Abstract The use of ultrafiltration (UF) to standardize milk protein concentration is a common technological strategy to improve cheesemaking efficiency. However, the impact of this technology on milk processing suitability, as well as on the yield and quality of Tybo cheese, a typical Argentine semi-hard variety, remains largely unexplored. The objective of this study was to evaluate the effect of increasing milk protein concentration through UF on coagulation properties, cheese yield and ripening in Tybo cheese, comparing fixed and casein-adjusted rennet dosing strategies. Cheese milk was standardized to three protein levels (3.7%, 4.8% and 6.0%) using ultrafiltered milk obtained with membranes of 10 kDa molecular weight cut-off. Coagulation behaviour, cheese yield, composition and proteolysis during ripening were evaluated. Increasing the concentration of milk proteins through UF significantly improved the protein, fat and total solids content, resulting in shorter coagulation times, lower whey volume and greater solids retention for casein-adjusted rennet dosing Tybo cheeses. Both theoretical and practical yields increased proportionally with protein concentration, showing relative improvements of up to 90% compared with the control. Cheese produced from UF milk exhibited higher fat and moisture contents but maintained typical pH and NaCl values for semi-hard varieties. Despite differences in milk composition, the overall pattern of proteolysis during ripening was similar among treatments. These results indicate that UF can effectively increase cheesemaking efficiency in semi-hard cheese manufacture, although appropriate adjustment of rennet dosage is required to maintain coagulation control when milk protein concentration is increased. Furthermore, this study provides novel insights into the technological behaviour of traditional Argentine semi-hard cheeses, contributing to a poorly documented area and supporting their industrial optimization.
Abstract Livestock agriculture is a major contributor to both climate change and air pollution, through emissions of methane and ammonia. Despite their shared origins, mitigation policies for greenhouse gases and air pollutants are usually developed independently, creating a risk that interventions targeting one emission may have an unintended impact (cross-effect) on the others. Here, we present a meta-analysis quantifying the cross-effects of nutritional interventions in dairy cows intended to reduce methane and ammonia emissions. Because few studies measure both gases directly, two proxies were also considered: milk urea nitrogen (MUN) for ammonia and volatile fatty acid profiles for methane, although after exploratory analysis only MUN was used. Data from 51 peer-reviewed studies (117 treatments) were synthesised using a hierarchical Bayesian model to estimate correlated treatment effects across studies targeting methane or ammonia mitigation. Although significant uncertainties remain, interventions designed to reduce either gas on average decreased both: studies intending to reduce methane reduced methane by 5.1% and MUN by 2.2%. Studies focused on ammonia reduced methane by 4.8% and MUN by 25%. The probability of achieving simultaneous reductions in both was 0.63 for ammonia reduction studies and 0.41 for methane reduction studies, indicating that positive cross-effects (co-benefits) are more common than trade-offs. When the correlation between methane and ammonia responses could be estimated, it was weak and more likely positive than negative (ρ = 0.096 for the more accurately estimated methane mitigation studies, with 90% credible interval [−0.173, 0.357]), suggesting biological and management linkages that favour joint mitigation. Studies with more rigorous experimental designs appeared to provide greater efficiency in estimating treatment effects, underscoring the value of robust methodology. Overall, our results demonstrate that coordinated nutritional strategies can deliver co-reductions in methane and ammonia emissions from dairy systems, supporting the development of integrated policies at the interface of climate and air-quality goals.
