Juška, Remigijus

Objectives: The transition period is defined by significant physiological and behavioural changes in dairy cows, which can affect enteric methane emissions. While rumination duration is often used as an indicator of health and welfare, its association with methane emissions is inconsistent across various studies. This study was aimed at exploring if categorising cows based on average daily rumination time could uncover significant variations in methane emissions and to determine particular ingestive and activity behaviours linked to methane output. Furthermore, we applied Principal Component Analysis (PCA) to condense complex behavioural data into comprehensible patterns associated with methane production. This study aims to elucidate behavioural predictors of methane through the integration of classification and multivariate analytics, thereby facilitating the formulation of precision-based emission mitigation strategies. Materials and Methods: Thirteen clinically healthy Holstein cows were observed from 40 days before parturition to 21 days after parturition. Feeding behaviours and rumination were continuously monitored using RumiWatch noseband sensors [Itin+Hoch GmbH, Switzerland]. Methane emissions were quantified twice daily utilising a laser methane detector [HESAI HS4000]. Cows were classified retrospectively into three categories based on average rumination time: low (<404 min/day), medium (404–500 min/day), and high (>500 min/day). Principal Component Analysis was conducted on behavioural data to identify components linked to methane emissions. Results: Methane emissions were highest in medium-rumination cows, followed by high and low groups; however, the differences were not statistically significant (p > 0.05). In cows with low rumination, methane exhibited a negative correlation with rumination chews (r = -0.52, p < 0.05). In cows showing high rumination, methane levels were inversely correlated with drinking gulps (r = -0.42, p < 0.05) and bolus count (r = -0.37, p < 0.05). The findings indicate that methane production is more closely associated with particular ingestive behaviours than with the duration of rumination itself. PCA identified six components that account for 79.97% of the overall behavioural variance. Component 5 exhibited a significant negative loading for methane (−0.62) and positive loadings for "Other Chews" and "Activity," suggesting that heightened non-rumination jaw movements and locomotor behaviour may forecast reduced methane emissions. Conclusions: Although average rumination time alone did not significantly account for methane variability, multivariate behavioural traits identified through PCA indicated crucial predictors of methane emissions. The integration of behavioural classification with sensor-based analytics may enhance targeted enteric methane mitigation strategies in dairy herds.

Addressing the challenge of mitigation GHG emissions from manure, we conducted a study to assess the effectiveness of various sorbents in reducing emissions of ammonia (NH₃), methane (CH₄), carbon dioxide (CO₂) from cattle manure during storage. Fresh liquid cattle manure was subjected to three treatments (30% sorbents): perlite (Group 1P), vermiculite (Group 2V), and superphosphate (Group 3S). The Control group (C) consisted of manure without any sorbents. The experiment was conducted under laboratory conditions utilizing 25-liter experimental tanks over a 37-day period. Gas emissions were quantified using passive chamber method. The results indicated that different sorbents could have very different effects on individual gas emissions, depending on the manure storage period. The most substantial reduction in emissions was observed for CH₄. At the beginning of the experiment, CH4 emissions were reduced by 90.2% (p≤0.005) in the 1P group, and by 77.2% (p≤0.05), in the group 3S compared to the C group. The reduction of NH₃ emissions was less pronounced, with superphosphate demonstrating the highest efficacy at the beginning of the experiment, achieving a 36.3% reduction (p≤0.05). However, by the end of the study, NH₃ emissions exhibited a slight increase (5–42.5%) compared to Group C, but the differences were insignificant. The lowest effectiveness was found with CO₂ gases. Results showed that perlite (1P) increased CO₂ emissions by 62.5% (p≤0.005) during the experiment. It can be concluded, that tested sorbents had different effects on various gases, which were influenced by the duration of manure storage.

