Assessment of ecosystem services provided by livestock agroecosystems in the tropics: a case study of tropical island environment of Guadeloupe.

The present study aims to assess (1) the ecosystem services (ES) provided by LFS and (2) the differential ES between local (Creole) and exotic breeds from pig, cattle and goat. The ES are defined as the benefits that humans derive from LFS. They were summarized in 12 ES indicators that cover services related to provisioning, ecological and socio-cultural aspects and territorial vitality. A total of 106 LFS units that covers the five agroecological zones of Guadeloupe were analysed. Functional typologies of LFS per species were created from surveys. The effect of breed on the ES indicators was tested. Results showed that the 40 pig LFS units were separated into 3 clusters that were differentiated in ES according to provisioning ES (cluster 1), cultural use and sale to the neighborhood (cluster 2) and pork self-consumption (cluster 3). The typology of the 57 farms with cattle distinguished 4 clusters with differences in ES provided in self-consumption (cluster1), ecological ES (cluster 2), socio-cultural ES for racing or draught oxen (cluster 3) and ES associated with territory vitality (cluster 4). The 66 goat LFS units were classified into 3 clusters different in ES concerning self-consumption (cluster 1), cultural aspects (cluster 2) and provisioning ES (cluster 3). Our study highlights that ES indicators are not breed dependent (P > 0.10) but rather livestock farming system dependent. The ES rely more on the rearing management than on the breed type, and up to now, there are no specifications in Guadeloupe to differentiate management between breeds.

Modeling chlordecone toxicokinetics data in growing pigs using a nonlinear mixed-effects approach.

The use of chlordecone (CLD), a chlorinated polycyclic pesticide used in the French West Indies banana fields between 1972 and 1993, resulted in a long-term pollution of agricultural areas. It has been observed that this persistent organic pollutant (POP) can transfer from contaminated soils to food chain. Indeed, CLD is considered almost fully absorbed after involuntary ingestion of contaminated soil by outdoor reared animals. The aim of this study was to model toxicokinetics (TKs) of CLD in growing pigs using both non-compartmental and nonlinear mixed-effects approaches (NLME). In this study, CLD dissolved in cremophor was intravenously administrated to 7 Creole growing pigs and 7 Large White growing pigs (1 mg kg-1 body weight). Blood samples were collected from time t = 0 to time t = 84 days. CLD concentrations in serum were measured by GCMS/MS. Data obtained were modeled using Monolix (2019R). Results demonstrated that a bicompartmental model best described CLD kinetics in serum. The influence of covariates (breed, initial weight and average daily gain) was simultaneously evaluated and showed that average daily gain is the main covariate explaining inter-individual TKs parameters variability. Body clearance was of 76.7 mL kg-1 d-1 and steady-state volume of distribution was of 6 L kg-1. This modeling approach constitutes the first application of NLME to study CLD TKs in farm animals and will be further used for rearing management practices in contaminated areas.

Genetic parameters for thermoregulation and production traits in lactating sows reared in tropical climate.

The objective of this study was to estimate the genetic parameters for thermoregulation traits and the relationships with performance of Large White lactating sows reared in a tropical humid climate. The thermoregulation traits were rectal temperature (RT), cutaneous temperature (CT) and respiratory rate (RR) during lactation measured in the afternoon (1200 h) and in the morning (0700 h). The production traits were sow's average daily feed intake (ADFI), litter BW gain (LBWg) and sow's proportion of BW change between farrowing and weaning (BWc). Complete data included 931 lactating performance on 329 Large White sows from the INRA experimental unit in Guadeloupe (French West Indies). Random regression models using linear spline functions were used for longitudinal data (RT, CT, RR and daily feed intake). Results showed that when ignoring values at the beginning and the end of lactation, the traits studied can be treated as the same trait throughout days of lactation, with fairly constant heritability and variance. However, largest heritabilities and genetic variances were estimated in mid-lactation. Heritability estimates on average performance during lactation were low to moderate for thermoregulation traits (0.35±0.09 for RT, 0.34±0.12 for CT and 0.39±0.13 for RR). Heritability estimates for production traits were 0.26±0.08 for ADFI, 0.20±0.07 for BWc and 0.31±0.09 for LBWg. Significant genetic correlations between thermoregulation traits and production traits were only obtained for ADFI and RR (0.35±0.12). From this study it can be concluded that thermoregulation traits are heritable, indicating that there are genetic differences in heat stress tolerance in lactating Large White sows.

