Zvonimir Steiner

Changes of thyroid hormones concentration in blood of sheep depending on age and reproductive status

Abstract The influence of the reproductive status was tested in the blood serum of 30 sheep (10 pregnant sheep on the 15th day prior to lambing, 10 lactating sheep on the 20th day of the lactation and 10 non-pregnant sheep). The influence of age was determined in the blood serum of 20 sheep and 20 lambs. Analysis of the impact of age in sheep and lamb on the concentration of thyroid hormones showed that 30-day old lambs had significantly higher (P<0.01) concentration of T3 and T4 compared to the other age categories of sheep. At the same time, 100-day old lambs had significantly higher concentration of T4 if compared to the 1 and 3-year old sheep. Referring to the reproductive status, there was significantly lower (P<0.01) concentration of T3 determined in the blood of lactating sheep than of non-pregnant and pregnant sheep. These findings point out unsatisfactory energy supply in the older sheep, sheep during late pregnancy and sheep at the beginning of lactation.

Concentration of selenium in soil, pasture, blood and wool of sheep

Investigations have been conducted on Slavonia during a threeyear period on six locations, two per each year during June (in the firstyear = Vinkovci and Beli Manastir; in the second year = Valpovo andDjakovo; in the third year Slatina and Donji Miholjac). Six samples fromthe soil, pasture and sheep wool, as well as 15 sheep blood samplesweretakenfromeachlocality.Therewasadeficitofseleniumcontentinthe soil on four locations in the second and third year (0.18; 0.14; 0.10and 0.07 mg/kg) and an adequate content on locations Vinkovci andBeliManastirinthefirstyear(0.98and0.71mg/kg).ThelocalityValpovowas characterized by the highest selenium concentration in pasture,blood and wool of sheep, as well as by the lowest blood enzymesactivities (ALT, AST, CK, LDH) when compared to other locations.Selenium concentration in pasture was under the critical range on alllocations (from 0.006 to 0.03 mg/kg DM), except the locality Valpovo inthe second year (0.05 mg/kg DM). Serum selenium concentrations(from 0.035 to 0.082 mg/L) on all locations were below the adequaterange for adult sheep and differed among locations. Activities ofenzymes in the blood of sheep (AST: 3.59, CK: 4.93 and LDH:6.87 µkat/L) showed severe selenium deficiency. Seleniumconcentrations in the wool were under the critical level on all locations(from <0.0002 to 0.06 mg/kg). The results regarding selenium in woolshowed that, apart from blood selenium and activities of plasmaenzymes (AST, CK, LDH), wool should also be taken in account as aselenium status indicator.Key words: blood, enzyme blood activity, selenium, sheep, soil,pasture, wool

Influence of housing systems on stillbirth and mortality rate in preweaning pigs farrowed by different gilt breeds

Abstract The aim of this paper was to investigate the influence of housing systems on stillbirth and mortality rate in preweaning pigs farrowed by different gilt breeds. The investigation included first farrowings of 225 Large White (LW) gilts, 297 Swedish Landrace (SL) gilts and 260 crossbreed gilts (LWxSL) in the period of five years. Despite of positive influence of straw through decreased number of stillborn pigs, especially in LW gilts, in further process of production until weaning, less appropriate microclimatic conditions developed in farrowing houses with straw, especially if accompanied with poor ventilation, can result with higher number of perished pigs and lower number of weaned pigs. Most sensible to unsuitable microclimatic conditions in straw bedded farrowing houses, according to the number of perished pigs before weaning, were the pigs from SL gilts, while the pigs from crossbreed gilts LWxSL were the most resistant. These results suggest that adding straw requires special attention on influence of such production on microclimate conditions in pigs’ biozone in order to maintain its initial benefits in the time of farrowing through the whole preweaning period, especially in pure breeds of gilts.