Effects of Chilling and Anoxia on the Irradiation Dose-Response in Adult Aedes Mosquitoes.

The success of the sterile insect technique (SIT) relies on the achievement of high levels of sterility and mating success of the factory-reared sterile males and thus their biological quality, which can be enhanced by the reduction of stress factors encountered during rearing, handling, and irradiation procedures. The achievement of consistent sterility levels requires reliable and standard irradiation protocols. Additionally, mosquito adults require immobilization prior to, and during irradiation to increase processing efficiency and to avoid physical damage caused by movement in restricted space. Common methods for immobilization include chilling and anesthetics such as nitrogen. Here we assessed the effects of chilling and exposure to nitrogen on the irradiation dose-response of Aedes mosquitoes, and their downstream effects on some male quality parameters including longevity and flight ability. We found that chilling does not incur damage in the insects in terms of longevity and flight ability when chilling duration and temperature are carefully controlled, and a recovery phase is provided. Irradiation in nitrogen shows high radioprotective effects during irradiation, resulting in reduced induction of sterility. Overall, longevity of males can be improved by irradiating in anoxia, however the exposure to nitrogen itself comes with negative impacts on flight ability. The results reported here will assist in the standardization and optimization of irradiation protocols for the SIT to control mosquito populations of medical relevance.

Prise en charge de la malnutrition aigüe chez l'enfant dans un hôpital secondaire sahelien

La malnutrition chez les enfants de moins de cinq ans est un problème majeur de santé publique dans les pays à faibles revenus, et contribue de manière significative à la mortalité dans cette tranche d'âge.Le but de ce travail était d'évaluer le profil épidémioclinique et thérapeutique des enfants malnutris pris en charge au centre de santé de référence de Nara.Méthode:IL s'est agi d'une étude rétrospective et descriptive,allant du 01/01/2016 au 31/12/2016.Tous les enfants d'âge compris entre 6 mois et 59 mois, admis pour malnutrition aigüe ont été inclus.Résultats:La malnutrition a été diagnostiquée chez quatre cent soixante un enfant, soit 15% des consultations et 50% des hospitalisations.L'âge médian était de 26 mois (2 mois 93 mois). Le sex ratio était 0,92 (M=222;F=239).Dixneuf pour cent des patients ont eu un sevrage progressif (n=90), et il a été brutal chez 371patients, soit 80%. La répartition des patients selon le Z score était le suivant: Z-score <-1 (n=15;3%), Z-score <-2 (n=46; 10%), Z-score <-3 (n=400; 87%). Le périmètre brachial moyen était de 105mm (99mm-124mm). A l'admission, l'hypoglycémie a été notée chez 45% (n=204). Les cas de marasme représentaient 80% (n=367) kwashiorkor 10% (n=48). La forme mixte de la malnutrition a représentée10% (n=46). Les pathologies associées à la malnutrition étaient: les pneumopathies (n=219; 47%), lepaludisme (n=115;25%) et les gastroentérites (n=68; 15%).Le F75 a été administré majoritairement pendant 3 mois dans 93% des cas. Pour la phase 2 du traitement, le Plumpy Nut et le F100 ont été respectivement administré à 88% et 12%.Le taux de récupération nutritionnelleétait de 95% (n=435).Cinq pour cent des patients sont décédés (n=26). La pneumonie a été la cause du décès dans 85% des cas. Le taux de guérison pour les cas de marasme et de kwashiorkor était respectivement de 94% et 93%.Conclusion:la malnutrition aigüe demeure fréquente et préoccupante en milieu pédiatrique sahelien. Une meilleure connaissance des mères sur le sevrage et la diversification alimentaire permettront d'améliorer l'état nutritionnel des enfants

The efficiency of a new automated mosquito larval counter and its impact on larval survival.