Interactions between sire family and production environment (temperate vs. tropical) on performance and thermoregulation responses in growing pigs.

The aim of this study was to evaluate the effect of 2 climatic environments (temperate [TEMP] vs. tropical humid [TROP]) on production and thermoregulation traits in growing pigs. A backcross design involving Large White (LW; heat sensitive) and Creole (CR; heat tolerant) pigs was studied. The same 10 F LW × CR boars were mated with related LW sows in each environment. A total of 1,298 backcross pigs ( = 634 pigs from 11 batches for the TEMP environment and = 664 pigs from 12 batches for the TROP environment) were phenotyped on BW (every 15 d from wk 11 to 23 of age), voluntary feed intake (ADFI, from wk 11 to 23), backfat thickness (BFT; at wk 19 and 23), skin temperature (ST; at wk 19 and 23), and rectal temperature (RT; at wk 19, 21, and 23). The feed conversion ratio was computed for the whole test period (11 to 23 wk). The calculation of the temperature-humidity index showed an average difference of 2.4°C between the TEMP and TROP environments. The ADG and ADFI were higher in the TEMP environment than in the TROP environment (834 vs. 754 g/d and 2.20 vs. 1.80 kg/d, respectively; < 0.001). Body temperatures were higher in the TROP environment than in the TEMP environment (35.9 vs. 34.8°C for ST and 39.5 vs. 39.3°C for RT, respectively; < 0.001). Most of the studied traits (i.e., BW, BFT, ADG, ADFI, and RT) were affected by sire family × environment interactions ( < 0.05), resulting in "robust" and "sensitive" families. Our results show a family dependency in the relationships between heat resistance and robustness, suggesting the possibility of finding genotypes with high production and low heat sensitivity. Further research is needed to confirm the genetic × environment interaction and to detect QTL related to heat tolerance.

Evaluation of the sustainability of contrasted pig farming systems: breeding programmes.

The sustainability of breeding activities in 15 pig farming systems in five European countries was evaluated. One conventional and two differentiated systems per country were studied. The Conventional systems were the standard systems in their countries. The differentiated systems were of three categories: Adapted Conventional with focus on animal welfare, meat quality or environment (five systems); Traditional with local breeds in small-scale production (three systems) and Organic (two systems). Data were collected with a questionnaire from nine breeding organisations providing animals and semen to the studied farming systems and from, on average, five farmers per farming system. The sustainability assessment of breeding activities was performed in four dimensions. The first dimension described whether the market for the product was well defined, and whether the breeding goal reflected the farming system and the farmers' demands. The second dimension described recording and selection procedures, together with genetic change in traits that were important in the system. The third dimension described genetic variation, both within and between pig breeds. The fourth dimension described the management of the breeding organisation, including communication, transparency, and technical and human resources. The results show substantial differences in the sustainability of breeding activities, both between farming systems within the same category and between different categories of farming systems. The breeding activities are assessed to be more sustainable for conventional systems than for differentiated systems in three of the four dimensions. In most differentiated farming systems, breeding goals are not related to the system, as these systems use the same genetic material as conventional systems. The breeds used in Traditional farming systems are important for genetic biodiversity, but the small scale of these systems renders them vulnerable. It is hoped that, by reflecting on different aspects of sustainability, this study will encourage sustainable developments in pig production.

Selection for residual feed intake in growing pigs: effects on sow performance in a tropical climate.

