An evaluation was conducted of the suitability for fattening in a semi-intensive system (mainly with fodders from permanent grassland) and the slaughter value of 15 young bulls of the Polish Red (PR) breed and 10 each of the White-Backed (WB) and Polish Black-and-White (BW) breeds. The reference group consisted of young bulls of the Black-and-White variety of the Polish Holstein- Friesian (HF) breed and the Simmental (SIM) breed, fattened on the same farms. Control fattening was carried out until the age of 18 months. Mean daily weight gain in the bulls of the native breeds during the control fattening period (which lasted 314-358 days) was 0.9 kg, similarly to HF, but significantly lower (P≤0.05) than in the Simmentals (986 g). During the entire fattening period, i.e. from birth to the age of 18 months, daily weight gain was 832 g in PR and 889-919 g in WB and BW. Dressing percentage was lowest in PR bulls (51.69%), and higher in WB (53.1%) and BW (53.49%), with values similar to the reference group, i.e. young bulls of the Simmental (52.97%) and HF (53.29%) breeds. The difference between PR and BW (1.8%) and HF (1.6%) was statistically significant (P≤0.05). In the EUROP classification system, the carcasses of the young bulls of the native breeds were most often placed in classes R- and O+ (conformation) and 2+ and 3- (fat cover), as in the case of young HF bulls. Carcasses of young Simmental bulls were assigned to much higher classes. The young bulls of the three Polish native breeds evaluated are good material for fattening in a semi-intensive system (mainly with fodder from permanent grasslands), while the young PR bulls were the least suitable
The aim of the paper was to discuss the factors determining the susceptibility of cows to mastitis, the most important for breeders, including losses incurred by milk producers due to the disease. Inflammations of mammary gland are common and the most awkward problem which dairy farmers face around the world. In the case of clinical udder inflammation, it is estimated that the cost of mastitis is about 200 € per cow with fluctuations from 100 even up to 1000 €. Resistance, i.e. the susceptibility of cows to mastitis, is conditioned genetically. The possibility of BoLA and lactoferrin gene polymorphism, using in the selection cows resistant to mastitis, is indicated. Bacteria inhabiting the mammary gland, and the living environment of animals are primarily the main etiological factor. Moreover, many authors indicate the differences between breeds of cows in resistance to mastitis. High-productive breeds are generally more susceptible to the udder inflammation, in comparison to the local breeds. The greatest reduction in milk yield is observed in the case of these breeds, and especially in Holstein-Friesian breed, in which the decline of daily yield at somatic cell count (SCC) amounting above 500,000 per ml of milk can reach 25%. The probability of mastitis occurrence increases with an age of cows and following lactation, and dry period is a time of increased risk. Higher incidence of inflammation is also associated with abnormalities in the construction of the udder (unevenly developed quarters, too long or too short teats). In recent years, a possible relationship between feeding system of cows with their resistance to udder infections has been reported. It is emphasized that a deficiency of selenium and vitamins A and E in the ration may contribute to the increase in the number of mastitis incidences. There are, however, unclear opinions of various authors on the effect of automatic milking system on udder health.
A total of 2,484 lactations in 760 Polish Holstein-Friesian cows were analysed. Calculations were made of length of life, length of productive life, total number of days in milk, number of calvings, ratio of days in milk to length of productive life, lifetime milk yield (kg), daily yield at the peak of lactation (kg) and lactation persistency as the percentage difference between daily milk production in the 2nd and 10th month in milk. The cows were divided into three groups according to lactation persistency (decrease in production): group I – up to 30%, group II – 30.1–50% and group III – over 50%. Lactation persistency significantly influenced (P≤0.01) length of life and efficiency of milk production in the analysed cow population. Cows with yield over 30 kg at the peak of lactation followed by a moderate decrease (40%) lived longest (over 6 years) and produced the most milk (nearly 28,000 kg). Yield of primiparous cows at the peak of lactation and its course were found to have a significant effect on length of life and lifetime milk production. The long period of high peak yield (over 30 kg of milk) in the primiparous cows in group I (with the best lactation persistency) in the long term proved to be detrimental, as these cows had the shortest productive life (2.3 lactations on average) and lifetime milk yield about 4,000 kg lower than in the cows in groups II and II (with the poorer lactation persistency).
