This longitudinal study aimed to quantify the effects of dietary supplementation of a direct-fed microbial (DFM) consisting of three lactobacilli isolates on milk yield, milk fat and protein yields, somatic cell count (SCC), and liveweight in a single dairy herd in Australia. A total of 150 dairy cows were randomly selected based on parity and days in milk and divided into two groups: control (n = 75) and DFM treatment (n = 75). Throughout the study, the two groups of cows were housed separately in a dry lot yard, and each group had their own feeding area. For the DFM treatment group, selected cows in mid-lactation were supplemented with 10 mL/cow/day of the DFM via top dressing of the feed for the remainder of the lactation and through the dry period, extending into subsequent lactation. The control group had no supplementation. The milk yield and liveweight were recorded daily. Milk samples were collected every two months for milk component analysis (fat, protein, and somatic cell count [SCC]). The DFM-treated cows gained more liveweight across the study (19.40 kg, 95% CI 0.44 kg; 38.30 kg, p = 0.05) compared to the control cows. In the second production year, the DFM-treated cows mobilized more liveweight (−6.06 kg, 95% CI −10.49 kg; −1.61 kg, p = 0.01) and produced more milk (0.39 L/d 95% CI 0.10; 0.89, p = 0.05). Over a full lactation, DFM cows yielded at least 258 L (95% CI 252 L; 265 L) more milk than controls. No significant differences were found in fat and protein yield or SCC. This study suggests that consistent and ongoing supplementation with a Lacticaseibacillus- and Lentilactobacillus-based DFM could have a positive effect on milk production, but further research is needed to understand the underlying mechanism.

This study was conducted at a commercial dairy farm in Queensland, Australia to evaluate the effects of feeding a lactic acid bacteria-based direct-fed microbial (DFM) during gestation on the metabolic profile of periparturient dairy cows and its effects on milk production and body weight. A total of 150 multiparous Holstein cows were randomly selected based on parity (2.3) and days in milk (130 DIM) and divided into two groups of 75 cows each (control and DFM). The control cows were assigned to a basal diet consisting of a silage-based partial mixed ration (PMR), concentrate fed in the dairy twice a day, and ad libitum pasture. The DFM group received the same basal diet supplemented with three strains of Lactobacillus top-dressed in the feed. The DFM supplementation continued during both the dry period and the subsequent lactation. A subset of 82 cows (40 control and 42 DFM) were monitored during the calving season (March to July 2022) to assess the metabolic profile and postpartum performance. Blood samples were collected during the periparturient period (−4 to −2 w prepartum, around calving, and at weeks 1, 3, and 6 postpartum) to measure the levels of metabolites, enzymes, and minerals. Overall, the serum glucose, NEFA, and chloride levels were higher, while protein and urea were lower in cows supplemented with the DFM (p < 0.005). The pre-calving levels of glucose were higher and the total bilirubin, urea, and BHB were lower in cows supplemented with DFM than in the control (p < 0.05). The post-calving levels of glucose and Mg were also higher in the DFM cows than in the control cows (p < 0.05). Average milk production at 110 DIM was significantly higher in the DFM cows compared to control cows (p = 0.03). Although the total milk production over 305 days was numerically greater in the DFM cows, the difference was not statistically significant (p = 0.3), whereas the milk protein percentage was higher in the control cows (p = 0.03). The body weight of the DFM cows was greater during the periparturient period (p = 0.001) than that of the control cows. In the DFM cows, glucose levels had a positive correlation (r = 0.16) with milk yield, at 110 DIM, while serum total protein had a positive correlation with body weight (r = 0.32) (p < 0.05). In conclusion, feeding Lactobacillus-based DFM during gestation can positively influence the metabolic profile of periparturient cows, which, in turn, may affect the milk production and body weight of postpartum dairy cows.