The aim of the study was to evaluate the consequences of a divergent selection for residual feed intake (RFI) during growth in a temperate environment (TEMP) on sow performance in a tropical environment (TROP). Sows came from a selection experiment conducted at INRA in which 2 lines were selected for larger (RFI(+)) or smaller (RFI(─)) feed intake than predicted from performance. In the first analysis, a subsample of data obtained in TROP conditions (49 lactations) was compared to those obtained in TEMP on their sibs mated with the same boars (54 lactations). In the second analysis, data obtained in the TROP environment (82 lactations) were analyzed for testing the effect of season (warm vs. hot) and line on sow performance. Except for the lactation length, the interaction between line and climatic environment was not significant for the others traits (P > 0.05). The ADFI expressed per kilogram of litter BW gain tended to be higher in the RFI(+) line bred in the TROP environment (P = 0.080), together with piglet BW at weaning, which tended to be lower (P = 0.080). The ADFI was lower in TROP than in TEMP (4.56 vs. 5.86 kg/d; P = 0.003), with negative consequence on litter BW gain and maternal BW loss. The RFI(-) sows tended to eat less feed than RFI(+) sows during lactation (4.55 vs. 5.86 kg/d; P = 0.099). Litter BW at weaning was higher in the RFI(─) line. The RFI(─) sows ate significantly less feed to produce 1 kg of litter than the RFI(+) sows and tended to lose a larger amount of BW during lactation than the RFI(+) sows (2.40 vs. 3.02 kg/kg and -0.66 vs. -0.39 kg/d, respectively, P < 0.10). Whatever the line, ADFI was reduced by about 21% in the hot season (P < 0.05). Litter BW gain was depressed (P < 0.05) in the hot season (1.72 vs. 2.08 kg/d in the warm season; P = 0.023). Lactation maternal BW loss tended to increase in the hot season (1.10 vs. 0.71 kg/d in the warm season; P = 0.016), but back fat loss remained constant (P = 0.295). In the TROP environment, the amount of feed required to produce 1 kg of litter was not influenced by the line in the warm season (2.53 kg/kg on average; P = 0.99), but it tended to be lower in the RFI(─) line when compared to the RFI(+) line in the hot season (2.06 vs. 3.45 kg/kg; P = 0.050). This higher apparent efficiency in RFI(─) sows was mainly related to greater maternal body reserve mobilization (i.e., BW and back fat losses). In conclusion, selection for low RFI during growth in a TEMP environment did not impair sow and litter performance in tropical conditions.

Economic values of body weight, reproduction and parasite resistance traits for a Creole goat breeding goal.

A specific breeding goal definition was developed for Creole goats in Guadeloupe. This local breed is used for meat production. To ensure a balanced selection outcome, the breeding objective included two production traits, live weight (BW11) and dressing percentage (DP) at 11 months (the mating or selling age), one reproduction trait, fertility (FER), and two traits to assess animal response to parasite infection: packed cell volume (PCV), a resilience trait, and faecal worm eggs count (FEC), a resistance trait. A deterministic bio-economic model was developed to calculate the economic values based on the description of the profit of a Guadeloupean goat farm. The farm income came from the sale of animals for meat or as reproducers. The main costs were feeding and treatments against gastro-intestinal parasites. The economic values were 7.69€ per kg for BW11, 1.38€ per % for FER, 3.53€ per % for DP and 3 × 10(-4)€ per % for PCV. The economic value for FEC was derived by comparing the expected profit and average FEC in a normal situation and in an extreme situation where parasites had developed resistance to anthelmintics. This method yielded a maximum weighting for FEC, which was -18.85€ per log(eggs per gram). Alternative scenarios were tested to assess the robustness of the economic values to variations in the economic and environmental context. The economic values of PCV and DP were the most stable. Issues involved in paving the way for selective breeding on resistance or resilience to parasites are discussed.

Simulated selection responses for breeding programs including resistance and resilience to parasites in Creole goats.

