Soil is the main matrix which contributes to the transfer of environmental pollutants to animals and consequently into the food chain. In the French West Indies, chlordecone, a very persistent organochlorine pesticide, has been widely used on banana growing areas and this process has resulted in a long-term pollution of the corresponding soils. Domestic outside-reared herbivores are exposed to involuntary soil intake, and tethered grazing commonly used in West Indian systems can potentially favour their exposure to chlordecone. Thus, it appears necessary to quantify to what extent grazing conditions will influence soil intake. This experiment consisted of a cross-over design with two daily herbage allowance (DHA) grazed alternatively. Six young Creole bulls were distributed into two groups (G1 and G2) according to their BW. The animals were individually tethered and grazed on a restrictive (RES) or non-restrictive (NRES) levels of DHA during two successive 10-days periods. Each bull progressed on a new circular area every day. The two contrasting levels of DHA (P<0.001) were obtained via a different daily grazing surface area (RES: 20 m2/animal, NRES: 31 m2/animal; P<0.01) offered to the animals by the modulation of the length of the tethering chain (RES: 1.9 m, NRES: 2.6 m). These differences in offered grazing areas resulted in DHA of 71 and 128 g DM/kg BW0.75, respectively for RES and NRES treatments. As expected, the animals grazing on the reduced area realized a lower daily dry matter intake (DMI) (RES: 1.12 kg/100 kg BW, NRES: 1.83 kg/100 kg BW; P<0.05) and present a lower organic matter digestibility (RES: 0.67, NRES: 0.73; P<0.01) than NRES ones, due in part to the shorter post-grazing sward surface height (RES: 3.3 cm, NRES: 5.2 cm; P<0.01) of their grazing circles. Soil intake was estimated on an individual level based on the ratio of the marker titanium in soil, herbage and faeces. Grazing closer to the ground, animals on RES treatment ingested a significantly higher proportion of soil in their total DMI (RES: 9.3%, NRES: 4.4%; P<0.01). The amount of ingested soil in the diet was not significantly different between the two treatments (RES: 98 g/100 kg BW, NRES: 78 g/100 kg BW; P>0.05) due to the lower DMI of RES compared with NRES treatment.

The aim of this work was to establish the response of growing sheep, goats and cattle to different nutritional environments. Data from 590 publications representing 2225 treatments were analysed. The results showed that each 10% increase in NDF was accompanied by 0.11 g/kg live weight (LW) and 0.32 g/kg metabolic live weight (LW0.75) decreases in DMI. Otherwise, the response of DMI to CP (CP%DM) content was curvilinear (P<0.01), without any significant difference in the slope between species. The percentage of concentrate (% CC) affected DMI curvilinearly, without any significant difference between species. This meta-analysis demonstrated the negative linear effect of NDF and the quadratic effect of CP concentration on organic matter digestibility (OMd). For growth performance, the three species responded curvilinearly to variations in metabolisable energy intake (MEI MJ/kg LW0.75) and digestible CP (DCPI g/kg LW0.75) intake (P<0.01). At the same level of MEI, average daily gain (ADG) varied with CP contents of the diet, and only the intercept differences were significant between the three levels (P=0.07). At the same level of DCPI, ADG varied with energy level (below maintenance (LE−−), 1 to 1.2×maintenance (LE−), 1.2 to 1.4× maintenance (ME+−), and >1.4, corresponding to maximum growth (HE+)). No significant difference was observed between LE−− and LE−, and no significant difference was observed between ME+− and HE+. For nitrogen balance, no difference was observed between species for a given level of nitrogen intake.

