Average number of bernes per animal according to sex and distribution in their respective quadrants
Abstract
Studies about Dermatobia hominis larvae have been described, but no data were found regarding dairy cattle from organic production system in tropical region. The herd consisted of 40 dairy crossbred zebu x taurine. Fortnightly inspection (915 inspections) with mapping for the presence of larvae in the body surface was carried out over the period of a year in the area of the Integrated Agroecological Production System –IAPS/RJ – a technical cooperation project. The results indicated predominance of parasitism in females (average 21.98). In males, the highest number of nodules were on the right side (4.46); in females, highest number of nodules were on the left side. The infestation in adults (average 31.55) was highest; animals in lactation were less infested (average 8.01); in young animals, the most infested side was the left; the most infested coat was the black on white (average 36.69); the less infested coats were red with typical shades (average 14.13) and light brown and dark (12.33). Each increment of 1 mm³ of water caused a mean increase of 1.03 in the relative risk of occurrence of dermatobiosis and with every one degree increased there was an average increase of 1.14 in the relative risk for infestation.
Keywords
- Nodular subcutaneous myiasis
- organic management
- bovine
1. Introduction
The study of seasonal variations of this fly allows us to know the periods of higher parasitic intensity, and also to correlate the facts operating in the growth of its population. Several authors are engaged in studying the seasonal variation of fly’s larva and its relation to climate elements: temperature, precipitation, and humidity, showing that the presence of the warble is associated with regions that have moderately high temperatures during the day and relatively cold overnights, median and abundant rainfall, dense vegetation, and a considerable number of animals. Also, the rainy season is the period of highest occurrence. Even with all these characteristics, the index of parasitism by
In conventional livestock, the larva population on the cattle is controlled with the use of chemical larvicide. On the other hand, organic rural properties must meet the standards contained in the 60th Article of Normative Instruction No. 46, 2011, Ministry of Agriculture and Supply, which regulates organic production in Brazil, restricting the use of allopathic medicines [1].
Several studies about seasonality and
2. Literature review
The parasitism rate of
2.1. Dermatobia hominis : Geographical distribution and biology
According to [2], flies of the species
In Colombia, [6] observed higher prevalence of
[11] described that the warble is distributed in approximately 20 states in Brazil, with higher abundance in Rio Grande do Sul, Santa Catarina, Paraná, Rio de Janeiro, Espirito Santo, Distrito Federal, and Goiás. The author mentions that the parasite does not occur in the states of Amapá, Rondônia, Ceara, Rio Grande do Norte, and Sergipe. According to the author, the soil conditions in these places do not offer conditions for the parasite to complete its life cycle. According to [4],
Observations related to seasonal variations in
By studying the seasonal fluctuation of
In southeastern Brazil, the months of spring and summer, which correspond to the rainy season, are the most favorable period of year for the occurrence of dermatobiosis in cattle. Smaller infestations happen during the dry season in the months of autumn and winter according to [16] and [17].
According to [18], in Brazil, losses caused by of
2.2. Body distribution of Dermatobia hominis larvae
A study on variations related to infestations of cattle by
[20] verified the parasite dynamics of warble, noting its incidence in relation to decubitus in cattle of the Canchin race, in São Carlos – SP. The incidence of parasitism was higher on the left side (14.2 nodules on average) compared to the right side (10.5 nodules). According to the author, the higher incidence of parasitism on the left side can be explained due to the fact that this region was more exposed to the vectors of
[24] observed a significantly higher frequency of
2.3. Organic dairy production system
In conventional livestock, the larva population on the cattle is controlled with the use of chemical larvicide; on the other hand, organic rural must meet the standards contained in the 60th Article of Normative Instruction No. 46, 2011, Ministry of Agriculture and Supply, which regulates organic production in Brazil, restricting the use of allopathic medicines [1]. The term “organic” refers to animal and vegetable food that are produced without the use of fertilizers; pesticides; insecticides; antimicrobials; antiparasitic, transgenic, or any other drug that may contain harmful residues to human health, including agricultural products to conventional dairy farms [25].
