[The effect of the light schedule on biochemical indicators in the blood, serum and urine of heifers during their estrus cycle].

The dynamics of 38 biochemical parameters of blood, serum and urine was studied in ten heifers during their oestrous cycle in a light house (80-340 lux) and a dark small house (10-40 lux). In the light stable a significant influence (P less than 0.05) was found to be exerted on five parameters and in the dark stable nine parameters, four being influenced in the same way in both houses: haematocrit value and haemoglobin in blood and cholesterol and progesterone in serum; the relationship of progesterone content in serum to the days of oestrous cycle was particularly high in the light house.

[The effect of a light regimen on the dynamics of biochemical indicators in the blood, serum and urine of heifers during 1 day].

Circadian dynamics of 38 biochemical parameters of the blood, serum and urine of heifers was studied under the natural light conditions of a light (160-180 lux) and dark (10-40 lux) small cow house. In each house, eight parameters were subject to a significant influence during the day, six of them being the same in both houses: calcium, chlorides, urea and thyroxine of blood serum, glucose and haematocrit in the blood of heifers. The comparison of parameters in different groups showed that different light regimes exerted a significant influence on calcium, chlorides, total protein, cholesterol, vitamin A and thyroxine in serum, haematocrit and leucocyte count in blood, and sodium and urea in the urine of heifers.

[Heat dissipation through the floor in piglet housing].

Trials were performed in 1980 and 1981 to test a new methodical procedure of measuring heat flow with Alfameter and to evaluate the dissipation of heat via the floor in piglet finishing houses with three large pig herds. It was demonstrated during the period of the study that slatted floors dissipated much more heat from the house, as compared with solid floors. The comparison of the density of heat flow over steel slats and plastic slats showed that the plastic slats wasted less heat: in the winter season the difference was 65 to 125 W/m2 and in summer 20 to 75 W/m2.

[Loss of heat through the skin in piglets in pigsties with and without windows].

In 1980 and 1981 tests were performed to verify the new methodical procedure of measuring heat flow by means of Alfameter and to evaluate the liberation of heat from the skin of piglets kept in two-storeyed cages in the finishing houses of the TEROZ TACHOV type. One of these houses was windowless, the other had windows. The temperature, humidity and flow rates of the air inside the houses were measured at the same time.

[The effect of feeding technics on dust levels in pig fattening barns].

Dust nuisance was studied in the pig fattening halls of the TEROZ TACHOV type in 1979 and 1980. One of these halls was equipped with the original feeding technology, in the other a set of gravity pipes was added to feeding line. The comparison showed that the house with the adjusted feeding system has much lower dust nuisance with a reduced content of respirable particles.

[Effect of the barn environment with and without windows in the rearing of pigs].

In the years 1979 and 1980 the microclimate in two types of calving rooms AGRA was studied: rooms with and without windows. A comparison demonstrated that in the rooms with windows the air flow in the zone of abode of animals was higher, rather cooling the piglets, which was not desirable. The light and working conditions in this calving room were better.

[Relations of certain indicators of ejaculate quality of breeding boars to seasonal changes in the microclimate in pigsties].

A yearlong evaluation of the semen volume, concentration and number of morphologically abnormal sperms of 1722 ejaculates from 53 boars of Large White, Duroc and Landrace breeds housed in one building was performed. Simultaneously, continuous registration of temperature and of the relative humidity of the sty climate was performed, and the cooling value and the air flow in the sty were determined. In the followed period also the conception rate of sows after the first insemination by semen of the studied set of boars was evaluated.

[The effect of suction and pressure type of ventilation on the microclimate of fattening stations and on the production performance of pigs].

The microclimate in fattening houses of the TEROZ TACHOV type was studied in two fattening seasons. One of the houses had the original ventilation based on negative pressure and the other was tested as to the function and effect of overpressure ventilation. Under the given conditions, the comparison of the two systems showed that the pressure ventilation drove more air through the zone where the animals were kept, and was connected with higher cooling.