The objective of the study was to update energy and protein requirements of growing sheep, goats and cattle in warm areas through a meta-analysis study of 590 publications. Requirements were expressed on metabolic live weight (MLW=LW0.75) and LW1 basis. The maintenance requirements for energy were 542.64 and 631.26 kJ ME/kg LW0.75 for small ruminants and cattle, respectively, and the difference was significant (P<0.01). The corresponding requirement for 1 g gain was 24.3 kJ ME without any significant effect of species. Relative to LW0.75, there was no difference among genotypes intra-species in terms of ME requirement for maintenance and gain. However, small ruminants of warm and tropical climate appeared to have higher ME requirements for maintenance relative to live weight (LW) compared with temperate climate ones and cattle. Maintenance requirements for protein were estimated via two approaches. For these two methods, the data in which retained nitrogen (RN) was used cover the same range of variability of observations. The regression of digestible CP intake (DCPI, g/kg LW0.75) against RN (g/kg LW0.75) indicated that DCP requirements are significantly higher in sheep (3.36 g/kg LW0.75) than in goats (2.38 g/kg LW0.75), with cattle intermediate (2.81 g/kg LW0.75), without any significant difference in the quantity of DCPI/g retained CP (RCP) (40.43). Regressing metabolisable protein (MP) or minimal digestible protein in the intestine (PDImin) against RCP showed that there was no difference between species and genotypes, neither for the intercept (maintenance=3.51 g/kg LW0.75 for sheep and goat v. 4.35 for cattle) nor for the slope (growth=0.60 g MP/g RCP). The regression of DCP against ADG showed that DCP requirements did not differ among species or genotypes. These new feeding standards are derived from a wider range of nutritional conditions compared with existing feeding standards as they are based on a larger database. The standards seem to be more appropriate for ruminants in warm and tropical climates around the world.

The main objective of the present work was to determine the nutritional value and the strategies of using green banana meal (BM) in growing pigs. Two trials involving a total of 96 growing pigs were designed to study the effect of the harvest stage on the nutritional and energy values of BM (trial 1) and to evaluate the consequence of feeding gradual levels of BM on growth performance and feeding behavior in growing pigs (trial 2). In trial 1, the digestive utilization of three diets including 40% BM were compared with a control (C) soybean meal-corn diet in two batches of 12 pigs. BM was obtained from fruits harvested at 750 degrees-days (DD; early harvesting stage), 900 DD (normal harvesting stage) and 1150 DD (late harvesting stage). In trial 2, 72 Large White pigs were grouped in pens of nine animals and were given ad libitum access to one of the four dietary treatments (two pens/diet) differing from the rate of inclusion of 900 DD BM (0%, 20%, 40%, 60%). The estimated energy apparent digestibility coefficients of BM increased with the harvest stage (75.5%, 80.7% and 83.2% for BM at 750, 900 and 1150 DD, respectively). Digestible energy and metabolizable energy values were higher for BM at 1150 DD (13.56 and 13.05 MJ/kg DM, respectively) than at 900 DD (13.11 and 12.75 MJ/kg DM, respectively) or at 750 DD (12.00 and 11.75 MJ/kg DM, respectively). In trial 2, average daily gain and feed conversion ratio were not affected (P>0.05) by the rate of BM inclusion (822 g/day and 2.75 kg/kg on average, respectively). Feed intake and feeding behavior parameters were not significantly influenced by the dietary treatments except for the rate of feed ingestion with a lower value for the diet with 40% of BM (27.4 v. 32.2 g/min on average; P<0.01) when compared with the other diets. Results of this study indicate that the energy value of BM increases with the harvest stage and that BM can be incorporated up to 60% in growing finishing pig diets.

