Effect of feeding management during the first 21 days postpartum, on direct and residual productive response and adaptation to grazing of multiparous Holstein dairy cows

Abstract

Intensification of dairy production systems in Uruguay has involved the implementation of strategies that includes confinement with total mixed rations (TMR) either in dry lots or in low-cost barns. Questions have emerged about the productive impact of its use in short periods during early lactation (e.g., first 21 d postpartum) in multiparous dairy cows. An experiment was carried out at the Research Station “Dr. Mario A. Cassinoni” of the School of Agronomy (Paysandú, Uruguay) to study the productive response of multiparous dairy cows after a period of contrasting feeding management during the first 21 d in milk (DIM). Two treatments were compared: T21 (n = 10) were fed a TMR diet ad libitum (29.9 ± 3.5 kg DM cow−1 day−1) and T0 (n = 13) cows started grazing the day after calving and were fed a TMR (13.3 ± 0.5 kg DM cow−1 day−1 plus 1 grazing session). At d 22 the T21 cows were moved to T0 treatment until 60 DIM. Data were analyzed as a complete randomized block design using the GLIMMIX procedure of SAS OnDemand software with a mixed model that included treatment, week and the interaction as fixed effect and block as random effects. Milk production on T21 was higher than T0 (40.1 vs. 35.1 kg cow−1 day−1; P = 0.007) during the differential feeding period (0–21 DIM). During the residual period (22–60 DIM) T21 cows tended to produced more milk than T0 (39.8 vs. 38.3 kg cow−1 day−1; P = 0.07). No differences were found in grazing behavior between treatments (T0: 237, and T21: 239 min−1 grazing day−1, P = 0.86). It seems that these differences in milk production might be related to a carryover effect of higher dry matter intake during the transition period as well as changes in selectivity (Chilibroste et al., 2015; Menegazzi et al., 2021). Changes in feeding management during the first 21 DIM had an impact on milk production of multiparous dairy cows. Further research is required to better understand the mechanisms involved in the direct and residual responses.