February 2015 Fertility and Breeding Notes

 
Doreen Corridan MVB MRCVS PhD 

Munster Cattle Breeding

 

Fertility in the 2015 breeding season begins now

Nutrition in the dry period and the first 10 weeks after calving is key in achieving high fertility and production in the following breeding season. Issues for this season are exceptional long dry period leading to over fat cows at calving and quota restrictions till 1st April.
Target
 
The target is to calve cows in a BCS of 3.0 to 3.25 and to minimise weight loss between calving and breeding to 0.5 BCS.
How can we do this?
Divide this period into 3 areas as follows and we will deal with each area individually.

Nutrition in the dry period and the first 10 weeks after calving is key in achieving high fertility and production in the following breeding season. Issues for this season are exceptional long dry period leading to over fat cows at calving and quota restrictions till 1st April.
Target The target is to calve cows in a BCS of 3.0 to 3.25 and to minimise weight loss between calving and breeding to 0.5 BCS.
How can we do this?Divide this period into 3 areas as follows and we will deal with each area individually.

Target

 

The target is to calve cows in a BCS of 3.0 to 3.25 and to minimise weight loss between calving and breeding to 0.5 BCS.


How can we do this?

Divide this period into 3 areas as follows and we will deal with each area individually.

 

 

Dry Period

There is huge danger of overfeeding dry cows with long dry periods, watch your March and April calvers.  Dry cows only need energy intakes of circa 6.5UFL depending on the stage of pregnancy. The energy value of grass silage is very variable and some silages will overfeed dry cows if fed ad-lib by 50% +.

 

Example

12Kg of grass silage DM with 0.8UFL provides 9.6 UFL/day.

Dry cow will be over fed by 50%!

Cows calving in BCS from 3.5-4.5+ (too fat) experience

More difficult calvings

More Retained afterbirths

Reduced Intakes after calving

Fatty Liver

Ketosis

Excessive Loss of Body condition

Diaplaced abomasum

Poor uterine Involution

Uterine infections

Immune system compromised

Reduced fertility

 

Action

Act now and dilute the silage with straw - depending on the BCS and silage quality need from 2-4 Kg of straw. It is not a good idea to restrict silage only as the rumen will not be full, need to fill the rumen and reduce the energy intake. 

 

Key point: Act now to avoid your late calvers becoming too fat-BCS and restrict energy intakes where required.

 

Prevent negative energy balance 2-3 weeks pre calving  to calving

Negative energy balance 2-3 weeks pre calving to calving is due to

Reduced appetite in cows with BCS greater than 3.25

Increased calf size

Social & group changes-incalf heifers especially as they join main herd.

Diet changes

Feeding not being offered or not in sufficient quantities in calving pens

 

Action

Reduce straw to 1Kg max and begin feeding some concentrates prior to calving to acclimatise the rumen for concentrate feeding after calving.

 

Key point: Avoid negative energy balance pre-calving, reduce straw and begin feeding concentrates in the final 2-3 weeks pre-calving.

 

First 8-10 weeks after calving

Energy balance in early lactation is likely the most important nutritional issue that will influence dairy cow fertility. To ensure negative energy balance is not excessive in early lactation maximising feed intake is critical. 

 

As we go from late pregnancy to 30 litres of production the intake requirement is more than doubled 8.1 to 17.5 UFL. Herds with higher conception rates to first insemination had significantly higher mean intakes of DM and UFL during the first 100 days of lactation.

It is possible to achieve acceptable levels of energy balance with grazing diets and 3Kg of concentrates in early lactation but this depends on your cows’ yield and quality grass availability (remember the influence of wet cold weather on grass intakes!).

 

Action

Avoid sudden changes in the diet as the rumen needs time to acclimatise, introduce concentrates 1-2 weeks pre calving and when going to grass graze by day only for 1 week prior to going out night and day.

Do the sums-Am I achieving the intakes I need? Calculate the deficit, if the deficit is 1.8 UFL per day cows will lose 0.5 BCs in 42 day.

Watch inclement weather

Get your silage analysed and practise good clamp management

Ensure cows and especially first calvers have adequate feed barrier space

Ensure 24 hour access to fresh feed (feed pushed up)

Water-clean no sediment, access, 100 litres/cow/day

Feeding high levels of starch (cereals/maize) increases insulin levelslinked with improved fertility