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Dear all, I would like to make a presentation on the problems of cattle breeding and rearing in high-yielding dairy herds.
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For today's lecture meeting, I have prepared a set of seven problems that I believe are important issues affecting this,
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What happens in dairy cattle herds engaged in dairy farming and milk production.
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The first problem relates to increasing milk yields and the consequences concerning them - the extinguishing of reproductive rates, the decrease in the lifespan of cows.
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The second problem concerns extending the lactation period, or the period of milk production in cows.
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The third problem, deals with a very important issue, that is, mastitis and the related consequences associated with the occurrence of this condition.
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The fourth problem relates to the balancing of rations, the appearance of excessive amounts of urea in milk and the consequences associated with this chemical component of milk in cows.
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The fifth problem relates to the consequences associated with the negative energy balance of cows.
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These consequences are primarily ketosis and the effects of high levels of ketone bodies in cows' milk.
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The sixth problem I would also like to mention as part of this meeting today concerns the departure from the quota system and the transition to a free-competitive system, which has happened since 2015 in Polish herds and European dairy herds.
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And the seventh problem also concerns an important issue it seems to me, that is, optimizing the chemical composition of milk and further improving its hygienic quality.
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Rising milk yields, the extinguishing of reproductive rates are phenomena that I have described here as part of problem one.
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The table on the slide shows changes in average milk yield for a 305-day lactation and the length of the inter-calving period of cows evaluated in Poland between 1980 and 2023.
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The data of this table report that the average milk yield for a 305-day lactation increased from 3297 to 9150 kg between 1982 and 2023.
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At the same time, the average length of the intercropping period has also deteriorated, increasing its level here from 389 days to 420 days.
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Thus, over the past 43 years in Poland, for every one-day increase in 305-day lactation productivity, there was this increase - a decrease or increase in the length of the inter-calving period by one day.
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Thus, the cited data report a negative correlation between milk yields in cows and the length of inter-calving periods.
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The second problem relates to increasing milk yields and their consequences in terms of a decrease in the lifespan of cows.
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The slide presents information indicating that the natural lifespan of cows is about 20 years at the moment.
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This means that a cow can potentially produce milk for as many as 15 consecutive lactations.
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However, as a result of increased milk yields, the potential lifespan of cows in modern herds is being significantly reduced.
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Thus, currently the longevity defined as the age of cows at slaughter was 5.8 years in the Netherlands, 5 years in the United States and in Poland it was exactly 5.7 years.
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The next slide presents another problem concerning the state of dairy cattle, the problem of extending the length of milk production.
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From the point of view of the length of time of milk production, that is, lactation, there are two basic systems in the world.
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Traditional system and extended lactation system.
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In the traditional production system, the standard lactation length for cows is 305 days.
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In contrast, in a system with extended lactations, this length of milk production is extended by 60 days to 390 days.
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In the extended lactation system, dairy cows calve not once every 12 months as in the traditional system, but twice every three years.
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That is, it converts three 12-month production cycles into two 18-month cycles.
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Currently, 55% of the country's cows produce milk under the extended lactation system.
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Another problem I would like to talk about in this lecture meeting concerns mastitis and its negative impact on the volume of milk production and the chemical composition of that milk.
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Dear all, due to the fact that cow's milk is produced under certain production conditions, an essential part of which is the microorganism environment,
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At the level of dairy cattle herds, there are numerous problems resulting from the penetration of bacteria into the milk located on the mammary gland of cows.
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These bacteria can cause inflammation under the common name of mastitis, so taking care of the high hygienic, cytological quality of the milk obtained from cows is a daily challenge for cattle farmers in the country and around the world.
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Thus, they can be compared to Sisyphean labor, meaning hard, monotonous, persistent work that never fully succeeds.
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Dear all, the effect of the presence of the microorganism in the milk of cows is the appearance of so-called somatic cells, which are the basic element of the immune response of animal organisms.
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Therefore, somatic cells are treated in modern knowledge in this field as a basic criterion for assessing the health of the mammary gland and the cytological quality of milk.
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Their number is widely regarded as a measure of udder health in dairy cows.
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Their number is an important criterion used in the purchase of milk in Poland and the European Union.
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Buying milk is possible with a somatic cell count of less than 400,000 per milliliter, in the United States less than 750,000 per milliliter.
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An important consequence of an elevated somatic cell count is also a decrease in milk yield, milk production, up to 12% in Subclinical States, and adverse changes in its chemical composition.
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Nationally and internationally, Massachusetts is a major economic problem.
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The country's economic losses are about 1 billion zlotys a year.
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Scientific results show that at least 30-40% of once-lactating cows in Poland suffer from clinical and subclinical udder inflammation.
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It is also widely accepted that the cause of 25% of all cows removed from herds, or culls, is untreated inflammation of the mammary gland.
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Another problem, of which I would like to say a few words, that dairy herds in our country are facing is the difficulty of balancing rations and the appearance of excessive amounts of urea in milk.
