Successful development of poultry farming can be achieved not only as a result of the creation of highly productive new breeds of geese, the improvement of diets for nutrients, but also in the conditions of stable epizootic well-being of infectious and invasive diseases. Parasitic diseases of domestic waterfowl account for a large proportion of other diseases and cause significant damage to geese farming. Among helminthiases of geese, infections caused by nematodes parasitizing in the gastrointestinal tract of birds, in particular Trichostrongylus tenuis, are quite common. The aim of this study was to study the distribution of trichostrongylosis among populations of domestic geese in the territory of Poltava region, Ukraine (Velyka Bahachka, Hlobyne, Hrebinka, Zinkiv, Karlivka, Poltava, Myrhorod, Shyshaky districts). The conducted scatoscopical studies showed that the average extensity and intensity of trichostrongylosic infestation was respectively 22.9 % and 89.7 ± 8.2 eggs per 1 g of poultry feces. Invasiveness in the region studied ranged from 17.2 to 26.7 % and from 20 to 380 eggs per 1 g of feces. At the same time, it was found out that the degree of affliction of domestic geese by the agent of trichostrongylosis in farms with different capacity and technology of keeping was significantly different. In individual farms and farms, the extensity and intensity of the invasion of geese is higher (24.4 % and 97.7 ± 10.7 eggs per 1 g of feces) than in the specialized geese farms (16.1 % and 70.3 ± 15.1 eggs in 1 g of feces). It has been found that goose trichostrongylosis is more frequently present in the mixinvasions of the digestive canal of the bird along with protosooses and nematodoses. Extensity of mixinvasions reaches 18.1 %, which is 78.9 % of the total number of patients at geese trichostrongylosis. Extensity of trichostrongylosic mono-invasion was 4.8 % (21.1 % of the total invasion of T. tenuis birds). The results of the conducted studies lead to a further, deeper study of the issues of epizootic features of trichostrongylosis of geese, taking into account the seasonal and age dynamics of invasion, as well as the effectiveness of therapeutic and preventive measures.

The aim of present study was to assess the time periods of exogenous development of Trichostrongylus tenuis nematodes that parasitize in domestic goose, and their survival in vitro. To do that, eggs of Trichostrongylus were obtained from excrement of infected birds and cultured in laboratory to the third stage larvae (L3). Culturing was performed at 15 0 C, 20 0 C and 25 0 C. Time periods of the parasitic development was analyzed, as well as their survival. According to results, the optimum temperature of embryonic and postembryonic development of T.tenuis is 25 0 C. The time period of exogenous development at 25 0 C was the shortest (five days), and survival was 83.67%. Decreasing temperature resulted in slower development of infectious larvae (10 days) of lower survival (58.67%). Developmental processes in eggs and larvae of Trichostrongylus were accompanied by changes in their sizes regardless of the temperature conditions. Parasitic embryogenesis was characterized by increasing length and width of eggs. Postembryonic development of nematodes was associated with inflating length and width of second stage larvae, but inflating length and decreasing width of third stage larvae.

Trichostrongylus tenuis Mehlin, 1846 is a helminth species that parasitizes in the gastrointestinal tract of birds and causes trichostrongylosis. Research on the differential features of the pathogen at various stages of development facilitates timely finding of the foci of infection and providing recommendations for prevention and control. In the present study, the differential species traits of male and female Trichostrongylus nematodes parasitizing in the domestic goose were examined. The nematodes were obtained in helminthological dissection of the intestine of birds kept at farms and private households in Poltava region, Ukraine. It was revealed that the morphological features of T. tenuis females that should be considered in species identification include the structural specifics of the reproductive system and the tail end. 22 metric parameters were suggested for species identification, including the female body measurements for different parts, specifics of vulva and anus location, sizes of the ovijector, sphincter, ejector and vulval area. Differences were found in the metric parameters of the lateral crests of the cuticle in female nematodes in relation to the position of crests on the parasite’s bodies. The cuticular crests were absent at 0.1 mm from the head and tail ends, and the length of crests was 9.3 mm in total. The longest and widest crests were observed in the middle of the body, the shortest were found in the anus area, and the narrowest crests were from the anterior part of esophagus to its middle. The distance between crests varied 0.2–3.0 μm, the longest at the transition of esophagus into the intestine and the shortest in area between the vulva and the anus. The metric parameters of T. tenuis eggs obtained from bird feces and in the nematode uterus differed significantly by 5 characters. The collected data on the morphological and metric parameters of females and eggs of T. tenuis can be used in species identification and understanding of the taxonomic position of that species.