Milk yield and quality was assessed in cows raised on low-input farms (traditional feeding), i.e. two breeds covered by genetic resources conservation (RP and BG) and the SM breed. The reference group was PHF HO cows from an intensive milk production system (PMR feeding). A total of 1,212 milk samples were collected from three periods of lactation: I (up to 120 days), II (121–200) and II (over 200). The milk was analysed for content of fat, protein, casein, lactose, dry matter, non-fat dry matter and the protein-to-fat ratio, coagulation time, heat stability and the percentage of fat globules in different size ranges. Fatty acid profile and cholesterol content were determined in a representative number of 180 milk samples. Daily yield in the native breeds in the third phase of lactation was 9.6 and 8.7 kg, which was slightly over 55% of their yield in phase I, compared to 66% in the SM and 73.4% in the reference group (PHF HO). The increase in fat and protein (including casein) in the milk during lactation was much higher in the native breeds, so its energy value in phase II of lactation was 11% higher in the BG cows and 9% higher in RP, but only 4% higher in the SM with regard to phase I of lactation. The milk fat from the Polish Red cows had the highest proportion of PUFA in each phase of lactation, including CLA, and the highest PUFA/SFA ratio. Over the course of lactation the percentage of large fat globules in the milk decreased, particularly in the native breeds (P≤0.01), while in the SM the differences were much smaller and statistically insignificant. Lactation persistency in both native breeds raised in a low-input system was worse than in the SM, but the increase in basic components during lactation was markedly higher, while that of cholesterol was lower.
The material for the study consisted of 80 samples taken from the longissimus lumborum (LL) and semitendinosus (ST) muscles of young bulls of five breeds (8 samples of each muscle per breed), including three native breeds included in the genetic resources conservation programme, i.e. Polish Red, White-Backed and Polish Black-and-White, which together with the Simmental and Polish Holstein-Friesian breeds. The content of the elements (K, Na, Mg, Ca, Zn, Fe, Mn, and Cu) analysed in the meat of the young bulls (fattened in a semi-intensive system on fodder from permanent grassland) was found to depend (in varying degrees) on the breed of cattle. The greatest differences (P<0.01 and P<0.05) were noted between the Polish Holstein-Friesians (PHF) and the remaining breeds, mainly in the content of Mg, Ca, Zn and Mn. The results obtained in the four other breeds for most of the macro- and microelements were more uniform, with the highest content noted in the muscles of the young bulls of the native breeds.
Nutritional Value and Technological Suitability of Milk from Cows of Three Polish Breeds Included in the Genetic Resources Conservation Programme
The study included milk obtained from cows of three native cattle breeds, i.e. White-backed (BG), Polish Red (RP) and Polish Black-and-White (ZB) kept under conventional conditions. The reference group consisted of milk from Polish Holstein-Friesian cows (PHF) maintained in the intensive system and milk from Simmental cows (SM) kept under conventional conditions. The following parameters were determined in 976 samples of milk: content of fat, protein, casein, lactose and solids; acidity (pH value); heat stability; rennet coagulation time; content of α-lactalbumin, β-lactoglobulin, serum albumin, lactoferrin and lysozyme. Additionally, a certain proportion of samples was investigated for fatty acid profile and content of macro- and microelements. Cows of native breeds produced milk of higher nutritional value (higher content of whey proteins and polyunsaturated fatty acids, including CLA) and more suitable for processing as compared to PHF cows. Milk from cows of the Polish Red breed was the most valuable in terms of these parameters, which can be associated with a distinctive phylogenetic origin of this breed. The favourable parameters in regard to the nutritional value and technological suitability of milk obtained from analysed population of cows of 3 breeds included in the programme of genetic resources conservation are therefore an important reason of validity for subsequent implementation of this programme.
Slaughter Value of Young Polish Black-and-White, White-Backed, Polish Holstein-Friesian and Limousin Bulls Under Semi-Intensive Fattening
The objective of the present study was to compare the slaughter value of young bulls of two breeds included in the genetic resources conservation programme, namely Polish Black-White and White-backed with young Polish Holstein-Friesian (dairy type) and Limousin (beef type) bulls. This is the first study to evaluate the meat performance traits of White-backed cattle in several-centuries history of the breed in Poland. It was determined that populations of White-backed and Polish Black-and-White cattle represent the dual-purpose type desirable in the genetic resources conservation programme. The indices obtained for the analysed traits of slaughter value from young Polish Black-and-White and White-backed bulls were intermediate between Polish Holstein-Friesian (dairy type) and Limousin (beef type), but closer to those of the Polish Holstein-Friesian breed. The analysed muscles of young bulls had a very similar content of basic chemical components. The relatively high amount of proteins (22.85-23.23%) in musculus longissimus lumborum and in musculus semintendinosus (22.43-23.06%) should be emphasized.