The Creole goat is a local breed used for meat production in Guadeloupe (French West Indies). As in other tropical countries, improvement of parasite resistance is needed. In this study, we compared predicted selection responses for alternative breeding programs with or without parasite resistance and resilience traits. The overall breeding goal included traits for production, reproduction, and parasite resilience and resistance to ensure a balanced selection outcome. The production traits were BW and dressing percentage (DP). The reproduction trait was fertility (FER), which was the number of doe kiddings per mating. The resistance trait was worm fecal egg count (FEC), which is a measurement of the number of gastro-intestinal parasite eggs found in the feces. The resilience trait was the packed cell volume (PCV), which is a measurement of the volume of red blood cells in the blood. Dressing percentage, BW, and FEC were measured at 11 mo of age, which is the mating or selling age. Fertility and PCV were measured on females at each kidding period. The breeding program accounting for the overall breeding goal and a selection index including all traits gave annual selection responses of 800 g for BW, 3.75% for FER, 0.08% for DP, -0.005 ln(eggs/g) for FEC, and 0.28% for PCV. The expected selection responses for BW and DP in this breeding program were reduced by 2% and 6%, respectively, compared with a breeding program not accounting for FEC and PCV. The overall breeding program, proposed for the Creole breed, offers the best breeding strategy in terms of expected selection responses, making it possible to improve all traits together. It offers a good balance between production and adaptation traits and may present some interest for the selection of other goat breeds in the tropics.

Adaptation to hot climate and strategies to alleviate heat stress in livestock production.

Despite many challenges faced by animal producers, including environmental problems, diseases, economic pressure, and feed availability, it is still predicted that animal production in developing countries will continue to sustain the future growth of the world's meat production. In these areas, livestock performance is generally lower than those obtained in Western Europe and North America. Although many factors can be involved, climatic factors are among the first and crucial limiting factors of the development of animal production in warm regions. In addition, global warming will further accentuate heat stress-related problems. The objective of this paper was to review the effective strategies to alleviate heat stress in the context of tropical livestock production systems. These strategies can be classified into three groups: those increasing feed intake or decreasing metabolic heat production, those enhancing heat-loss capacities, and those involving genetic selection for heat tolerance. Under heat stress, improved production should be possible through modifications of diet composition that either promotes a higher intake or compensates the low feed consumption. In addition, altering feeding management such as a change in feeding time and/or frequency, are efficient tools to avoid excessive heat load and improve survival rate, especially in poultry. Methods to enhance heat exchange between the environment and the animal and those changing the environment to prevent or limit heat stress can be used to improve performance under hot climatic conditions. Although differences in thermal tolerance exist between livestock species (ruminants > monogastrics), there are also large differences between breeds of a species and within each breed. Consequently, the opportunity may exist to improve thermal tolerance of the animals using genetic tools. However, further research is required to quantify the genetic antagonism between adaptation and production traits to evaluate the potential selection response. With the development of molecular biotechnologies, new opportunities are available to characterize gene expression and identify key cellular responses to heat stress. These new tools will enable scientists to improve the accuracy and the efficiency of selection for heat tolerance. Epigenetic regulation of gene expression and thermal imprinting of the genome could also be an efficient method to improve thermal tolerance. Such techniques (e.g. perinatal heat acclimation) are currently being experimented in chicken.

The complex nature of mixed farming systems requires multidimensional actions supported by integrative research and development efforts.

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.

There is room for selection in a small local pig breed when using optimum contribution selection: a simulation study.

