1. Can we enhance fertility with grain?
Chris Burke
Farmers Forum Roadshow April 2015

2. Feed her grain
Cow calves
A miracle happens
Cow is more fertile

3. How could grain help? Starch In theory, cow…. Cycles faster
Glucose
In theory, cow….
Cycles faster
Stronger heats
More fertile +
Ovary
Insulin
60-75% of DM is non-structural carbohydrate (NSC), 90% being starch.
Gong et al., 2002; Garnsworthy et al., 2009; Burke et al 2010
Insulin-like Growth Factor 1(IGF-1)

4. We hypothesised that..
At a farm-system scale:
…feeding 4 kg DM of maize/barley grain during the first 5 weeks after calving:
Gets cows cycling faster
Increases the 6-week in-calf rate
What is the basis of this hypothesis?

5. The ‘carbohydrate’ study
Conducted by Scott McDougall, Cognosco
Funded by dairy farmers (DairyNZ Inc) and MBIE
900 cows in 3 commercial herds
For 5 weeks after calving, cows assigned to:
Starch diet: 4 kg barley/maize grain
Fibre diet: 5 kg Soyhull/PKE (or pasture only)
Starch diet – Non-fibre CHO = 34%
Fibre diet – Non-fibre CHO = 22%

6. Did grain feeding improve fertility?
Fibre
Starch
Sig.
3-wk Submission rate (%) 90 88
P = 0.05
Conception rate (%)* 58 53
P < 0.001
6-week in-calf rate (%) 84 79
Not-in-calf rate (%) 4 6
*to first AB during the first 3 weeks mating

7. Why didn’t grain improve fertility?
Consistent with Irish studies (Kennedy et al., 2002 )
Complex interactions of feed substitution, BCS, DMI, genetics, timing, control group, etc.
Grain did not get cows cycling faster
Fibre
Starch
Sig.
Calve to 1st ovulation*
31.0
28.9
n.s.
Calve to 1st oestrus*
33.5
32.7
(*Subsample of 96 cows per herd, wkly milk progesterone by Shane Leane, Moorepark)

8. Take home message
Reproductive performance is not improved with a high starch feed (e.g. grain)
Go to the InCalf programme to navigate through the complexities of improving reproductive performance
Improving reproductive performance should not be one of the reasons for feeding grain
Nutrition is only part of it, and may not be what is limiting reproductive performance
dairynz.co.nz/incalf

9. Can we enhance fertility with grain?
Chris Burke
Farmers Forum Roadshow April 2015

10. Not likely! The general conclusion was that:
…. increasing the proportion of non-structural carbohydrate (NSC) in the early lactation diet reduced reproductive performance.

11. Extra slides beyond here:

12. 5 wks postcalving 4 wks precalving Isoenergetic diets
Pre: n.s
Post: P = 0.01
Pre x Post: n.s
5 wks postcalving
4 wks precalving
Burke et al., 2010
Isoenergetic diets
Cows cycled 8 day faster when fed 5 kg DM grain after calving
That increased the 6-wk in-calf rate by 17%
Past-grain had an 81% first service conception rate (vs %)
But only 16 cows per treatment in a very well controlled study

13. Timeline Actual DMI for in-shed supplements
Weekly pre- & post-grazed pasture mass
Intake estimates
Control diet*
Early and late foetal-aging PDs AB
Bull
High NSC diet (grain) -4
(PSM) +5
+12
-12
Also measured PPAI (milks on d 21, 28, 35 & 42 +/- 3 d) and metricheck/BCS (d 28 +/- 3) in Herd 2
*Control diet – Low NSC supplement for Herds 1 & 3; pasture/pasture silage for Herd 2

14. Feed analysis estimates
Herd 1
Herd 2
Herd 3
NSC
Con
Pasture
7.9
13.5
10.8
Maize silage
4.9 -
1.5
Pasture silage
1.1
PKE/DDG
3.6
Hay/Straw
0.3
Canola
0.2
Maize-barley grain (75:25)
4.0
4.1
PKE/soy hulls (50:50)
5.0
Total DM intake
16.8
17.8
18.7
14.6
16.4
17.3
ME (MJ)
248
242
229
171
206
199
Metabolisable protein (kg)
2.52
2.73
2.81
2.31
2.26
2.46
Non-fibre carbohydrate (%)
33.5
22.2
33.8
22.9
36.9
22.5

15. Did grain feeding improve health?
Control
High NSC
Sig.
BHBA (mmol/L) *
(95% CI)
1.29
( )
0.58
( )
P < 0.01
Subclinical ketosis (%)
Clinical ketosis (%)
Metricheck +ve (%)
BCS
*14 ± 3 d postpartum

16. Liveweight & Milk production
Control
High NSC
Sig.
Liveweight (kg)
449.4
448.0
P = 0.72
Milk volume (l)
21.9
22.3
P = 0.08
Fat %
4.50
4.57
P = 0.19
Protein %
3.78
3.77
Log SCC x 1,000
4.14
3.90
P < 0.01