Milk production in organic systems does not reach 0.1% of national production, which is about 25 million liters per year, due to several factors, such as: rural extension work enabling the process to small producers; the lack of scientific research adapting livestock production in organic system to the tropical reality; as well as food pasture fertilizers, racial patterns, and health care with the herd, such as endo- and ectoparasites control and mastitis [26].
3. Materials and methods
3.1. Location
The study was conducted from September 2009 to August 2010 in an area that belongs to the Sistema Integrado de Produção Agroecológica (Integrated Agroecological Production System) – SIPA (Fazendinha Agroecológica Km 47), technical cooperation project between Embrapa Agrobiologia, Empresa de Pesquisa Agropecuária do Estado do Rio de Janeiro (Agriculture Research Corporation of Rio de Janeiro State) (PESAGRO – Rio /Seropédica), and Universidade Federal Rural do Rio de Janeiro (Rural Federal University of Rio de Janeiro) [27]. SIPA is located in the city of Seropédica, metropolitan region of Rio de Janeiro state, currently occupying 70 hectares and incorporating, in addition to vegetable production area and fruits, a fragment of forest, a forest garden, and areas of agroforestry and ornamental species. Pastures subdivided into paddocks total 30 hectares.
3.2. Weather
The meteorological data used were temperature (T) of the air, relative humidity (RH), and precipitation (PP) obtained from the Agrometeorological station situated in SIPA’s area.
The climate is hot and humid with little pronounced winter. The average temperature of the coldest month is higher than 20 ° C (68°F) and the maximum temperature in the summer can exceed 40 ° C (104° F). The rainfall is characterized by the existence of a rainy season in summer and dry in winter. The annual rainfall is around 1.300 mm, although it is mostly rainy in spring and summer, the occurrence of prolonged drought is common in the months of January and February [27].
3.3. Animals
The herd consisted of 40 crossbred dairy animals Zebu x European (Gir x Holstein), divided into lots of young and adult animals. The young ones were divided into two further lots: suckler calves (birth to 6 months) and weaned calves (from 7 months to 18 months or 330 kg), and a lot of adult animals consisting of dry cows, in lactation, and a bull. The determination of the coat of animals followed the Girolando characterization [28]. (Figures 1 A, B, C, and D).
3.4. Management of animals
The management system was semi-intensive: the animals remained in the corral during the day, where accumulation of manure could take place, and returned to the grass in the late afternoon. A physical model for organic milk production is implemented. Throughout the management, animal welfare, including avoidance of psychological stress in the herd, is prioritized. All the pickets have access to clean drinking fountains with good-quality water and shaded areas with afforestation. Containment fences are electrified and made with flat wire, in order not to represent a risk of injury to the animals.
The pastures are used in a rotation system. To supply the smaller forage production that happens in the dry period (period of lower growth of pastures), a cultivated area is managed to offer a forage supply in the trough. It is estimated that the period of lowest forage production in the region begins in mid-June and goes on until late October; that is, 135 days (or nine Fortnights) of drought and lower temperatures at night. A dairy Gir bull is used to ensure the reproduction of cows as well as the welfare of animals.
3.5. Health Management
The health management system established was developed for the SIPA project “Fazendinha Agroecológica Km 47.” It is based on the folowing: animal welfare, strategic control of parasites, and homeopathic therapy, always stressing prevention as the most important aspect with regard to treatment. The specific objective was the reestablishment and maintenance of herd health in that organic system, and the general goal was to facilitate the structuring of an experimental organic dairy cattle system.
Homeopathic medicines have been prepared by the Pharmacy School from Instituto Hahnemanniano do Brasil. Drugs are in accordance with the rules of the Brazilian Pharmacy in the form of liquid presentation, and packaged in appropriate amber glass containers. The ways of administration are oral, nasal, or vaginal.
As already mentioned, throughout the management, the priority is the animal’s welfare, including avoiding of psychological stress in the herd. “Good management practices in dairy cattle with emphasis on preventive health” established for this breeding system follow the definitions of the 60th Article of Normative Instruction No. 46, 2011, Ministry of Agriculture and Supply.