The trial aimed to assess the effect of adding Camelina cake to the chicken diet to improve the muscle fatty acid profile while maintaining growth performance. The trial was conducted with 5% and 10% Camelina cake inclusion levels in the diet. A total of 210 one-day-old, sex-unrelated chickens were assigned to three dietary treatment groups. The control group received a diet consisting of wheat and soy meal, while the treatment groups had part of the soy meal replaced with 5% Camelina cake (CAM5) or 10% Camelina cake (CAM10). The results indicated that Camelina cake positively affected the production of healthier breast and thigh meat. Specifically, the levels of various Omega-3 fatty acids, which are considered beneficial for human health, were significantly higher in the treatment groups compared to the control group. The greatest increase was observed in α-linolenic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids, which increased by as much as 1.7 to 2.67 times (p ≤ 0.05) in both treated groups. Additionally, the total n-3 PUFA content increased by 2,36 – 3.36 times (P ≤ 0.05), while the n-6/n-3 PUFA ratio, TI index, and total trans fatty acids decreased. The inclusion of 10% Camelina cake had a greater effect on n-3 PUFA content compared to the 5% inclusion level. Analysis of the chickens’ growth showed that neither 5% nor 10% Camelina cake supplementation did not affected their growth performance. In summary, the inclusion of 10% Camelina cake in chicken feed can enhance the nutritional profile of the meat, particularly by increasing n-3 PUFA content, without negatively affecting the chickens’ growth.

This study investigates the relationship between methane emissions and physiological, behavioural, and haematological parameters in dairy cows during the transition period. Methane emissions were monitored alongside variations in rumination, feeding behaviour, and blood markers three weeks before calving, on calving day, and three weeks post-calving. Cows were retrospectively classified into low, medium, and high rumination groups according to their average daily rumination duration to investigate the effects of behavioural influences. During the prepartum period, the methane concentration was moderately positively correlated with drinking time (r = 0.41, p < 0.01) and weakly negatively correlated with chews per minute (r = −0.358, p < 0.05). Significant negative correlations were noted with chloride (r = −0.42, p < 0.01) and glucose levels (r = −0.41, p < 0.01). Following calving, methane emissions showed a positive correlation with haematocrit (r = 0.41, p < 0.01) and a negative correlation with haemoglobin (r = −0.47, p < 0.01). A haematological analysis revealed a notable negative correlation with platelets during calving (r = −0.64, p < 0.05). Individual dry matter intake (DMI) was recorded for each period, showing a significant drop on calving day. This intake fluctuation coincided with a significant rise in methane yield on calving day (p < 0.001). In the low rumination time group, methane was moderately negatively correlated with rumination chews (r = −0.52, p < 0.05), while in the high rumination group, a moderate negative correlation was observed with drinking gulps (r = −0.42, p < 0.05), and a weak negative correlation was observed with bolus events (r = −0.37, p < 0.05). Despite behavioural variations, methane emissions showed no substantial differences among groups with low, medium, and high rumination times, suggesting a minimal direct influence on rumination duration. These findings emphasise the complex interactions between feed intake, metabolism, and methane emissions, underscoring the importance of integrating behavioural and physiological indicators to develop targeted strategies for enteric methane mitigation while providing baseline data from healthy cows that could guide future research on methane emissions in cows undergoing postpartum metabolic disorders.

Genetic selection of cows with lower methane emissions is a promising strategy for mitigating greenhouse gas emissions in livestock. However, understanding the relationship between methane emission traits and other phenotypic characteristics remains challenging. Therefore, this study aimed to assess and compare enteric methane emissions from Lithuanian local breeds (Ash-grey, White-Backed and old genotype Lithuanian Red) reared under extensive production conditions, with those from widely bred Holstein cows, which are kept under intensive production conditions. Individual methane emissions were recorded using a Laser Methane Detector (LMD). Based on a methane measurement protocol, including outlier analyses and physiological aspects, methane traits were determined reflecting respiration, eructation and average methane emissions were derived. The dataset comprised 754 records from 80 cows. Our findings showed that the average daily methane emissions from Lithuanian local breeds cows were 20.7% lower (p<0.01) than those from Holstein cows. Among local breeds, the highest methane emissions was determined from White-Backed cows, which were 9.3% higher than from old genotype Lithuanian Red and 13.6% higher than from Ash-grey cows. However, completely different results were obtained when calculating methane emissions per unit of production. The calculations revealed that Holsteins and old genotype Lithuanian Red cows emitted significantly less methane, amounting to 16.1±0.7 and 16.7±1.7 g of methane per kilogram of milk, respectively. While methane emissions from Ash-grey cows were 57.5 and 51.8% higher, from White-Backed cows were 60.1 and 54.4% higher, respectively. In summary, our results suggest that although enteric methane emissions from Lithuanian local breeds cows were lower, methane emissions per kilogram of milk were significantly higher compared to those from intensive breed cows.

