A Pilot Study on the Feasibility of an Extended Suckling System for Pasture-Based Dairies

Abstract

This study investigated cow-calf productivity in a 10-week, pasture-based, extended suckling system featuring part-time cow-calf contact and once-a-day milking. A total of 30 dairy cows and their calves were assigned to two treatments: (1) cow and calf managed in an extended suckling system; or (2) cow and calf separated at birth and managed as usual. Cow-calf pairs grazed together during the day and spent the night separated by fence-line contact. The dams were reunited with the calves after once-a-day milking every morning. The commercial treatment pairs were separated after birth, and cows were milked twice a day and managed within the farm herd. Commercial calves were reared and managed as per commercial Australian practices. Cow-calf dams yielded 9 L/cow/day less saleable milk (p < 0.001), and their milk had lower fat (p = 0.04) but a higher protein percentage (p < 0.001) than commercial cows during pre-weaning. However, milk yield and composition were comparable post-weaning. Dam-suckled calves gained weight faster and were therefore weaned 2 weeks earlier than commercial calves, which were offered 8 L/day milk. This study has demonstrated a novel system of extended cow-calf suckling that could be practical to implement in pasture-based dairies. The long-term effects and scalability of the extended suckling system described here require further validation.

Keywords: cow-calf contact; dam contact; dam rearing; pastoral systems; seasonal calving.

Figure 1

The TIA cow-calf suckling system. Schematic (not to scale) of the paddocks used to house the cow-calf pairs. Daily management steps are represented by numbers 1–4 on the figure and are described in the following sentences. (1) Milking: In the morning, after spending the night separated from the calves, cows were walked from the experimental paddock to the dairy shed for milking. (2) Cow-calf contact: Dams were returned to the day paddock after milking, and calves joined them 30 min later. Cows and calves spent the day in the AM area, with full contact. (3) Separation: Cows and calves were separated each night at approximately 1700 h. Cow-calf pairs were first walked to the gate separating the day and night paddocks. The calves were drafted into their pen while the cows waited at the gate. The separation gate was opened after all the calves were in the pen and locked away for the night, giving the cows access to the night paddock. (4) Overnight fence contact: The cows spent the night in the PM area, and the calves were within their pen. Fence-line contact was maintained.

Figure 2

The mean daily milk yield (litres) produced per cow per week of lactation in the commercial and suckled treatments. Error bars: 95% CI.

Figure 3

The mean calf weights (kg) at birth and weeks 3, 6, and 9 of the rearing period. Average daily gain (ADG) was significantly different between weeks 3 and 9 of rearing (p ≤ 0.05). Error bars: 95% CI.