Search
Search Results
-
Saccharomyces cerevisiae growth kinetics study dairy byproduct
169-172Views:443By guess, annual volume of milk whey is 185–190 million tons and this volume probably will increase next years. Whey has significant biochemical oxygen demand due to its high organic matter content so whey as sewage is one of the most pollutant by-products in the food industry. Apart from environmental pollution, benefit of several whey constituents for human health is another reason to utilize whey. Corn and potato, as well as the processing of milk in the food industry in large quantities of by-products generated by low cost, substantial quantities of starch and lactic acid, which are due to high biological oxygen demand are considered as hazardous waste. Some of them are destroyed sewage storage tanks, and those products are excellent substrates for the growth of microorganisms could be. The traditional nutrient solution optimization methods are solution and time-consuming and are not able to determine the real optimum because of the interaction of factors involved.
-
Estimating Genetic Parameters using a Random Regression Model
53-55Views:327One of the most important part of the genetic evaluation using a random regression model is the estimation of variance components. This is the topic of many papers because the large computational costs. We can use restricted maximum likelihood (REML), Gibbs sampling and ℜ method for the estimation of genetic parameters. The variance components are necessary to calculate the heritabilities and repeatabilities.
The aim of our paper is to estimate the variance components using a random regression repeatability model from test day data set of Hungarian Holstein-Friesian dairy cows and to analyse the change of additive genetic and permanent environmental variance, heritability and repeatability over lactation. -
The effect of season on the microbiological status of raw milk
95-99Views:374Many factors can influence the microbiological quality of raw cow’s milk. In this study, our aim was to determine whether there was any difference between the microbiological statuses of milk produced in different seasons. Samples were collected and analysed from five dairy farms in Hajdú-Bihar County, from February to November in 2019. During our studies, total plate count (TPC), coliform count and Staphylococcus aureus count of raw cow’s milk samples were determined.
There was no significant difference (P>0.05) between the mean TPC values detected in the milk collected in winter and autumn, but that values were significantly (P<0.05) lower than in the milk samples collected in spring and summer. Similarly to the TPC, in the case of coliform bacteria the lowest mean colony count was detected in the samples collected in winter. The difference was significant (P<0.05), compared to the values observed in the samples collected in summer. S. aureus was detected in bulk milk of only two farms in excess of 1.0 log10 cfu/ml. Also in case of S. aureus, there was a significant difference (P<0.05) between the values observed in the samples collected in winter and in summer. Samples from spring and summer contained the highest amount of S. aureus.
Based on the results of our studies, in the case of almost all farms the mean TPC, coliform and S. aureus counts were lower in the samples collected in winter, than in the samples collected in summer. The fact that the samples collected in winter contained the lowest amount of colonies could be attributed to the inhibition of growth of mesophilic microorganisms below 8 °C. Furthermore, the fact that we observed the highest colony counts in samples collected in summer, can be related to the heat stress of cows during the summer due to unfavorable weather conditions (high temperature and humidity).
-
Upgrading breeding value estimation in beef cattle
451-458Views:334This paper gives a summary of the possibility for applying genomic information for breeding value estimation in beef cattle breeding. This process is called genomic prediction and is now widely used in dairy cattle globally as well as in some beef and sheep populations. The advantage of genomic prediction is a more accurate estimate of the genetic merit of an individual at a young age thereby facilitating greater annual genetic gain, predominantly through shorter generation intervals. Genomic predictions are more advantageous for sex-linked (e.g., milk yield), low heritability (e.g., fertility) and difficult-to-measure (e.g., feed intake) traits. The larger the reference population, on average, the more accurate the genomic predictions; additionally, the closer genetically the reference population is to the candidate population, the greater the accuracy of genomic predictions. Research is continuing on strategies to generate accurate genomic predictions using a reference population consisting of multiple breeds (and crossbred). Retrospective analysis of real-life data where genomic predictions have been operation for several years clearly shows a benefit of this technology.
-
Effect of feeding linseed on the fatty acid composition of milk
45-50Views:521In the last decades many researches were made to change the animal product food’s composition. The production of better fat-compound milk and dairy products became a goal in the name of health conscious nutrition. These researches were motivated by the non adequate milk fat’s fatty acid composition. There have been made researches in order to modify the milk’s fatty acids’ composition to reach the expectations of functional foods. With the optimal supplement of the feed can be increased the proportion of the polyunsaturated fatty acids and can decreased the saturated fatty acids. Row fat content of milk was not decreasing in the course of examination neither of the cold extruded linseed nor the whole linseed supplement as opposed to observations experienced by other authors. In case of monounsaturated and polyunsaturated fatty acids when supplementing with cold extruded linseed the most significant change was observable in the concentration of the elaidic acid, oleic acid, linoleic acid, alfa-linolenic acid, conjugated linoleic acid. In case of saturated fatty acids the quantity of palmitic acid and myristic acid lowered considerably. When observating the feeding with whole linseed the concentration of many fatty acids from the milkfat of saturated fatty acids lowered (caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid). The quantity of some unsaturated fatty acids was showing a distinct rise after feeding with linseed, this way the oleic acid, alfa-linolenic acid, conjugated linoleic acid, eicosadienoic acid. The aim of the study was to produce food which meets the changed demands of customers as well. The producing of milk with favourable fatty acid content from human health point of view can give scope propagate the products of animal origin.