Many producers throughout WA have introduced serradella and biserulla and more recently vetch into their crop rotations. The benefits of these pastures to the cropping phase are well documented, but there is a lack of data available on their potential to improve carrying capacity, lamb growth rates or ewe reproductive performance. This project aims to quantify via participatory research the performance of lambs and ewes grazing these pastures to enable their use to be optimised in mixed farming systems. Demonstration sites will be established on up to 20 farms over 2-years to investigate the following:
- Lamb growth rates in late spring/early summer when grazing annual pasture legumes versus other pastures or stubbles
- Ewe reproductive rates from grazing annual pasture legumes versus other pastures or stubbles prior to and or during joining in early summer
Lamb growth rates
At each farm, at least 100 lambs will be split post weaning and allocated to graze serradella, biserulla or vetch versus crop stubbles or alternative pastures. The bigger the mobs the better but the minimum requirement is 50 lambs per mob and the animals need to graze for a minimum of one month. Feed on offer (kg DM/ha), nutritive value of the feed (energy and protein content) and liveweight will be measured at the start of grazing and then monthly until the end of grazing. All measurements will be completed by project staff from Murdoch University.
Ewe reproductive rates
At each farm, at least 400 ewes will be allocated to either serradella, biserulla or vetch versus crop stubbles or alternative pastures. The minimum requirement is 200 ewes in each group but flocks can be larger. The ewes will graze the different options for at least 4 weeks pre-joining and this can be continued through joining if preferred. Ewe liveweight and condition score will be measured at allocation and then monthly until the end of grazing. Feed-on-offer and nutritive value will be measured whenever the ewes are weighed and condition scored. Ewes will be combined from the end of grazing until pregnancy scanning. All measurements will be completed by project staff, and the project can also assist with the costs of scanning for multiple foetuses if required.