Abstract Enteric fermentation in ruminants is the largest agricultural source of methane (CH₄) and contributes to global warming. Practical mitigation strategies are therefore needed for sustainable dairy production. This study evaluated a silage inoculant composed of bacteriocin-producing lactic acid bacteria (LAB) strains, Lactococcus lactis subsp. lactis SL242 and Lactiplantibacillus plantarum LP58 in late-lactation, spring-calving Holstein cows. Thirty cows were housed indoors and fed inoculated or control silage for 7 weeks. Daily milk yield and CH₄ emissions were measured, milk composition was analysed weekly and body weight and body condition scores (BCSs) were recorded biweekly. Dry matter intake (DMI) was determined using the n -alkane technique in week 4 of the experimental period to allow the animals to be fully adapted to the experimental diets, with estimated LAB intake of ∼10 11 CFU/cow per day. Treatment had no effect on DMI (12.4 ± 0.34 kg/cow per day), concentrate intake (4.3 kg/cow per day), milk yield or BCSs. However, a significant treatment-by-week interaction was observed for milk composition, with transient increases in milk fat concentration and milk solids production in the LAB group during weeks 4 and 5. Rumen microbiota analysis (16S rRNA sequencing) revealed distinct beta diversity clustering between groups at weeks 4 and 7. No overall reduction in CH₄ was observed, but emissions were numerically lower (5.8%) during weeks 4–7, with the greatest decrease (7.7%) at week 5 in the LAB group. These findings suggest that bacteriocin-producing LAB may transiently influence rumen microbial communities and reduce CH₄ output. Further research is warranted to optimise delivery strategies and maximise their potential to support sustainable dairy production.
Abstract Individuals with metabolic disorders such as phenylketonuria (PKU) and kidney stone disease may be unable to consume conventional dairy products because of their high phenylalanine content. This study used different concentrations of glycomacropeptide (GMP; 2.5% and 3.0%) and starch (1.5% and 2.0%), which served as the independent formulation variables. All other ingredients, including coconut water (CW), Yoghurt culture, fermented unsalted butter, iota-carrageenan, inulin, sugar, stevia and stabilizers, were added at the same levels in all formulations. Physicochemical properties, antioxidant capacity, lactic acid bacteria viability, phenylalanine concentration and in vitro inhibition of calcium oxalate (CaOx) nucleation, growth and aggregation were assessed in the prepared Yoghurt samples during 14 days of 4°C storage. Among the tested formulations, F-4 (3% GMP and 2% starch) exhibited the most favourable physicochemical, microbiological and functional properties. The resulting reduced-sugar Yoghurt contained ultra-low phenylalanine (only 8.403 mg/100 g), well below the recommended dietary intake for individuals with PKU. Furthermore, F-4 demonstrated superior antioxidant stability, the highest microbial viability and the lowest syneresis during storage. It inhibited CaOx crystal nucleation, growth and aggregation by up to 30.87%, 33.24% and 36.85%, respectively, suggesting potential anti-urolithiasis activity. Sensory evaluation of the F-4 GMP–CW Yoghurt confirmed high consumer acceptability. Collectively, these findings indicate that the optimized F-4 GMP–CW fermented Yoghurt may provide metabolically tailored nutrition by combining phenylalanine restriction with moderate anti-urolithiatic activity. It may therefore have potential as a functional food to support nutritional management while offering antioxidant and anti-urolithiasis-related benefits.
This research communication describes the evaluation of automated milk feeder (AMF) data for early detection of bovine respiratory disease (BRD) in dairy calves under commercial conditions. BRD is a major health challenge in the dairy industry, contributing to increased morbidity and mortality. Early identification could reduce its impact and improve herd health management. Five commercial dairy farms in Quebec, Canada, representing diverse calf man-agement practices, were enrolled. Daily AMF data - including milk consumption (mL/day), drinking speed (mL/min) and numbers of rewarded and unrewarded visits - were collected over 1 year. The dataset comprised 90,088 daily records from 1,995 Holstein calves. Calves first accessed AMF between 7 and 14 days of age, depending on farm practices. Disease records were obtained from producers, and calves were classified as ill at their first treatment for BRD. The proportion of calves treated for BRD ranged from 20% on Farm 2 to 24% on Farm 3. Healthy and BRD calves were paired by month and duration of AMF use (+/- 2 days). Linear mixed mod-els were fitted for each farm with health status, days relative to treatment, month, and their interactions as fixed effects, and calf as a random effect. Heterogeneity between farms was evi-dent in the results, and multiple farms showed a significant difference between healthy calves and those with BRD for each of the studied parameters, but with different days associated with the significant result. The earliest significant differences were observed at 0 days for drinking speed, -5 days for the number of unrewarded visits, -3 days for both consumption and the number of unrewarded visits, -4 days for the number of unrewarded visits and -5 days for both consumption and drinking speed on Farms 1-5, respectively. AMFs show promise for early BRD detection, but detection timing and the usefulness of specific measurements vary across farms.
