Prophylactic use of an ultra-diluted complex on health, metabolism, and performance of weaned Holstein calves and its carryover effect up to first lactation.

The objective of this study was to evaluate the effect of an ultra-diluted complex supplemented as a prophylactic strategy on the incidence risk of diseases, metabolism, and performance of weaned Holstein calves immediately after grouping. Additionally, the objective was to investigate the carryover effects on heifer-raising and first-lactation periods, in a double-blind, placebo-controlled trial. A total of 184 weaned Holstein calves (83 ± 7.9 d of life; 112.5 ± 11.7 kg of body weight; values are mean ± standard deviation) were allocated to 8 paddocks in a completely randomized block design experiment. During a 112-d period, animals received a total mixed ration and were randomly allocated into 2 groups: (1) CON: placebo-control (basal diet + calcium carbonate, top-dressed at 30 g/animal per day of placebo), or (2) UD: ultra-diluted complex (basal diet + TopVita-Real H, top-dressed at 30 g/animal per day of sulfur (10-60) + viola tricolor (10-14) + caladium seguinum (10-30) + zincum oxydatum (10-30) + phosphorus (10-60) + carduus marianus (10-60) + colibacillinum (10-30) + podophyllum (10-30) + vehicle: calcium carbonate; quantum sufficit 1 kg). Incidence risk of diseases, number of days with disease, and mortality events were recorded daily. Performance measurements and blood collection were carried out at enrollment and every 28 d until the end of the study period. The incidence risk of digestive problems was higher for the CON group. Additionally, the CON group had higher cumulative number of days per calf affected by tick-borne disease. Blood analysis revealed that CON calves had increased mean corpuscular hemoglobin amount and concentration than UD calves on d 28 after enrollment and had increased serum albumin and total protein concentration on d 84. Furthermore, higher albumin to globulin ratio was found in CON calves than in those of UD group at enrollment; however, on d 56, the inverse was observed. On d 28 after enrollment, CON calves had increased serum cortisol concentration. Regarding body measurements, higher withers height and body depth were detected in UD calves, on d 28 and d 84, respectively. Finally, higher culling risk was observed in the CON group during the heifer-raising period. In conclusion, a lower incidence risk of digestive problems and days with tick-borne disease were detected in the UD group. Additionally, systemic inflammation was improved by UD complex based on circulating inflammation and stress biomarkers on specific days after enrollment. However, UD product did not improve performance at the post-weaning, heifer-raising, and first-lactation periods.

Short communication: Partial replacement of ground corn with algae meal in a dairy cow diet: Milk yield and composition, nutrient digestibility, and metabolic profile.

This study was undertaken to evaluate the effects of partially replacing dietary ground corn with a microalgae meal from Prototheca moriformis (composed of deoiled microalgae and soyhulls) on milk yield and composition, nutrient intake, total-tract apparent digestibility, and blood profile of lactating dairy cows. Twenty multiparous Holstein cows (57.7±49.4d in milk, 25.3±5.3 of milk yield, and 590±71kg of live weight at the start of experiment, mean ± standard deviation) were used in a cross-over design experiment, with 21-d periods. Diets were no microalgae meal (CON) or 91.8g/kg of microalgae meal partially replacing dietary ground corn (ALG). Cows showed similar milk yield and composition. The 3.5% fat-corrected milk production was 30.2±1.34kg/d for CON and 31.1±1.42kg/d for ALG. Despite cows having similar dry matter intake, ALG increased neutral detergent fiber and ether extract intake. In addition, cows fed ALG exhibited higher ether extract digestibility. No differences were detected in glucose, urea, amino-aspartate transferase, and gamma-glutamyl transferase blood concentrations. Feeding ALG increased the total cholesterol and high-density lipoprotein in blood compared with CON. The microalgae meal may partially replace ground corn in diets of lactating cows without impairing the animal's performance.