To achieve consistent and standardized rearing for mosquito immature stages, it is crucial to control the initial number of larvae present in each larval tray. In addition, maintaining an optimal and synchronized development rate of larvae is essential to maximize the pupal production and optimize male sorting in a mass-rearing setting. Manual counting is labor intensive, time consuming and error prone. Therefore, this study aimed to investigate the use of a customized automated counter for the quantification of mosquito larvae. The present prototype of the mosquito larval counter uses a single counting channel consisting of three parts: a larvae dispenser, an electronic counting unit and computer control software. After the separation of the larvae from eggs and debris, batches of different numbers of Aedes aegypti first instar larvae were manually counted and introduced into the counter through the upper loading funnel and channeled out from the bottom of the counter by gravitational flow. The accuracy and repeatability of the mosquito larval counter were determined in relation to larval density and water quality. We also investigated its impact on larval survival. Results showed an impact of larval density and water quality on the accuracy of the device. A -6% error and a repeatability of +/- 2.56% average value were achieved with larval densities up to 10 larvae/mL of clean water. Moreover, the use of the mosquito larval counter did not have any effect on larval survival or development. Under recommended conditions, the mosquito larval counter can be used to enumerate the number of mosquito larvae at a given density. However, future developments involving the use of multiple channels or larger input larvae container would help to expand its use in large-scale facilities.

[Vectorial transmission of malaria in a village along the Niger River and its fishing hamlet (Kéniéroba and Fourda, Mali)]. / Transmission vectorielle du paludisme dans un village du bord du fleuve Niger et son hameau de pêche (Kéniéroba et Fourda, Mali).

A better understanding of malaria transmission dynamics is an essential element in the development of any targeted vector control strategy. The objective of this study was to better understand malaria transmission dynamics along the Niger River in Sudan savanna zone of Mali. Trough cross-sectional surveys, Anopheline larvae were collected by WHO standard dipping technique, and vector adults by Human Landing and pyrethrum spray catches methods. The vector population was composed of An. gambiae s.l. (> 99%) and An. funestus (< 1%). An. gambiae s.l. was composed of 96% and 98% of An. gambiae s.s. respectively in Kéniéroba and Fourda. An. gambiae s.s. was in majority composed of its molecular form M in both locations. The density of An. gambiae s.l was higher in the dry season in the immediate vicinity of the river (fishing hamlet Fourda) compared to farther inland Kéniéroba. The average infection rate of An. gambiae s.l. was 3.63% and 4.06% in Kéniéroba and Fourda respectively. The average entomological inoculation rate (EIR) during the study period was almost similar in Kéniéroba (0.70 infective bites/person/month) and Fourda (0.69 infective bites/person/month). The means EIRs over each of the rainy season 2006 and 2007 were always higher than the one of the dry season 2007 in both localities, with much smaller amplitude in Fourda than in Kéniéroba. However, the level of the transmission was 2.31 (0.37/0.16) times higher in Fourda than in Kéniéroba during the dry season.We conclude that in Sudan savanna zone of Mali, malaria transmission along the river is continuous throughout the year, but it is more intense in the immediate vicinity of the river during the dry season than during the rainy season in opposition to more distant localities to the river and vector control should not be focused only on the rainy in such setting.

Swarming behaviour in natural populations of Anopheles gambiae and An. coluzzii: review of 4 years survey in rural areas of sympatry, Burkina Faso (West Africa).

The swarming behaviour of natural populations of Anopheles gambiae and An. coluzzii (formerly known as An. gambiae S and M forms, respectively) were investigated through longitudinal surveys conducted between July 2006 and October 2009 in two rural areas of south-western Burkina Faso where these forms are sympatric. In both sites, the majority of swarms were recorded above visual markers localised among houses. In Soumousso, a wooded area of savannah, 108 pairs caught in copula from 205 swarms were sampled; in VK7, a rice growing area, 491 couples from 250 swarms were sampled. If segregated swarms were the norm in both sites, many visual markers were shared by the two forms of An. gambiae. Furthermore, mixed swarms were collected annually in frequencies varying from one site to another, though no mixed inseminations were recorded, corroborating the low hybrid rate previously reported in the field. The occurrence of inter-specific mate-recognition mechanisms, which allow individuals to avoid hybridisation, is discussed.

Mustard bran in lactating dairy cow diets.

