H. D. Norman*, J. R. Wright, R. H. MillerAnimal Improvement Programs LaboratoryAgricultural Research Service, USDA Beltsville, MD 20705-2350duane.norman@ars.usda.gov

ADSA – 2011 (1)

Consequence of changing standards for somatic cell count on US Dairy Herd Improvement herds Abstr. 352

NormanADSA– 2011 (2)

U.S. milk quality measures Bulk tank somatic cell count (BT-SCC)

Monitored by USDA Data from 4 of 10 Federal Milk Orders

(FMO) 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

NormanADSA– 2011 (3)

98 99 00 01 02 03 04 05 06 07 08 09 10200

225

250

275

300

325

350

318311 316 322 320 319

295 296288

276262

233 228

Year

SCC

(100

0s)

U.S. DHI TD SCC (all breeds)

NormanADSA– 2011 (4)

BT-SCC limits

Country

SCC limit(cells/mL)

Australia 400KE.U. 400KNew Zealand

400K

Norway 400KSwitzerland 400KCanada 500KU.S. 750K

CA, ID, OR LESS

NMPFproposed SCC limits

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

NormanADSA– 2011 (5)

U.S. versus E.U. SCC monitoring

Individual farmIndividual farmSCC sample

4 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

NormanADSA– 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

NormanADSA– 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 and herd size

NormanADSA– 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

NormanADSA– 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

18Proposed U.S. (400K)Current E.U. (400K)Proposed U.S. (500K)Proposed U.S. (600K)Current U.S. (750K)

Date

Herd

non

com

plia

nce,

%

NormanADSA– 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

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

Milk

non

com

plia

nce,

%

NormanADSA– 2011 (11)

SCC noncompliance – means*

NoncomplianceSCC standard Herd, % Milk, %750K, current U.S. 0.9 0.2600K, proposed U.S. 2.7 0.7500K, proposed U.S. 6.2 2.0400K, proposed U.S. 14.1 5.8400K, current E.U. 7.8 3.1

*November 2009 – October 2010

NormanADSA– 2011 (12)

SCC herd noncompliance – herd size

1–49 50–99 100–149 150–199 200–299 300–499 500–999 1,000+02468

101214161820

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

Cows in herd

Herd

com

plia

nce,

%

NormanADSA– 2011 (13)

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

NormanADSA– 2011 (14)

Opinion There has been a surprisingly large

decline in SCC in the U.S. and we believe it’s because of the required payment for quality (on SCC) in 4 FMO plus other voluntary incentives in the other markets.

We hope that whatever regulations are enacted in the future will not disrupt the success of the SCC incentives that seems to be working.