The basic requirements under Article 60 of MAPA IN No. 46 [1] are as follows: (1) follow the principles of animal welfare at all stages of the production process; (2) keep hygiene and health throughout the breeding process, consistent with current health legislation and the use of products that are authorized in organic production; (3) provide preventive health techniques; (4) offer nutritious healthy food, with quality and in correct amounts according to the nutritional requirements of each species; (5) offer good-quality water and in appropriated quantities, free of chemical and biological agents that may compromise their health and vigor, quality product and natural resources, according to the parameters specified by law; (6) the use sanitary facilities that are functional and comfortable; and (7) dispose in an environmentally appropriate way, the production wastes.
Vaccinations against FMD, brucellosis, clostridial diseases, salmonellosis, and rabies follow the current schedule in health-surveillance Ministry of Agriculture Livestock and Supply. Homeopathy is the adopted therapy for treatment and prevention of major diseases of dairy cattle, with a Homeopathic protocol developed for this creation system.
A supplement freely provided to the entire herd was formulated according to this system, composed of salt, sulfur (for animal feeding), and dicalcium phosphate.
3.6. Monitoring dermatobiosis (berne)
Inspection was performed biweekly (mapping the presence of larvae), totaling 915 inspections. The animals were inspected by anatomical demarcation, and their body divided into antimeres: anterior upper right (RADS), anterior lower right (RADI), posterior upper right region (RPDS), lower right posterior region (RPDI), anterior upper left (RAES), left anterior inferior (RAEI), posterior upper left region (RPES), and posterior lower left region (RPEI). The presence of the larvae (Figure 2) was observed in the different regions, and the data recorded in documents, according to the methodology of [29], with modifications (Figure 3).
3.7. Statistical Analysis
The berne description of the amounts into categories of each attribute were studied, and performed some exploratory data analysis through bar charts, box plots and calculating the average number of warble per studied animal. To compare the berne counts among the quadrants defined by anatomical demarcation, we used nonparametric Wilcoxon and Kruskal-Wallis test [30], due to the presence of nonnormal data [31]. To verify the association between the inherent variables to the animals and climate we used the generalized linear bivariate model of
In the period of study, 915 berne counts in cattle were made (inspections), in which 391 were in adult cattle, 356 in weaned calves, and 168 in suckling calves. Of the total, 784 females and 131 males were counted. Of the 915 counts, 354 were made in cattle coat with red color in typical shades, 180 in fur animals with white on black, 87 in cattle with black color coat, 198 counts in animal with light brown and dark coat, and 96 counts in animal with black on white coat.
To adjust the climate data to the study database, the average was calculated for each of them (Average temperature, rainfall, and relative humidity) taking into consideration a fifteen-day delay period preceding the collecting day.
All statistical analyses were performed using statistical package R [33].
4. Results and discussion
The results of monitoring of the herd dermatobiosis indicated that there was a significant predominance of parasitism in the females (total average 21.98 bernes per female against total average rating of 8.37 bernes per male), as shown in Figure 4 (A), where the average number of nodules per sex in each animal is observed. Also, greater variability in females than in males was observed, as shown in Figure 4 (B). Also in relation to gender, males showed a higher number of nodes on the right side (total of 4.46 against 3.90 on the left), where the RPDs (Posterior Right Upper Region) was the most infested (2.16). In females, the highest number of nodules were concentrated on the left side (total of 11.17 against 10.70 on the right) and RADS (Anterior Right Upper Region) was the most affected (6.98). Table 1 shows the average number of nodules per animal according to sex. It was found that there was significant difference (p-value <0.001) regarding the amount of bernes between males (8.37) and females (21.98).
