Short Feeding Period Research Articles

Urine distribution and grazing behaviour of female sheep and cattle grazing a steep New Zealand hill pasture

Much of the nitrogen (N) excreted by grazing animals is within highly concentrated urine patches. The N that is not used by plants is likely to be lost through leaching, emitted as N gases or added to the soil organic N pool. The present study used custom-made global positioning system (GPS) and urine sensors on 20 non-lactating ewes and 20 non-lactating beef heifers grazing steep hill country to determine potential critical source areas for N loss to the environment. Bite counters on four sheep and five heifers showed when and where animals were eating. Animals were monitored simultaneously on 0.5 ha adjacent paddocks over 8 days. Sheep and cows urinated a mean (±s.d.) of 21.2 ± 6.1 and 9.0 ± 3.0 times/day, respectively. Eating started soon after sunrise and increased during the day to reach a maximum in the hour before sunset, after which the eating activity of both species was near zero for most of the night, except for a short feeding period at around 0300 hours. The urination frequency of sheep increased as eating activity increased during the day, but this relationship was not seen in heifers. Land classified as easy hill country (≤12°) comprised 31% of the sheep paddock and contained 23% of the urination events. In contrast, although the easy hill country comprised 33% of the cattle paddock, 46% of the urine patches were in this area. Although aerial application of N mitigation products to whole paddocks or farms is uneconomic, the results of the present study suggest that mitigation products could possibly be cost-effectively targeted to easy contoured, cattle-grazed hill country areas accessible by farm vehicle.

Don Wayne Fawcett, 1917–2009

Don Wayne Fawcett, 1917–2009

Selenium in Intravenous Nutrition

Selenium (Se) is an essential nutrient for human beings, with serious consequences resulting from clinical deficiency. It therefore should be provided intravenously to all patients who require parenteral nutrition (PN). Moreover, because the effects of suboptimal status are variable and unclear, this supplementation should be provided from the beginning of the course of PN. In most patients receiving PN at home or after surgery, 60-100 mcg/day will meet their requirements. Patients who commence PN already depleted in selenium may require more. Critically ill patients or those with severe burns may have higher requirements. There is good evidence that up to 400 mcg/day is beneficial in burn patients, but the evidence is inconclusive regarding the benefit of high-dose selenium in severe sepsis. Where increased Se provision is used, or in long-term PN, selenium status should be monitored by measurement of plasma Se together with a measure of systemic inflammatory response syndrome, such as C-reactive protein. There are many research issues, including which biochemical measurements best reflect tissue function, especially immune function in seriously ill patients, the clinical consequences of suboptimal biochemical Se status, whether high-dose Se improves outcome in critically ill patients, and whether extra Se always should be given with extra intakes of other antioxidants.

Effects of Different Hormones on Sex Reversal of Rainbow Trout (Oncorhynchus Mykiss Walbaum) and Production of All-Female Populations

ABSTRACTThe sex reversion technique in fish is widespread in many countries. The development of these techniques is desirable because rainbow trout males reach their gonad maturity earlier compared to the females. A feeding trial was conducted to examine the supplemental effects of three hormones-17α-Methyltestosteron, 11β-hydroxyandrostenedione, 17α-Ethynyltestosterone on sex reversal and growth performance of rainbow trout. Control groups were fed with commercial diets for rainbow trout without hormones. These sex reversed functional males were reared for brood stock until they attained sexual maturity. Thereafter, normal rainbow trout eggs were fertilized with the sperms taken from sex reversed males for producing all-female populations. Also sex reversal ratio and growth performance were determined in hormone-treated groups.Examination of the results showed that 17α-Methyltestosterone was the most effective hormone treatment. The highest sex reversal ratio with 86.67±6.67% was observed in group treated with 3 mg/kg 17α-Methyltestosterone for 60 days. 11β-hydroxyandrostenedione and 17α-Ethynyltestosterone released lower rates and produced quite equal results. Also highest intersex ratio of 46.67±6.67% was recorded in group treated with 30 mg/kg 17α- Ethynyltestosterone for 40 days but the rate was below 20% nearly in all other groups. Even though 17α-Ethynyltestosterone seemed the best, the individuals with unaltered sex were observed in range of33.33±6.67% in group fed with 3 mg/kg 17α-Methyltestosterone for 30 days. It is very likely that the phenomenon is due to the short feeding period.

