Project code: D-54-11
Duration 16 months commencing December 2010
Team and Leader Ryan Law, Shane McGettrick, Alastair Wylie and Conrad Ferris
Organisations involved AFBI (Hillsborough, Newforge and Stormont)
Background and Summary
During early lactation, high yielding dairy cows are unable to consume sufficient food to support high levels of milk production, resulting in severe and prolonged periods of negative energy balance and excessive body reserve mobilisation. Research has shown that severe negative energy balance (NEB) increases the interval from calving to the commencement of luteal activity (Canfield and Butler, 1991; Lucy et al., 1992), extends the interval to first service (Butler et al., 1981) and decreases conception rates (Domecq et al., 1997).
Reducing negative energy balance in early lactation is difficult as the cow has a high genetic capacity to produce milk. Increasing the energy density of the diet, by increasing the amount of concentrates being offered, is an option; however, this can actually drive milk production if the diet contains sufficient protein. Furthermore, feeding high concentrate levels can lead to rumen acidosis and/or displaced abomasums which may in turn further increase negative energy balance, and potentially severely reduce milk production and reproductive performance.
An alternative approach is to reduce the concentrate levels in the total diet during early lactation. The aim is to reduce the rapid increase in milk production in early lactation and to reach peak milk yield later in lactation, closer to peak dry matter intake. Reducing the concentrate proportion will lower the dietary protein content of the total diet. Dietary protein supply is a key driver of milk production as the cow has a limited capacity to rely on body protein resources to maintain a high level of milk production (Oldham, 1984). Furthermore, a high forage intake, at a reduced dietary concentrate level, will promote the development of the rumen and potentially increase dry matter intake once supplemented with concentrate after a low concentrate start-up period.
The proposed study will examine the effects of reducing concentrate level in early lactation on milk production performance, milk quality, body tissue reserves, cow health, energy status and subsequent reproductive performance. This study will compare a rapid concentrate build-up strategy (by day-10), with two slower concentrate build up strategies (by day-10 and day-42). The study follows on from the study conducted during winter 2009/2010, in which either a rapid or delayed (commencing day-28) concentrate build up strategy was examined.
Objective of the proposed study:
To examine the impact of three concentrate build up strategies in early lactation on milk production performance, milk quality, body tissue reserves, cow health, energy status and subsequent reproductive performance.
This study will involve a total of 90 high yielding dairy cows allocated to 3 treatments. The study will run for the first 20-weeks of lactation.
Treatments (summarised in Figure 1)
1. Rapid build-up of concentrate from calving (maximum reached by day-10)
2. Intermediate build-up of concentrate from calving (maximum reached by day-26)
3. Slow build-up of concentrate from calving (maximum reached by day-42)
· Milk yield, composition and progesterone concentrations
· Live weights and condition score
· Dry matter intakes
· Metabolic status via blood analysis
· Health e.g. mastitis, displaced abomasums, lameness, ketosis and hoof health via locomotion scoring
· Classification of vaginal mucus and reproductive parameters
· Faecal scoring
Figure 1: Concentrate build-up strategy in early lactation
1. December 2010 – All cows calved and on study
2. May 2011 – Completion of study
3. Summer 2011 – Collate data
4. August 2011 - Outcomes of study presented to Industry
5. March 2012 – Final report to AgriSearch
1. Emerging concept: opportunity to test in Northern Ireland
2. Delayed build up of concentrates may improve rumen health and promote forage intake throughout lactation
3. Potential reduction in concentrate inputs throughout lactation
4. Reducing negative energy balance in early lactation will potentially improve fertility
5. Potential to improve economic performance