Maximizing Value from Transition Cow Diets

Published on Tue, 09/18/2018 - 9:43am

 Maximizing Value from Transition Cow Diets

 By Michael Cox

 The transition time period from dry to fresh is one of the most intense, stressful and critical periods in a cow’s production cycle. Managing the diet over this period will aim to meet the maintenance requirements of the dry cow, before transitioning to a higher energy close-up and fresh diet. Correct management and use of transition cow diets will allow dairymen to set the cow up for optimum performance in the up-coming lactation.

Low-energy diet
Transition cow diets typically focus on high fiber and low energy as key components of the diet. Straw is most commonly used to bulk up the diet with fiber which will dilute higher energy ingredients and prevent cows from getting over-fat during the dry period. For example, a typical far-off transition cow diet where cows are eating 30lbs dry matter could be made up of 20% straw and 50% corn silage, with the remainder of the diet comprising of other ingredients such as haylage, wet gluten, grain, minerals etc.

Generally, dry cows (and youngstock) are seen as easy targets for cost savings to be made, particularly be cheapening the ration and feeding poorer quality feedstuffs. However, this could be penny-wise, pound-foolish approach, as the consequences of a poor transition diet will not be seen until weeks later when cows fail to breed-back on time, reach peak milk and have increased health issues. Granted, some small strategic savings can be made without compromising future cow performance if producers work closely with their nutritionist. Chad Mullins, a dairy nutritionist based out of Missouri believes that savings can be made in the diet without negatively impacting cow health; “A simple saving that I’ve found useful is to replace some of the expensive chlorine in the diet with more methionine, which is cheaper and can still maintain the benefits associated with chlorine,” Mullins says.

Stocking rates
Regardless of the diet composition that is used, correct stocking rates in the transition cow pens is necessary to provide fair access to all cows and avoid excessive bullying. One free-stall per cow will aid in optimum recovery and help keep a steady flow of healthy cows moving out to the milking herd. Cows should be grouped according to Body Condition Score, expected calving date and age. If possible, heifers and a small number of cows in poorer body condition should be grouped together. Both sets of cows will benefit from this grouping; the mature cows benefiting from less competition with heifers compared to the main herd, while the heifers will benefit from the slight bullying and ‘toughening-up’ the older cows will give them. Research coming out of Dairy NZ in New Zealand suggests that heifers introduced to groups of older cows during the early transition period will have less body condition loss by breeding time, compared to heifers that are introduced to the main herd post-calving. It would appear that early introduction allows heifers time to acclimatize and regain the inevitable body condition score losses before breeding time comes around.
Fresh pens should be cleared out as quickly as possible to maintain low stocking rates, with cows sent to the lactating herd on a consistent basis once they have recovered from calving and any health issues. Balancing the amount of time a cow spends in the fresh pen can be a catch 22 situation; do we allow cows spend greater time in the fresh pen and force close up cows spend more time in the ‘dry’ pen or vice versa? Mullins believes that the best way to tackle this necessary evil is to keep cows away from the fresh pen as long as possible, and prioritize fresh cow time post calving. Stocking rates in the close-up and fresh pens should not be comprised, as feed intakes of transition diets and resting time will suffer.

High intakes
Of course, the challenge in the close-up phase of the transition period is keeping dry matter intakes as high as possible before calving. Intakes can drop by 30%-40%, so ration formulations need to be adjusted to provide the cow with increased energy, protein etc. Although the dry cow diet may have been based on straw and long fiber/low energy, the close-up diet will benefit the cow most of it is similar to the fresh cow diet. Including half-rates of the major ingredients in the fresh cow diet during the close-up phase will not only increase energy and protein pre-calving, but also adjust the rumen to deal with the more energy dense lactation diet in the near future. The close-up diet can contain similar ingredients to the fresh-cow diet, apart from buffers and minerals. We will still need the cow in the correct DCAD range, so save those buffers and minerals for the ‘add-pack’ post-calving.
Research from Texas A&M University Extension suggests that cows should have reached at least 85% of their peak dry matter intake by two weeks after calving. If this target is not being reached, it is likely that the transition cow diet is in need of closer attention. Dry matter intake, as apposed to energy density of the diet, is key to energy intake and low negative energy balance. Intakes can be stimulated by increasing sugar levels in the diet, providing non-forage fiber instead of straw/hay and reducing starch levels.
The transition cow diet should also physically mirror the lactation diet, in terms of chop length and sortability. Long fibers such as straw should be chopped to 1 inch or less in length which will aid in increasing intakes. Density should also be similar between the transition diet and fresh diet. If necessary, water can be added to the more fibrous close-up diet to raise the density and reduce any sorting issues.
The benefits of transition cow diets are well documented, but these benefits can only occur if correct diet composition, pen stocking rates and high intakes are achieved. Although it can be tempting to cut costs in transition diets given the current milk market conditions, it will almost always pencil out better to maximize the value of the transition diet through good management and give the cow every chance to perform well in the next lactation.