Does supplementing linoleic acid to cows during the last two months of pregnancy impact transfer of passive immunity to calves? Research presented at the American Dairy Science Association’s annual meeting says “yes.”

Cows in the study received diets formulated to supply minimum amounts of linoleic acid and supplemented either without fat, or with saturated fatty acids at 1.75 percent of dietary dry matter (DM), or with calcium salts of unsaturated fatty acids enriched in linoleic acid at 2 percent of dietary DM.

Within two hours of birth, calves were given colostrum from their own dam or from a dam fed the same dietary treatment as the calf’s dam using an esophageal feeder. Passive immunity was assessed by measuring concentration of IgG in colostrum and in serum, as well as total protein concentrations in serum at 0 hours and 24 hours of life.

Apparent efficiency of absorption was calculated, considering serum as 9.9 percent of body weight. Body weight at birth did not differ among treatments;  however, calves born from multiparous cows were heavier than those born from first-lactation cows (93.7 pounds vs. 81 pounds). Concentration of colostral IgG was greater from multiparous cows fed fat than from those not fed fat pre-partum. Feeding fat to first-lactation cows had no effect on colostral IgG. As a result, intake of IgG by calves born from multiparous cows fed fat pre-partum was greater than that of calves born to cows not fed fat. Serum concentrations of IgG tended to be greater at 24 hours in calves born from cows fed fat compared with those not fed fat. Among fat source, those calves born from cows fed saturated fat tended to have greater serum concentrations of IgG at 24 hours.

Also, calves born from cows fed fat pre-partum tended to be more efficient at absorption of IgG. Recovery rate from diarrhea during the first 15 days of calf age tended to be faster for those calves born from cows fed fat pre-partum than calves born from cows fed a control diet.