The objective of the study was to investigate the influence of different amounts of camelina cake in chicken feed on their growth performance, nutrient digestibility and meat fatty acid composition. The base part of the control group (C) diet consisted of corn and soybean meal, while in the diets of the experimental groups the soybean meal was replaced by 5% camelina cake in the CAM5 group and 10% in the CAM10 group. Study results showed that the growth performance indicators of CAM5, CAM10 groups chickens did not differ from the C group. Although the digestibility of dry matter (P ≤ 0.01), organic matter (P ≤ 0.01) and protein (P ≤ 0.05-P ≤ 0.01) was lower in the CAM5 and CAM10 groups, the inclusion of camelina cake positively impacted meat fatty acid composition. We found significantly higher levels of various beneficial fatty acids in CAM5 and CAM10 groups: the muscles of the chickens of experimental groups contained 2.49 – 3.80 (P ≤ 0.01) -linolenic, 1.7 – 2.67 eicosapentaenoic (P ≤ 0.01), 1.83 – 2.28 docosapentaenoic (P ≤ 0.01), 1.73 – 2.17 docosahexaenoic acids (P ≤ 0.05-P ≤ 0.01), 1.72 – 2.47 total LC n-3 PUFA (P ≤ 0.05-P ≤ 0.01) and 2.29 – 3.36 total n-3 PUFA (P ≤ 0.01) times more than in the muscles of the control group. Also, significantly better n-6/n-3 and linoleic /linolenic ratio, as well as thrombogenic index, were found in the both experimental groups (P ≤ 0.01). The optimal n-6/n-3 PUFA ratio was determined in CAM10 group and according to the European Commission Nutrition Claims, the meat of chickens grown in the CAM10 group can be classified as a source of Omega-3 fatty acids based on the ALA content

Livestock manure storage is a significant source of gas emissions. Application of various manure additives is one of possible ways to reduce gas emissions. Therefore, this study was conducted to evaluate the effectiveness of sorbents for NH3, CO2 and CH4 emissions from dairy cattle manure. The study was carried out on laboratory scale, using 90-litter tanks. Three treatments, including biochar, peat and dolomite were applied to stored fresh cow liquid manure. The manure was stored for 42 days under a constant ambient temperature of 14°C and 60-62% relative humidity. The emission reductions were evaluated by the treatments as compared to the control group without sorbents. The results of the study showed that average NH3 emission without using sorbents during all study period was 9.2±1.6 mg/m2/h, using biochar - 8.7±1.4 mg/m2/h, peat 9.3±21.7 mg/m2/h, and dolomite 9.1±1.5 mg/m2/h. The addition of biochar reduced NH3 emissions from manure by 5.9%, dolomite - by 0.6%, however, peat increased the emission by 0.8%. The highest average CO2 emission was fixed from manure with dolomite treatment - 155.1±8.2 mg/m2/h, and the lowest from biochar treatment - 120.5±8.0 mg/m2/h, (P=0.03). CO2 emissions from manure without sorbents and manure with peat were 133.1±8.2 mg/m2/h and 147.5±9.8 mg/m2/h, respectively. It was found that the highest emissions value in all groups were observed in the first week, then they gradually decreased and at the end of the study were negligible and the differences between the various treatments were the most insignificant. The highest positive correlation (0.973) between NH3 and CO2 emissions was determined for manure treated with dolomite. Sorbents reduces CH4 emissions from manure on average by 33.6%. In summary, it can be concluded that sorbents most efficiently reduced gas emissions in the first week after adding the sorbents to manure, then this effect decreased. The most effective emission reduction was achieved using biochar. However, at the same time, it can be stated that the ability of sorbents to reduce gas emissions from liquid cow manure is not high, perhaps due to the specific property of cattle manure to for a natural crust during storage.

