Heritability and genetic correlation of production and reproduction traits of Simmental cows

Improvement of production capacity of cattle in terms of increasing the production of milk, milk fat and number of calves, greatly depends on phenotype and genotype variability, heritability and correlation between desirable traits, as well as on the production level of the cattle population. Heritability, as a value expressing and measuring average additive gene effect, is one of the major characteristic of quantitative traits from the point of view of creating genetically high-value cattle populations. Knowledge of the heritability is necessary in the estimation of the beeeding value of cattle and has significant impact on the selection of breeding method. Genetic correlations are very important in indirect selection where changes in one trait are induced through selection of other traits between which a genetic correlation exists. Genetic correlations can be determined in all cases where heritability coefficient can be calculated. This research included 3.461 first calving Simmental cows under control, with lactation concluded within one year. All first-calvers were reared on individual farms in the territory of Republic of Serbia. In this study, heritability and genetic correlations between the the following milk and fertility traits were investigated: duration of lactation (days)- DL, milk yield in standard lactation (kg)- MY, milk fat content in standard lactation (%)- MFC, milk fat yield in standard lactation (kg)- MFY, yield of 4% FCM in standard lactation (kg)- 4%FCM, age at first calving (days)- AC and duration of service period (days)- DSP.Key words: Heritability, genetic correlations, milk yield, fertility, Simmental breed

The biodegradation of wheat straw by Pleurotus ostreatus mushrooms and its use in cattle feeding

The influence of Pleurotus ostreatus enzymes on wheat straw degradation was investigated in laboratory conditions. Chopped and pressure-pasteurized straw with 24% dry matter was seeded with mushroom mycelium. Analyses of the straw were done on day 15, 30, 45, 60, 90 and 120 after seeding. The mushroom collection was done four times. After seeding, NDF decreased from 824 to 485 g kg(-1), ADF from 561 to 412 g kg(-1). A similar tendency was found for hemicellulose and cellulose, while it was not so pronounced for lignin. Ash content increased from 62.6 to 97.8 g kg(-1). Degradation rates calculated for individual constituents of cell wall components were: hemicellulose 0.902, lignin 0.450, NDF 0.402, cellulose 0.290 and ADF 0.276% day(-1). The obtained results show that a substantial part of straw dry matter was degraded by the mushroom enzymes. The effects were most notable for cell-wall components which allowed successful use of the straw as a substrate for mushroom growth. It was assumed that spent Pleurotus compost may be used as a part of the cattle diet. That was investigated in a feeding trial where compost formed 0% (Control), 10% (Group I) and 17% (Group II) of dietary dry matter. It was found that animals would not consume mixed ration with more than 17% DM from compost. The decrease in daily gain was observed with the increase of compost level in the diet. Average daily gains were 1150, 1140 and 990 g day(-1) respectively. Animals in Group II had significantly lower gain compared with Control and Group I (P lt 0.01). The utilization of dry matter per kg of gain had a tendency to decrease with the increased amount of compost in the diet

Electric field measurements in a kHz-driven He jetthe influence of the gas flow speed

International audienceThis report focuses on the dependence of electric field strength in the effluent of a vertically downwards-operated plasma jet freely expanding into room air as a function of the gas flow speed. A 30 kHz AC-driven He jet was used in a coaxial geometry, with an amplitude of 2 kV and gas flow between 700 sccm and 2000 SCCM. The electric field was measured by means of Stark polarization spectroscopy of the He line at 492.19 nm. While the minimum and the maximum measured electric fields remained unchanged, the effect of the gas flow speed is to cause stretching of the measured profile in spacethe higher the flow, the longer and less steep the electric field profile. The portion of the effluent in which the electric field was measured showed an increase of electric field with increasing distance from the capillary, for which the probable cause is the contraction of the plasma bullet as it travels through space away from the capillary. There are strong indications that the stretching of the electric field profile with increase in the flow speed is caused by differences in gas mixing as a function of the gas flow speed. The simulated gas composition shows that the amount of air entrained into the gas flow behaves in a similar way to the observed behaviour of the electric field. In addition we have shown that the visible length of the plasma plume is associated with a 0.027 molar fraction of air in the He flow in this configuration, while the maximum electric field measured was associated with a 0.014 molar fraction of air at gas flow rates up to 1500 SCCM (4.9 m s−1). At higher flows vortices occur in the effluent of the jet, as seen in Schlieren visualization of the gas flow with and without the discharge

Electric field measurements in a kHz-driven He jet - The influence of the gas flow speed

\u3cp\u3eThis report focuses on the dependence of electric field strength in the effluent of a vertically downwards-operated plasma jet freely expanding into room air as a function of the gas flow speed. A 30 kHz AC-driven He jet was used in a coaxial geometry, with an amplitude of 2 kV and gas flow between 700 sccm and 2000 SCCM. The electric field was measured by means of Stark polarization spectroscopy of the He line at 492.19 nm. While the minimum and the maximum measured electric fields remained unchanged, the effect of the gas flow speed is to cause stretching of the measured profile in space - the higher the flow, the longer and less steep the electric field profile. The portion of the effluent in which the electric field was measured showed an increase of electric field with increasing distance from the capillary, for which the probable cause is the contraction of the plasma bullet as it travels through space away from the capillary. There are strong indications that the stretching of the electric field profile with increase in the flow speed is caused by differences in gas mixing as a function of the gas flow speed. The simulated gas composition shows that the amount of air entrained into the gas flow behaves in a similar way to the observed behaviour of the electric field. In addition we have shown that the visible length of the plasma plume is associated with a 0.027 molar fraction of air in the He flow in this configuration, while the maximum electric field measured was associated with a 0.014 molar fraction of air at gas flow rates up to 1500 SCCM (4.9 m s\u3csup\u3e-1\u3c/sup\u3e). At higher flows vortices occur in the effluent of the jet, as seen in Schlieren visualization of the gas flow with and without the discharge.\u3c/p\u3