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The appearance of urea, ladies and gentlemen, in the milk of cows is a result of the nature of transformations in the digestive tract, resulting in an excess of ammonia undigested by microorganisms in the body.
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This highly poisonous chemical is detoxified in the liver and converted to urea.
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The primary reason for excessive urea levels in milk is, of course, excess protein in rations and energy-protein imbalance.
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There are a number of factors in the production environment that affect urea levels, among them the frequency of feed,
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The number of milkings, the length of the interval between milkings, body weight, cows, the amount of water intake, the level of sodium and potassium supplementation of rations, and the rumen reaction.
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When it comes to modern zootechnical knowledge, the possibility of using the knowledge of urea concentration, it is generally used for two purposes,
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that is, to evaluate the energy and protein balance of the rations used and thus reduce labor costs.
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They can also use this urea information as biomarkers to identify opportunities for nitrogen mitigation in the environment.
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In the evaluation of urea levels, the most important information is the evaluation of protein levels in the rations used to feed dairy cattle.
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An increase in the proportion of specific protein in the dry weight of the ration from 13% to 18% leads to an increase in the concentration of urea from 70 to 150 milligrams per liter, respectively.
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The figure on this slide shows the regression curve for protein levels in feed and urea levels in cows' milk.
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Another important factor in diagnosing urea levels in milk is daily milk yield.
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The graph on this slide shows the optimal concentration of urea in the milk of cows with different daily yields.
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The data show an increasing proportion of urea with increasing daily milk yield in cows.
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The end result of assessing urea levels in milk is its practical use in evaluating the balance of rations used in feeding cows.
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By selecting cows whose milk is characterized by certain ranges of urea content,
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as a biomarker of protein levels in rations and protein in milk as a biomarker of energy content in rations.
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Based on the data cited in the presentation, it should be noted that in the country 56.30% of milk samples meet the criterion of balancing protein needs in rations
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and only 35% of milk samples meet the criterion of balancing the energy needs of the rations used in feeding cows.
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An important part of using information on urea levels in cow's milk is the ability to reduce nitrogen excreted by dairy cattle.
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This issue is particularly important because of concerns about the contribution of agriculture to nitrogen pollution, particularly the escape of ammonia into the atmosphere.
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On a dairy farm, the primary source of ammonia is the nitrogen in manure urea and animal urine, which hydrolyzes to ammonia and carbon dioxide.
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Thus, a cow properly fed annually emits about 40 kilograms of ammonia into the atmosphere. It is estimated that the country's annual ammonia emissions each year are about 386,000 tons, of which cattle emit as much as 155,000 tons.
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The table on this slide presents the significance of urea levels in milk for annual ammonia emissions to the atmosphere.
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On this table, they indicate that an increase in milk urea levels from below 150 milligrams to above 250 milligrams results in an increase in ammonia emissions to the atmosphere from 32.3 kilograms to 57.7 kilograms.
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One practical option for addressing ammonia emissions from dairy herds is the use of cow toilets.
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The purpose of their use is to separate urine from fecal enzymes that cause the conversion of urea to ammonia. In these photos, I show such implementation toilets for cattle.
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Will the cows accept this possibility? The future will show.
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On the next slide I show another problem, concerning the consequences of a negative energy balance in dairy cows and the emergence of ketosis as the most important metabolic disease in dairy cattle losses.
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I would like to say that there is an energy deficit in the bodies of high-yielding dairy cows during the first 10 weeks or so.
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Animal organisms strive to reduce its, run energy reserves stored in the form of subcutaneous fat.
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As a result, the level of fatty acids in the blood increases - in cows, of course - by up to tenfold.
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In a situation of insufficient energy coverage, incomplete combustion of free fatty acids occurs, leading to the appearance of so-called "free fatty acids" in the blood, urine and milk of cows.
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ketone bodies and the appearance of the most important metabolic disorder in cows, that is, ketosis.
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Cows in a period of energy deficit use up subcutaneous fat reserves accumulated during the drying-out period.
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This is a natural mechanism for meeting energy needs in cows.
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In a cow that at the time of parturition was in a condition set at three and a half points, there is a reduction in body weight during the first 60-80 days of lactation of about one-half to one kilogram per day.
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For this reason, the evaluation of the condition of cows is currently treated in dairy herds as an important element, an important factor in preventing the consequences of energy deficiency in rations.
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In situations of unbalanced energy needs, cows develop a negative energy balance and the appearance of this condition, which is called ketosis.
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Ketosis is one of the most important metabolic diseases in dairy herds nationally and internationally. It is a typical occupational disease of high-yielding, milk-producing cows.
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The primary symptoms of ketosis include an abnormal elevation of the fat level in milk above 5% while the protein level falls below 2.9%.
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The fat-protein ratio is raised to above 1.1%.
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Dear all, ketosis occurs in 7-14% of the total number of cows in a herd. In some high-milking herds, the percentage of cows affected can be as high as 50%.
