consequence for u.s. dairy herds of imposing different scc standards

H. Duane NormanAnimal Improvement Programs LaboratoryAgricultural Research Service, USDA Beltsville, MD 20705-2350

duane.norman@ars.usda.gov

NMC – 2011 (1)

Consequence for U.S. dairy herds of imposing different SCC standards

NormanNMC – 2011 (2)

U.S. milk quality measures

Bulk tank somatic cell count (BT-SCC) Monitored by USDA Data from 4 of 10 FMOs Accounts for nearly 50% of U.S. milk

supply

Herd test-day somatic cell count (TD-SCC) Herds in DHI Accounts for 94% of U.S. DHI herds

NormanNMC – 2011 (3)

U.S. SCC (all breeds)

NormanNMC – 2011 (4)

BT-SCC limits

Country

SCC limit(cells/mL)

Australia 400KCanada 500KE.U. 400KNew Zealand 400KNorway 400KSwitzerland 400KU.S. 750K

CA 600K

NMPFproposed SCC limits

Date Cells/mL1-1-2012 600K1-1-2013 500K1-1-2014 400K

NormanNMC – 2011 (5)

U.S. versus E.U. SCC monitoring

Individual farmIndividual farmSCC sample

2 consecutive3-month means over limit

3 of 5 consecutive samples over limit

Producer suspension

Geometric mean of 3 monthly BT-SCC

Consecutive monthly BT-SCC

Value used

400K cells/mL750K cells/mLBT-SCC limit

E.U.U.S.Program characteristic

NormanNMC – 2011 (6)

Export concerns

E.U. change in SCC sampling point from bulk truck or plant silo to individual farm

3-month mean (E.U.) used as single reference for period, which allows more time to reduce future SCC

Geometric mean (E.U.) mathematically lower than arithmetic mean (U.S.) and requires recalculation

NormanNMC – 2011 (7)

SCC noncompliance comparison

Current E.U. and U.S. SCC standards as well as 3 NMPF proposed standards

Percentage of herds

Percentage of milk supply

Examined by month, herd size, and state

NormanNMC – 2011 (8)

Data

SCS converted to SCC for 14,854 DHI herds

Herd requirements

15–26 tests (Jan. 2009 – Oct. 2010)

≥10 cows for all test days

Herd TD-SCC used as proxy for BT-SCC

Each cow SCC weighted by her TD milk yield

NormanNMC – 2011 (9)

SCC herd noncompliance – month

Jun 09

Jul 09

Aug 09

Sep 09

Oct 09

Nov 09

Dec 09

Jan 10

Feb 10

Mar 10

Apr 10

May 10

Jun 10

Jul 10

Aug 10

Sep 10

Oct 10

0

2

4

6

8

10

12

14

16

18

Current U.S. (750K)Proposed U.S. (600K)Proposed U.S. (500K)Proposed U.S. (400K)Current E.U. (400K)

Date

He

rd n

on

com

plia

nce

, %

NormanNMC – 2011 (10)

SCC milk noncompliance – month

Jun 09

Jul 09

Aug 09

Sep 09

Oct 09

Nov 09

Dec 09

Jan 10

Feb 10

Mar 10

Apr 10

May 10

Jun 10

Jul 10

Aug 10

Sep 10

Oct 10

0

2

4

6

8

Current U.S. (750K)Proposed U.S. (600K)Proposed U.S. (500K)Proposed U.S. (400K)Current E.U. (400K)

Date

Milk

no

nco

mp

lian

ce,

%

NormanNMC – 2011 (11)

SCC noncompliance – means*

NoncomplianceSCC standard Herd, % Milk, %750K, current U.S. 0.9 0.2

600K, proposed U.S. 2.7 0.7500K, proposed U.S. 6.2 2.0400K, proposed U.S. 14.1 5.8

400K, current E.U. 7.8 3.1

*November 2009 – October 2010

NormanNMC – 2011 (12)

SCC herd noncompliance – herd size

1–49 50–99 100–149 150–199 200–299 300–499 500–999 1,000+0

2

4

6

8

10

12

14

16

18

20

Current U.S. (750K)

Proposed U.S. (600K)

Proposed U.S. (500K)

Cows in herd

He

rd n

on

com

plia

nce

, %

NormanNMC – 2011 (13)

SCC herd compliance – state

Current U.S., 750K

Current E.U., 400K

Proposed U.S., 500K

Proposed U.S., 600K

Proposed U.S., 400K

<5%5–9.9%10–24.9%25–50%

NormanNMC – 2011 (14)

Conclusions

E.U. changes in SCC enforcement led to reconsideration of stricter U.S. standards

If 400K U.S. SCC limits were used, noncompliance would be higher than if current E.U. standard was applied

For U.S. producers to meet stricter SCC standards, sound management and culling for milk quality need to be emphasized