The synthetic antioxidant, ethoxyquin, adversely affects immunity in tilapia (Oreochromis niloticus)

Ethoxyquin (EQ) has been used as an antioxidant in livestock, aquaculture and pet foods. Animal food safety law has established the upper limit of EQ in animal feed at 150 mg kg⁻¹. However, the risk of EQ at the approved level for aquaculture feed (150 mg kg⁻¹) to fish health is unknown. Here, we examine the effect of EQ on the immunity of tilapia (Oreochromis niloticus). EQ concentration in the blood reached 0.16 mg L⁻¹ in fish fed EQ at the approved level. This level of EQ inhibited phagocytic activity of leucocytes in vitro and antibacterial activity of whole blood in vivo. Furthermore, pyknosis in the liver was observed throughout the duration of feeding. However, after 30 days of experimental challenge with feed containing 150 mg kg⁻¹ of EQ, no significant difference was observed in mortality. Although EQ at the approved level in feed causes immunosuppression in fish, the severity of immunosuppression does not lead to a lowering of disease resistance for short feeding periods.

Blood and haemoglobin meal as protein sources in diets for gilthead sea bream (Sparus aurata): effects on growth, nutritive efficiency and fillet sensory differences

Two parallel experiments were conducted to evaluate the effect of partial substitution of fish meal by two different animal protein sources, blood meal (B) and haemoglobin meal (H) at 0, 50 and 100 g kg−1 of level inclusion in diets for gilthead sea bream, considering a long feeding period for juveniles (Trial 1) and a short feeding period (Trial 2) for on‐growing fish. In Trial 1, 33 g juveniles were fed for 242 days and the fish fed with 5% and 10% of haemoglobin dietary inclusion obtained less growth, although feed efficiency, protein efficiency ratio and muscle composition were similar in all diets. In Trial 2, 179 g initial weight fish were fed for 164 days and growth of fish fed H10 showed the lowest growth, although nutrient efficiency and muscle composition were not affected significantly. The results of these experiments demonstrated that blood meal can substitute fish meal (up to 10%) with no effect on performance, but may lead to sensory differences compared with fish fed diet 0, while the inclusion of 5% blood meal had no effect on growth or sensory characteristics. Fish fed 10% haemoglobin inclusion had the poorest growth values.

Parallel activation of de novo lipogenesis and stearoyl-CoA desaturase activity after 3 d of high-carbohydrate feeding

BackgroundHigh-carbohydrate (HC) diets increase de novo lipogenesis (DNL), but effects on stearoyl-CoA desaturase (SCD) are not so well studied. ObjectiveThe objective was to investigate DNL and SCD in liver and adipose tissue by using fatty acid ratios after short-term dietary intervention. DesignEight subjects consumed isoenergetic 3-d HC (10% fat; 75% carbohydrates) or higher fat (HF; 40% fat; 45% carbohydrates) diets (sugar to starch ratio: 60:40 for both) in a crossover study. Blood was taken from an artery and a vein draining subcutaneous adipose tissue. DNL and SCD activity were investigated by using the ratios of 16:0 to 18:2n−6 and of 16:1n−7 to 16:0, respectively. A test meal, including [U-13C]palmitate was given to trace dietary fatty acid incorporation into VLDL-triacylglycerol (TG). The conversion of intravenously infused [2H2]palmitic acid to [2H2]palmitoleic acid in VLDL-TG was quantified as a specific marker of hepatic SCD activity. ResultsThe VLDL-TG 16:0/18:2n−6 ratio, which reflects hepatic DNL, was greater after the HC diet than after the HF diet (P = 0.02). With the HC diet, increased plasma TG concentrations correlated with 16:0/18:2n−6 ratios (r = 0.76, P = 0.028). Plasma VLDL-TG and adipose venous nonesterified fatty acid (NEFA) 16:1n−7/16:0 ratios were higher after the HC diet (fasting: P = 0.01 and P = 0.05, respectively; postprandial: P = 0.03 and P = 0.05, respectively). Changes in fasting VLDL-TG 16:0/18:2n−6 and 16:1n−7/16:0 ratios were associated (P = 0.06). The contribution of total fatty acids from splanchnic sources (including DNL) was higher after the HC diet (P = 0.02). Expression of lipogenic genes in subcutaneous adipose tissue was not significantly affected by diet. ConclusionParallel activation of DNL and SCD was found after a short period of HC feeding.