Selection progress must be carefully balanced against the conservation of genetic variation in small populations of local breeds. Well-defined breeding programs with specified selection traits are rare in local pig breeds. Given the small population size, the focus is often on the management of genetic diversity. However, in local breeds, optimum contribution selection can be applied to control the rate of inbreeding and to avoid reduced performance in traits with high market value. The aim of this study was to assess the extent to which a breeding program aiming for improved product quality in a small local breed would be feasible. We used stochastic simulations to compare 25 scenarios. The scenarios differed in size of population, selection intensity of boars, type of selection (random selection, truncation selection based on BLUP breeding values, or optimum contribution selection based on BLUP breeding values), and heritability of the selection trait. It was assumed that the local breed is used in an extensive system for a high-meat-quality market. The simulations showed that in the smallest population (300 female reproducers), inbreeding increased by 0.8% when selection was performed at random. With optimum contribution selection, genetic progress can be achieved that is almost as great as that with truncation selection based on BLUP breeding values (0.2 to 0.5 vs. 0.3 to 0.5 genetic SD, P < 0.05), but at a considerably decreased rate of inbreeding (0.7 to 1.2 vs. 2.3 to 5.7%, P < 0.01). This confirmation of the potential utilization of OCS even in small populations is important in the context of sustainable management and the use of animal genetic resources.

A meta-analysis of the effects of high ambient temperature on growth performance of growing-finishing pigs.

High ambient temperature (T) is one of the most important climatic factors influencing pig performance. Increased T occurs sporadically during summer heat waves in temperate climates and year round in tropical climates. Results of published experiments assessing the effects of high T on pig performance are surprisingly variable. Thus, a meta-analysis was performed to aggregate our knowledge and attempt to explain differences in the results across studies on the effect of increased T on ADFI and ADG in growing-finishing pigs. Data for ADFI and ADG were extracted from 86 and 80 trials, respectively, from articles published in scientific journals indexed in PubMed, Science Direct, and from proceedings of scientific meetings through November 2009. Data on ADFI and ADG were analyzed using a linear mixed model that included the linear and the quadratic effects of T and BW, and their interactions as continuous, fixed effects variables, and the trial as a random effect factor (i.e., block). In addition, the effects of housing type (2 levels: individual and group housing) and the year of publication (3 levels: 1970 to 1989, 1990 to 1999, and 2000 to 2009) on the intercept and the linear regression term for T (i.e., the slope) were also tested. Results showed that high T had a curvilinear effect on ADFI and ADG and that this effect was more pronounced in heavier pigs. Across T, ADFI was less when pigs were group-housed. The intercept and the regression coefficient (slope) for T were significantly affected by the year of publication. The effect of increased T was greater in more contemporary works, suggesting that modern genotypes could be more sensitive to heat stress than older genotypes of lesser growth potential. In conclusion, pig performance decreases at an accelerating rate as T is increased. The large between-study variability on the effects of high T on pig performance is partially explained by differences in pig BW and to a lesser extent by the year the study was published.

Effect of temperature on thermal acclimation in growing pigs estimated using a nonlinear function.

Ninety-six Large White growing barrows were used to determine the effect of temperature on thermoregulatory responses during acclimation to increased ambient temperature. Pigs were exposed to 24°C for 10 d and thereafter to a constant temperature of 24, 28, 32, or 36°C for 20 d. The study was conducted in a climate-controlled room at the INRA experimental facilities in Guadeloupe, French West Indies. Relative humidity was kept constant at 80% throughout the experimental period. Rectal temperature, cutaneous temperature, and respiratory rate were measured [breaths per minute (bpm)] 3 times daily (0700, 1200, and 1800 h) every 2 or 3 d during the experiment. The thermal circulation index (TCI) was determined from rectal, cutaneous, and ambient temperature measurements. Changes in rectal temperature, respiratory rate, TCI, and ADFI over the duration of exposure to hot temperatures were modeled using nonlinear responses curves. Within 1 h of exposure to increased temperature, rectal temperature and respiratory rate increased by 0.46°C/d and +29.3 bpm/d, respectively, and ADFI and TCI decreased linearly by 44.7 g•d(-2)•kg(-0.60) and 1.32°C/d, respectively until a first breakpoint time (td(1)). This point marked the end of the short-term heat acclimation phase and the beginning of the long-term heat acclimation period. The td(1) value for ADFI was greater at 28°C than at 32 and 36°C (2.33 vs. 0.31 and 0.26 d, respectively, P < 0.05), whereas td(1) for the TCI increase was greater at 36°C than at 28 and 32°C (1.02 vs. 0.78 and 0.67 d, respectively; P < 0.05). For rectal temperature and respiratory rate responses, td(1) was not influenced by temperature (P > 0.05) and averaged 1.1 and 0.89 d, respectively. For respiratory rate and rectal temperature, the long-term heat acclimation period was divided in 2 phases, with a rapid decline for both variables followed by a slight decrease (P < 0.05). These 2 phases were separated by a second threshold day (td(2)). For rectal temperature, td(2) increased significantly with temperature (1.60 vs. 5.16 d from 28 to 36°C; P < 0.05). After td(2), the decline in rectal temperature during the exposure to thermal challenge was not influenced by temperature, suggesting that the magnitude of heat stress would affect thermoregulatory responses only at the beginning of the long-term heat acclimation period. The inclusion of random effects in the nonlinear model showed that whatever the temperature considered, interindividual variability of thermoregulatory responses would exist.

