Productive and economic response to concentrate supplementation by grazing dairy cows at high stocking

Resumen

Small-scale dairy systems contribute to ameliorate rural poverty and to local milk supply. Their sustainability is limited by high feeding costs, mainly from purchased concentrates (CC); whereas a higher reliance on quality forage may improve profitability; but high stocking rates may justify high CC use. The objective of this work was to assess the productive and economic response by grazing dairy cows to levels of CC under grazing of ryegrass–white clover pastures under high stocking rate (4 cows/ha). Six Holstein milking cows were replicated assigned 3 X 3 Latin Square arrangements. Daily milk yield and composition were recorded, and feed intake estimated from utilised metabolizable energy. Treatments were: T1= 1.0 kg T6= 3.0 kg and T6= 6.0 kg concentrate/cow/d. There were significant differences (P<0.05) for milk yield, with T6 having higher yields than T1 and T3. There were no significant differences in milk protein or fat content among treatments (P>0.05). Herbage intake was significantly (P<0.05) lower in T6, with no differences (P>0.05) between T1 and T3. There were no differences in margins over feeding costs, but feeding cost per kg of milk was 2.2 times higher in T6 compared to T1, and margin per kilo of milk was 26 % higher in T1 than T6. Although milk yields are higher with T6, T1 and T3 require less expenditures and margins are similar. Supplementation may alleviate high grazing pressure that deteriorates pastures, ensuring the long-term sustainability of small-scale dairy farming systems.