Two trials using lactating Holstein cows were conducted to evaluate effects of a diet containing oriental mustard bran on dry matter intake (DMI), milk production, milk components, and organoleptic properties. In experiment 1, 34 lactating cows (24 multiparous and 10 primiparous; days in milk ≥ 50 d) were used in a switchback design to determine the lactational response and organoleptic quality of milk when the diet contained 8% oriental mustard bran (MB) versus a control diet (CON). Mustard bran replaced a portion of soybean meal and all the beet pulp in the CON diet. Milk yields were greater for cows fed the MB diet; however, no differences were found in DMI, 3.5% fat- (FCM) or solids-corrected milk. Milk components and components production were not affected by treatment. Milk organoleptic qualities were not affected by diet. In experiment 2, 22 lactating cows (16 multiparous and 6 primiparous; days in milk ≥ 21 d) were assigned randomly within parity to receive MB or CON from wk 4 to 19 postpartum in a randomized complete block design. Cows were fed CON wk 1 to 3 postpartum. The MB diet contained the same ingredients as the CON, except sunflower seed and a portion of soybean meal were replaced with mustard bran. Milk and components data were collected during wk 3 postpartum and used as covariates to adjust treatment means. Intake was greater for cows fed the MB diet; however, daily milk, 3.5% FCM, and solids-corrected milk yields were not different between diets. Milk components and component yields were not affected by treatment. Milk urea concentration was less for cows fed the MB diet. Although cows fed the MB diet had greater DMI, this was not translated into a higher milk 3.5% FCM/DMI production efficiency ratio. During experiment 2, many cows fed MB experienced minor to severe hemolysis with bloody urine. This hemolysis believed to be caused by the S-methyl-cysteine sulfoxide contained in mustard bran could have affected milk production efficiency. The increased milk yield observed in experiment 1 was not observed in experiment 2. Adding 8% of MB to lactating cow diets had a mixed effect on DMI and milk production. Milk component yields and milk quality were not affected. Feeding this level of MB presents a hemolytic danger to lactating dairy cows.

[Study of the quality of life of hemodialysis patients at the University Hospital of Point G (CHU) in Bamako- the study of 30 cases]. / Etude de la qualite de vie des malades hemodialyses au CHU du Point G a Bamako (a propos de 30 observations).

AIMS: To assess the social and psychological state development of our patients six months after their dialysis treatment. PATIENTS AND METHODS: It was about a prospective study within January to June 2006. The data collection was conducted on personal search records and a questionnaire "Choice Health Experience Questionnaire" (CHEQ). The CHEQ self managed assessed the mental health, the physical health, the sexual and social functioning, the concept of sleeping disorders, familial life, leisure's and education's level. The typing was done on Epi Info 6,0 and the analyse on SPSS10. RESULTS: They where 20 men and 10 women or a ratio sex of 2. The average age was 40.36 years ±13.08. Twenty three patients (76.7%) were satisfied of their life in general. Four patients (13.3%) were depressed, two had sleeping disorders. Fifteen men (75%) had erection disorders. CONCLUSION: Our patients' quality of life in iterative haemodialysis remains satisfactory. A better care taking of the anaemia is necessary because it plays an important role in the erection disorders.

[Tuberculosis in chronic hemodialysis patients at the Teaching Hospital of Point G (CHU) in Bamako]. / La tuberculose chez les hemodialyses chroniques au CHU du Point G a Bamako (a propos de 10 observations).

AIMS: To determine the frequency and the diagnostic difficulties of tuberculosis of haemodialysis patients. PATIENTS AND METHODS: The study was about a retrospective analyse of patients haemodialysis records treated for tuberculosis within January 2003 to April 2006. The tuberculosis check-up contained a questioning, a meticulous clinic examination, thorax radiography, a tuberculosis intra dermoreaction (IDR) and the search of Koch Bacillus (BK) in biological liquids. RESULTS: Tuberculosis was identified to 15.52% of haemodialysis patients (10/95). The average age of our patients was from 44.3 years, with a ratio sex of 2.5 in favour of men. Tuberculosis infection happened on average 27.4 months after the beginning of the haemodialysis. We found out 50% of extra pulmonary tuberculosis (three peritoneales and two pleurales); and 50% of pulmonary tuberculosis. The IDR was positive in two cases (2/6). The search of BK didn't succeed. We reported three deaths. CONCLUSION: The effect of tuberculosis to chronic haemodialysis patients is very high. The diagnostic is sometimes difficult and is based only on specific therapeutic test.