Effect of Breed and Feeding System on Content of Selected Whey Proteins in Cow's Milk in Spring-Summer and Autumn-Winter Seasons
The objective of the present study was to evaluate the effect of breed and feeding system on the content of selected whey proteins in cow's milk collected in the spring-summer and autumn-winter periods. A total of 2,278 milk samples from Black- and Red-and-White variety of Polish Holstein-Friesian cows and Simmental and Jersey cows were examined. In each sample the content of selected whey proteins, i.e. alpha-LA, beta-LG, lactoferrin, BSA and lysozyme, was analysed by RP-HPLC method. Evaluation of the simultaneous effect of breed and production season on whey protein content showed significant interactions (P≤0.05 and P≤0.01) for all analysed whey proteins. The milk of Simmental cows kept in the conventional system was characterized by a higher content of whey proteins (with the exception of BSA), in comparison to the cows managed under TMR system. Furthermore, for most of the evaluated components, except the content of BSA and lysozyme and the alpha-LA/beta-LG ratio, the simultaneous effect of feeding system and production season was also found.
The aim of the study was to evaluate selected indicators of the technological suitability of milk from four breeds of cow housed in free-stall barns and fed in a TMR system. A total of 1, 146 milk samples were analysed, collected from cows of the breeds Polish Holstein-Friesian (Black-and-White and Red-and-White populations), Jersey, and Simmental. The following were determined in the samples: content of solids non-fat and casein, protein-to-fat ratio, active and potential acidity, heat stability, rennet clotting time, and milk fat dispersion. Despite the use of a mono-diet (TMR) year round, somewhat higher daily milk yield was obtained in the spring/summer season, but the differences were statistically significant (P≤0.01) only in the case of PHF RW. The milk obtained in the autumn/winter season contained more solids-non-fat, including casein, and in the case of JE and PHF HO the differences were statistically significant (P≤0.01). It also had significantly higher heat stability and a longer rennet clotting time (P≤0.01), with the greatest differences noted in the case of the SM breed. Milk from this period also had a higher percentage of fat globules with a diameter. 6 ≥m. The concentration of solids-non-fat, including casein, increased significantly (P≤0.01) over the course of lactation in all of the breeds evaluated. The stage of lactation did not significantly affect clotting time, heat stability, or milk fat dispersion.
The aim of the research was to evaluate the influence of calf age on proximate composition, fatty acid composition and mineral contents, as well as postmortem ageing under vacuum on the inherent properties of musculus longissimus lumborum of Limousin suckler beef aged to 6, 7 or 8 months. The moisture, protein, fat, and ash content, fatty acid composition, mineral concentrations and intrinsic properties (pH, electrical conductivity, drip and cooking loss, shear force, and CIE colour parameters) were determined. The calf age significantly (P≤0.05) correlated with an increased protein content and energy value of meat and decreased water:protein proportion. Moreover, increased age correlated with higher concentrations of Mg (P≤0.01), Zn and Fe (P≤0.05) and reduced concentrations of Cu (P≤0.05). The fatty acid composition was similar irrespective of calf age, with the exception of CLA content, which was significantly (P≤0.01) reduced in older animals. Muscles of calves aged 6 months were significantly lighter, less red, and showed the most significant drip loss compared to the muscles of older animals. There was no significant (P>0.05) interaction between calf age and postmortem ageing for the intrinsic properties analysed. Postmortem ageing under vacuum resulted in a significant decrease (P≤0.05) in the shear force of meat (irrespective of the age of the calves). The lack of significant differences, especially with regard to the meat pH, shear force, fatty acid composition, and with the significantly higher content of protein and major elements (Fe, Mg and Zn) in relation to the slaughter age, indicates the validity of increasing the duration of fattening of the Limousin calves reared with their mothers on the pasture until the age of 8 months, which is a maximum in this category.