The effect of two feeding systems (indoors and at pasture) on intake and digestion of fresh grass was studied at two stages of regrowth (21 and 35 days of regrowth) in two parallel experiments. In Experiment 1, 10 adult Martinik rams weighing, on average, 50.5 (±0.9) kg, including four fitted with rumen cannula, were randomly allocated to two groups according to a 2 × 2 Latin Square design. These rams consumed a 21-day regrowth of Digitaria decumbens grass diet during two successive 28-day periods, indoors (five rams) or at pasture (five tethered rams). In Experiment 2, 10 other Martinik rams weighing, on average, 45.5 (±0.9) kg, including four fitted with rumen cannula, were randomly allocated to two groups according to a 2 × 2 Latin Square design. These rams consumed a 35-day regrowth of D. decumbens grass diet during two successive 28-day periods, either indoors (five rams) or at pasture (five tethered rams). For the indoors groups, in vivo organic matter digestibility (OMD) was measured by total collection of feces. In addition, OMD was estimated indoors and at pasture using the fecal CP (CPf) method (OMDCPf). Organic matter intake (OMI) was then estimated using OMDCPf and fecal organic matter output (OMICPf). Correlations of 0.49 and 0.77 were found between in vivo OMD and OMDCPf (P < 0.05) and between OMI and OMICPf (P < 0.001), respectively. OMDCPf was 1.8% (P < 0.05) and 2.7% (P < 0.01) lower indoors than at pasture at 21 and 35 days of regrowth, respectively, whereas OMICPf indoors was 1.1 and 1.16 times that registered at pasture at 21 and 35 days of regrowth, respectively. The higher OMDCPf at pasture was linked to the higher selective behavior of rams at pasture, whereas the differences in OMICPf between the two feeding systems were linked to differences in the total bulk density of the grass. These studies show that differences in OMDCPf and OMICPf exist between animals fed indoors and at pasture with the same forage and that these differences may vary according to the stage of regrowth of the grass offered.

Mixed farming systems (MFS) have demonstrated some success by focusing on the use of integrative and holistic mechanisms, and rationally building on and using the natural and local resource base without exhausting it, while enhancing biodiversity, optimizing complementarities between crops and animal systems and finally increasing opportunities in rural livelihoods. Focusing our analysis and discussion on field experiences and empirical knowledge in the Caribbean islands, this paper discusses the opportunities for a change needed in current MFS research–development philosophy. The importance of shifting from fragile/specialized production systems to MFS under current global conditions is argued with an emphasis on the case of Small Islands Developing States (SIDS) and the Caribbean. Particular vulnerable characteristics as well as the potential and constraints of SIDS and their agricultural sectors are described, while revealing the opportunities for the ‘richness’ of the natural and local resources to support authentic and less dependent production system strategies. Examples are provided of the use of natural grasses, legumes, crop residues and agro-industrial by-products. We analyse the requirement for a change in research strategies and initiatives through the development of a complex but necessary multi-/inter-/trans-disciplinary teamwork spirit. We stress as essential the collaboration and active participation of local and regional actors, stakeholders and end-users in the identification of research priorities, as well as the generation, exchange and dissemination of knowledge and technology innovations, while strengthening the leadership roles in the conduct of integrative and participative research and development projects.

A total of 24 castrated male Creole were used for digestibility studies on three sugarcane (SC) products: final molasses, SC juice and ground SC. Digestibility of macronutrients were determined in three consecutive experimental trials between 35 and 60 kg BW. The first trial measured the effect of a constant rate of incorporation of those SC products in a control diet (23% on a dry matter (DM) basis) on digestibility of energy and nutrients. The second and the third trials were designed to determine the effects of increasing rates of inclusion of SC juice and ground SC in the control diet on the digestibility of nutrients and energy. The DM content of molasses, SC juice and ground SC were 74.3%, 19.3% and 25.8%, respectively. Free sugar contents were 73.8%, 81.6% and 51.5% of DM for molasses, SC juice and ground SC, respectively. In contrast with molasses and SC juice, NDF content of ground SC was very high (40.3% DM). Energy digestibility coefficients (DC) were 99.0% and 83.6% for SC juice and molasses, respectively. For ground SC, amounts and composition of intakes differed from feed allowance as a consequence of chewing-then-spitting out most of the fibrous contents of ground SC. Expressed as a percentage of energy intake and energy allowance, DC of energy for ground SC were 68.6% and 31.9%, respectively. On an intake basis, digestible energy (DE) and metabolisable energy (ME) values were higher for SC juice (17.3 and 17.2 MJ/kg DM, respectively) than for molasses (13.1 and 12.6 MJ/kg DM, respectively) or ground SC (12.3 and 11.8 MJ/kg DM, respectively). On an allowance basis, the corresponding values for ground SC were only 5.7 and 5.6 MJ/kg DM, respectively. The gradual inclusion rate of SC juice in the diet up to 66% resulted in a linear increase of the DC of the diet organic matter and energy (P < 0.001) by 0.10% per 1% in SC juice DM. On the other hand, the partial substitution of the control diet by ground SC up to 74% resulted in a linear (P < 0.05) reduction of digestibility of nutrients and energy. Each 1% increase of ground SC incorporation rate resulted in a 0.13% and 0.61% linear decrease of DC of the energy, expressed as a percentage of energy intake or energy allowance, respectively. In conclusion, our study provides updated energy values of SC products usable as energy sources for feeding pigs.