Short feeding period of carrot psyllid (Trioza apicalis) females at early growth stages of carrot reduces yield and causes leaf discolouration

AbstractOverwintered adult carrot psyllids [Trioza apicalis Förster (Homoptera: Psylloidea: Triozidae)] damage carrot [(Daucus carota ssp. sativum L.) (Apiaceae)] seedlings by phloem feeding on the leaves. The aim of this study was to investigate the carrot root and shoot growth in relation to carrot psyllid density during early growth stages. One, two, or three carrot psyllids were allowed to feed on carrot seedlings for 3 days. Leaf damage was measured at the 8‐leaf stage, and root, leaf fresh weight, and number of true leaves were measured at harvest. Both the age of the carrot seedling at infestation and the psyllid density had a significant effect on leaf damage at the 8‐leaf stage: seedlings damaged at the cotyledon stage exhibited more leaf damage than seedlings damaged at the 1‐leaf stage. A higher psyllid density significantly reduced the carrot root weight at harvest. The significant interaction of psyllid density with seedling age indicates that differently aged carrot seedlings responded differently to feeding: one psyllid feeding for 3 days at the cotyledon stage caused a significant yield loss, whereas three psyllids were needed to cause the same impact at the 1‐leaf stage. Carrot leaf weight at harvest was not reduced by carrot psyllid feeding: leaves recovered from the damage but roots did not. Our results confirm the farmers’ observations that a trap replacement period of 1 week for carrot psyllid monitoring is too long, especially at the cotyledon stage. Severe leaf discolouration on damaged carrots was observed at harvest. The possible reasons for this discolouration, such as toxin excreted in psyllid saliva or plant pathogenic mycoplasma infection, are discussed.

Feeding and management practices affect quality improvement in wild-caught edible crab ( Cancer pagurus)

About 80% of the Norwegian landings of edible crab ( Cancer pagurus) are females. Meat content is often poor also for hard-shelled crabs. Feeding has proved to increase the quality, however the feeding process is costly and should be as short as possible still providing the required product quality. The crab fishery season coincides with the females' reproduction period which affects the quality and body composition. Egg-carrying crabs are of no commercial value. The development of the gonads is therefore of great importance for a feeding management of crabs. A study was conducted to test if meat yield and quality increased over time in the peak season (September). Groups of females were fed a diet of saithe ( Pollachius virens) fillet for 10, 24 and 33 days. An unfed reference group was killed, boiled and quality assessed at the start of the experimental period and compared with fed groups assessed in the same way at the termination of the feeding period. The improvement of quality traits was a continuous process, with a linear increase in total subjective impression, hepatopancreas lightness and gonadosomatic index (GSI) correlated with time of feeding or cumulative feed intake. Two different methods of inactivating the claws, banding and nicking, were compared during the feeding period. The treatments gave no difference in feed intake or external quality like lost legs and tips. Gonad and hepatopancreas were examined during several short experimental periods (3–4 weeks) expanding from just before until after the peak fishery season. In August, September and October/November GSI increased but no increase was seen in hepatosomatic index (HSI). Crabs with GSI between 15 and 18 (%) seemed to be close to spawning. In October/November 40% of the crabs spawned, in December 6.7%. No development in GSI was present in December but HSI increased for fed crabs. After the peak spawning period in October/November most of the remaining crabs do not start the onset of gonad development before the following year. Fed crab at this time of the year will be of a different body composition, with more hepatopancreas and less roe. Several factors may influence the economy in a feeding program. However, the short feeding period makes it possible to feed several batches in a year. In a growing market and with increasing knowledge in quality grading technology of live crabs, feeding of edible crab may be worthwhile in the future.

Kale-based out-wintering systems for weaned Aberdeen Angus cross and Limousin cross steers during a winter store period

Since de-coupling of CAP subsidy schemes from actual animal production, lowering the costs of finishing cattle production systems is one of the key challenges facing the beef industry. One of the largest costs associated with finished cattle production from spring-born suckled calves is the costs of over-wintering the weaned steer calf once the suckling phase is over. The capital tied up in buildings is a major component of these costs in countries such as the UK where the relatively harsh winter environments have traditionally led to many weaned suckled calves being housed and fed conserved forages over the winter months to ensure adequate performance. Previous work (Hyslop et al, 2006) has shown that under appropriate field conditions, non-lactating, spring calving suckler cows can be out-wintered on both grazed kale or turnip based-systems with an acceptable degree of animal performance. The objective of the current study was to determine liveweight (LW) changes in weaned spring-born suckled calf steers when managed outdoors on kale-based grazing systems during a short winter feeding period and to assess the dirtiness of steers hides at the end of the kale grazing period.