La tuberculose chez les hemodialyses chroniques au CHU du Point G a Bamako (a propos de 10 observations)

Objectif : determiner la frequence et les difficultes du diagnostic de la tuberculose chez les patients Hemodialyses. Patients et Methodes : il s'agissait d'une analyse retrospective des dossiers de patients dialyses Traites pour tuberculose de janvier 2003 a avril 2006. Le bilan de tuberculose a comporte un Interrogatoire; un examen clinique minutieux; une radiographie du thorax; une intradermoreaction a la tuberculine (IDR); ainsi que la recherche de bacilles de Koch (BK) dans les liquides biologiques. Resultats : la tuberculose a ete notee chez dix patients soit 15;52des hemodialyses (10/95 Patients). L'age moyen de nos patients etait de 44;3 ans; avec un sexe ratio de 2;5 en faveur des hommes. L'infection tuberculeuse survenait en moyenne 27;4 mois apres le debut de l'hemodialyse. Nous avons retrouve 50de tuberculose extra pulmonaire (trois peritoneales et deux pleurales) et 50de tuberculose pulmonaire. L'IDR etait positive dans deux cas (2/6). La recherche de BK a ete Infructueuse. Nous avons recenses trois deces. Conclusion : l'incidence de la tuberculose chez les hemodialyses chroniques est tres elevee. Le diagnostic est tres souvent difficile et ne peut reposer que sur l'epreuve therapeutique specifique

Synchronization of carbohydrate and protein sources on fermentation and passage rates in dairy cows.

Four ruminally cannulated Holstein cows in midlactation were randomly assigned to a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments to evaluate two nonstructural carbohydrate sources (corn or barley) with two sources of ruminally undegradable protein (soybean meal or extruded soybean meal) on milk production, ruminal fermentation, and digesta passage rates. Milk production (25.1, 27.5, 23.8, and 23.5 kg/d for the corn and soybean meal, corn and extruded soybean meal, barley and soybean meal, and barley and extruded soybean meal, respectively) and dry matter intake per unit of body weight (3.9, 4.1, 3.7, and 3.7%) were greater for cows fed corn than for cows fed barley and were similar for cows fed soybean meal or extruded soybean meal. Concentrations of ruminal NH3-N were greater for cows fed the corn and soybean meal diet than for cows fed other diets (15.0, 10.4, 9.0, and 11.3 mg/dl). Rumen volatile fatty acid concentrations were greater for cows fed corn than barley (133, 139, 121, and 118 mumol/ml). Fractional passage rates of solids from the rumen were greater for cows fed the barley and soybean meal diet than cows fed the corn and soybean meal diet (3.4, 3.9, 4.2, and 3.8%/h), and ruminal liquid dilution rates were similar for cows fed all diets (11.2, 11.0, 11.1, and 11.9%/h). The attempt to synchronize ruminal nonstructural carbohydrate and crude protein degradability produced minimal benefits for midlactation dairy cows.

Evaluation of corn distillers grains and ruminally protected lysine and methionine for lactating dairy cows.

Twelve multiparous Holstein cows averaging 57 d (36 to 77 d) postpartum at the start of the experiment were utilized in a replicated 4 x 4 Latin square design. Dietary protein supplements were 1) soybean meal, 2) soybean meal plus ruminally protected Lys and Met, 3) corn distillers grains, and 4) corn distillers grains plus ruminally protected Lys and Met. Dry matter intakes were lower for cows fed diets containing soybean meal than for cows fed diets containing corn distillers grains. Milk yield increased with the corn distillers grains (34.3, 34.0, 35.3, and 36.7 kg/d for cows fed diets 1 through 4, respectively), especially when supplemented with ruminally protected Lys and Met. Milk protein yield and percentage were increased by amino acid supplementation. Milk fat yield and percentage were unaffected by diet. The only milk protein fraction affected was nonprotein N, which was lower in the milk of cows fed corn distillers grains. Lysine, Met, and Phe were indicated as the most limiting amino acids for all diets when using amino acid extraction efficiency and transfer efficiency to indicate limiting amino acids. When corn distillers grains were supplemented with ruminally protected Lys and Met, milk yield and milk protein yield and percentage increased because the diet containing corn distillers grains was probably deficient in Lys.

