No abstract

The objectives of this experiment were to determine whether feeding anionic salts to prepartum Holstein cows affected their calf's colostral IgG passive transfer and whether adding sodium bicarbonate to a colostrum replacer (CR) would increase the efficiency of IgG absorption. Forty Holstein cows and their resulting calves were assigned to a 2 x 2 factorial arrangement of treatments in a randomized complete block design based on expected date of calving. Three weeks before the projected due date, cows were placed on 1 of 2 treatments: a diet without anionic salts (dietary cation-anion difference of +77 mEq/kg) or a diet with anionic salts (dietary cation-anion difference of -100 mEq/kg). Within 45 min after birth, all calves received 1 dose of a commercially available CR (132g of IgG) without or with supplemental sodium bicarbonate (19.5 g/dose). A half-dose of CR (66g of IgG) and sodium bicarbonate (9.75g) was fed at 6h of age. Calves received milk replacer at 12, 24, 36, and 48h. Blood samples were obtained from calves at 0, 6, 12, 24, and 48h and were analyzed for IgG concentration. Cows fed the diet supplemented with anionic salts had lower DMI on d 8, 5, 4, and 1 and lower urine pH 2 and 1 wk before parturition compared with cows fed the diet without supplemental anionic salts. Calves born from dams receiving anionic salts had similar IgG concentrations (15.1 vs. 14.4g/L) and apparent efficiency of absorption values (29.2 vs. 28.2%) compared with calves born from dams not fed anionic salts. Calves receiving supplemental sodium bicarbonate in the CR had higher serum IgG concentrations at 12 (14.4 vs. 12.0g/L), 24 (16.3 vs. 13.2g/L), and 48h (14.6 vs. 11.2g/L) and higher apparent efficiency of absorption values (31.2 vs. 26.1%) than calves that did not receive sodium bicarbonate in the CR. Calves receiving sodium bicarbonate also had greater area under the curve values for IgG absorption compared with calves not receiving sodium bicarbonate. There was a trend for an interaction with calves born from dams fed anionic salts having a greater area under the curve when fed supplemental sodium bicarbonate. Of the 40 calves in the study, 90% obtained adequate passive transfer (serum IgG > or = 10g/L). This study indicates that feeding anionic salts to the dam has no effect on passive transfer, whereas adding sodium bicarbonate to the CR increased IgG uptake in calves.

Kelp is a common feed additive used on many dairy farms in the United States. However, few data are available supporting the efficacy of its addition to cattle feed. The purpose of this study was to evaluate the taste preferences of calves provided with 0, 30, or 60 g of kelp daily in a sequential elimination experiment. Calves in this study always ranked the control treatment first when given a choice and consumed 34.5% more dry matter from the control treatment in the first 3-d segment of the experiment. During the second feeding segment (d 4 and 5), when the control treatment was removed, daily dry matter consumption was reduced in 4 out of 6 calves compared with control calves when this treatment was available (first feeding segment). However, calves did not differentiate between the 2 amounts of kelp. Results indicated that calves preferred calf starter grains without kelp.

No abstract

The objective of these experiments was to compare 4 total mixed rations fed to USDA-certified organic dairy cows in New England. Forty-eight Jersey cows from the University of New Hampshire (UNH) and 64 Holstein cows from the University of Maine (UMaine) were assigned to a 2 × 2 factorial arrangement of treatments testing the main effects of corn silage versus grass silage as the forage base and commodity concentrates versus a complete pelleted concentrate mixture. Treatment diets were fed as a total mixed ration for 8 wk during the winter and spring months of 2007, 2008, and 2009. Milk yield, component, and quality data were recorded and used to calculate the value of the milk produced for each cow. The dry matter intake (DMI) was recorded and used to calculate the average cost per cow per day of each diet. Income over feed costs were calculated for each diet using milk value and feed cost data. Feed cost and income over feed cost data were resampled using bootstrap methodology to examine potential patterns. Milk yield, milk fat and true protein concentrations, and SCC were similar among treatments. Cows at UNH fed corn silage tended to have higher DMI and lower milk urea nitrogen than did cows fed grass silage, whereas cows fed pellets had higher DMI than cows fed commodities. Cows at UNH fed commodities tended to have higher body condition scores than those fed pellets. Cows at UMaine fed commodities tended to have higher DMI than did cows fed pellets, and cows fed corn silage had lower milk urea nitrogen than did cows fed grass silage. Body weights and body condition scores were not different for cows at UMaine. Feed costs were significantly higher for corn silage diets and diets at UNH containing pellets, but not at UMaine. The calculated value of the milk and income over feed costs did not differ among treatments at either university. Bootstrap replications indicated that the corn silage with commodities diet generally had the highest feed cost at both UNH and UMaine, whereas grass silage diets containing commodities generally had the lowest cost. In contrast, the grass silage with commodities diets had the highest income over feed cost in the majority of the replications at both UNH and UMaine replications, whereas the corn silage with commodities diets had the lowest rank. Similar results were observed when forage prices were increased or decreased by 5, 10, and 25% above or below the actual feed price. Feeding a grass silage-based diet supplemented with commodity concentrates may have an economic advantage for dairy producers in New England operating under an organic system of production.