Effect of feeding time on the performance of a sequencing batch reactor treating a mixture of 4-CP and 2,4-DCP

This paper investigated the biodegradation kinetics of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) separately in batch reactors and mixed in sequencing batch reactors (SBRs). Batch reactor experiments showed that both 4-CP and 2,4-DCP began to inhibit their own degradation at 53 and 25 mg l −1, respectively, and that the Haldane equation gave a good fit to the experimental data because r 2 values were higher than 0.98. The maximum specific degradation rates ( q m) were 130.3 and 112.4 mg g −1 h for 4-CP and 2,4-DCP, respectively. The values of the half saturation ( K s) and self-inhibition constants ( K i) were 34.98 and 79.74 mg l −1 for 4-CP, and 13.77 and 44.46 mg l −1 for 2,4-DCP, respectively. The SBR was fed with a mixture of 220 mg l −1 of 4-CP, 110 mg l −1 of 2,4-DCP, and 300 mg l −1 of peptone as biogenic substrate at varying feeding periods (0–8 h) to evaluate the effect of feeding time on the performance of the SBR. During SBR operation, in addition to self-inhibition, 4-CP degradation was strongly and competitively inhibited by 2,4-DCP. The inhibitory effects were particularly pronounced during short feeding periods because of higher chlorophenol peak concentrations in the reactor. The competitive inhibition constant ( K ii) of 2,4-DCP on 4-CP degradation was 0.17 mg l −1 when the reactor was fed instantaneously (0 h feeding). During longer feedings, increased removal/loading rates led to lower chlorophenol peak concentrations at the end of feeding. Therefore, in multi-substrate systems feeding time plus reaction time should be determined based on both degradation kinetics and substrate interaction. During degradation, the meta cleavage of 4-chlorocatechol resulted in accumulation of a yellowish color because of the formation of 5-chloro-2-hydroxymuconic semialdehyde (CHMS), which was further metabolized. Isolation and enrichment of the chlorophenols-degrading culture suggested Pseudomonas sp. and Pseudomonas stutzeri to be the dominant species.

An in situ postexposure feeding assay with Carcinus maenas for estuarine sediment-overlying water toxicity evaluations

This study developed and evaluated a short-term sublethal in situ toxicity assay for estuarine sediment-overlying waters, with the crab Carcinus maenas (L.) based on postexposure feeding. It consisted of a 48-h in situ exposure period followed by a short postexposure feeding period (30 min). A precise method for quantifying feeding, using the Polychaeta Hediste ( Nereis) diversicolor Müller as food source, was first developed. The sensitivity of the postexposure feeding response was verified by comparing it to that of lethality, upon cadmium exposure. The influence of environmental conditions prevailing during exposure (salinity, temperature, substrate, light regime, and food availability) on postexposure feeding was also addressed. The potential of this in situ assay was then investigated by deploying organisms at ten sites, located in reference and contaminated Portuguese estuaries. Organism recovery ranged between 90% and 100% and a significant postexposure feeding depression (16.3–72.7%) was observed at all contaminated sites relatively to references.

Factors enabling Epinotia granitalis (Lepidoptera: Tortricidae) overwintered larvae to escape from oleoresin mortality in Cryptomeria japonica trees in comparison with Semanotus japonicus (Coleoptera: Cerambycidae)

The factors involved in the successful escape of overwintered larvae of Epinotia granitalis from host oleoresin in the phloem of Cryptomeria japonica were studied. The mortality, period, and body weight of E. granitalis overwintered larvae while feeding on the phloem of C. japonica were compared with the same parameters for Semanotus japonicus larvae. The seasonal fluctuation in the ability of C. japonica to form traumatic resin canals in the phloem was also assessed. The oleoresin mortality of E. granitalis was low compared with that of S. japonicus. Although both species started feeding on approximately the same date in spring, the feeding period of E. granitalis was only about 24 days, showing that E. granitalis faced the danger of host oleoresin for a shorter period than S. japonicus. The larval weight of E. granitalis was consistently greater than that of S. japonicus through the phloem-feeding period of E. granitalis, and the growth rate was also higher in E. granitalis, suggesting that E. granitalis had a better ability to avoid host oleoresin. These results demonstrated that not only the feeding habits, that is, the tendency of a single larva to feed at several sites, but also the shorter feeding period and larger body size were probably the important factors facilitating escape of E. granitalis from host oleoresin mortality. Furthermore, the ability of C. japonica to form traumatic resin canals increased after the starting date of larval feeding in spring. Because E. granitalis finished feeding before the culmination of the ability of C. japonica to form traumatic resin canals, it was likely that the shorter feeding period was the most important factor in enabling E. granitalis to escape from mortality by host oleoresin.