Fibre Bragg gratings (FBGs) continue to be used in a wide variety of different telecommunications products such as filters, pump stabilisers and dispersion compensators. The increased specifications being demanded by successive generations of FBG components mean that higher manufacturing controls are needed to ensure high quality performance. One of the key areas of concern has been the effect of the laser exposure on the tensile strength of the fibre, since this affects yield, quality and lifetime of the FBG device. No comparative study has, to the best of our knowledge, so far been conducted to measure the relative merits of different exposure conditions. We present measurements of the degradation of the strengths of Corning SMF28 and intrinsically photosensitive fibres from laser exposure with the following lasers: excimer lasers at 193nm and 248nm and argon-ion laser at 244nm. A comparison is presented of the fibre pull strengths under varying illumination conditions with the different laser systems and a methodology established for favourable exposure conditions for FBG writing with reduced fibre strength degradation.

Low pasture biomass production and fodder scarcity are among the major challenges affecting productivity of dairy cattle farms in Sri Lanka. As a potential solution to this, two Napier hybrid cultivars, CO-5 and Sampoorna, were recently introduced, and a field experiment was conducted to evaluate their growth, dry matter production, and nutritional composition from May to September 2020 to identify the optimum stage of harvest during the Yala season of the year. Plant measurements and samples were collected at five harvest intervals (4, 6, 8, 10, and 12 weeks after planting, respectively), with the plant samples subjected to biomass and nutritional assessments. The number of tillers and leaf length significantly differed (p = 0.01) between the two cultivars at 4 weeks harvesting interval (HI), whilst the number of leaves differed at 12-week HI, respectively. Dry matter yield increased (p = 0.16) almost linearly, whilst crude protein declined exponentially with CO-5 greater than Sampoorna (p = 0.057; 9.3% vs. 8.7%), with increasing harvesting intervals, respectively. In vitro organic matter digestibility and in vitro metabolizable energy contents were similar across weeks 4, 6, and 8 but then decreased. This study demonstrates that higher dry matter yields (12.54 t/ha) can be obtained through harvesting both cultivars at 12 week HIs, but from a nutritional perspective, harvesting at 6 week HIs during Yala season of the year would be optimum for farmers.

Low pasture biomass production and fodder scarcity are among the major challenges affecting productivity of dairy cattle farms in Sri Lanka. As a potential solution to this, two Napier hybrid cultivars CO-5 and Sampoorna were recently introduced and a field experiment was conducted to evaluate their growth, dry matter production and nutritional composition during May to September 2020. Plant measurements and samples were collected at five harvest intervals (4, 6, 8, 10 and 12 weeks after planting), with the plant samples subjected to biomass and nutritional assessments. The number of tillers and leaf length differed (P=0.01) between the two cultivars at 4 weeks harvesting interval (HI) whilst number of leaves differed at 12 HI respectively. Dry matter yield increased (P=0.16) almost linearly whilst crude protein declined exponentially with CO-5 greater than Sampoorna (P=0.057; 9.3% vs 8.7%), with increasing harvesting intervals respectively. In-vitro Organic Matter Digestibility and In-vitro Metabolizable Energy contents were similar across weeks 4, 6 and 8 but then decreased. This study demonstrates that higher dry matter yields (12.54 t/ha) can be obtained by harvesting both cultivars at 12 HI, but from a nutritional perspective harvesting at 6 HI during Yala season of the year would be optimum for farmers.

This 16-month study aimed to evaluate the extended effects of administering direct-fed microbials (DFM) on milk yield and components in 150 dairy cows. The cows were randomly divided into two groups: control (n=75) and DFM (n=75) based on parity and days in milk. Throughout the study, the two groups of cows were housed separately in a free stall yard, and each group had their own feeding area. The DFM group received 10 ml/cow of the Lacticaseibacillus- and Lentilactobacillus-based DFM via top dressing of the feed during lactation and drying off. Milk yield and liveweight were recorded daily. Milk samples were collected every two months for milk components analysis. Both groups produced less milk in the second production season due to adverse weather conditions. DFM cows gained more liveweight across the study (19.40 kg, 95% CI 0.44; 38.30) compared to controls. In the second season, DFM cows lost weight at a slower rate (-6.06, 95% CI -10.49; -1.61) during the postpartum period and produced more milk (0.39 L/d 95% CI 0.10; 0.89). Over a full lactation, DFM cows yielded at least 258L (95% CI 252L; 265L) more milk than controls. No significant differences were found in fat yield, protein yield, or somatic cell counts. The study suggests that prolonged DFM administration positively impacted milk production, but further research is needed to understand the underlying mechanism.