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The covariance structure was estimated by REML for a joint genetic evaluation of production and reproduction traits for Czech Landrace (58 258 records) and Czech Large White (167 161 records) pigs using four-trait animal models. The following traits were analysed: lean mean percentage at the end of the performance test in the field, estimated from ultrasonic measurements unadjusted for live weight (LM), average daily gain in field test (in g/day) calculated as weight at the end of the test divided by age at the end of the test (ADG), number of piglets born alive in parity 1 (NBA1) and number of piglets born alive in parity 2 and subsequent parities (NBA2+). The heritabilities were in the range from 0.30 to 0.37 for LM, from 0.13 to 0.18 for ADG, from 0.09 to 0.13 for NBA1 and from 0.10 to 0.14 for NBA2+, depending on the breed and on the model (herd-year-season random or fixed). Genetic correlations between production and reproduction traits were estimated to be non-zero. Correlations between traits caused by the herd-year-season effect were mostly positive. As a general conclusion, the joint genetic evaluation of production and reproduction traits is recommended. The herd-year-season effect should be preferably considered as random.

The amelioration of aflatoxicosis in broiler chickens was examined by feeding two concentrations of yeast component (esterified glucomannan; EG). EG, incorporated into the diet at 0.5 and 1 g/kg, was evaluated for its ability to reduce the detrimental effects of 2 mg total aflatoxin (AF; 82.72% AFB₁, 5.50% AFB₂, 10.20% AFG₁ and 1.58% AFG₂) in diet on growing broiler chicks from 1 to 21 d of age. A total of 240 male broiler chicks (Ross-308) were divided into 6 treatment groups [control, AF, EG (0.5 g/kg), AF plus EG (0.5 g/kg), EG (1 g/kg), and AF plus EG (1 g/kg)]. Compared to the control, AF treatment significantly decreased body weight gain from week 2 onwards. AF treatment also caused significant decreases in serum total protein, albumin, total cholesterol, triglyceride, glucose, inorganic phosphorus, creatinine levels and alanine-aminotransferase (ALAT) activity but increased the aspartate-aminotransferase (ASAT) activity. Red blood cell, haematocrit, haemoglobin, thrombocyte, and lymphocyte counts and tibial crude ash levels were significantly reduced by AF treatment, while significant increases were seen in heterophil counts. The addition of EG (1 g/kg) to an AF-containing diet significantly improved the adverse effects of AF on haematological parameters, total protein, albumin values and ASAT activity. EG (1 g/kg) also partially improved body weight gains (59%) and the other biochemical parameters influenced by AF treatment. The addition of EG (both 0.5 and 1 g/kg) to the AF-free diet did not cause any considerable changes in the investigated values. These results clearly indicated that EG (1 g/kg) addition effectively diminished the adverse effects of AF on the investigated values. Also, the higher dietary concentration of EG (1 g/kg) was found more effective than the lower concentration (0.5 g/kg) against the adverse effects of AF on the variables investigated in this study.

There is a constant increase in demand for large numbers of high-quality oocytes of domestic mammals for various reproductive biotechnologies. Prolonged in vitro culture represents one of the many possible ways of meeting this demand. However, oocytes further cultured in vitro after reaching the stage of metaphase II undergo the complex process called "ageing", which decreases the quality of oocytes. The aim of the present study was to improve the culture conditions for in vitro matured porcine oocytes by supplement of the epidermal growth factor (EGF) or the insulin-like growth factor 1 (IGF-1) in order to reduce the adverse effects of ageing. Supplement of either EGF or IGF-1 had no significant effect on the ageing of porcine oocytes. Significant effects were demonstrated when the oocytes were cultured with both EGF and IGF-1. A combination of 10 µg EGF/ml with 25 ng IGF-1/ml was the most effective. Oocytes aged under these conditions retained very good developmental competence. We observed development to the morula (21%) or blastocyst (25%) stage in oocytes aged for 1 day with EGF and IGF-1. Porcine oocytes matured in vitro are more resistant to the ageing when cultured in the presence of both EGF and IGF-1 and these conditions retain an elevated developmental competence for a certain time.

The evaluation of effects of some non-genetic factors (sex, litter size, age of dams and year of study) on the growth of 85 kids of the Brown Short-haired breed was carried out in a period of two successive years. The analysis of the growth of all kids revealed that in the time interval from birth to Day 90 of age daily gain and final body weight were 181.3 g and 19.52 kg, respectively. As far as the effect of sex was concerned, the intensity of growth was significantly higher in males than in females (P ≤ 0.01) in all periods under study. From birth to Day 90, the respective daily gains of males and females were 200.6 g and 162.0 g. As far as the litter size was concerned, it was found out that daily gains of singles and triplets were higher than those of twins and that the differences between single kids and twins were significant (P ≤ 0.01) in all periods under study. Specifically, daily gains of single kids, twins and triplets in the time interval from birth to Day 90 were 201.4 g; 167.1 g and 175.6 g, respectively. The analysis of the effect of age of dams on daily gains revealed significant effects of this factor on daily gains in the time intervals of Day 30 - Day 60; Day 60 - Day 90; Day 30 - Day 90 and from birth to Day 90 (P ≤ 0.05). With the exception of the period from birth to Day 30, the highest daily gains were recorded in kids of four-years-old dams in all other periods under study. In both years of study, all kids were reared under nearly identical conditions but the effect of year of study on the growth was significant.