Lignin represents one of the most abundant plant-derived polymers. It is mostly present in the cell wall, and its primary role is to provide mechanical support to the plant. Chemical processes during wood-pulping yield diverse technical lignins with distinct characteristics. Due to their complex and variable nature, technical lignins are often undervalued and are mainly used as burning fuel in mills. However, various technical lignins have been shown to possess antimicrobial properties. Consequently, there is an increasing interest in understanding the properties and conditions that underlie their antimicrobial characteristics and how we can utilize them for practical applications. This review, for the first time, comprehensively summarized the antimicrobial activities of technical lignins and their potential antimicrobial applications.

Our objective was to evaluate the effects of dietary starch concentration on milk production, nutrient digestibility, and methane emissions in lactating dairy cows. Thirty mid-lactation cows were randomly assigned to either a high-neutral-detergent-fiber, low-starch diet (LS; 20.2% starch) or a low-neutral-detergent-fiber, high-starch diet (HS; 25.2% starch) following a 3-week acclimation. The study lasted 8 weeks, with milk sampling and gas measurements conducted weekly during acclimation and at weeks 2, 4, 6, and 8. Blood and fecal samples were collected during acclimation and week 8. Compared with LS cows, HS cows produced 1.9 kg/d more energy-corrected milk (4.45% increase), with higher yields of true protein (+0.13 kg/day), lactose (+0.10 kg/day), and total solids (+0.24 kg/day). Dry matter and organic matter digestibility was 4.2 and 4.3% higher, respectively, in the HS group. The milk fatty acid (FA) profile differed, with LS cows having greater mixed FA content and HS cows showing higher de novo FA content and yield. Although methane production tended to be higher in HS cows (+25 g/day), methane yield decreased by 8.8%. Overall, the HS diet improved milk production, nutrient digestibility, and environmental efficiency by reducing methane yield in dairy cows.

Summary: Limited hepatic export of triacylglycerol within lipoproteins can contribute to fatty liver disease in transition dairy cows. Dietary supplementation with choline may enhance the hepatic synthesis of phosphatidylcholine (PC), which is required to assemble and process very-low-density lipoproteins. We evaluated the effects of feeding rumen-protected choline on lipoprotein triacylglycerol and phospholipid concentrations in nonlactating, pregnant Holstein cows experiencing negative energy balance. Our findings suggest that rumenprotected choline supplementation increases lipoprotein triacylglycerol concentrations and modifies hepatic PC concentrations, potentially improving liver health in prepartum dairy cows.

We investigated the effects of feeding incremental amounts (0%, 3%, and 6% of diet DM) of the red seaweed Chondrus crispus on DMI, milk yield and milk components, enteric CH₄ emissions, nutrient utilization, ruminal fermentation and microbiota relative abundance, and I metabolism in dairy cows. Eighteen organic certified Jersey cows (12 multiparous and 6 primiparous) averaging (mean ± SD) 94 ± 45 DIM, 22 ± 5.2 kg of milk/d, and 485 ± 54 kg of BW in the beginning of the study were used in a replicated Latin square design with three 24-d periods (14 d for diet adaptation and 10 d for data and sample collection). Diets were fed as TMR, with the control treatment (0% C. crispus) consisting of (DM basis) 60% mixed mostly grass baleage and 40% ground corn-soybean meal-based concentrate mash, with forage and grain (up to 2.1% each) replaced by 3% and 6% C. crispus in the remaining 2 diets. Feeding increasing amounts of C. crispus linearly decreased DMI and daily BW gain. However, no linear or quadratic effect was observed for the concentrations and yields of milk fat, true protein, and lactose, and the yields of milk, 4% FCM, and ECM. The concentration of MUN showed a quadratic response (lowest in the 3% C. crispus diet), and that of plasma urea N decreased linearly with feeding increasing levels of C. crispus. Similarly, enteric CH₄, CO₂, and H₂ production all decreased linearly in cows fed C. crispus. In contrast, no linear or quadratic effect was detected for CH₄ yield and CH₄ intensity. Whereas energy loss as CH₄ and heat production decreased linearly, energy efficiency utilization variables did not respond linearly or quadratically to supplementation with C. crispus. The apparent total-tract digestibilities of OM and NDF, and the urinary excretion of urea N (% of N intake) and uric acid tended to decrease linearly with C. crispus. The ruminal molar proportion of acetate increased quadratically, and that of isovalerate decreased linearly in response to C. crispus inclusion in the diet DM. Furthermore, no linear or quadratic effect was observed for the relative abundance of most ruminal microbiota taxa. Iodine intake, milk I concentration and yield, and fecal I excretion increased linearly, and urinary I excretion increased quadratically in cows fed C. crispus, with no linear or quadratic effect in the plasma concentrations of thyroid hormones and whole blood cell composition. Overall, increasing dietary levels of C. crispus decreased DMI and enteric CH₄ production linearly without compromising milk yield and milk composition.

