Sue McCoard from Agresearch takes Angus Kebbell through effective feeding systems to increase sheep milk production while ensuring lamb growth and health

This week on Factum-Agri the first episode in a series on sheep milk. I caught up with scientist Sue McCoard from Agresearch on farm systems for dairy sheep.

Her research focuses mostly on understanding the effects of the environment on lifetime animal performance. And by environment she is including things like the quality and the amount and type of diets that we feed our animals, including specific nutrients, effects of different management practices, such as weaning ages, and rearing practices. She has a particular interest in young stock which includes the prenatal period, so before our lambs and calves are born, which and includes the pregnant Damn, but also her progeny. That spans across cow and sheep dairy systems, as well as dairy, beef and meat sheep production 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.

As a result of this Agresearch studied the design of effective feeding systems suitable for the New Zealand grass-fed context to increase milk production while ensuring lamb growth and health.

“Over the last 10 years or so I've been involved with a wide group of people looking at different aspects of dairy sheep production systems, both on and off farm. For me personally I've worked closely with the dairy sheep industry and my colleagues and the research sector, particularly around lamb rearing systems. So this is including things like understanding factors that are affecting land survival, evaluating different types of rearing systems on the growth and health and both the meat and milk production of our lambs.”

“So it's included evaluation of different feeding systems, weaning systems, feed formulations, and those sort of things. And we've looked at animal performance, cost of production, and also the impact on the biology of the animal. As a physiologist, I'm particularly interested in how those environmental effects affect the animal itself, including its metabolic and immune system and gastrointestinal developments, I work with a wide range of colleagues in that space. We've also been doing some work on natural and artificial rearing systems, but also looking at better utilization of the surplus juvenile animals from our dairy sheep systems for novel meat products, which is quite an exciting and a very important area for the industry.”

The project aims were:

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.

Agresearch 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.

Have a listen to the interview with Sue above to hear the full story, and tune in next week as the dairy sheep story continues.

Angus Kebbell is the Producer at Tailwind Media. You can contact him here.