

4. Casanova-Lugo F, Ramirez-Aviles L, Parsons D, Caamal-Maldonado A, Piñeiro-Vázquez A, Díaz-Echeverría V. Environmental services from tropical agroforestry systems. Rev Chap Cienc For Amb 2016;(22)1-16. [ Links ]

5. Herrera J, Hernández A, Noda A. Estudio preliminar de la conducta alimentaria de cabras lecheras en un sistema silvopastoril. Rev Cub Cienc Agr 2007;41(4):329-332. [ Links ]

6. Albores-Moreno S, Alayón-Gamboa J, Ayala-Burgos AJ, Solorio FJ, Aguilar-Pérez C, Olivera-Castillo L, Ku-Vera JC. Effects of feeding ground pods of Enterolobium cyclocarpum Jacq. Griseb on dry matter intake, rumen fermentation, and enteric methane production by Pelibuey sheep fed tropical grass. Trop Anim Health Prod 2017;49. [ Links ]

7. Piñeiro-Vázquez AT, Canul-Solis RJ, Jiménez-Ferrer G, Alayón-Gamboa AJ, Chay-Canul AJ, Ayala-Burgos JA, Aguilar-Pérez C, Ku-Vera JC. Effect of condensed tannins from Leucaena leucocephala on rumen fermentation, methane production and population of rumen protozoa in heifers fed low-quality forage. J Anim Sci 2018;31(11):1738-1746. [ Links ]

8. Bottini-Luzardo MB, Aguilar-Pérez CF, Centurión-Castro FG, Solorio-Sánchez FJ, Ku-Vera JC. Milk yield and blood urea nitrogen in crossbred cows grazing Leucaena leucocephala in a silvopastoral system in the Mexican tropics. Trop Grass-Forr 2016;4(3):159-167. [ Links ]

9. García ME. Modificaciones al sistema de clasificación climática de Köppen: para adaptarlos a las condiciones climáticas de la República Mexicana. Quinta ed: Instituto de Geografía, UNAM; 2004. [ Links ]

10. Unión Internacional de Ciencias del Suelo . Grupo de Trabajo WRB. Base Referencial Mundial del Recurso Suelo. Primera actualización. Informes sobre Recursos Mundiales de Suelos No. 103. FAO, Roma. 2007. [ Links ]

11. Bacab-Pérez HM, Solorio-Sánchez FJ. Forage offer and intake and milk production in dual purpose cattle managed under silvopastoral systems in Tepalcatepec, Michoacan. Trop Subtrop Agroec 2011;13:271-278. [ Links ]

12. Piasentier E, Bovolenta S, Malossini F, Susmel P. Comparison of n-alkanes or chromium oxide methods for estimation of herbage intake by sheep. Small Ruminant Res 1995;18:27-32. [ Links ]

13. Palma JM, Román L. Cambios en la conducta ingestiva de ovinos al cambiar la altura inicial del pastoreo de Leucaena leucocephala. Zoot Trop 2008;26(3):371-378. [ Links ]

14. Association of Oficial Analytical Chemists . Methods of analysis. 15th ed. Washington, DC. 2004. [ Links ]

15. Van Soest PJ, Robertson JB, Lewis BA. Methods for dietary fiber, neutral detergent fiber and nonstarch polysaccharides in relation to animal nutrition. J Dairy Sci 1991;74:3583-3598. [ Links ]

16. Tilley JMA, Terry RA. A two-stage techniques for the in vitro digestion of forage crops. J British Grassl Soc 1963;18:104-111. [ Links ]

17. Ramírez A, Buntinx S, Tapia C, Rosiles R. Effect of breed and age on the voluntary intake and the micro mineral status of non-pregnant sheep. 1. Estimation of voluntary intake. Small Ruminant Res 2000;37:223-229. [ Links ]

18. SAS Institute. SAS User´s Guide: Statistics. Ver.9.2. SAS Institute. Cary, N.C. USA 2004. [ Links ]

19. Salinas-Chavira J, Pérez JA, Rosales JA, Hernández EA. Efecto de niveles crecientes de pulido de arroz en la degradabilidad ruminal de materia seca y comportamiento productivo de ovinos en engorde. Rev Cub Cienc Agr 2013;7(4):375-380. [ Links ]

20. Silva TM, Medeiro A, Olveira RL, Neto SG, Riveiro MD, Bagaido AR, Riveiro OL. Peanut cake as a substitute for soybean meal in the diet of goats. J Anim Sci 2015;93:2998-3005. [ Links ]

21. Kennedy PM, Charmley E. Methane yields from Brahman cattle fed tropical grasses and legumes. Anim Prod Sci 2012;52:225-239. [ Links ]

22. Sohail HKS. Nutrients intake, digestibility, nitrogen balance and growth performance of sheep feal different silages with or withoot concentrates. Trop Anim Heal Prod 2010;(43)705-801. [ Links ]

23. Barros-Rodríguez M, Solorio-Sánchez J, Ku-Vera J, Ayala-Burgos A, Sandoval-Castro C, Solís-Pérez G. Productive performance and urinary excretion of mimosine metabolites by hair sheep grazing in a silvopastoral system with high densities of Leucaena leucocephala. Trop Anim Heal Prod 2012;(44)1873-1878. [ Links ]

24. Arcos ADN., Aguilar UE, Sanginés GJR, Lara PE. Comportamiento productivo de corderos alimentados con Moringa oleífera o Trichanthera gigantea. 1ª ed. Perspectivas y avances de la producción animal en México. Universidad Autónoma de San Luis Potosí; 2016;109-115. [ Links ]

25. Izaguirre F, Martínez TJJ, Jiménez FJO, Posada CS, García CCG, Martínez PC. Respuesta reproductiva y productiva de borregas Pelibuey a la suplementación con hojas de Caulote (Guazuma ulmifolia), Guaje (Leucaena leucocephala) y Yaite (Gliricidia sepium) en condiciones de trópico húmedo. Liv Res Rur Dev 2011;23(10):1-10. [ Links ]

26. López AD, Hernández MJ, Rojo R, Sánchez DF, López VN, Fattah ZMSA et al. Effects of exogenous enzymes and application on nutrient intake digestibility and growth performance of Pelibuey lambs. Trop Anim Health 2016;5(1399):1-6. [ Links ]

27. Fernández PA, Homen NSP, Lolato RO, Mauro SE, Giordano PG, Silva OJ et al. Intake and ingestive behavior of lambs feed diets containing amoniated buffel grass hay. Trop Anim Health Prod 2017;49:717-724. [ Links ]

28. Benítez D, Pérez MB, Ramírez SA, Blanco A, Camejo N, Castellanos ME et al. El manejo de la finca ganadera de montaña. Ed. Alfa Europe Aid, IIA Jorge Dimitrov, Bayamo, Cuba. 2007. [ Links ]

29. Iraola J, Muñoz E, García Y, Hernández JL, Tuero O, Moreiro E. Conducta alimentaria de bovinos machos en pastoreo restringido, suplementados con granos de destilería de maíz durante el periodo poco lluvioso. Rev Cub Cienc Agr 2013;47(3):255-260. [ Links ]

30. Gutiérrez D, Enriquez A, Sarduy L. Conducta alimentaria de crías caprinas en pastoreo de estrella (Cynodon nlemfuensis). Rev Cub Cien Agr 2007;41(2):135-138. [ Links ]

Received: December 18, 2017; Accepted: September 13, 2018

Creative Commons License Este es un artículo publicado en acceso abierto bajo una licencia Creative Commons