Effects of the level of sugarcane molasses on growth and carcass performance of Caribbean growing pigs reared under a ground sugarcane stalks feeding system.

The influence of the level of sugarcane (SC) molasses on growth performance, carcass traits, and meat quality in Creole (CR) growing pigs fed with ground sugarcane stalks (GCS)-based diet was studied in a mixed farming system context. The aim of the study was to optimize the growth performance of CR pigs with SC-molasses as an energy source in this unconventional feeding. A total of 32 CR pigs were used from 30 to 60 kg of body weight (BW). The experimental dietary treatments consisted of four levels of inclusion of SC-molasses (200, 400, 600, and 800 g DM/d/pig) into a GCS diet, for diets 1, 2, 3 and 4 respectively. The GCS allowance was based on live BW (170 g/kg BW/d) and the diets were supplemented with a soya-bean meal supplement (350 g/d of a 49.2% CP and 16.6 MJ DE/kg). All the pigs were slaughtered at 60 kg BW. Increasing the level of molasses did not affect (p > 0.05) average BW gain (254 g/d), CP intake (154 g/d) and sugar extraction rate from the total ration (85%). A gradual inclusion of molasses in a GCS-based diet did not affect the carcass and meat quality of CR pigs. In conclusion, molasses supplementation does not allow the increase of growth performance in GCS fed pigs.

Effects of dietary protein level and amino acid supplementation on performance of mixed-parity lactating sows in a tropical humid climate.

Eighty-six mixed-parity Large White sows were used to determine the effect of diets with reduced CP content or supplemented with essential AA on 28-d lactation performance under humid tropical climatic conditions. This experiment was conducted in Guadeloupe (West French Indies, latitude 16 degrees N, longitude 61 degrees W) between February 2007 and January 2008. Two seasons were distinguished a posteriori from climatic measurement variables continuously recorded in the farrowing room. The average minimum and maximum ambient temperatures and average daily relative humidity for the warm season were 20.5 and 28.2 degrees C, and 93.8%, respectively. The corresponding values for the hot season were 22.7 and 29.4 degrees C, and 93.7%, respectively. The dietary experimental treatments were a normal protein diet (NP), a low protein diet (LP), and a NP diet (NP+) supplemented with essential AA. The NP and LP diets supplied the same levels of standardized digestible Lys (i.e., 0.80 g/MJ of NE), and the NP+ diet supplied 0.95 g/MJ of NE. No interaction between season and diet composition was noted on any response variable evaluated. The ADFI was decreased (P < 0.05) in the hot season (i.e., 3.69 vs. 4.72 kg) and therefore decreased by 500 g per degrees C increase of ambient temperature under high relative humidity conditions. The ADFI tended to be greater with the LP and NP+ diets when compared with the NP treatment (i.e., +10%, P = 0.08). Litter BW gain and mean BW of piglets at weaning were greater (P < 0.05) during the warm season than during the hot season (2.3 vs. 1.8 kg/d and 7.5 vs. 7.1 kg, respectively). Milk production and composition were not affected by dietary treatments but were affected by season (8.1 vs. 6.8 kg/d, for warm and hot seasons, respectively; P < 0.01). The sows fed LP and NP+ diets tended to have decreased backfat thickness losses (3.3 and 3.8 mm, respectively; P > 0.08). In conclusion, the hot season in humid tropical climates, which combines high levels of temperature and humidity, has a pronounced negative impact on performance of lactating sows. Diets with low CP content or supplemented with essential AA can attenuate the effects of hot and humid season by increasing ADFI in lactating sows.

