Abstract. Milk is composed of more than 400 fatty acids, approximately 100 proteins and peptides, lactose, vitamins and minerals. These components have a high bioavailability and health-promoting properties to humans. They also influence technological usefulness of milk for processing. The aim of the study was to determine the influence of cow’s age, level of productivity and lactation phase on milk composition with particular emphasis on the share of protein fractions and lactoferrin in milk of Polish Holstein-Friesian cows. Milk samples were collected from primiparous (P; n = 60) and multiparous (M; n = 60) cows in three phases of lactation (I – 30–60 days; II – 90–120 days; III – 210–240 days) with differentiation on cows with low (L; < 30 kg/milking) and high (H; > 30 kg/milking) performance. Lower (P ≤ 0.01) level of α-casein was found in milk from cows ML I and MH I comparing with primiparous cows in this phase of lactation. Milk from cows PH III was characterised by lower (P ≤ 0.05) share of α-lactalbumin comparing with milk from cows in I stage of lactation in all groups. It was observed that in subsequent phases of lactation milk was characterized by higher content of lactoferrin. In general, in multiparous cows somatic cell count (SCC) was higher comparing with primiparous cows. The obtained results can be explain by the greater number of infections of the mammary gland in older cows so the level of antibacterial components increases as well as the fact that with lactation phases mammary gland becomes more and more susceptible.
Abstract. The aim of the study was to elaborate a new scoring system of chosen elements in performance test of Polish Konik horse. In the analysis, 42 horses were included. Test scores of two approaches were statistically elaborated: of the system in force and obtained on the basis of new intervals divided according to their mean values and SD. Multifactorial analysis of variance and T-Tukey test were performed. Low variation of individual performance test scores suggests a necessity for modification of the score system in force. The necessity also results from the change of score level in effect of using the new scoring system. The method of estimating the following traits is particularly controversial: behaviour, step length in walk, return of breath frequency to standard and effort test which belong to elements usually maximally scored. In consequence, they do not function as selection criteria.
Abstract. The aim of the study was to analyse milk yield and the frequency of use of a milking robot by Polish Holstein-Friesian cows. The study was carried out on a farm where a double-stall Astronaut milking robot from Lely was installed in a free-stall slatted-floor barn for 120 cows. The material for the study was obtained from the herd management system and comprised 850 milking records. Daily milk yield (in kg), number of milking sessions per day, and average milk yield per milking were analysed. The experimental factors were lactation number (primiparous and multiparous cows), daily milk yield (≤ 15 kg, 15.1–25.0 and >25.0 kg) and stage of lactation (≤ 100 days, 101–200 days and> 200 days). The cows in the herd were found to use the milking robot with an average frequency of 2.49 times a day. No significant differences were noted in daily yield or frequency of milking between primiparous and older cows. They also did not differ significantly in terms of milk yield per milking. The level of daily yield influenced the milking frequency. Use of the milking robot was most frequent among primiparous and multiparous cows with daily yield of more than 25.0 kg of milk (2.82 and 2.67 times per day, respectively). In the case of both primiparous and multiparous cows, an increase in daily milking frequency was accompanied by an increase in the amount of milk obtained per milking. In the group of primiparous cows, the daily milking frequency increased in the three successive stages of lactation. Increased milking frequency was also found to be linked to a decrease in the amount of milk obtained in one milking. In the multiparous cows, the daily milk yield and quantity of milk per milking decreased systematically in successive stages of lactation, while the daily milking frequency varied irregularly.
Abstract. The experiment was conducted during the summer production cycle. Broiler chickens kept on litter – group I and on litter with access to pasture – group II. Throughout the experiment, mortality were recorded. During the second rearing period, when outdoor temperatures were high, radiation and rectal temperature was measured in birds, and blood was collected to determine the levels of thyroid hormones, glucose, corticosterone, and hematocrit. Broiler chickens from group I were characterized by higher mortality compared to group II. In group I, rectal temperature was found to increase during the 6th week of rearing. In broilers from group II, T3 decreased and T4 increased with an increase in air temperature. The lower body temperature of broiler chickens and the smaller proportion of dead chickens in the group with outdoor access may suggest that this housing system helped to increase the thermal comfort of birds during the summer heat. It can therefore be concluded that housing with outdoor access improves the welfare of broiler chickens exposed to heat stress.
Abstract. The aim of the study was to evaluate the effect of wood pyrolysis temperature on the content of polycyclic aromatic hydrocarbons in selected sausage products. The study material consisted of rural sausage smoked in traditional way in two chambers. The tested PAH content of the samples was determined by liquid chromatography (HPLC). Studies have shown that running a smoking process at an average temperature of 551.2°C resulted in a significant reduction in the concentration of polycyclic aromatic hydrocarbons compared to their content in the article smoked at an average temperature of 675.2°C. The concentration of benzo(a)pyrene in smoked sausage at lower temperatures was in accordance with the applicable standards. And the sum of the four PAHs, both at higher and lower temperatures, exceeded the current recommendations.
Abstract. The aim of the study was to compare the growth and body conformation of ducks raised in a semi-intensive and an intensive system. The material for the research was Pekin Star 53 H.Y. crossbred meat ducks of French origin. The ducks were reared for 8 weeks. The birds from group I were reared in an intensive system and the birds in group II in a semi-intensive system. At the completion of the rearing period, at 8 weeks of age, the mean body weight of the birds in group I, reared intensively, was 3480.3 g, while that of the group II birds, reared in the semi-intensive system, was 3000.2 g The results indicate had irrespective of sex, young ducklings, i.e. in the first 3 weeks, had the fastest growth rate. The massiveness index in the birds’ first week of life was on average 1.7% for males and females in both groups. In the eighth week it was 11.4% and 11.0% in groups I and II. In both study groups the males had higher or significantly higher massiveness indices on all weeks of live. It should be noted that females had a lower massiveness index than the males and a higher compactness index. The compactness index, defined as the percentage ratio of the chest circumference to the trunk length, continually decreased as the ducks grew older: it was on average 144.7% in group I and 142.6% in group II in the first week and 117.7% and 119.3% in the eighth week.
Abstract. The aim of this work was to assess the content of selenium in cow milk served in milk machines in Szczecin in accordance to a season. The research material included samples of milk collected in 5 milk machines located in Szczecin. The study was targeted to the evaluation of selenium content in accordance to a season. The mean content of selenium in milk from milk machines was diversified in a particular seasons and ranged from 0.013 to 0.034 µg · ml–1. The mean selenium content in cow milk from milk machines was 0.023 µg/ml. The lowest level of selenium was noted in summer (0.013 µg · ml–1), whereas the highest was found in autumn (0.034 µg · ml–1). No statistically significant differences were observed between the content of selenium in milk in winter and spring but in case of other seasons the noted differences were significant. Our study has shown that a particular attention has to be paid on the content of selenium in cow milk in summer, as in 72.22% of the tested samples the level of Se was marginal, and in 27.78% the level was deficient. Low concentration of selenium in cow milk in summer indicates that the animals residue in an area poorly supplied in this element. Thus, it is particularly relevant to introduce an early-diagnostics program evaluating the levels of selenium in dairy cattle and showing the possible need of selenium supplementation in cows.