The influence of genetic potential on lactation curve and survival response of commercial dairy cattle to early lactation non-steroidal antiinflammatory (NSAID) drug administration

Abstract Text: Previous research has indicated that the attenuation of inflammation in early lactation through the use of NSAID has a beneficial effect on whole-lactation milk production. Multiparous dairy cattle were blocked by breed, dystocia, and twin births, and assigned to 1 of 3 treatments at 12-36 h post-parturition (n = 153). Treatments were 1 placebo bolus on the first day of treatment and 3 consecutive daily drenches of sodium salicylate (125 g/cow/d; SAL); 1 bolus of meloxicam (675 mg/cow) and 3 drenches of an equal volume of water (MEL); and 1 placebo bolus and 3 daily drenches of water (CON). Daily milk production was averaged by week of lactation for statistical analysis. As reported previously, there was a significant increase in daily milk production and whole-lactation milk yield following NSAID administration, and a tendency for fewer cows receiving MEL to leave the herd up to 300 days in milk compared to CON. For all cows with at least 8 weekly milk observations reported (n = 130), lactation curves were fit to the MilkBot® model (DairySight LLC, Argyle, NY) to estimate decay, persistence, ramp, and scale. In brief, “decay” describes the rate of decline in daily milk production following peak, and it is used to mathematically derive persistence; “ramp” describes the rate of incline in daily milk production up to peak; and “scale” is a factor that is used to adjust the magnitude of the lactation curve without altering its shape. As a main effect, NSAID did not influence any of these parameters (P ≥ 0.15); however, there was a significant interaction between the predicted transmitting ability for milk production (milk PTA) and NSAID treatment for decay of the lactation curve (P = 0.02; n = 121). A significant milk PTA and NSAID interaction was also detected for survival (P < 0.01). While milk PTA itself had a significant effect on risk of leaving the herd, such that lower milk PTA was associated with increased risk of leaving (P = 0.02), there was no evidence of this relationship in cows who had received either NSAID treatment. In conclusion, NSAID administration protected cattle with lower genetic potential from removal from the herd, possibly through an interaction with persistency of milk production in later lactation.

Keywords: lactation, persistence, inflammation, risk