Dry cows have different nutritional requirements to lactating cows
Providing cost-effective diets that promote health and performance during the transition from the dry cow period to peak production is a difficult balance. Will Brocklehurst, Feeding Specialist at Alltech InTouch, offers a step-by-step guide.
The lactation cycle of a dairy cow is the period — lasting 305 days, on average — between calvings, which is commonly divided into four phases:
- Early lactation
- Mid-lactation
- Late lactation
- The dry cow period
Peak milk refers to the highest level of daily milk production you can expect from your milking heifers and mature cows in early to
mid-lactation. On average, peak milk is a two-to-three-week window that arrives 40 to 60 days post-calving.
Any problems within the first 40 days can have a significant impact on a cow’s peak milk — and, therefore, on the overall herd performance. Meeting the evolving needs of cows as they transition from late pregnancy to early lactation and onto peak production is, therefore, vital. These are the factors with the biggest impact on the transition to peak performance:
- Minimising cow stress pre-calving,
- Ensuring dry matter intakes post-calving,
- Supplying energy for peak milk yield,
- Selecting the right feed additives.
The most stressful moment in a dairy cow’s year arrives at the point of calving when she is required to do multiple things at once. If we get it right, we’ll have a stronger foundation for the following lactation.
Minimising pre-calving stress
Unfortunately, getting it right is not always straightforward. The costs of major mistakes during this period can be substantial. Subclinical milk fever, in particular, can pose a big problem. It has been correlated with the common metabolic issues that often manifest around calving and sometimes go on to affect the lactation. Here are the top three areas we recommend focusing on as you prepare your cows for calving and early lactation:
Feeding
Dry cows have different nutritional requirements to lactating cows. Aim for body condition scores (BCS) of 3.0 to 3.5 and keep cows from reaching scores of 4 or above.
Over-conditioned cows have significantly lower intakes in the dry period, which correlates with intakes post-calving. There are several dietary strategies that help tackle this issue but no matter what route you take, consult with an on-farm nutritionist.
Grouping
Splitting dry cows into two groups — far-off and close-up — can help. This allows better matching of the cows’ needs during pregnancy and control of their dry matter intake as calving approaches.
Floor space tips
- Stock cows at 80–85% of full capacity.
- Allow a minimum of 75cm and up to 90cm of feed space/cow.
- Provide a minimum of 10cm of linear water trough space/cow.
Cow comfort
Management plays a huge part in reducing stress at the calving. The Cow Signals concept, which focuses on creating a stress-free calving line, can go a long way toward reducing stress. The three most important aspects of housing during this period are providing the cows with proper feed, plentiful clean water and a comfortable lying space. Each one can affect a cow’s comfort and dry matter intake.
Post-calving intakes
Post-calving attention should shift to maximising the cows’ feed intakes. Ahead of calving, dry matter intakes can drop by around 30%, and then remain low 24 to 48 hours after. The risk is having insufficient nutrient reserves to help cows recover from calving and cope with the demands of early lactation.
Tips to avoid issues associated with a drop in dry matter intake include:
Feeding and hydration
Freshly calved cows must eat and drink immediately after calving because this affects their dry matter intake for up to 12 weeks. More immediately, eating sufficient amounts quickly post-calving adds weight to the rumen and fills the void left by the calf, so reducing the likelihood of a displaced abomasum.
Water intake is also closely related to feed intake. A cow’s water intake will likely drop pre-calving and she may be slightly dehydrated at calving. Unless we remedy that, it could have an impact on her feed intake.
Grouping
Grouping fresh cows together for a period of two to three weeks post-calving can be useful. This enables closer monitoring of cows and priority given in terms of feed, water, lying space and ventilation.
Social stress and hierarchical bullying are important, especially in heifers. Managing this stress can help maintain intakes. Heifers could also benefit from being grouped separately for the whole first lactation.
Rumen fill
Monitor the cow’s rumen fill and BCS during the initial fresh period to give you clues on how well she is eating. Cows often lose around half a point of their BCS post-calving — but if this happens too suddenly, it could be caused by suboptimal intakes or a poor ration formulation.
Energy for peak milk yield
Milk yields normally peak around 40 to 60 days post-calving. However, maximum intakes won’t be reached until 70 to 84 days post-calving. The cow is, therefore, not in a position to consume enough energy from her diet to support her lactation requirements. This is referred to as a negative energy balance. If rations are not managed correctly, the cow’s gut microbiome won’t adapt quickly enough, which can lead to rumen acidosis — a precursor to other health and performance challenges. Fibre-digesting rumen bacteria require a pH of 6.5 to work effectively. The bacterial population is adversely affected at pH 6 or below, which occurs when there’s an increase in lactic acid production or rumen acidosis. Tips to reduce rumen acidosis risks when transitioning to peak yield include:
Will Brocklehurst, Alltech InTouch
Rumen buffers and protected fats
Provide freshly calved cows with free access to rumen buffers, like sodium bicarbonate, to help stabilise rumen pH. It is important to monitor intakes closely to gain an idea of how much pressure the rumen is facing from the diet. If rumen buffer intakes are high, reformulating the ration may be wise.Feed rumen-protected fats to help increase or maintain energy densities within the fresh ration whilst alleviating some of the pressure on the rumen.
Ration mix quality
Pay close attention to the ration mix quality. A poorly mixed ration that allows sorting of concentrate ingredients will only exacerbate the problems noted above.
Feed and feeding behaviour
If cows are being fed concentrates in the milking parlour or are using out-of-parlour-feeders, be aware of the impacts of “slug feeding” and inconsistent intakes. This may also be an issue if cows run out of ration at the feed barrier, emphasising the importance of regular feed push-ups and feeding times. While feed may be expensive, operating at a 5% leftover rate when cows are in the fresh group is recommended to ensure that their performance capabilities are being maximised. Provide good-quality, digestible neutral detergent fibre (NDF) in the ration. NDF stimulates rumination and effective cud chewing.
Selecting feed additives
There is a wide and diverse range of feed additives on the market. Here are some aspects to consider:
Rumen function and fat reserves
Maximising rumen function up to peak lactation is fundamental. Live yeasts, like Yea-Sacc, can stabilise rumen fermentation and help cows adjust to a higher concentrate ration.
Cows that have to mobilise their own internal fat reserves to support energy requirements at peak lactation are at greater risk of ketosis, fatty liver and BCS losses. Rumen-protected choline can support liver health and function during the transition period and support dry matter intake, milk yield and milk solids, post-calving.
Protein
Over-feeding protein can cause wasted energy as the cow’s system works to remove the excess protein. Alternatively, insufficient protein will lower microbial activity and the rate of digestion. Optigen offers a steady release of soluble non-protein nitrogen (NPN). When formulated correctly, NPN helps improve rumen function and volatile fatty acid output, providing more energy to the cow. Amino acid supply must also be balanced. Rumen-protected forms are the best choice.
Supplementation
Oxidative stress caused by fat mobilisation, poor air quality and physical injuries at calving will affect the cow’s immune system. Proper vitamin and mineral supplementation — particularly with vitamin E and selenium, which are antioxidants — can help cows overcome oxidative stress. Organic forms of selenium, like Sel-Plex, are more bioavailable to the animal.