The effects of defaunation on growth and digestion were measured in sheep fed fresh Digitaria decumbens grass cut at four stages of regrowth 14, 28, 42, and 56 days, and with different protein to energy (P/E) ratios. Two completely randomized designs trials (growth and digestion) were conducted using faunated animals, defaunated rams and protozoa free lambs. The digestion trial: eight faunated and eight defaunated rams fitted with ruminal and duodenal cannulas were fed 4 diets (diets D1 to D4) to measure digestion parameters. The dietary P/E ratios were 120 (D1), 130 (D2), 130 (D3), and 140 (D4) g PDIN/UFL (Protein Digested in the small Intestine supplied by microbial protein from rumen-degraded protein/Feed Unit for Lactation) and the grass stages of regrowth were 56, 42, 28, and 14 days, respectively. Increasing the dietary P/E ratios increased dry matter intake (DMI) and the total tract digestibility of organic matter (OM), NDF and CP. Defaunation decreased DMI, except for rams fed D4 diet. Defaunation also decreased total tract digestibility of OM except for rams fed D1 diet and that of NDF except for rams fed D1 and D4 diets. Increasing the dietary P/E ratios also increased nitrogen intake and ammonia (NH3) concentration in the rumen, whereas defaunation decreased them. The dietary P/E ratio increased non-NH3 nitrogen and microbial nitrogen duodenal flows and microbial efficiency. Defaunation did not affect duodenal flows of neither non-NH3 nitrogen and microbial nitrogen or microbial efficiency. The growth trial: 20 faunated and 20 protozoa free lambs were fed four diets (diets D5 to D8) to measure their average daily gain (ADG). The dietary P/E ratios were 60 (D5), 70 (D6), 80 (D7) and 100 (D8) g PDIN/UFL and the stages of regrowth were 56, 42, 28, and 14 days, respectively. DMI of lambs increased with P/E ratio. Protozoa free lambs had greater DMI than faunated ones when fed D7 diet (80.8 v. 74.9 g/kg LW0.75, respectively). The ADG of the lambs increased with P/E ratio. Fed on the same D5 diet, protozoa free lambs had greater ADG than faunated lambs (29.8 v. 11.6 g/day, respectively). In conclusion, animal response to defaunation was modulated by the P/E ratio of the D. decumbens grass diets. Defaunation increased ADG of lambs fed forage with the lowest P/E ratio, while digestion and nitrogen duodenal flows of rams fed the lowest P/E ratio were not affected.