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Animal Total | 8.3 7 | 21.98 |
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Left quadrant | Lower Anterior | 0.59 | 1.55 |
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Upper Posterior | 1.44 | 2.58 |
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Upper Anterior | 1.75 | 6.46 |
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Lower Posterior | 0.12 | 0.60 |
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Total | 3.90 | 11.17 |
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Right quadrant | Lower Anterior | 0.29 | 1.51 |
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Upper Posterior | 2.16 | 1.88 |
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Upper Anterior | 1.89 | 6.98 |
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Lower Posterior | 0.12 | 0.55 |
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Total | 4,46 | 10,75 |
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A significant prevalence of parasitism in females agrees with the results found by [24]. Regarding the most infected body region, there was divergence of results in other studies since all author studies cited here [19, 13, 21, 22, and 23] indicate a predominance of infestation in the anterior region, unlike the results found in males in this study, where the most affected body region was the posterior upper right region (RPDS) with an average of 2.16 bernes per animal. Also, in relation to the group of males in the herd, the prevalence of nodules on the right (total of 4.46 against 3.90 on the left) contradicts the results found by [19] in the study of Viamão – RS; as well as [20], who observed that the incidence on the left side is related to prevalence of the right lateral-sternal decubitus at rest time. [21] also found prevalence of parasitism on the left and [22] in a study conducted in Seropédica – RJ found no statistically significant difference between the number of nodules on the right and left sides of cattle.
Considering the age of the animals, it was found that the number of adult animals that were affected by berne (total of 31.55) was significantly higher (p <0,001) than younger animals of the herd (total of 8.0 in suckling calves and 12.21 in weaned calves); the variability in this group was also higher than the variability in the younger group. In the group of young animals, the most affected ones by the parasitosis were weaned calves and (total of 12.21 per animal), therefore, the group of suckler calves was the least infested by the larvae of
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The animal Total | 8.01 | 12.21 | 31.55 |
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Left quadrant | Lower Anterior | 0.47 | 0.73 | 2.38 |
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Upper Posterior | 1.65 | 1.83 | 3.28 |
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Upper Anterior | 1.63 | 3.53 | 9.37 |
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Lower Posterior | 0.29 | 0.38 | 0.76 |
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Total | 4.04 | 6.47 | 15.71 |
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Right quadrant | Lower Anterior | 0.40 | 0.78 | 2.19 |
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Upper Posterior | 1.69 | 1.38 | 2.48 |
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Upper Anterior | 1.69 | 3.23 | 10.68 |
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Lower Posterior | 12.26 | 12.43 | 0.62 |
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Total | 4.02 | 5.79 | 15.68 |
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This study regarding the age of the animals, including the evaluation of results referring to the sides in which the highest level of infestations occurred, has shown in the youth group and adult group an agreement with results of previous researches. But, in the adults’ group and in the suckling calves’ group, although presenting a predominance of infestation on the left side (total of 15.71 and 4.02, respectively), it was observed that the most infested body region was the RADS (Anterior Superior Right Region), averaging 10.68 bernes per animal and RPDS (Posterior Superior Right Region), averaging 1.69 bernes per animal, respectively, different from that indicated in previous studies by [19] held in Viamão – RS, as well as [20], which linked the prevalence of parasitism on the left side to the right lateral-sternal decubitus at rest time. [21] also found prevalence of parasitism on the left and [22] in Seropédica – RJ did not find statistically significant difference between the number of nodules on the right and left sides of cattle.
Considering the presence of the larvae of
In Table 3 we observe the average number of bernes per animal according to type of animal coat. There is a significant difference (p-value <0.001) comparing the amount of bernes between the coats. In Figure 5 (A) the average number of bernes per coat type in each animal is shown. Figure 5 (B) shows the variability of the total number of bernes in relation to the type of coat of the animal.
According to a study conducted by [24], the parasite frequency of occurrence was higher in dark-coat animals (black) unlike what was found in this study.