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As for the consequences of the occurrence of this phenomenon, it is extensive. These include worsening reproductive rates, reducing milk yields, and reducing cows' resistance to various infectious diseases, including mastitis.
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On the next slide, I would like to touch on the sixth issue in this lecture meeting, which is about limiting milk production, moving actually away from this quota limit system and moving to a free-competitive system.
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I would like to remind you at this point that since the Great Bourgeois Revolution in France and the overthrow of the feudal system at the end of the 18th century, a new socio-economic system has emerged in the world - the capitalist system.
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These capitalist socio-economic relations are based on three guiding principles. That is, in private ownership of the means of production, profit maximization and market play, competition as a method of determining the volume of milk production and its price.
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In cattle breeding and milk production, the capitalist system can be said to have been in effect since 2015. Until this year the quota system was in force, it was withdrawn.
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Accordingly, the last quota year took place in 2014-2015, which means for the country's dairy sector at the moment a transition to this free-competitive capitalist system when it comes to regulating milk production.
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Two things are most important in my opinion to state. So first, competition based on capitalist mechanisms for regulating production, based on the size of scale and cost of production.
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Economies of scale in production will be a factor that will give an advantage to large dairy producers, and secondly, a reduction in the number of dairy producers over the long term - let's hope it's as small as possible.
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Another problem is that of optimizing the chemical composition of milk and further improving its quality.
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In general, it must be said when analyzing this problem that the chemical composition of milk, cows is not constant. The variability of the content of the main components of milk from a population of cows kept under the conditions of the southern Podlasie,
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measured by the magnitude of the coefficient of variation for fat, protein, lactose, urea were 19.5%, 13.8%, 5.3% and 48.6%, respectively.
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The modification of the chemical composition of milk is the result, of course, of the presence of a number of factors that, at the production level, consistently vary the level of its individual components.
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In domestic conditions, these include, season, age, cows, stage of lactation and gestation, condition during the period of milk production, diseases, - mainly metabolic and, of course, udder diseases and feeding technologies used.
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From the point of view of the health-promoting values of milk, cows in the future should be considered in my opinion the following options for its modification.
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Securing a low ratio of omega 6 to omega 3 fatty acids, which should be near the ratio of 2 to 1,
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Increasing the proportion of oleic acid to 25-30% of milk fat at the expense of palmitic acid, increasing the proportion of milk with A2 beta-casein variant, increasing the concentration of conjugated linoleic acid
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Increasing the concentration of selenium in milk and securing stable iodine levels.
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A2 milk problem. Ladies and gentlemen, I would like to say here as part of this problem that one of the basic fractions of the most important milk protein, casein,
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which is beta-casein, has two genetic variants, A1 and A2. The beta molecules, A1 and A2, are essentially identical. Only one of the 209 amino acids differs.
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At position 67 of the protein chain, the A2 variant has proline, while the A1 mutant has histidinel at this position.
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The spatial structure of A1 casein does not allow it to be digested confidently into individual amino acids, this is very important information.
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Digestion of the A1 variant leads to a number of consequences due to the fact that the beta-casomorphin 7 peptide is formed there.
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Beta-casomorphin 7 is an opioid, the same as morphine and heroin, so consuming milk with A1 casein may be associated with a higher risk of common civilization diseases.
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The A2 casein variant is common in nature and is one form of beta casein, in virtually all mammals except cows. Unfortunately, in cattle, few once cows have only A2 genes, resulting in the presence of only this desirable A2 casein.
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These breeds are found, right, to make things more interesting, on other continents, in other countries, namely Africa and Asia. Animals in Poland and other highly developed countries, on the other hand, mostly have A1-A1 genes in their genotypes and produce only A1 or A1 and A2 casein. And their milk contains A1 and A2 caseins equally.
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For these reasons, cows are being selected around the world to produce milk containing A2 caseins. One of the pioneering countries in this regard is Australia, where A2 milk already accounts for 12% of the Australian market for milk production consumed in the country.
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And in conclusion, I would like to say that among the most significant problems in the rules of dairy existence is the increasing milk yield, which means a decrease in the length of their life and lowering reproductive rates, extending the length of the milk production period,
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which we call lactation, the deterioration of reproductive indices, the occurrence of inflammation of the mammary gland, their negative impact on milk yield and quality, difficulties in balancing rations, the appearance of milk inequalities,
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undue amounts of urea in milk, the consequences of a negative energy balance in dairy cows, the occurrence of ketosis and ketone bodies in cow's milk, the departure from the quota system,
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limitation of milk production and the transition to a free-competitive system and the associated increase in milk unit yield as a basic condition for achieving success in the competitive game in the milk market.
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And the last problem that we discussed in the lecture was optimizing the chemical composition and further improving the hygienic quality.
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That's all I wanted to say as part of this lecture meeting.
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Thank you very much for your attention.
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Thank you very much.