Faecal indices were evaluated to assess organic matter digestibility (OMD) for small ruminants fed with Digitaria decumbens. A continuous digestibility trial was conducted with five Creole bucks and five Black-belly rams, fed with fresh cut Digitaria decumbens from 15 to 70 days of re-growth. The amount of herbage offered, the refusals and the faeces were weighed daily for each animal during 55 days. Herbage and faeces samples were kept to determine dry and organic matter (DM and OM), crude protein (CP), neutral and acid detergent fibre (NDF and ADF) and lignin contents (ADL). OMD was calculated per week and per animal. Predictive regressions of OMD were calculated for each species, from all the faecal components measured (CPf, NDFf, ADFf and ADLf), using linear or curvilinear models. Regressions from CPf had the lowest residual standard error (<0·028) when calculated for each species, compared with regressions from the other faecal components. Among the regressions from CPf, the lowest standard error of the predictive parameters was obtained with a model in the form of a-b/CPf, for each species. The latter allows prediction of OMD at pasture, consistent with theoretical energy requirement for both goats and ewes grazing a Digitaria decumbens based sward.

So far, little has been done on the effect of nitrogen fertilizer on intake and digestibility in tropical grazing conditions. The effect of two nitrogen levels, 0 (NF) and 50 kg/ha (F) for three successive grazing cycles, on organic matter intake (OMi) and digestibility (OMd) for Creole heifers (208 kg live weight) was determined. Two groups of four tethered heifers, allowed 18 kg of dry matter daily, grazed individual NF or F circular areas at 28 re-growth days. The heifers were moved and watered daily. Sward characteristics (height, herbage mass, morphological and chemical composition and in situ tiller measurements), OMi, OMd and feeding behaviour (biting rate, bite size, intake rate, grazing and ruminating times) were evaluated simultaneously per circular area.

Under nitrogen fertilizer, the stems elongated rapidly (by 133%) as did the leaves, but to a lesser extent (by 40%). Consequently, canopy height, leaf and stem masses and crude protein content increased (respectively by 100%, 66%, 186% and 40%), while total bulk density decreased (by 10·5%). Throughout the successive grazing cycles, there was a particular effect on leaf number, both in the F and NF swards, whereas this parameter was not affected by the fertilizer level. Under fertilizer, OMi and OMd were both 9% greater than for the NF sward. The increase in herbage CP content partly explains the rise in OMi, and there is evidence that rumen load has a determining effect on OMi. Leaf mass is the major factor accounting for the 9% increase in OMd under fertilizer regime. On the other hand, whatever the fertilizer regime, OMd was positively influenced by the greater leaf number throughout the grazing cycles. Biting rate, bite size and intake rate were determined respectively by sward height, CP content and stem fraction, whereas grazing and ruminating times were partially influenced by sward characteristics.

The research was carried out at the animal experimental station of the National Agricultural Research Institute of the French West Indies (Guadeloupe) in 1999. Effects on intake and digestion by sheep of addition of Gliricidia leaves to a diet of 35-day-old Digitaria decumbens (pangola) hay, have been studied. In a first trial (a 4×4 Latin Square design), four rams were fed four diets: hay (G0); hay plus 1300 g of Gliricidia (G0·25), hay plus 2600 g of Gliricidia (G0·50), hay plus 3900 g of Gliricidia (G0·75). Total dry matter intake (DM), hay and Gliricidia intake, total tract and rumen digestibility of DM and its components, microbial and total nitrogen flows were estimated. In a second trial (a 2×2 Latin Square design), the same animals received hay (G0) or Gliricidia (G1·00) ad libitum to estimate the rumen turnover of pangola and Gliricidia fibrous particle. Neutral detergent fibre and crude protein content of the Digitaria decumbens hay and Gliricidia were 746 and 51, 458 and 198 g/kg dry matter respectively. Total dry matter intake (DM) varied from 42·7 to 76 g DM/kg LW0·75 from G0 to G0·75. The rate of substitution of pangola by Gliricidia (decrease of pangola intake for one unit Gliricidia consumed) was 233 g/kg. The digestibility of cell-wall linearly decreased with increasing level of Gliricidia in the diet. No digestive interaction was registered in the mixed diets. The total nitrogen and microbial nitrogen duodenal flows increased with the level of Gliricidia in the diet. The rumen turnover of fibrous particles of Gliricidia was double that of pangola. The incorporation of Gliricidia in diets increases their nutritive value by higher intake and intestinal nitrogen duodenal flows, but no positive digestive interaction was observed between pangola hay and Gliricidia leaves.

