Optimising Cow Performance and Feed Utilisation
Conditions in the dairy industry are very challenging but there are more opportunities to improve profitability now than have been available in the past two years. The feeding strategy for your dairy herd will allow you to take advantage of these opportunities in the following ways:
- Improve milk production to both dilute fixed costs and increase the opportunity to profit from a favourable margin over feed cost.
- Ensure the herd’s total diet is correctly balanced to optimise rumen function, allowing the milk response to feed inputs to be maximised, leading to a reduction in overall feed costs.
- Use the appropriate supplementary feeds to help increase forage production and utilisation per hectare. As forage (pasture, silage and hay) is usually the largest feed input, increasing its utilisation can result in significant cost savings.
- Put in place a calf and heifer rearing programme to ensure animals grow to their genetic potential and allow greater selection as well as ensuring reproductive performance is optimised to achieve target in-calf rates for your herd.
One of the first considerations is whether to aim for production per cow or per hectare. Under grazing conditions, cows optimise their milk production when they can be highly selective, whilst eating as much as they like. However, this leads to substantial pasture wastage, unless followers such as dry cows or heifers are used to graze the residual pasture.
Conversely, milk production per hectare is maximised by grazing a high proportion of the pasture. Although this does not allow cows to eat as much as they like or to be selective, it minimises pasture wastage, reducing the cost of the pasture eaten. The down side of this is low production per cow.
The best of both worlds is to aim for high milk production per cow and per hectare, which can be achieved with supplementary feeding.
Responses vary to supplementary feeding. It is important to understand both why and how this happens as this helps determine how to optimise milk responses to feed inputs. The most influential factors in deciding response to supplementary feeding are shown below.
Cow Factors | Feed Factors |
Genetic potential for milk production | Forage availability and nutrient content |
Stage of lactation | Supplement availability and nutrient content |
Feed level in relation to milk production potential | Feed costs |
Environmental stress |
After taking the above factors into consideration, is the cost of supplementary feeding justified by an adequate increase in production? The optimum amounts of dietary energy, protein and other nutrients to maximise profit is determined by the interaction of cow and feed factors, as well as feed costs and milk prices.
Responses to supplements may occur during the period of feeding (immediate response plus cumulative response) as well as after the period of feeding (residual response or carryover effect). The sum of the immediate, cumulative and residual responses is the total response and is often double the immediate response. This should be taken into account in assessing the economics of supplementary feeding.
Responses to supplements are often quoted as litres of milk per kilogram (l/kg) of supplement or kilograms of supplement required to produce a litre of milk (kg/l). Milk and supplement prices are applied to this ratio to determine whether or not supplementary feeding is profitable, but this does not tell the full story. A more realistic assessment of the benefits of feeding supplements would include the economic benefits arising from the following factors:
- Higher stocking rates are possible, increasing milk income per hectare. Also, pasture use is improved as the cows consume a greater proportion of what is grown, reducing the cost per tonne of the pasture eaten.
- Cows fed supplements maintain better body condition score when pasture availability is low, increasing their ability to reach their milk yield potential and reducing the time to their first oestrus after calving.
- When milk prices are high, feeding supplements can increase net milk income.
- Feeding supplements when pasture availability is low can increase lactation length.
- Appropriate supplementation can increase milk protein content when the energy intake from pasture is low.
- The growth of heifers and cows that have not reached mature size is promoted, increasing their appetite and milk production potential in future lactations, as well as in the current one.
Checklist
- Determine the cost of growing both the pasture and forage supplements fed to the dairy herd.
- Forages are often deficient in a variety of key nutrients and supplements play an important role in cost-effectively filling the gap between nutrients supplied by the pasture and nutrients required at different stages of lactation.
- Feeding concentrates affects pasture management and it is possible to increase grazing pressure or stocking rate as well as increasing the proportion of pasture actually eaten by the cows. This reduces the cost of pasture eaten.
- The best milk response to feeding concentrates is during early lactation, when cows calve down with a body condition score of 4.5 – 5.5.
- Cows of high genetic potential will give larger responses to concentrates than cows of lower genetic potential, provided that they are well grown.
- If cows are small and in poor body condition score, many of the nutrients supplied by the concentrates will go into improving body condition. These cows will give a small milk response in the short term and a larger milk response over time.
- If young cows have not reached their potential mature size due to under-feeding, they will divert a lot of the nutrients from concentrates into increasing body size. These cows will give a small milk response to concentrates in the short term, but in the long term, their appetites and milk production are likely to increase.
- To maximise profit from feeding, consider the availability, nutrient content and cost of the pasture, conserved forages and concentrates available, as well as the likely milk potential of the cows and the milk price.
Last updated: 2008-01-16