The distribution and inversion polymorphism of chromosomally recognized taxa of the Anopheles gambiae complex in Mali, West Africa.

Data from polytene chromosome studies on the Anopheles gambiae complex in Mali were reviewed. The banding pattern was successfully scored in 17,705 specimens from 76 sampling sites representing the main ecological strata of the country. Two members of the complex, namely An. arabiensis and An. gambiae, were found widespread and frequently sympatric, with the latter prevalent in most localities. Population genetic analysis of the inversion polymorphisms indicated the existence of panmictic conditions for An. arabiensis only, whereas the parallel study of An. gambiae supported its splitting into at least three reproductive units, characterized by different 2R chromosome arrangements, designated Bamako, Mopti and Savanna. The chromosomal evidence was consistent with the hypothesis of complete reproductive isolation between Bamako and Mopti. Partial isolation between these two taxa and Savanna was suggested by the scoring of hypothetical hybrid 2R heterokaryotypes in various samples, but the actual hybrid origin of these specimens was not confirmed. Different patterns of geographical and seasonal distribution were shown as follows. An. arabiensis prevails in arid savannas (Sahel and Northern Sudan savanna) out of the flooded or irrigated zones; it is able to withstand the most arid conditions of Saharan localities and its breeding might extend throughout the dry season. An. gambiae Savanna and Bamako prevail in relatively humid savannas (Southern Sudan savanna) and their breeding generally occurs only during the rainy season. The Savanna taxon was almost absent in flooded or irrigated zones and in riverine localities; the Bamako taxon is distributed along the upper river Niger and its tributaries. An. gambiae Mopti extends its range in all ecological zones present in Mali including the Sahel and predesertic areas, showing high relative frequencies up to absolute dominance in flooded or irrigated areas; its breeding is highly successful also during the dry season. Rainfall at the sampling sites was found to correlate positively with the frequency of Savanna and negatively with the frequency of Mopti. The remarkable ecological flexibility of the latter was found associated with wide seasonal and geographical variations in its 2R inversion polymorphism bc/u. Higher frequencies of the bc arrangement were recorded both in the Southern localities during the dry season and in the Northern more arid localities during the rainy season. The absence or scarcity of An. arabiensis and An. gambiae Savanna in most flooded or irrigated zones suggests their competitive exclusion by An. gambiae Mopti.

Optimizing the utilization of animal fat and ruminal bypass proteins in the diets of lactating dairy cows.

Fifty cows were used to evaluate the lactational response to diets containing additional fat as tallow and increased amounts of RUP (bypass proteins) with or without molasses. Cows were blocked by parity and calving date and randomly assigned to one of five diets from wk 4 to 16 postpartum. Treatments were 1) control (soybean meal), 2) bypass proteins (blood meal, meat and bone meal, corn gluten meal, soybean meal), 3) molasses and bypass proteins, 4) fat and bypass proteins, and 5) molasses, fat, and bypass proteins. Cows were fed for ad libitum intake a total mixed diet that contained 25% corn silage, 25% alfalfa hay, and 50% concentrate mix (dry matter basis). Production of milk was higher for cows fed diets containing fat and bypass proteins; molasses and bypass proteins; and molasses, fat, and bypass proteins than for cows fed the diet with bypass proteins alone, but production was similar for cows fed the control diet and diets containing bypass proteins alone. Production of milk was similar for cows fed the diet with molasses and bypass proteins and for cows fed the diet with fat and bypass proteins. Milk protein percentages were higher for cows fed the diet with molasses and bypass proteins than for those fed the diet containing fat and bypass proteins. The dry matter intake, body weight gains, and body condition scores were unaffected by treatment. For all diets, Met, Lys, and Phe were the first three limiting essential amino acids for milk protein synthesis. Production was increased by including either fat or molasses with bypass protein, but there was no clear advantage of including both fat and molasses in the diet.

