Friday, March 29, 2024

Reducing the impact of NEB for mating

Avatar photo
It is important to identify any at-risk animals and manage them accordingly.
DSM said 3-NOP can reduce methane emissions from ruminant animals, including cows, sheep and goats, by 30%.
Reading Time: 3 minutes

By: Samantha Tennent and Mat O’Sullivan

Greater than 1.0 body condition score (BCS) loss in early lactation will significantly impact the health, production and reproduction of a cow. And if too many cows within the herd lose large amounts of condition there can be substantial collective impacts.

A negative energy balance (NEB) is when the energy demands for lactation, maintenance and activity are not met by dietary intake and the cow is forced to mobilise its fat and muscle to provide energy to meet the deficit. All cows enter into a state of NEB for six to eight weeks after they have calved and some condition loss is inevitable.

But before mating starts, cows need to have stopped losing condition and be in a state of positive energy balance. So how can you minimise condition losses and support the herd before mating starts?

Use the transition period
From three weeks pre-calving until about three weeks post-calving cows are facing many physiological challenges and careful management will help set them up for optimal performance. It is important to identify any at-risk animals and manage them accordingly. 

Cows that are below BCS are at direct risk of infectious disease, such as metritis and mastitis, and cows that are above are more at risk of metabolic diseases, such as milk fever and ketosis, which weaken the immune system, also putting them at risk of metritis and mastitis.

So it is good practice to allocate feed according to BCS. Cows at or above target BCS should be fed 90% of their daily energy requirements for two to three weeks before calving. And cows that are below target BCS should be fed 100% of their daily energy requirements.

After calving the aim is to reduce their BCS loss and the biggest driver in this period is the nutritional management as a springer and the management of how energy is spent relative to intake. Typically, it takes around 10-20 days post-calving for a cow’s appetite to return to optimal – this is the period of steepest condition loss.

Greater losses than 1.0 BCS indicate poor feeding from six weeks post-calving, ill health or a cow that was greater than BCS 5.5 at calving. To manipulate energy expenditure during this period strategies like once-a-day milking for several weeks with adequate feed can support a positive energy balance situation.

But cows that are milked twice daily can still have good outcomes if strategies like identifying thinner cows and separating them from the main herd and/or preferentially feeding them are employed. This removes the competition from the older, more dominant cows and improves energy status and BCS. Using these kinds of strategies will increase the potential for a more successful mating result.

Get ready for mating
After the post-calving BCS loss, cows should begin to gain BCS, which is affected by their genetics and nutrition. Early calving cows should be gaining BCS before planned start of mating but research does show cows that are producing high levels of milk production gain less BCS than lower yielding cows during milking. 

If cows are offered poor-quality pasture in the lead up to mating it may impact their voluntary intakes due to the high neutral detergent fibre (NDF) content. If this is a problem there will be high residuals, but low energy intakes and condition loss. Managing pasture quality and strategic use of supplements in the pre-mate/mating period is crucial to ensure energy intakes are at or exceeding maintenance and milk energy demands.

If cow BCS and pasture residuals are on target adding supplements to the diet will not improve reproduction. But if supplements are needed, ensure they are good-quality and free from spoilage. The decision on supplement type should be based on the cost/benefit of the predicted milksolids response as research suggests there is no reproductive benefit of feeding high-starch supplements, such as grains, compared with high-fibre feeds, for example PKE or pasture silage.

But the majority of outcomes are relative to BCS at calving and productivity losses can be mitigated by achieving targets, BCS 5.0 for mixed age cows and 5.5 for first and second calvers. So whether or not the cows hit them this season there is a great opportunity to improve for next season.

Who am I? Samantha Tennent is the general manager WelFarm Ltd and Mat O’Sullivan is the InCalf trainer and co-director at the Veterinary Centre Oamaru.

This article originally appeared in the August 2022 issue of Dairy Farmer.

Total
0
Shares
People are also reading