Dermatofilose e controle das helmintoses gastrintestinais em pequenos ruminantes no Semiárido Nordestino, Brasil.

Abstract

The objective of this study was to evaluate several alternatives for the control of dermatophyllosis and parasitic control of sheep and goats in the semiarid region: 1) control of dermatophyllosis in irrigated pastures; 2) the control of gastrointestinal parasitoses in irrigated rotational grazing; 3) the study of some factors necessary to be known for the selective treatment, such as the different susceptibility between adult goats and young goats and the dynamics of infection in the beginning of the rains. This thesis is compound by three papers. In the first, 17 outbreaks of dermatophilosis are reported in three Santa Inês and Santa Inês x Dorper sheep farms, raised in areas irrigated with rotational grazing, with stockings of 5 to 11 animal units per hectare in the municipality of Belém do São Francisco, Pernambuco. Outbreaks occurred after periods of rain, affecting sheep of different ages, with morbidity from 0.77% to 31%. Clinical signs were characterized by crust-forming dermatitis that easily detached, leaving areas of alopecia. In cultures in 5% sheep blood agar medium was isolated Dermatophilus congolensis. The animals were separated from the herd and treated with 70,000 IU of procaine benzylpenicillin and 70 mg of dihydrostreptomycin sulfate per kg of body weight and all recovered. It is concluded that dermatophilosis is an important endemic disease in sheep in irrigated rotational grazing and high stocking systems, which occurs more frequently after periods of rain and can be controlled with isolation of the animals followed by a single application of penincillin and streptomycin. In the second paper we report the control of gastrointestinal nematodes in a farm in the Municipality of Belém do São Francisco, Pernambuco, from April 2013 to September 2014, in a herd of 646 to 859 crossbred Dopper sheep with Santa Inês, reared in an area Of 12 ha of coast cross grassland (Cynodon dactylon) divided into 24 paddocks. For grazing the sheep were divided into two groups, one of ewes lambs and the other of dry sheep and lambs of more than two months, which grazed three days in each paddock. The paddocks had 36 days of rest. Anti-helminth resistance testing was performed at the beginning of the experiment and annually, which resulted in the annual change of the product used. In the second year, for faecal collections and for selective anthelmintic treatment, the ewes and the dry sheep were divided into two subgroups each: fat and lean. Each month, 10% of the sheep of each subgroup were collected for OPG and coproculture. Samples of grass were collected every two months to count and identify grass larvae. During the 18-month study, approximately 3797 sheep were treated individually, equivalent to 6.49 treatments per sheep (3.97 in 2013 and 2.52 in 2014). The most prevalent helminth in coprocultures (50-85%) and pasture (83.2%) was Haemonchus contortus. The lowest numbers of infective larvae in the pasture (94 to 111 larvae L3 / kg DM) occurred on days 35 and 2 to 8 of grazing. The highest numbers occurred between days 17 to 20 (374 to 761 L3 / kg DM). The meat production of the farm was 1023 kg per hectare and the profitability of 3.31%. It is concluded that the grazing of the potters for three days, with a rest of 36 days, with the use of selective treatment, allows tocontrol the gastrointestinal helminths in irrigated rotational grazing systems. However, it is necessary to perform anti-helminthic parasite resistance tests annually to circumvent this problem. In the third paper, in five farms with herds from 11 to 63 goats, from March 2013 to January 2015, feces from all goats were collected for fecal egg counts on a monthly basis. In any farms was not necessary to treat during periods of drought. In 2013, with rainfalls of 265-533 mm per year, it was not necessary to treat during the rainy season and in 2014 with precipitations of 604-778 mm it was necessary to treat 30-60 days after the first rains in three darms. In these three faerms was found multiresistance to anthelmintics. It was found that the FEC of the lactating goats was significantly larger than the FEC of the dry goats and the kids. In conclusion, in the semi-arid region, generally, it is not necessary to treat goats grazing in the caatinga during the dry season. In the rainy season the parasitic load increases 2-3 months after the first rains. In both drought and rainfall, the farmer should monitor the herd using FEC or other criteria (anemia, submandibular edema) to determine the need for antihelmintic treatment.