Effectivity of systematic spraying cattle with deltsid against blood-sucking midges on the pasture

The attack of blood-sucking midges causes the decrease in milk production in cattle. According to published data the loss can range from 5.19 to 53.4 %. In order to protect livestock against midges in Russia synthetic pyrethroids are widely used. From this group of drugs deltsid has proven itself as 4 % emulsifiable concentrate of deltamethrin. The aim of our research was to study the effect of hair sprays cattle with deltsid on the number of lice on pastures and milk production of cows. The studies have been conducted in animal farms in the south of the Tyumen region in 2003-2005 and 2008. Cows before pasture were sprayed with 0.001 % strength (by active substance) with an aqueous emulsion spray of deltsid using the method-average rate of 0.5 liters per animal with the help of the developed members of the research institute horizontal spray booms of full tubes with universal set at the gates of the enclosure. The census of midges was carried out using butterfly net with removable pouches. Entomological efficacy of treatment was assessed by comparison of the number of midges on the experimental and control pastures counts. The loss in milk production was calculated on the basis of “the method for determining severity of insect complex” midges' cattle” developed by us. The studies found out that the loss of milk yield of cows in the south of the Tyumen region, may reach in some years 9.88 %. Systematic hair graze cattle spraying with 0.001 % strength (by DI) of deltsid water emulsion ensure reduction of overall numbers of black flies in a pasture in 1.7-7.0 times and therefore shortens the period of mass flight. This allows you to get more from each cow for 0.231 liters of milk per day, or 1.45 %, therefore, it increases the profitability of cattle.