We aimed to evaluate the effects of prepartum supplementation of different I sources (Ascophyllum nodosum [ASCO] meal and ethylenediamine dihydroiodide [EDDI]) on colostrum yield of cows, and blood concentrations of glucose, BHB, and thyroid hormones and growth of dairy calves. Forty multiparous Holstein cows were blocked by lactation number and expected calving date and assigned to 1 of 4 treatments 28 d before parturition: (1) EDDI supplemented (11 mg/d) to a basal diet to meet the NRC (2001) I concentration of 0.5 mg of I/kg of DMI (control = CON [0 g/d of ASCO meal]; actual I concentration = 0.68 mg/kg of DMI), (2) CON plus 57 g/d of ASCO meal (low seaweed = LSW), (3) CON plus 113 g/d of ASCO meal (high seaweed = HSW), or (4) CON plus 151.3 mg/d of EDDI formulated to match the amount of I provided by HSW (HEDDI). Forty-one calves were blocked based on their dams' treatments and received 300 g of IgG via colostrum replacer immediately after birth. At 24 h after calving, calves were offered (DM basis) 676 g of milk replacer (25.3% CP, 16.5% fat) until d 49, and 338 g until weaning. Free choice texturized starter (28.2% CP) and water were offered ad libitum from 24 h to 8 wk of life. Blood samples were collected for analyses of IgG (0 h and 24 h of age), thyroid hormones (d 14, 28, and 56 of age), and BHB (weekly). On d 5 of life, a xylose challenge was conducted by supplementing 0.5 g of D-xylose/kg of BW, with blood samples taken over a 12-h period. Weekly skeletal and BW measurements were also recorded. The concentration of colostral fat was greater in HSW than HEDDI cows, and it tended to increase linearly with ASCO meal supplementation. Although I intake increased linearly with feeding incremental amounts of ASCO meal to close-up cows, the transfer of I from feed to colostrum decreased quadratically. Neither I intake nor colostral I transfer efficiency changed when feeding HSW versus HEDDI. Calves born to HSW dams had a greater initial BW and final hip height, as well as tendencies for greater weekly hip height and final withers height compared with HEDDI calves. Calf BW gain tended to decrease linearly with ASCO meal supplementation. The 24 h apparent efficiency of absorption of IgG tended to increase in HSW versus HEDDI calves. Plasma glucose concentration on d 5 of life decreased linearly in response to incremental levels of ASCO meal. Furthermore, the plasma concentration of biweekly total thyroxin, and whole blood concentrations of weekly BHB and final BHB responded quadratically to ASCO meal, with the lowest values observed for LSW calves. In summary, prepartum supplementation with incremental amounts of ASCO meal to close-up cows did not change colostrum composition. However, feeding HSW versus HEDDI increased colostral fat concentration in cows, as well as initial BW in calves.

A meta-analysis and a meta-regression were conducted to compare DMI, production performance, feed efficiency (FE), and milk N efficiency (MNE; milk N yield/N intake) of Holstein and Jersey cows. Only experiments in which purebred Holsteins and Jerseys enrolled in the same study, under similar experimental conditions, were used to build the datasets (n = 30 peer-reviewed articles). The weighted raw mean difference (WMD) between breeds was computed for each comparison, and weights were assigned based on the inverse of the variance. A meta-regression was run to explore the effect of continuous (year of publication, DIM, and dietary concentrations of NDF, CP, and forage) and categorical (forage type: corn silage, alfalfa/grass-clover mix, and other forage sources ["others"]) covariates on the WMD of different variables. Jerseys had lower DMI (-4.15 kg/d), milk yield (-10.8 kg/d), yields of milk fat (-61.6 g/d) and milk true protein (-211 g/d), and ECM yield (-5.11 kg/d) than Holsteins. In contrast, concentrations of milk fat (+16.1 g/kg) and milk true protein (+6.98 g/kg), DMI (% of BW [+0.44%] and % of metabolic BW [MBW = BW^0.75; +0.64%], and ECM yield (% of BW [+0.64%] and % of MBW [+1.63%]) were greater in Jersey than Holstein cows. Whereas FE (milk yield/DMI) was lower (-0.26 kg/kg) in Jerseys than Holstein cows, breed did not affect FE (ECM yield/DMI) and MNE. Year of publication widened the WMD of milk fat and milk true protein concentrations and ECM yield (% of MBW), and it narrowed that of DMI (kg/d), milk true protein yield, and N intake, favoring Jerseys over Holsteins in recent publications. In addition, DIM narrowed the gap between breeds for the variables yields of milk, ECM yield (kg/d), milk fat, and milk N yield, and widened the gap for DMI (% BW and % of MBW) and ECM yield (% of BW and % of MBW), all in favor of Jerseys as lactation progressed. Dietary concentrations of NDF, CP, and forage collectively affected the WMD of BW, yields of milk and milk lactose, milk true protein and milk lactose contents, ECM yield (% of BW and % of MBW), FE (milk yield/DMI), and N intake, but did not consistently benefit Holsteins or Jerseys. Corn silage affected all WMD, except milk fat yield, ECM yield (% of BW and % of MBW), FE (ECM yield/DMI), and MNE. Relative to corn silage, alfalfa-grass/clover mix diets affected the WMD of DMI (kg/d and % of MBW), milk yield, milk fat and milk true protein yields, ECM yield (kg/d), N intake, and milk N yield, favoring Holsteins over Jerseys. Compared with corn silage, the forage type others affected the WMD of milk fat and milk true protein concentrations, DMI (% of BW), and ECM yield (% of BW and % of MBW), benefiting Jersey versus Holstein cows. In conclusion, the WMD of FE (ECM yield/DMI) and MNE were similar between breeds and the continuous (year of publication and DIM) and categorical (forage type) covariates largely influenced the WMD of several variables.