Effect of sugarcane diets and a high fibre commercial diet on fresh meat and dry-cured ham quality in local Caribbean pigs.

The effects sugar cane (SC) diets and a milling by product diet on meat quality characteristics of fresh meat and dry-cured ham were studied on a total of 48 Creole (CR) pigs. Pigs were fed with a control soya-bean meal corn diet (C1), a soya-bean meal wheat diet (C2), a SC fresh juice diet (SC-J), or a ground cane diet (SC-G). Average BW gain was 657, 530, 546, and 200g/d for diets C1, C2, SC-J and SC-G, respectively. Lean cuts (i.e., ham and loin) were significantly higher in SC-G than in C1 pigs (472 vs. 424g/kg; P<0.01); intermediate values were found for C2 and SC-J pigs (427 and 412g/kg, respectively). The ultimate pH in LD muscle was lower in SC-J than the other groups (5.44 vs. 5.65; P<0.01). The intra muscular fat (IMF) content in LD was significantly higher in SC-J diet and lower in SC-G diet (1.9% and 1.0%, respectively); intermediates values were found for C1 and C2 diets (1.4% on average). Ham weight losses during 6 months drying period were lower for SC-G fed pigs (9.7% vs. 12.4%; P<0.05) whereas weight losses during the 12 months drying period were not affected by diet. The TBA value in dry-cured ham was not affected by diet (P>0.05) whereas the fatty acids profiles of subcutaneous fat in SC-J and SC-G pigs contained more mono-unsaturated and less polyunsaturated fatty acids than in C1 and C2 groups. Significant effects of dietary treatment were found for dry-cured ham sensory quality parameters.

Effect of temperature level on thermal acclimation in Large White growing pigs.

The effect of temperature level (24°C, 28°C, 32°C or 36°C) on performance and thermoregulatory response in growing pigs during acclimation to high ambient temperature was studied on a total of 96 Large White barrows. Pigs were exposed to 24°C for 10 days (days -10 to -1, P0) and thereafter to a constant temperature of 24°C, 28°C, 32°C or 36°C for 20 days. Pigs were housed in individual metal slatted pens, allowing a separate collection of faeces and urine and given ad libitum access to feed. Rectal (RT) and cutaneous (CT) temperatures and respiration rate (RR) were measured three times daily (0700, 1200 and 1800 h) every 2 to 3 days during the experiment. From day 1 to 20, the effect of temperature on average daily feed intake (ADFI) and BW gain (average daily gain, ADG) was curvilinear. The decrease of ADFI averaged 90 g/day per °C between 24°C and 32°C and 128 g/day per °C between 32°C and 36°C. The corresponding values for ADG were 50 and 72 g/day per °C, respectively. The 20 days exposure to the experimental temperature was divided in two sub-periods (P1 and P2, from day 1 to 10 and from day 11 to 20, respectively). ADFI was not affected by duration of high-temperature exposure (i.e. P2 v. P1). The ADG was not influenced by the duration of exposure at 24°C and 28°C groups. However, ADG was higher at P2 than at P1 and this effect was temperature dependent (+130 and +458 g/day at 32°C and 36°C, respectively). In P2 at 36°C, dry matter digestibility significantly increased (+2.1%, P < 0.01); however, there was no effect of either duration or temperature on the digestibility of dry matter at group 24°C and 32°C. RT, CT and RR were measured three times daily (0700, 1200 and 1800 h) every 2 to 3 days during the experiment. Between 28°C and 36°C, RT and CT were lower during P2 than during P1 (-0.20°C and -0.23°C; P < 0.05), whereas RR response was not affected by the duration of exposure whatever the temperature level. In conclusion, this study suggests that the effect of elevated temperatures on performance and thermoregulatory responses is dependent on the magnitude and the duration of heat stress.

