Sheep milking is a growing industry in New Zealand with a 50 percent increase in sheep milk producers between 2019 and 2021. Cited as sustainable and good for the environment, farmers and scientists see sheep dairy farming as a solution to reducing nitrogen (N) leaching and greenhouse gas (GHG) emissions.
At the same time, sheep milk has a unique compositional and nutritional profile that makes it an ideal food source for infants, women, athletes, and older people who would benefit from higher absorption of important nutrients like amino acids. And, when produced by a pasture-based country like New Zealand, this natural and wholesome product can be sold for a premium.
Diversification could reduce the environmental impact of dairy
Clean and green, quality farming systems, being environmentally friendly and profitable and innovation are all the things that enable New Zealand products to fetch a premium worldwide.
Whilst sheep milk provides an opportunity for diversification, New Zealand is taking a very pragmatic approach – using research to endorse the sustainable reputation of New Zealand sheep milk products in international markets. The industry is working hard to improve efficiencies, reduce costs and focus on sustainability, namely soil and water integrity, product traceability, nutrient-dense pastures, and increased output.
NZ Crown Research Institute, AgResearch, has been heavily involved with Sheep Milk NZ to determine the environmental footprint of sheep dairying with a specific focus on N leaching and GHG emissions.
N Leaching is the loss of nitrate as water drains through the soil profile, moving out of the range of plant rooting systems. It is recognised worldwide as an environmental and economic concern. In New Zealand, agricultural systems have been identified as a significant contaminant source to underlying groundwater and surface water bodies. Nitrogen can also be lost via gaseous admissions (e.g. nitrous oxide) to the atmosphere.
Studies in 2017 and 2018 looked at N leaching on farms near Taupo in the North Island and Telford in the South Island. There was 50 percent more pasture growth and N cycling in the sheep treatment compared to cow farms. They attributed this to less compaction of the soil and more even spread of urine. Urinary N extraction (kg/ha) was 50 percent less for sheep than cows too.
The studies also showed differences in the N leaching rate between low and high rainfall years and soil type. Light pumice soils had higher rates of N leaching than heavier clay soils. AgResearch has stressed that these were preliminary findings, and that further testing was needed.
To address GHG emissions, the other major environmental challenge for farmers in New Zealand, AgResearch compared two cow systems with five sheep dairy systems. It showed that dry matter intake (production intensity) was the key driver of GHG emissions. And, whilst emissions per kg milk solids were similar, with a significantly higher return per hectare from sheep dairying, less intensification and reducing farm GHG emissions is possible.
Fresh water is another important environmental issue for New Zealand. With livestock intensification and the need for high-producing pastures, farmers have resorted to using large amounts of fertiliser. Increased amounts of nitrate have ended up in waterways. Dry, hot summers result in an increase of algael blooms, which affect oxygen variability and creates O₂ extremes. Low and high O₂ extremes are lethal to life in the waterways. New Zealand scientists believe that if sheep milk has a smaller footprint on water quality than traditional New Zealand dairying, then the time is right for diversification.
The nutritional benefits of sheep milk
Compared to cows’ milk, it contains 60 percent more protein and twice as much calcium, zinc and leucine (an amino acid essential for growing muscles). It is also easier to digest, resulting in higher absorption of important nutrients like amino acids. Sheep milk contains B vitamins which are good for energy, vitality and managing stress, vitamin C and is naturally low in sodium.
Sheep’s milk infant formula is being promoted on the basis that both the fat and protein components are considered easier for babies to digest. Like goat milk, sheep milk only contains A2 beta casein, and therefore is more suitable for those who react to the A1 beta casein in cow’s milk. Also, like goat milk, fat is naturally homogenised and has smaller globules and more medium chain triglycerides (MCT) which are again easier to digest.
Because of its high calcium content, sheep milk helps with the prevention of osteoporosis. The fat profile of sheep milk is also thought to assist cholesterol reduction. These features can help promote consumption of sheep milk to adult and older aged consumers.
Many biopeptides found in milk have antibacterial, antiviral and anti-inflammatory properties. The bioactive substances of sheep's milk also show anticancer properties. Sheep milk, thanks to its fatty acid profile, is claimed to prevent the occurrence of type 2 diabetes, Alzheimer's disease, and cancer.
Whilst cow and goat milks are similar in composition, sheep milk is higher in protein, fat and total solids. Therefore, less sheep milk is needed to make cheese products – up to 40 percent less in fact.
The high solids content of sheep milk also means it can be frozen and stored for up to a year, still retaining good processing properties.
From harvesting sheep milk through to making products, think GEA
At GEA, we recognise and support the trend to farming and producing food more sustainably. With our global team of farming and engineering experts being our greatest strength, we take an integrated approach to "better engineering" which keeps us at the forefront of food production.
GEA offers the complete process line: from gentle and safe milk extraction to innovative machinery that processes milk into various products (powders, cheeses, food products), through to packaging them ready for market. We use innovative engineering to enable businesses to provide a range of consumer products to meet the constantly evolving health and lifestyle needs of the World’s population.
GEA Farm Technologies New Zealand is leading the way in developing sheep milking technology. The team works closely with industry specialists AgResearch, SheepMilk New Zealand, Spring Sheep Milk Co, Maui Milk and the steadily growing group of sheep milking farmers to ensure GEA products are fit for market, enhance throughput, support better efficiency, profitability and sustainability on farm and ultimately meet GEA’s vision of "engineering for a better World".
GEA sheep milking solutions support better milking practise, including automatic cluster removal, milk yield indication and herd management software. Add to that feeding systems, manure management, milk cooling and storage, dairy hygiene and readily available technical support. In a nutshell, GEA offers farmers the baseline innovation and technology necessary for less intensive, higher output farms.
Even better, these high throughputs, animal friendly milking parlors for the smaller ruminants (sheep and goats) can be easily retrofitted into existing bovine sheds – rotary or double-up parlors – minimising the cost of conversion.
New Zealand farmer Rhys Darby is a recent convert to sheep milking – switching due to the increasing environmental pressure on traditional dairy. With GEA’s support, he has successfully converted a 36-a-side herringbone traditional dairy parlor into a 42-a-side sheep milking parlor with rapid exit stalling.
GEA was his first choice based on prior experience with the GEA iFLOW rotaries, which had proven to be reliable, low maintenance and animal friendly. Rhys was also confident GEA would provide the support he needed in a new industry.
The retrofitted GEA sheep milking system, with in-shed feeding, automated plant technology and rapid exit stalling was designed for ease of use and maximum milking efficiency. It has delivered exactly that. "We get excellent throughput" says Rhys, "milking takes roughly 5 minutes per row. So, we’re milking 600 ewes in just over an hour (with one to two labour units)."
The future of sheep milking
Due to the current scale and cost, only a minimal amount of sheep milk is being made into milk powder around the world. However, this is a growing market – although globally still a niche market - and there is no denying that this is a sector to watch.