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Dairy cattle crossbreeding and milk production

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Dairy cattle crossbreedingand milk production.The aim of this study was to compare the results of milk performance of purebred Polish Holstein-Frisian (PHF) cows and their crossbreeds (PHF x SRB). Data for the analysis originated from the Polish Federation of Dairy Cattle Breeder and Producers - cows reports. The results indicate a positive influence of the breed on milk composition: fat, protein and dry matter content and somatic cell count. purebred Polish Holstein-Frisian (PHF) cows had significantly higher (p≤0.05) milk yield for both the 100 and 305 days milking. The milk production of MM cows is lower by 15.89%, at 100 days of lactation, and by 34.57% in the full lactation than PHF.
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Analysis of productivity indicators in dairy farms

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The aim of the paper was to analyse the relation of milk yield per cow with a set of production factors on sample data from six dairy farms located in the central region of Poland. The farms, which were the subject of the study, carried out an intensive production, achieving milk yield over the national average. The research showed an increase in milk yield with increasing number of cows in the herd, which, in practice, can lead to increased loads in milking installations in farms keeping more cows.
Externalities occur when the decisions of production and consumption made by one market participant are directly affected by the decisions and actions of others, whilst this impact is not fully reflected in market prices. In case of livestock production, the examples are: agricultural landscape, biodiversity, carbon dioxide and methane emission, unpleasant odour and animal welfare, all called environmental externalities. The aim of the paper is to estimate the potential costs and benefits of possible changes in requirements associated with public goods and externalities generated by agriculture on the example of upgraded animal welfare standards in milk production. It was found, that implementing higher animal welfare standards may lead to a labourious increase in milk production. It may result in a farming scale decrease, an increase in labour costs (and production costs) and consequently lead to the deterioration of financial conditions. Revenues per cow increased in the analysed scenario in the case of the small and medium scale farms and remained stable in the case of the large scale farm. However, farm income decreased in the case of all farms. This is mainly due to employment, depreciation and an increase in financial costs.
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The paper aims to examine the influence of selected animal welfare aspects on the net farm income. Data used in the study were collected under the EDF (European Dairy Farmers) program in 280 farms representing 22 European countries. It was analyzed using the variance and covariance analysis. Following animal welfare aspects were taken into consideration: access to pasture, frequency of milking, culling rate, period between calvings and milk yield. Combinations of each two aspects were also taken into account. Milk production is one of the most important branches in Polish agriculture. Net farm income obtained by milk producers are influenced by factors related to animal welfare. It was found, that farms providing animals with access to pasture are characterized by lower culling rate and milk yield than farms not providing animals with access to pasture. At the same time farms providing animals with access to pasture obtain higher net farm income. The limitation in revenue causes by decreased in milk yield is recompensed by savings in costs. It might be supposed, that this result is related both, to improved health status of animals, and lower costs of feeding. That confirms, that access pasture is a very important determinant of net farm income. Another important factor determining net farm income in milk production is culling rate. Farms characterized by higher culling rate obtain lower net farm income.
The postpartal period in high-yielding dairy cows can be characterized as a time when animal has to undergo several important changes affecting all the organism. After pregnancy and parturition, organism has to adapt itself to the lactation and this stressing experience contributes to the high incidence of health disorders. These include ketosis, fatty liver, milk fever, retained placenta, metritis, mastitis, laminitis, and other metabolic and reproductive disorders. They may become clinically manifested in later stages of the reproduction cycle but have their primary cause in early postpartal period. To overcome these problems, every farmer has to practice good herd health management, especially when considering the transition period. To discover the weak points of the herd management we can use some indices that can be determined from the blood samples of dairy cows after partuition. We collected blood samples from 170 dairy cows of Slovak spotted breed 1 to 8 weeks after parturition. None of them manifested clinical signs of any illness. We divided them into the 6 groups depending on the number of weeks post partum.We observed and evaluated the main blood-chemistry parameters of energy and liver metabolism (glukose, triglycerides, total lipids, total cholesterol, non-esterified fatty acids, beta-hydroxybutyrate, total bilirubin), protein metabolism (total immunoglobulins, total protein, albumine, Creatinin, urea) and levels of some serum enzymes (AST, GGT, ALP, CPK, LDH). Even though there were no alterations in the health status present in that time, we found out that some indices, mostly of energy and liver metabolism, such as serum levels of non-esterified fatty acids, triglycerids, etc. were altered. This fact can help us to trace the potentially threatened individuals and to iniciate the steps that would minimize further damage.
The objective of this study was to determine relationships between sire effect, milk production in young cows, their performance in subsequent lactations, fertility, conformation and productive longevity. A total of 1724 cows that first calved between 2003 and 2005 were analyzed during 4475 lactations. The cows were kept in 10 barns located in the Provinces of Pomerania and West Pomerania, Poland. The analysis covered 1085 daughters of 145 local Polish Holstein-Friesian (PHF) sires and 639 daughters of 128 imported Holstein-Friesian (HF) sires, including 437 cows culled after the first lactation, 445 cows culled after the second lactation and 140 long-lived cows. Research has shown that among first-calf heifers and the second lactation cows more than 55% of daughters of imported bulls and about 48.75% of daughters of domestic bulls were culled. Essentially higher results of sort ratings concerning the overall appearance, body conformation, udder quality and frame size, efficiency of milk and its components were acquired after the imported bulls. High milk production levels, exceeding 8000 kg of milk in the first and second lactation, had an adverse effect on the productive life of cows. A correlation between milk production of milk cows and their productive longevity was proved as evidenced by the fact that cows which were used for at least five lactations produced less milk and its components as the first-calf heifers than cows which were scrapped later.
Cow longevity in herds of different milk production levels and herd size. The effect of herd production level and herd size on cow longevity was studied using the SYMLEK system data on 12045 Polish Holstein-Friesian cows (Black-and-White variety) from 1371 herds. The cows, which belonged to the active population in Pomerania and Kujawy, first calved in 2008 and were used or disposed from the herds by the end of 2015. FREQ and GLM procedures from the SAS package were used in the statistical calculations. With increases in herd size (from ≤20 to >200 cows) and herd production level (from ≤6000 to 9000 kg milk), the culling level increased (p≤0.01) while the proportion of cows sold and alive decreased. Cow longevity was differentiated (p≤0.01) by herd size. As the number of cows in the herd increased, the lifespan and the length of productive life, as well as number of calvings decreased. The effect of herd production level on cow longevity was not statistically confirmed.
Presented are results of a study on the influence of air temperature and humidity on milk production by 174 Holstein-Friesian cows kept in a free stall barn. Occurrence of heat stress in three technological groups of cows with help of temperature-humidity index (THI) was specified. The result of heat stress was a decrease in milk yield. There was a strong correlation found (P=0.05) between minimum THI, temperature and milk yield. Delay of decrease in milk production as related to maximum temperature (TMAX) in most cases was 2 days (P=0.05). Significant differences were shown between THI average hourly values (from 1 to 6 units) in particular areas of the barn when the average daily THI >68. Duration of total air temperature exceed 21°C in each technological group was investigated. It was concluded that the number of hours above the critical temperature for the cows in group 1 was 90 and 42-44 for the remaining groups, which resulted in the largest decrease in milk yield in group 1. The obtained results indicate the need to evaluate the microclimate parameters in several specific places related to the existence in the barn technological groups. Predicting the risk of heat stress should take into account the zoning in the barns related to variations of temperature and humidity conditions. This will enable the selection of appropriate functional, utility and technical solutions to maintain optimum welfare of cows in free stall barn.
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