The contribution of the facultative feeding period to echinoid larval development and size at metamorphosis: a comparative approach

Planktotrophic invertebrate larvae have two dissociable stages during development, a facultative feeding period, whose length is determined by the amount of maternal provisioning in the egg, and an obligate feeding period, whose length is determined by the quantity of exogenous energy needed to reach metamorphic competence. Here we set out to experimentally test the impact of feeding during the facultative feeding period at two food concentrations (limiting and nonlimiting) on larval development time and juvenile quality. We used two closely related subtropical sand dollar species that differ in the quantity of maternal investment for these comparisons: Leodia sexiesperforata (large egg, long facultative feeding period) and Mellita tenuis (small egg, short facultative feeding period). We found that feeding during the facultative period accelerates development to metamorphosis only in M. tenuis and only at the high food ration. Feeding during the facultative feeding period had no effect on development time for M. tenuis at a food limiting concentration and for L. sexiesperforata at either food concentration. Furthermore, we found feeding during the facultative period to significantly increase quantity of carbohydrates and lipids at metamorphosis only for M. tenuis in nonlimiting food concentration. Thus, our data reveal a two-fold benefit of the facultative feeding period for a poorly provisioned species under high food conditions but little effect on a well-provisioned species. We discuss our results in reference to McEdward's [McEdward, L.R., 1997. Reproductive strategies of marine benthic invertebrates revisited: facultative feeding by planktotrophic larvae. Am. Nat. 150, 48–72] facultative feeding model.

Response of a subarctic salt marsh plant community to foraging by captive lesser snow geese

Foraging intensity and faecal inputs are important determinants of plant community response to herbivory. We used captive adult lesser snow geese (Anser caerulescens caerulescens), which feed on both above- and below-ground plant tissues, to manipulate foraging intensity and faecal inputs to plots in a sedge meadow in spring, 1996. We measured plant and soil characteristics throughout the growing season of 1996 and in August 1997. We analysed three contrasts: grazed plots versus ungrazed controls, plots with a short period of feeding (3 goose-hours) versus plots with a long period of feeding (6 goose-hours), and grazed plots with faeces versus grazed plots without faeces. Although grazed plots had an order of magnitude higher foraging intensity than that imposed by wild geese in the marsh, there was no effect of feeding on biomass or nitrogen concentration in the dominant species, Carex ramenskii and Triglochin maritimum, after one and two growing seasons. The amount of forage removed by geese did not differ between plots grazed for long and short periods, indicating that geese were able to remove little additional biomass after 3 hours due to low availability. Therefore, the amount of biomass removed by geese was a better indicator of foraging intensity than the time geese fed on plots. The presence of faeces had no effect on biomass or nitrogen concentration in Carex ramenskii or Triglochin maritimum, or on rates of net nitrogen mineralization in soils. Thus, faeces did not appear to increase nitrogen availability for plants in this marsh, probably because faecal density was low.

Effect of starvation and feeding of larvae during 4th stadia on pupation and adult size in Dacne picta (Coleoptera: Erotylidae).

The effects of feeding and starvation during the 4th larval stadium on the later development of Dacne picta (Coleoptera: Erotylidae) were observed by rearing under various diet regimens on dried fruiting bodies of shiitake mushroom, Lentinula edodes. When the food was removed after different durations of feeding, pupation occurred at ca. 7 d after removal of the food resource irrespective of the duration of the feeding period. The body size of eclosed adults increased with longer feeding periods. We investigated the feeding response of larvae provided mushrooms as food after different durations of initial feeding and starvation periods. Two responses were observed. Larvae either resumed feeding on the mushrooms (re-feeding individuals) or did not resume feeding (non re-feeding individuals), and these patterns resulted in large and small adult size, respectively. Re-feeding during the larval stage only influenced the body size of individuals which had had short initial feeding and starvation periods, and the percentage of re-feeding individuals also decreased with the protraction of the initial feeding and starvation periods. Adult body size of non re-feeding individuals decreased with protraction of the starvation period between feedings. This indicates that the pupation of larvae depends on larval mass and duration of the starvation period. The threshold larval size of males at metamorphosis was significantly smaller than that of females. This pattern of larval growth and pupation of the beetles would be advantageous when completing immature development on a short-lasting food resource. Further, such size dependent pupation of larvae would result in larger size of females than males, and synchronization of pupation and eclosion.

