Radko Loučka

Enteric pathogens can impair health and growth during the preweaning period, while non-antibiotic feed additives may support gastrointestinal resilience. This pilot study evaluated a liquid blend of glycerol esters of organic and fatty acids and saponins in 20 Holstein calves assigned at birth to control group or additive groups (n = 10 per group). Calves were housed and fed individually. From the fourth milk feeding to weaning at 60 d of age, additive calves received 2.5 mL of the product/L of whole milk immediately before feeding (15 mL/calf per day), whereas control calves received the same milk without the additive. Body weight was recorded on days 1, 30, and 60; starter disappearance and the presence or absence of diarrhea were recorded daily. Fecal samples collected at 1, 2, 3, 4, 6, and 8 weeks of age were examined for selected protozoa and bacteria. Overall average daily gain (0.910 vs. 0.841 kg/d; p = 0.194) and cumulative starter disappearance (16.016 vs. 11.087 kg/calf; p = 0.228) were not statistically different between treated and control calves. Diarrhea was detected for 6.6 days per calf in the control group and for 7.6 days per calf in the additive group (p = 0.401). Cryptosporidium spp. scores were higher in treated calves at weeks 1 and 6 (p = 0.039 and p = 0.041, respectively), providing no evidence of inhibition. Giardia spp. detection was lower in treated calves at week 2 (p = 0.041). Campylobacter coli detection was lower at week 2 (p = 0.019) and showed a suggestive reduction at week 6 (p = 0.088). Klebsiella pneumoniae was detected only in controls at weeks 2, 3, and 6, whereas Clostridium perfringens showed no consistent treatment response. These exploratory findings do not establish efficacy, but support larger, appropriately powered studies using longitudinal models and quantitative pathogen measurements.

The aim of the study was to investigate the effect of calcareous marine algae (Lithotamium calcareum)-based rumen content buffer (CMA) included in concentrated feed within total mixed ration (TMR), fed to 34 peak lactation (87–144 days in milk) Holstein dairy cows, randomized into two groups (group A, n = 17; group B, n = 17), wearing collars with accelerometers, and housed a in barn with automatic feed-weigh troughs. During the first phase P1, group A received TMR with CMA (TMR-E) and group B was fed TMR without the buffer (TMR-C). For P2, the treatments in the groups were exchanged. Feed intake, feeding time (FT), rumination time (RT), milk yield, milk composition, and rumen pH were measured by barn technologies, and rumen fluid and feces composition were analyzed in the laboratory. Differences between the TMR-E and TMR-C in most parameters under study were statistically insignificant, except overall FT and RT, which differed significantly between the groups. Group A, feeding at P1 by TMR-E, exhibited higher FT and RT than Group B (202 min/cow/day vs. 184 min/cow/day, and 486 min/cow/day vs. 428 min/cow/day, respectively). The RT significantly increased after switching from TMR-C to TMR-E. This implies that the buffer effect is delayed and persists after the withdrawal. In the group of cows that received control TMR without buffer in the first phase, RT and milk protein content increased significantly in the first week after the addition of buffer.

Maize silage is one of the most important feeds for ruminant nutrition and various production methods can have a significant impact on their quality, especially the utilization of nutrients. The objective of the study was to evaluate the effect of conventional and shredlage processing of harvested maize on kernel processing, fermentation profile, physically effective fibre and digestibility of maize silage. A stay-green maize hybrid was harvested with a conventional forage harvester (CON; theoretical length of cut 10 mm; conventional rollers with a 30% difference in roller speed; the rollers have a horizontally teeth; 1-mm roll clearance) or a shredlage processor (SHR; theoretical length of cut 25 mm; Shredlage crop processor with 50% difference in roller speed; the rollers have sawtooth teeth with a counter-rotating spiral groove; 1-mm clearance) and stored in experimental silos. The experimental silages were analysed for chemical composition (dry matter, organic matter, crude protein, crude fibre, neutral detergent fibre, starch), fermentation parameters (pH, lactate, acetate, ammonia), processing quality (kernel processing score, particle size), physically effective neutral detergent fibre (peNDF) and in vivo nutrient digestibility. The shredlage processing (SHR) of maize plants did not have an effect on the silage fermentation profile. On the other hand, the SHR treatment significantly increased kernel processing score (p < 0.01) and peNDF content (p < 0.01). SHR also increased in vivo digestibility significantly, namely that of dry matter (DM), organic matter, starch, crude fibre and neutral detergent fibre (NDF). An increase in nutrient digestibility leads to higher values of NEL. The presented results show positive effects of shredlage processing on quality and digestibility of maize silage.

Farmers need information on which maize hybrid is best and under what conditions. They demand that this information be clear, simple and easily understood. This study aims to estimate the potential for milk production (MPP) and the biochemical methane potential (BMP) production from fresh maize hybrids. Using these indicators from fresh maize, information on the differences between hybrids can be effectively obtained, albeit with some of the shortcomings of this proposed method. Samples of fresh maize plants (n = 384) from four hybrids were evaluated at two locations over four consecutive years (from 2018 to 2021). The dry matter content, averaged across all hybrids, all years and both locations, was 371 ± 42.3 g.kg⁻¹. The colder and wetter the year, the significantly higher the starch content, lower the amylase-treated neutral detergent fibre content (aNDF) and lower the crude protein (CP), which was reflected in lower BMP. Weather did not significantly affect the net energy of lactation (NEL) or MPP values. The location significantly affected all monitored indicators, except BMP. The earlier the hybrid was at harvest time, the lower the NEL and MPP but the higher BMP contents were. This study is preliminary and must be repeated with more hybrids and under more different conditions.