Effects of breed and season on performance of lactating sows in a tropical humid climate.

A total of 179 lactations obtained on 71 multiparous sows [30 Creole (CR) and 41 Large White (LW)] between June 2001 and July 2004 were used to determine effects of breed (CR vs. LW) and season (hot vs. warm) in a tropical humid climate on performance during a 28-d lactation period. Mean daily ambient temperature was greater during the hot season than during the warm season (26.0 vs. 23.8 degrees C), and relative humidity was similar in both seasons (85% on average). For both breeds, ADFI was reduced (-700 g/d, P < 0.01), sow BW loss was greater (17 vs. 12 kg, P < 0.01), and piglet growth was reduced (197 vs. 210 g/d, P < 0.05) during the hot vs. the warm season. At farrowing, LW sows were heavier (255 vs. 186 kg, P < 0.01) and had less backfat (21 vs. 40 mm, P < 0.01) than CR sows. The growth rate of CR piglets was lower than that of LW piglets (192 vs. 215 g/d, P < 0.01). A breed x season interaction was observed (P < 0.05) for ADFI and sow BW loss. During the hot season, the reduction of ADFI was more pronounced in LW than in CR sows (-910 vs. -470 g/d). Regardless of the season, BW loss of CR sows remained constant (14.2 kg), whereas it increased during the hot season for LW sows (10 kg). The weaning-to-estrus and the weaning-to-conception intervals were not affected by breed or season and averaged 4.8 and 6.1 d, respectively. The rectal temperature was greater (0.3 degrees C) during the hot season than during the warm season and greater in LW than in CR sows (39.1 vs. 38.8 degrees C, P < 0.10). This study confirms the negative effect of hot season in a tropical humid climate on performance of lactating sows and that breed can have a significant effect on lactation performance. The results also suggest that CR sows are more heat tolerant than LW sows.

Effects of season and breed on the feeding behavior of multiparous lactating sows in a tropical humid climate.

The effects of breed and season on performance and feeding behavior were studied during 76 lactations in multiparous Large White (LW; n = 17) and Creole (CR; n = 23) sows reared in a humid tropical climate. The experiment was conducted in Guadeloupe (French West Indies, latitude 16 degrees N, longitude 61 degrees W) between May 2002 and July 2004. Average daily ambient temperature was greater during the hot season than during the warm season (26.0 vs. 23.8 degrees C), but relative humidity was similar in both seasons (85% on average). The daily fluctuations of ambient temperature and relative humidity were similar for both seasons. At farrowing, BW was lower (187 vs. 265 kg) and backfat thickness was greater (40 vs. 22 mm) in CR than in LW sows (P < 0.01). Sows were offered feed ad libitum between the fifth and the 26th day of lactation. There was a breed x season interaction (P < 0.05) for ADFI. During the hot season the reduction of ADFI was more pronounced in LW than in CR sows (-1,100 vs. -300 g/d). Irrespective of breed and season, the daily number of meals was 9.0. The meal size and the rate of feed intake were greater in LW than in CR sows, respectively (555 g and 153 g/min vs. 390 g and 83 g/min; P < 0.01). The diurnal proportion of ADFI was greater in CR than in LW sows (0.60 vs. 0.41; P < 0.01). The reduction in ADFI in LW sows during the hot season was mainly related to a reduction in feed intake during the day rather than during the night (-1.3 vs. -0.2 kg; P < 0.01). Duration of standing was not affected by breed or season, and it averaged 120 min/day. This study confirms the negative effect of the hot season on feeding behavior of lactating sows. It also suggests a better acclimation to daily high temperatures and a greater heat tolerance in CR compared with LW sows, at least for eating behavior.