Effects of incorporation of urea and saccharose in diets, on intake and digestion by sheep of a 35-day-old pangola (Digitaria decumbens) hay, have been studied according to a 4 × 4 Latin-square design. Sixteen rams were given four diets: hay (C); hay plus urea (U, 23 g/kg hay); hay plus saccharose (S, 60 g/kg hay), hay plus urea and saccharose (SU). Acid-detergent fibre and crude protein (CP) content of the roughage were 395 and 78 g/kg dry matter (DM) respectively. Intake of hay (g DM per kg live weight0.75), supplemented with urea and sugar (42⋅9), was lower (F < 0.05) than with other diets (47.2, s.e. 1.6). The organic matter (OM) total tract and ruminal digestibility of the diet C, S, U and SU were 0.622, 0.590, 0.615 and 0.587 (s.e. 0.007); 0.361, 0.380, 0.378 and 0.345 (s.e. 0.015) respectively. Effective degradation and nylon bag kinetics of DM degradation were higher with U and SU compared with S or C. Few differences were observed between diets for ruminal concentration of volatile fatty acids. The ruminal ammonia concentrations were higher (P < 0.05) for the diets with urea than without urea (78 v. 215 mg/l). The efficiencies of the microbial synthesis (g nitrogen per kg OM fermented in the rumen) were, 23.6, 22.4, 24.9 and 29.3 (s.e. 1.7) for the diets C, U, S and SU respectively.

Even though additional urea increased nitrogen availability for ruminal bacteria, urea supplementation did not affect significantly intake or digestion of the pangola hay of medium CP content used in this experiment.

The intake and digestion of fresh and dried Digitaria decumbens grass by rams was compared using a 2×2 factorial design. The experiment took place in Guadeloupe (French West Indies) in 1996. Eight rams (mean liveweight: 45·7±3·1 kg) were maintained in metabolism cages. Digitaria decumbens grass was cut daily and distributed to four of them, the other four were fed the following day with the equivalent forage which had meanwhile been dried for 20 h at 60°C. Chemical composition (g/kg of dry matter (DM)) of the two diets based on neutral detergent fibre (NDF, 713, S.E. 18), acid detergent fibre (ADF, 361, S.E. 13) and crude protein (CP, 90, S.E. 4) was similar. The DM intake (61·0 and 53·2 g/W0·75, S.E. 2·0, P<0·05), the NDF (0·753 and 0·727, S.E. 0·004, P<0·011) and CP (0·588 and 0·544, S.E. 0·014, P<0·09) total tract digestibility of fresh and dried herbage were different. Nylon bag estimates of effective DM degradability and fractional degradation rates (per h) in the rumen were 0·436, 0·414 (S.E. 0·005, P<0·004) and 0·048, 0·038 (S.E. 0·002, P<0·02) for fresh and dried grass, respectively. Rumen digestibility of organic matter and NDF were 0·516, 0·541 (S.E. 0·021) and 0·763, 0·692 (S.E. 0·019), respectively. The rumen turnover rates of particles (per h) were 0·024 and 0·015 (S.E. 0·001, P<0·05) for fresh and dried forage respectively. The efficiency of microbial protein synthesis (g microbial nitrogen/kg organic matter apparently degraded in the rumen) was similar with the two diets : 33·5 and 33·0 (S.E. 3·3, P<0·9) for fresh and dried forage respectively. In conclusion, fresh Digitaria decumbens was nutritionally superior to dried. This is probably due to a faster degradation rate and a lower rumen retention time of the fresh forage.