Lactational evaluation of protein supplements of varying ruminal degradabilities.

Twelve lactating Holstein cows (9 multiparous and 3 primiparous) were used in a replicated 3 x 3 Latin square design with three periods of 4 wk each to evaluate diets containing three protein supplements that varied in ruminally undegradable protein and amino acid (AA) composition. Diets contained either 44% crude protein (CP) solvent-extracted soybean meal, expeller (mechanically extracted) soybean meal, or a blend of animal and vegetable proteins as the protein supplement. The animal and vegetable blend consisted of equal portions of protein from blood meal, corn gluten meal, meat and bone meal, and soybean meal. All diets contained 33.3% alfalfa haylage, 16.7% corn silage, and 50% of the respective concentrate mix (dry matter basis). Diets contained 17.4, 17.8, and 17.8% CP and 34, 45, and 45% of CP as ruminally undegradable protein, respectively. Dry matter intake, milk production and composition, and body weight were similar among treatments. Uptakes of AA by the mammary gland were similar among treatments. The apparent first-limiting AA for each diet was likely Met, but Lys and Phe were also potentially limiting. Varying degrees of protein degradability and AA composition within the range of this study did not affect lactational responses, indicating that all of these protein supplements were adequate to support milk production.

Ruminal degradation, amino acid composition, and intestinal digestibility of the residual components of five protein supplements.

Two ruminally cannulated Holstein cows (approximately 202 DIM) were used to determine the in situ degradability of five protein supplements: blood meal, meat and bone meal, corn gluten meal, expeller soybean meal, and solvent extracted soybean meal. Dacron bags containing 4 g of each supplement in duplicate were soaked in water and then incubated in the rumen for 0, 3, 6, 12, 18, and 24 h for 3 d. Four extra sample bags of each supplement were incubated in the rumen for 12 h to determine the in vitro intestinal digestibility and AA analysis of the residues. Protein supplements were also analyzed for their AA content. Ruminal degradability of individual supplements varied. Solvent soybean meal was the most degradable, and blood meal was the least degradable. Specific first-limiting essential AA were isoleucine for blood meal and meat and bone meal, lysine for corn gluten meal, and methionine for the soybean meals. The RUP fraction in solvent-extracted and expeller soybean meals tended to be more intestinally digestible than did the protein in blood meal and meat and bone meal. In general, all protein supplements, except solvent-extracted soybean meal, were high in RUP and had the potential to provide good quality AA to complement microbial AA for production.

Evaluation of diets containing supplemental fat with different sources of carbohydrates for lactating dairy cows.

A study was conducted to evaluate the lactational response of high producing cows to diets supplemented with fat that contained additional ruminally degradable carbohydrate from a molasses plus fat product and dried whey. Forty Holstein cows were randomly assigned within lactation group to receive diets containing 2% tallow with or without molasses or dried whey wk 4 through 16 postpartum. Cows were fed 1) the control TMR of 25% corn silage, 25% alfalfa hay, and 50% concentrate mix, 2) the TMR containing fat, 3) the TMR containing molasses and fat, or 4) the TMR containing dried whey and fat. Production of milk and 3.5% FCM was increased by supplemental fat. Milk protein and fat percentages were not affected by supplemental fat with or without molasses or dried whey. The DMI and BW were similar for all diets. Production efficiency (3.5% FCM/DMI) was higher for cows fed supplemental fat diets, and cows fed tallow alone were more efficient than those fed tallow with molasses or dried whey. Tallow did not influence ruminal concentrations of various VFA. Molar percentage of butyrate was higher for cows fed the TMR containing molasses plus fat or dried whey plus fat than for cows fed the TMR containing fat. The TMR containing 2% tallow increased milk production, but no economic advantage was derived from inclusion of an additional ruminally fermentable carbohydrate as molasses or from dried whey with fat.

Nonstructural carbohydrate and undegradable protein sources in the diet: growth responses of dairy heifers.