The aim of this study was to assess the effect of different maize processing technologies, comparing treatments with conventional rollers (control), MCC MAX rollers and a Shredlage crop processor on the quality of chopped maize. All the three types of chopped maize were harvested on the same day from the same field where the same maize hybrid was grown. The chemical composition of chopped maize, degree of grain processing and particle size fractions, and the effect of the treatments on rumen disappearance of dry matter, organic matter, NDF and starch were assessed. The highest degree of grain processing was achieved with the Shredlage processor (79.2%), and at the same time this processing method had a tendency to produce the highest proportion of physically effective fibre (37.2%). Compared to the conventional rollers (control), the chopped maize produced using the Shredlage processor had higher disappearance of dry matter, organic matter and NDF after 48 h of rumen incubation and of starch after 24 h of incubation. The MCC MAX rollers provided higher disappearance of all nutrients compared to the control treatment after both 24 and 48 h of incubation.

The aim of this study was to confirm the hypothesis that artificial brushes administered to the rumen can partially replace the function of structural fibre, and increase milk production or quality. To mitigate the risks of feeding low levels of physically effective neutral detergent fibre (peNDF) to cattle, the administration of ruminal mechanical stimulating (RMS) brushes was examined in 22 high-yielding lactating Holstein dairy cows. The cows were divided into an experimental group equipped with RMS brushes and a control group without RMS. Cows were fed four experimental total mixed rations (TMR) consisting of fixed amounts of alfalfa silage, maize silage, rush corn cob mix silage and different proportions of brewer's grains, concentrate and wheat straw. The TMRs had the following 4 peNDF contents: 10.9%. 13.0%, 12.6% and 14.0%. The duration of the experiment was 18 weeks. All cows were fed TMRs with a low structural fibre content near levels associated with a risk of subacute ruminal acidosis (SARA). For the RMS brush group, 3 RMS brushes were inserted orally into the rumen using a special applicator. The effects of RMS brushes on feed intake, rumen fermentation and milk production were evaluated. Ruminal fluid (250 mL) was taken using a stomach tube for pH, volatile fatty acids and ammonia nitrogen analysis. A significant increase was found for the feed intake and milk yield of the RMS group fed the TMRs with 13.0% peNDF although no relationship between peNDF content and RMS TMRs was found. No significant increase in milk quality, rumen pH or rumen fermentation metabolites was declared for the group with RMS brushes. Although RMS brush technology only partially reduced the requirements for peNDF, it may decrease the risk of SARA.

Selected maize hybrids were analyzed according to the in vivo digestibility of the silage. Eight tested hybrids were grown, harvested, and ensiled under identical conditions. The effect of earliness (early maturity group FAO 230–260 vs moderately early maturity group FAO 290–340) significantly ( P < 0.05) affected the chemical composition, fermentation quality, and digestibility of neutral and acid detergent fibre. Type of kernel endosperm (dent vs flint) differed by digestibility of nutrients. Digestibility of dry matter, organic matter, and neutral detergent fibre was the highest for silage of the dent hybrid FAO 250 (73.7, 75.7, and 67.6%, respectively) and these digestibility values were significantly ( P < 0.05) lower for silage of the dent hybrid FAO 320 (61.1, 63.4, and 51.4%, respectively). It was concluded that the digestibility differs mainly in dent-type hybrids. All correlation coefficients between the digestibility values were significantly ( P < 0.05) high.

Maize genotype selection represents a practical tool influencing forage yield and quality. The main objective was to investigate the contribution of genotype, site, and year to variability of maize yield and quality in the environment of Central Europe. Totally 63 maize genotypes at 11 sites over a 7-year period were evaluated for dry matter yield (DMY), dry matter content (DM), starch, cob, neutral detergent fibre (NDF), in situ digestibility of stover NDF (NDFD), and organic matter (OMD). The genotype showed the highest variability from all factors where stover NDFD varied from 261 to 529 g kg^-1 and stover OMD from 376 to 609 g kg^-1. In contrast to the whole-plant, variability of stover traits was more closely related to NDF than the DM content. Under standardized plant DM, all tested factors were significant and allowed interpretation of 70 and 60% of total variation of yield and quality for stover and whole plant, respectively. The average contributions of genotype, site, and year were 30, 7, and 5%, respectively. For variability in plant productivity and nutritive value, the importance of maize genotype selection was more than two times higher than the contribution of environment.

A significant effect of year on maize nutritive value has been reported in many studies; however, the direct effect of year on both nutritive values and fermentation traits of maize silage has not been directly investigated. During a 7‐year period (2006–2012), we investigated the following variables of 597 maize silages commercially produced in bunker silos on farms in the Czech Republic: dry‐matter content (DM), crude protein (CP), starch, amylase‐treated neutral detergent fibre (aNDF), acid detergent fibre (ADF) and net energy lactation (NEL), as well as fermentation traits such as pH, contents of lactic acid (LA), acetic acid (AA), butyric acid (BA) and the ratio between LA and volatile fatty acids. The effect of year and DM explained 16 and 30% of the variability in nutritive and fermentation traits respectively. Although a common silage DM content was used for each year, the climatic effect of year significantly changed almost all tested variables, but particularly aNDF, ADF, starch, AA and BA. The year contribution to trait variability effect was as much as two times higher for fermentation traits (12·6%) as for nutritive value (6·1%). Temperature–precipitation relationships associated with achieved maize yield were considered as factors explaining the year effect. Temperature and precipitation averaged over the full vegetation period had low relevance to nutritive and fermentation traits. This study reveals the importance of year‐to‐year variation in silage nutritive value and fermentation, which could be useful for understanding the contribution of year to these changes in both field experiments and national assessments.