The effect of ammonium ferric hexacyanoferrate on reducing radiocaesium transfer from grass silage to sheep

A study was carried out to examine the effect of ammonium ferric hexacyanoferrate (AFCF) on the transfer of radiocaesium from grass silage to the tissues of male lambs. During ensiling, a formic acid based additive and AFCF were sprayed on grass contaminated with 134Cs and the mixture was allowed to incubate for 45 days. A dose of 21 mg AFCF d-1, fed to sheep offered contaminated silage for fourteen days, reduced 134Cs transfer to muscle by 45% compared to that of control sheep. An equivalent dose of AFCF administered in a capsule reduced transfer by only 3%. In another experiment, AFCF intake of 50, 100 and 150 mg d-1 for ten days reduced 134Cs transfer to sheep muscle by 75, 82 and 86%, respectively. In control lambs, of average live weight 38 and 47 kg, the feed to muscle 134Cs transfer coefficient averaged 0.15 d kg-1, but equilibrium between tissue and feed 134Cs had probably not been reached due to the short feeding period. Increasing doses of AFCF from 0 to 150 mg d-1 increased the faecal/urinary 134Cs ratio from 2 to 42.;

Satiation-dependent, intra-cohort variations in prey size selection of young roach (Rutilus rutilus).

Feeding rate and behaviour of juvenile roach in a non-depleting patch consisting of Daphnia magna of two size classes (optimal and much smaller) were studied in 20-min experiments. The medium size group (standard length 26-28 mm), large (28-32 mm), and small (24-26 mm) fish differed significantly in the proportion of small prey eaten. During a short initial period of burst feeding (1-5 min) only large prey were selected by all fish. The switch from large to small prey occurred much earlier in small than in large roach. During the initial period small fish had higher feeding rates. In small fish, small prey made up about 30% of the food biomass consumed during the whole 20-min feeding period, whereas in large fish small prey played a minor role (about 2%). Within the medium-sized group, one subgroup of fish, characterized by early switching to small prey, showed a feeding behaviour similar to small fish, whereas the other subgroup, which switched later, behaved like large fish. Neither the apparent prey size model nor optimal foraging theory, even in its dynamic version, were supported by the data. It is suggested that vigilance against predators changes the initial energy-maximizing strategy in hungry fish to a time-minimizing strategy in partially satiated fish. Intra-cohort variations in prey size selection might be related to social status of the fish. Social status may affect prey size selection and feeding rate, and thus result in different growth rates and size differentiation.

Simple techniques for labelling prey and gut content analysis in short-term feeding experiments with fish larvae

Techniques were developed for labelling prey, and for gut content analysis in fish larvae. Labelling consisted of a short feeding period of the prey (rotifer and Artemia metanauplii) on black-drawing ink before supplying them to the larvae. Prey labelling was rapid and remained stable for at least 3 h when transferred into seawater. In addition, a method was tested to facilitate the observation of larval gut contents. The method, based on Dawson's technique, involved fixation, removal of lipids and clearance of turbot ( Psetta maxima) larvae, which become transparent and ready for gut content analysis. This treatment did not interfere with the black ink label of the ingested prey.

Reproductive pattern of three amerindian communities from Costa Rica

The bases of the reproductory models of three indigenous communities from Costa Rica belonging to the same cultural area (Chibcha) but with different social, economical and environmental conditions were studied. In this situation it was observed how the study of the data on fertility and fecundity, analyzed together with other reproductory and social characteristics of women, can precisely determine the reproductory model of the communities to which they belong. A homogeneous fecundity was presented in the studied communities, but one which responded to different reproductory patterns. Starting from the multivariate analysis of the fertility variables, the studied women were divided into two groups. One of the groups presents the highest levels of length of breast feeding period and amenorrhea, together with the near total lack of artificial breast feeding and the early introduction of normal feeding. This model is predominant among the Guaymies. The other one, together with the short period of breast feeding and amenorrhea, shows an early introduction of the bottle and a late one of solid food in the feeding process. It is characteristic of the Huetars. This links a certain reproductory model to an indigenous community and a way of life. The reproductory pattern, a clearly biological model, to an ecological and cultural environment.