Abstract #T408

# T408
Fetal programming on dairy cows: Effect of dam’s parity and days in milk at conception on first-lactation milk yield in dairy cows.
Ayelen Chiarle1, Ramiro Rearte1, Santiago Corva1, R. Luzbel de la Sota1,2, Mauricio Giuliodori1, Alejandro Relling*1,3, 1Fac. Cs Veterinarias, UNLP, La Plata, Argentina, 2CCT La Plata, CONICET, Argentina, 3IGEVET, CCT La Plata, CONICET, Argentina.

Fetal programming is defined as nutritional and/or endocrine changes that happen in the cow during gestation that may change expression of some genes on the adult life of the progeny. These changes may have an impact on the progeny’s performance. Therefore, the objective of the current study was to evaluate the effect of dam’s parity (1 through 8) and days in milk (DIM) at conception on the daughter`s first lactation milk yield accumulated up to 150 d (MY150, kg). Data from dairy cows (n = 159.886) and their daughters (n = 201.547) from 1131 Argentinean dairy herds from ARPECOL (La Plata, BA, Argentina) were included in the study. Data were analyzed as completely randomized block design with a mixed model (SAS 9.3). The model included the fixed effects of parity (1 through 8) and DIM at conception, divided into quartiles (1st: >77 d, 2nd: 77–115 d; 3rd: 115–190 d; 4th: <190); and the random effects of dam and dairy herd (block). Mean DIM for each quartile were 57, 94, 148 and 296 d. Linear, quadratic and cubic polynomial contrasts were used for mean separation. The daughters’ MY150 decreases (P-value Linear < 0.01, Quadratic < 0.01, Cubic > 0.10) when parity number increases. Mean MY150 were 2915, 2879, 2862, 2853, 2844, 2846, 2837 and 2835 kg for 1st, 2nd, 3rd, 4th, 5th, 6th, 7th and 8th parity, respectively. In addition, daughters’ MY150 increases (P-value Linear < 0.01, Quadratic < 0.05, Cubic > 0.10) when DIM at conception increases. Mean MY150 were 2851, 2858, 2863, and 2863 kg for those conceived on average at 57, 94, 148 and 296 DIM, respectively. In summary, physiological changes related to parity and DIM at conception have an impact on progeny’s MY150.

Key Words: dairy cattle, fetal programing, progeny milk yield