Thirty-five 3-mo-old 150-kg Holstein heifers were fed diets containing two nonstructural carbohydrate sources (corn or barley) with two quantities of undegradable protein (soybean meal or extruded soybean meal) for 9 wk in a 2 x 2 factorial arrangement to evaluate NRC guidelines that the diet contain increased quantities of undegraded intake protein. Total mixed diets fed for ad libitum intake contained approximately 17.4% CP, consisting of 16.7% corn silage (DM basis), 33.3% chopped alfalfa hay, and 50% concentrate mix. Average daily gains were greater for heifers fed extruded soybean meal, but response was greater when heifers were fed barley-extruded soybean meal (1.12, 1.13, 1.05, and 1.23 kg/d for corn-soybean meal, corn-extruded soybean meal, barley-soybean meal, and barley-extruded soybean meal, respectively) than diets of barley-soybean meal. Extruded soybean meal increased DMI (5.9, 6.1, 5.2, and 6.7 kg/d), but DMI were similar when diets based on corn or barley were fed. Diets with greater concentrations of undegraded intake protein fed to dairy heifers resulted in greater DMI and average daily gains, but responses were greater when heifers were fed diets based on barley rather than corn. These results suggest that current NRC recommendations for undegraded intake protein fed to 3- to 6-mo-old dairy heifers are too high; diets containing 35 to 40% undegraded intake protein should be sufficient.

Ecological genetic studies in the chromosomal form Mopti of Anopheles gambiae s.str. in Mali, west Africa.

Among the sibling species of the Afrotropical Anopheles gambiae complex, the nominal taxon (An. gambiae s.str.) is the major malaria vector. Its bionomics suggest a man-dependent speciation process which involves, in West Africa, various incipient species chromosomally recognized by different combinations of 2R paracentric inversions. One of the most recent evolutionary steps of such a speciation process appears to be the chromosomal form Mopti, which is associated with dry season irrigation in arid zones, and is characterized by a remarkable ecological flexibility related to three 2R alternative arrangements, namely bc, u and +, whose expected karyotypes are found in Hardy-Weinberg equilibrium. The study of this chromosomal polymorphism in samples from a 16-locality transect in Mali shows wide variations and highly significant correlation with both temporal and spatial climatic differences. Mosquitoes homokaryotypic for 2Rbc are the actual dry season and arid areas breeders. The regular rise of 2Rbc frequency, up to fixation, during each dry season, corresponds to the South-North clinal increase of the same arrangement along the transect, from about 30% in the humid savanna to near fixation in the South-Saharan zone. This coherent ecological genetics case provides full support to the hypothesis of the adaptive nature of paracentric inversions. Moreover, the very peculiar system of combinations of contiguous 2R inversions, utilized by Mopti as well as by other chromosomal forms of An. gambiae, suggests a process of polygenic reorganization based on linkage disequilibria and involving the inversions as driving selection units.

Response of calves to diets that varied in amounts of ruminally degradable carbohydrate and protein.

Holstein calves were used wk 1 to 12 after birth to evaluate three sources of nonstructural carbohydrates that differed in ruminal degradability (corn, barley, and dried whey) with two sources of CP (normal and extruded soybean meal) that also differed in ruminal degradability. Nonstructural carbohydrates were most degradable in the dried whey diets and least degradable in the corn diets, and protein was more degradable in soybean meal than in extruded soybean meal. Pelleted diets were formulated to be isonitrogenous at 18% CP and contained (DM basis) 20% ground alfalfa hay, the respective carbohydrate and protein sources, vitamins, minerals, and antibiotic premix. All calves received 4.5 kg/d of milk during wk 1 to 4 and 2.3 kg/d during wk 5. The BW gains during wk 1 to 12 were higher (.80, .70, and .70 kg/d) for calves fed corn than for those fed barley and dried whey, respectively, and were slightly higher for calves fed extruded versus normal soybean meal (.76 and .71 kg/d). Corresponding DMI (1.47, 1.34, and 1.31 kg/d) were higher for calves fed corn than for those fed barley and dried whey and were higher for calves fed extruded versus normal soybean meal (1.43 and 1.32 kg/d). Trends in BW gains and feed intakes for wk 1 to 5 and 6 to 12 were similar. Feed to gain ratio was similar for all diets in all periods. The BW gains of calves tended to be greater when they were fed diets containing nonstructural carbohydrates and protein that was less ruminally degradable.