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Grasses of ryegrass (Lolium) and fescue (Festuca) genera play an important role in the nutrition of high-yielding dairy cows, but fescue x ryegrass hybrids (Festulolium braunii) are also increasingly used. The growing popularity of F. braunii can be attributed to its supreme agronomic traits, combining the high yield potential of ryegrass: Lolium multiflorum and Lolium perenne, and the high resistance of fescue: Festuca pratensis, F. arundinacea and F. arundinacea var. glaucescens, to biotic and abiotic factors. The aim of this study was to analyze the composition of nitrogen fractions in the herbage of different Festulolium braunii cultivars harvested at different dates. Three F. braunii cultivars were studied: Felopa, Lofa and Perun. The chemical composition of herbage (dry matter - DM, crude protein - CP, water-soluble carbohydrates - WSC, neutral detergent fiber - NDF, acid detergent fiber - ADF) and nitrogen fractions (A, B1, B2, B3, C) were determined in accordance with the Cornell Net Carbohydrate and Protein System (CNCPS). In the analyzed forages, highly significant differences (P < 0.01) were noted in the content of DM and WSC, which were affected by both experimental factors. Significant (P < 0.05) differences in the NDF content of herbage were found between cultivars. In the analyzed forages, significant differences (P < 0.05) were noted in CP, which was affected by both experimental factors. The cultivar Felopa had the highest CP content. The content of WSC decreased at successive harvests. The cultivar Lofa had the highest crude fiber content and a lower content of WSC than the remaining Festulolium hybrids. The harvest date had a significant effect on the composition of all nitrogen fractions, and the proportions of fractions B2, B3 and C were also highly significantly (P < 0.01) affected by a cultivar. The composition of fractions B3 and C was influenced by both experimental factors at P < 0.01. Significant (P < 0.05) differences were observed for fractions A. In all analyzed forages, fraction B2 had the highest share of the total nitrogen pool. The share of fraction B3 increased, whereas the content of fractions B1 and B2 decreased in fourth-cut herbage. The share of acid detergent-insoluble nitrogen (ADIN) increased at successive harvests, which decreased the nutritional value of forage. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of a harvest time on the chemical composition and dry matter degradability of perennial ryegrass (Lolium perenne L.) depending on a swath and cultivar (Bajka - diploid; Baronka - tetraploid). The herbage was harvested at four times of the day (6:00, 10:00, 14:00, 18:00) - the first swath on 15th May 2012, and next after 4, 5 and 6 weeks. Chemical composition and dry matter degradability after 48 hours of in vitro incubation were determined. All the analyzed treatments had an impact on the content of DM, crude protein and soluble and structural fractions of carbohydrates. The diploid cultivar had a greater content of DM, WSC and aNDF (P < 0.01) and a lesser content of crude protein and ADF (P < 0.01) compared with the tetraploid cultivar. Dry matter of the first swath herbage was characterized by the greatest content of WSC and the least content of aNDF (P < 0.01). In each consecutive swath, the WSC content significantly decreased (P < 0.01) while aNDF increased (P < 0.01). The increase in DM content between 14:00 and 18:00 was due to the deposition of products of photosynthesis, which is confirmed by a parallel increase in the concentration of WSC. The effect of treatments on the degradability of DM in vitro has not been confirmed, but the results indicate a smaller impact of a cultivar than the harvest management. Numerous interactions between the analyzed treatments indicate the need to choose the harvest time depending on a genotype and swath. Ruminal degradability indicates that high value ryegrass can be obtained regardless of the harvest time during the day. However, greater suitability for ensiling was shown by the diploid cultivar harvested at 10:00 and the tetraploid harvested at 18:00. [ABSTRACT FROM AUTHOR]

The aim of this study has been to determine the effect of a diet containing β-carotene and omega-3 fatty acids on the biochemical and nonspecific humoral immunity indicators and on the results of rearing calves to day 60 of life. The study was conducted in 2011-2012, on a herd of Polish Holstein- Friesian cows. 54 calves from the herd were divided into 3 groups, 18 animals in each: CTR, TRT1 and TRT2. During the colostral period lasting for 5 days after birth, calves were drinking the mother's colostrum. From 6 to 60 days, calves were watered milk replacer formulation. The control group (CTR) consisted of calves after the colostral period given milk replacer formulation without any supplementation. In the two other groups, calves received milk replacers with the supplementation of β-carotene (TRT1 group) in the amount of 25 mg/calf/day or a suspension of liver omega-3 oil (TRT2 group) in the amount of 5 g/calf/day. All calves received solid feed ad libitum. The research showed that the parameters of the metabolic profile of calves (ALT, ASP, CHOL, GLU, UREA, ALP, TG, CRE) were within the normal range, indicating good health of the calves. Moreover, the supplementation had a positive impact on the chosen immunological parameters, including a higher IgG concentration, especially at the end of the milk drinking period. The result of β-carotene in a diet was the highest daily gain in the period from 30 to 60 days of life among the analysed groups of calves. No such effect was achieved in the TRT2 group of calves, as their body weight was the lowest. However, noteworthy is the beneficial impact of beta-carotene and omega-3 oil on the non-specific humoral immunity parameters, which was manifested by fewer cases of clinical diarrhoea and upper respiratory tract diseases. [ABSTRACT FROM AUTHOR]

Changes in the amino acid profile of protein during ensiling depend on the proteolytic potential of plant species, the rate of the wilting and acidifying of ensiled herbage and, on the other hand, on the microbiological processes and fermentation of amino acids. The interaction of these factors determines the subsequent efficiency of nitrogen utilization in the rumen. The aim of this study has been to determine the influence of ensiling in round bales on changes in the amino acid content in lucerne and red clover silages. The amino acid composition was determined by analyzing the content of amino acids in herbages and silages. The lucerne silage protein was characterized by a higher contribution of all amino acids except Trp in comparison with red clover silage. Ensiling in bales of wilted lucerne and clover herbage lowered the content of Asp, His (P < 0.01), Ile, Lys (P < 0.05) in both plants. The ensiling process and plant species affected (P < 0.05) the total content of amino acids per 100 g of protein, where the range of changes in both raw materials was different. The loss of amino acids observed during the ensiling of wilted lucerne in round bales should be regarded as typical, whereas changes in the amino acid profile of red clover should be considered as atypical. A significantly higher ADIN content in red clover than in lucerne silage indicates that a rapid and significant increase of temperature occurred in experimental bales, which were characterized by a low degree of density, and this temperature rise strongly affected the availability of amino acids of the red clover protein also to the current microflora in the silage. Ensiling in round bales changed the amino acid profile of the lucerne and red clover protein. The ensiling process in this technology, however, severely deteriorated the quality of the red clover protein by lowering the content of all essential amino acids except Cys and Met. [ABSTRACT FROM AUTHOR]