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Total per animal | 17.08 | 14.13 | 36.69 | 29.82 | 12.33 |
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Left quadrant | Lower Anterior | 1.80 | 0.86 | 3.37 | 1.59 | 0.31 |
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Upper Posterior | 1.05 | 1.70 | 5.04 | 2.33 | 1.98 |
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Upper Anterior | 4.30 | 4.72 | 10.69 | 8.74 | 2.57 |
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Lower Posterior | 0.44 | 0.38 | 0.91 | 0.80 | 0.40 |
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Total | 7.59 | 7.66 | 19.94 | 13.46 | 5.25 |
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Right quadrant | Lower Anterior | 1.26 | 0.85 | 2.79 | 2.30 | 0.47 |
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Upper Posterior | 1.08 | 1.07 | 3.01 | 2.83 | 2.44 |
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Upper Anterior | 6.82 | 4.25 | 10.22 | 11.02 | 3.83 |
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Lower Posterior | 0.53 | 0.35 | 0.83 | 0.48 | 0.39 |
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Total | 9.59 | 6.52 | 16.52 | 16.08 | 7.07 |
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As shown in Table 4, the months of highest occurrence of dermatobiosis were November and December, 2009, while the lowest levels of infestation by larvae of
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Rainy season | Spring | September/2009 | 26 | 1.381 | 63 | 2.263 |
October/2009 | 21 | 821 | 52 | 1.886 | ||
November/2009 | 35 | 1.422 | 99 | 3.546 | ||
Summer | December/2009 | 33 | 1.393 | 104 | 3.748 | |
January/2010 | 5.3 | 223 | 20 | 709 | ||
February/2010 | 3.1 | 125 | 11 | 409 | ||
Dry season | Autumn | March/2010 | 0.2 | 10 | 0.2 | 8 |
April/2010 | 0.5 | 24 | 1,2 | 43 | ||
May/2010 | 0.6 | 32 | 2.3 | 82 | ||
Winter | June/2010 | 0 | 2 | 0.2 | 6 | |
July/2010 | 0.1 | 3 | 0.4 | 6 | ||
August/2010 | 4 | 209 | 5.8 | 198 |
The fluctuation of the larvae of
Risks relating to possible risk factors (intrinsic characteristics of the animal itself – gender, age coat, and climatic factors – rainfall, average temperature, and relative humidity) related to the occurrence of dermatobiosis are shown in Table 5. The results found, with reference to climatic variables, showed that with regard to rainfall and relative humidity, each increase of 1 mm³ of water generates an average increase of 1.03 in the relative risk of occurrence of dermatobiosis in the herd, and each increase of 1°C in average temperature generates an average increase of 1.14 of relative risk to infestation by larvae of
Also, with regard to the results shown in Table 5, it was observed that adult females of the herd presented a relative risk 2.63 times higher than males to infestation by larvae of
Adult bovine animals had a relative risk for dermatobiosis 3.94 times higher than suckler calves, while weaned calves showed a relative risk of 1.52 times more than the suckling calves.
The black on white coats were the most susceptible to infestation by larvae of
The white on black coats showed a relative risk 2.98 times higher for developing dermatobiosis than light and dark-brown coated animals.
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Male (ref.) | 1.00 | [1.00; 1.00] |
Female | 2.63* | [2.47; 2.79] |
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Suckler calves (ref.) | 1.00 | [1.00; 1.00] |
Weaned calves | 1.52* | [1.43; 1.62] |
Adult animals | 3.94 | [3.72; 4.17] |
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Brown (ref.) | 1.00 | [1.00; 1.00] |
Black white | 2.98* | [2.84; 3.12] |
Black | 2.42* | [2.29; 2.56] |
White black | 1.39* | [1.30; 1.48] |
Red | 1.15* | [1.09; 1.20] |
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1.03* | [1.02; 1.04] |
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1.14* | [1.13; 1.15] |
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1.03* | [1.02; 1.04] |
The area occupied by Fazendinha Agroecológica Km47 incorporates a fragment of forest, a forest garden, and areas of agroforestry, and the climate is hot and humid with rainfall characterized by a rainy season in summer, and according to [4], the habitat of
5. Conclusions
The ideal coats in this situation are the light and dark red and brown coated in typical shades;
The degree of infestation was significantly higher in females than in males;
It was not possible to say that there is influence of the right external–lateral decubitus in a parasitized body side;
The temperature is the climatic factor that most influenced the parasitosis;
The largest infestation rates occurred during the rainy season between spring and summer.
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