The effect of pasture allowance and concentrate supplementation type on milk production performance and dry matter intake of autumn-calving dairy cows in early lactation

Effect of increasing pasture allowance and concentrate supplementation on animal performance and microbial protein synthesis in dairy cows

“…Pre-grazing herbage mass averaged 1673 kg DM ha -1 (above ground level), for the two pasture allowances. This was similar to the 1,800 kg DM ha -1 (above ground level), of pasture mass reported by Hernandez-Mendo and Leaver (2004) and Pulido et al (2010) but, higher than the amount reported by Perez-Prieto et al (2011). In the dairy production systems of this geographical region, where animals graze all year round, having to wait for a pre-grazing herbage mass similar to the spring conditions reported by Pulido et al (2009) would mean keeping the animals without grazing for long periods of time, which is not possible under these conditions.…”

“…Post-grazing herbage mass averaged 1372 ± 100 and 1241 ± SD 82 kg DM ha -1 , for the high and low herbage allowance, respectively. The area offered daily in the low pasture allowance (124 m 2 cow -1 ) was 29.5% less than in the high pasture allowance, which is similar to the average reported by Pulido et al (2010) and higher in 30 m 2 than in the report of Pérez-Prieto et al (2011). Similar pasture allowances were used in spring grazing by (Pulido et al 2009) but with higher pre-grazing herbage mass.…”

“…According to Tas and Susenbeth (2007), increasing the DM intake increases the PD excretion in urine, causing a higher microbial nitrogen flow to the duodenum. This data could explain the differences between allantoin and PD/CT ratio, similar to obtained intakes of DM (15.6 kg DM -1 d -1 for high and 13.5 kg DM -1 d -1 for low pasture allowance) and to previous studies (Bargo et al 2002, Pulido et al 2010. However, when expressing the efficiency of MN synthesis as a function of the intake of digestible organic matter (g MN kg -1 organic matter intake, MOI), the level of intake did not show any effect on the efficiency of MN synthesis for both allowances (31.2 and 32.9 g MN kg -1 MOI, for high and low pasture allowance, respectively), indicating that the use of energy did not improve with nitrogen for its deposition as microbial nitrogen.…”

“…However, a higher pasture allowance would prevent from an abrupt fall in the milk yield of the cows and therefore there is a tendency towards a higher persistency (P = 0.07), similar to the previously described (Pulido et al 2010). It is possible that the cows receiving a low pasture allowance might have been using their body reserves to compensate for the lower DM intake and therefore reduce the impact in milk production (McEvoy et al 2008), causing a decrease in body condition and in the live weight of these cows.…”

Evaluation of blood metabolites in dairy cows grazing under two pasture allowances and supplemented with corn silage under restricted grazing conditions

“…Particularly, the fall pasture presents a low DM content and herbage mass (<170 g kg −1 ; ≤1.800 kg DM ha −1 , respectively), which limits feed intake (Ruiz-Albarrán et al, 2012). In addition, high crude protein content (200 to 300 g kg −1 DM) and low nonstructural carbohydrates (50 to 250 g kg −1 DM) are present and generate a lack of synchrony in the ruminal degradation of both fractions (Pulido et al, 2010). The foregoing, in addition to the increase of requirements on fall-calving dairy cows, ensures that pasture diets alone are generally insufficient to meet the requirements of dairy cattle (Pérez-Prieto et al, 2011), predisposing the presentation of metabolic-nutritional imbalances .…”