Sheep Milk: Nutrition and farm systems

Can we improve milk production, lamb growth and health in dairy sheep farming via improved nutrition?

Lamb rearing

Lamb rearing systems have been developed to support the range of needs of different sheep milk producers using different farm systems and flock sizes.

High-quality pasture-based systems can support improved productivity and profitability for dairy sheep. The results are unique sheep milk with highly desirable flavour characteristics for drinking and high-yielding cheese making.

Effective feeding systems

New Zealand dairy sheep are, in general, low-producing (0.5-4L/d) compared to dairy sheep in other parts of the world (4-6L/d) – this is likely a consequence of a combination of genetics and animal nutrition.

Developing systems that provide appropriate nutrition while maximising our grass-fed advantage is the longer-term sustainable option to improve milk yield per ewe while increasing both on-farm efficiency and cost-effectiveness.

Therefore, we researched the design of effective feeding systems suitable for the New Zealand grass-fed context to increase milk production while ensuring lamb growth and health.

Aim

The project aimed to:

Design a suite of lamb-rearing systems to meet the needs of our farmers while maintaining health and productivity of the lamb, as it grows into a productive adult.
Test feeding systems to support high production and high milk quality for the future industry.

Method

We engaged with industry partners to test four rearing systems and three feeding systems. We measured:

Animal health aspects such as digestive function, immune function, growth rate, feed conversion efficiency, lamb health and future production
Food production aspects such as milk production, feed requirements, ewe health, milk composition and functional flavour components.

Results

The study produced many outcomes.

Restricting milk can lead to early weaning

Restricting milk intake to increase solid feed intake in the first four weeks of life can lead to early weaning at six weeks of age without compromising the long-term productivity of male lambs.

Ad libitum milk feeding promotes early growth

High hard feed intakes before weaning require careful management to transition lambs to pasture. Pasture can be used as a supplement to milk if the rearing system allows, to minimise potential problems at weaning.

Robust immune system

Rumen digestion processes and the development of the young lambs’ immune system are quite robust across a range of rearing systems.

Once-a-day milking successful

Once-a-day milking while still rearing the lamb with its mother can be used to successfully achieve both high milk harvest and low-cost rearing.

Interactive manual

Lamb rearing management practices to achieve good outcomes are documented in an interactive manual.

Growth pathways

Growth pathways during puberty influence hogget mating success and may influence later milk production through udder development.

Feeding systems influence production and flavour

Feeding systems can influence the production and flavour of sheep milk. Ewes fed a total mixed ration (TMR) indoors produced milk with higher concentrations of the compounds associated with strong flavor (vBCFAs) than ewes grazing on pasture. The milk from ewes fed the TMR also had a higher flavour value than milk from pasture-grazed ewes which would likely cause a more 'sheepy' flavour of products such as cheese, yoghurt and powder.