The objective of this study was to investigate a connection between CH4 emissions and reticulorumen pH and temperature. During the experiment, we registered the following parameters: reticulorumen pH (pH), reticulorumen temperature (RR temp.), reticulorumen temperature without drinking cycles, ambient temperature, ambient relative humidity, cow activity, heat index, temperature–humidity index (THI), and methane emissions (CH4). The experimental animals were divided into two groups based on the reticulorumen pH: 1. pH < 6.22 and 2. pH 6.22–6.42. We found that cows assigned to the second pH class had higher (46.18%) average values for methane emissions (p < 0.01). For the other indicators, higher average values were detected in cows of the first pH class, RR temperature (2.80%), relative humidity (20.96%), temperature–humidity index (2.47%) (p < 0.01), and temperature (3.93%) (p < 0.05), which were higher compared to cows of the second pH class. Reticulorumen pH was highly negatively correlated with THI and temperature (r = −0.667 to 0.717, p < 0.001) and somewhat negatively with heat index, relative humidity, and RR temperature (r = −0.536, p < 0.001; r = −0.471 to 0.456, p < 0.01). Cows with a higher risk of heat stress had a higher risk of lower reticulorumen pH.

Manure acidification is recognized as one of best treatments available to reduce ammonia emission from manure.However, the potential to reduce the emissions of polluting gases, as well as the effects on crop yield have been poorly studied. Therefore, this study was conducted to evaluate the effect of acid treatment on NH3 and other GHG emissions from manure and assess the effects on plant nutrient utilization. The effect of manure acidification on gas emissions was investigated on laboratory scale at LUHS Animal Science Institute. The study was performed using 20 litre manure tanks, gas emissions were measured by the passive chamber method. Field trials were conducted to evaluate the effects of acidified slurry on crop yield, using slurry acidification techniques in-field. Both acidified and non-acidified cattle slurry was applied to barley and spring wheat. Control fields were fertilized with mineral fertilizers. Slurry was acidified with H2SO4 to target pH 6.0. Our study showed that the emission rate for non-acidified cattle manure was as follows: NH 3: 11.6, CH4: 1.33 and CO2: 251.9 mg/(m2/60s), respectively. Acidification of manure to pH7 has reduced NH3 emissions by 39.6% and CH4 emissions by 29.5%. Higher level of manure acidification (pH5) gave even better emission reduction results: by 75.6% for NH3, and even by 91.8% for CH4. Different results were found for CO 2 emission, which showed that the emission rate could be 22.2% higher with pH7, and 27.8% lower with pH5. Field trials have shown that acidification of slurry can have a positive effect on crop yield. For barley, acidified slurry resulted in 13.1% higher yield and 3.43% higher protein content in comparison with untreated slurry, and 14.1% higher yield and 9.15% higher protein content in comparison with mineral fertilization. Smaller differences were found in the spring wheat fields, where acidified slurry resulted in 3.7 and 4.9% higher yield compared to untreated slurry and mineral fertilization, respectively. In summary, it can be concluded that mild acidification of cattle manure and slurry can be a successful solution to help farmers reduce NH3, CO2 and CH4 emissions and at the same time improve the fertilization value of manure.

The objective of the study was to determine the effects of dietary hempseed or camelina cakes rich in n-3 polyunsaturated fatty acids (PUFA) on the fatty acid profile of liver lipids and carcass characteristics of ducks. A total of 108 one-day-old male ducks were allocated to 3 dietary treatments. The Control (C) group diet was supplemented with 15 and 20% rapeseed cake from days 1 to 23 and 24 to 49, respectively, whereas the rapeseed in Experimental 1 (HE) and Experimental 2 (CA) was replaced by hempseed cake and camelina cake in the same proportion, respectively. Inclusion of dietary hempseed cake resulted in higher carcass yield (P < 0.05) and growth performance (P < 0.05) but did not increase the proportion of liver n-3 PUFA (P > 0.05). Dietary enrichment with camelina cake reduced carcass yield (P < 0.05), feed intake (P < 0.01) but had no significant effect on the body weight and feed conversion ratio (P > 0.05) of ducks. The amount of n-3 PUFA and long-chain (LC) n-3 PUFA in the CA group was 2.47 and 2.35 times (P < 0.01) higher compared with that of the C group, respectively. The inclusion of dietary camelina has helped to produce a healthier human nutrition liver with an n-6/n-3n PUFA ratio of 3.38.