Effects of early postpartum sodium salicylate treatment on long-term milk, intake, and blood parameters of dairy cows.

Previous research has shown that cows who receive treatment with nonsteroidal anti-inflammatory drugs after calving may have increased milk yield beginning near peak lactation, resulting in greater 305-d milk production. It has not been demonstrated whether this response is associated with greater feed intake following the first 3 wk of lactation. Dry matter intake (DMI) and milk yield were measured daily for 56 cows over the first 120 d in milk. Cows in their second parity and greater were blocked by parity and alternately enrolled 12 to 36 h after calving into 1 of 2 treatments: either 3 daily drenches of water or 3 daily drenches of a similar volume of water containing 125 g of sodium salicylate (SAL) beginning 12 to 36 h after calving. Cows were housed in individual stalls to monitor DMI. Blood samples were collected before calving and on the last day of treatment, as well as at 7, 11, 14, 18, 21, 35, 49, 63, 77, 91, 105, and 120 d in milk. The SAL treatment did not affect estimated 305-d milk, fat, or protein yields (from monthly test days), daily milk yield or components, energy-corrected milk, fat-corrected milk, or DMI; however, an interaction between parity and treatment was observed for DMI, where second-parity SAL cows had decreased intake with no differences observed in older cows. This resulted in a parity by treatment interaction for the ratio of energy-corrected milk to DMI. Similarly, no main effects of treatment were observed for plasma glucose, β-hydroxybutyrate (BHB), or fatty acid concentrations, but we noted interactions between treatment and parity for glucose, BHB, and insulin. Older cows had greater plasma glucose and insulin concentrations and decreased plasma BHB following SAL but no differences were observed in second parity animals. Alterations in glucose and insulin resulted in a tendency for a treatment by time interaction for the revised quantitative insulin sensitivity check index. Feeding behavior was also altered following SAL administration, resulting in fewer but longer meals, as well as a tendency for greater meal weight. A tendency for a treatment by week interaction for inter-meal interval was observed, as well as a parity by treatment interaction for meal weight. Despite the lack of a milk yield response, SAL had a prolonged programming effect on feeding behavior and blood variables over the first 120 DIM, with responses largely dependent on parity.