Effect Of Trace Mineral Source Research Articles

Effect of Replacing Dietary Inorganic Forms of Zinc, Manganese, and Copper with Complexed Sources on Lactation and Reproductive Performance of Dairy Cows

ABSTRACT One hundred eighty multiparous Holstein cows (90 cows/treatment) were blocked according to calving date and randomly assigned to a study to determine the effect of trace mineral source on performance. Treatments were 1) all trace minerals supplied by inorganic sources or 2) inorganic minerals (360 mg Zn/d, 200 mg Mn/d, and 125 mg Cu/d) replaced with amino acid complexes of Zn, Mn, and Cu (CTM, Availa-4, Zinpro Corporation). Neither level nor source of Co supplementation differed between dietary treatments. Cobalt was supplemented as Co carbonate to supply 12 and 23 mg Co/d to dry and lactating cows, respectively. Cows received their respective treatments from 60 d prior to calving through 200 d oflactation. Replacing inorganic trace minerals with CTM tended to increase (P = 0.06) milk protein yield (1.09 vs. 1.05 kg/d) and tended to decrease (P = 0.15) linear SCC. There was no effect oftreatment on milk yield and yields of 3.5% fat-corrected milk and energy corrected milk. Feeding CTM increased (P = 0.005) BCS (2.97 vs. 2.86), decreased (P = 0.02) culling rate (13.3 vs. 25.6%) and tended (P = 0.07) to increase incidence of retained placentas (13.3 vs. 6.7%). Feeding CTM also tended to decrease (P = 0.15) incidence of metritis (14.4 vs. 16.7%) and to increase (P = 0.15) first service conception rate (21.9 vs. 19.1%). Replacing inorganic trace minerals with those supplied by CTM tended to improve lactation performance and reduced culling rates.

Effects of Trace Mineral Source and Feeding Method on the Productivity of Grazing Braford Cows

Braford cows (n = 160) were used to evaluate the effects of trace mineral source and feeding method on cow herd productivity over 3yr. In yr 1, cows were stratified by age and randomly allocated to one of eight groups (n = 20 cows per group). Cows were allotted to 8 of 16 bahiagrass pastures (8.0ha each, one empty pasture between groups) and were rotated each week. Cow groups remained intact throughout the study with the exception of culled cows, which were replaced with 3-yr-old pregnant heifers. Cows were offered 2.27kg of liquid molasses daily from early November until mid April. One mature Braford bull was placed into each cow group starting in early January, where the bull remained for 90 d. Bulls were rotated through cow groups each week. Two main factors were randomly applied to groups in a 2 × 2 factorial arrangement (two groups per treatment): 1) trace mineral source (inorganic vs organic) and 2) mineral feeding method (free-choice vs control-fed in a molasses supplement). Cow BW, body condition score (BCS), pregnancy rate, calving interval, and calf BW at weaning were obtained. Mineral intake was measured each week in pastures where mineral source was provided for ad libitum intake. In yr 1 and 2, liver biopsy collections were conducted for the determination of mineral status at the start and end of winter supplementation on the same six randomly chosen cows. Cows assigned to free-choice treatments consumed 23% less (P<0.001) mineral compared with control-fed cows, resulting in a greater (P<0.05) decrease in liver Zn (yr 1) and liver Cu (yr 2) concentration compared with control-fed cows. Mineral source and feeding method had no effect on cow BW, cow BCS, and calf BW at weaning. Young cows (3 and 4yr of age) consuming organic minerals had a greater pregnancy rate during yr 2 (P<0.05) and 3 (P=0.15) and a lesser (P<0.05) calving interval in yr 1 and 3, compared with cows consuming inorganic minerals. The supplementation of organic minerals (Cu, Zn, Mn, and Co) appears to increase the reproductive performance of young, but not mature, grazing Braford beef cows consuming molasses-based supplements.

Effects of Feeding Complexed Zinc, Manganese, Copper, and Cobalt to Late Gestation and Lactating Dairy Cows on Claw Integrity, Reproduction, and Lactation Performance

Three hundred multiparous Holstein cows (150 cows per treatment) were blocked according to calving date and randomly assigned to a study to determine the effect of trace mineral source on incidence and severity of claw lesions, reproduction, and lactation performance of dairy cattle. Treatments were 1) all trace minerals supplied by sulfates(ITM)or 2) 360mg Zn from Zn amino acid complex, 200mg Mn from Mn amino acid complex, 125mg Cu from Cu amino acid complex, and 12mg Co from Co glucoheptonate per day(CTM;Availa®; Zinpro Corporation, Eden Prairie, MN) replacing an equivalent amount of Zn, Mn, Cu, and Co from sulfates. Cows received assigned treatments from 21 d prior to calving through 250 d of lactation. Cows fed CTM produced 1.2kg more (P < 0.05) milk, energy-corrected milk, and 3.5% fat-corrected milk than cows supplemented with ITM. The CTM treatment reduced (P < 0.05) days open by 22 d and tended to increase (P < 0.15) percentage of cows pregnant by 150 d in milk (54.8% vs 42.7%) and first service conception rate (27.4% vs 18.4%). Cows fed CTM tended to have a lesser incidence (P < 0.15) of claw disorders than cows fed inorganic trace minerals at 75 d postpartum (23.6% vs 34.1%) and numerically lower incidence at 250 d postpartum (10.0% vs 17.7%). The CTM treatment increased yield of milk, decreased days open, and tended to increase first service conception rates, increase percentage of cows pregnant at 150 d in milk, and decrease claw disorders at 75 d postpartum.