Veterinary Services 

Centers for Epidemiology and Animal Health December 2002

_________________________________________________________________________________________________________________________ 

Highlights of NAHMS Dairy 

2002: Part 1 

In 2002, the National Animal Health Monitoring 

System (NAHMS) conducted a study of dairy 

operations in the United States. The Dairy 2002 

study was conducted in 21 major dairy States and 

was designed to provide information to both 

participants and industry from operations 

representing 82.8 percent of U.S. dairy operations 

and 85.5 percent of U.S. dairy cows. Data were 

collected from December 31, 2001, to February 12, 

2002. 

The following highlights were excerpted from 

the report released in December 2002: Dairy 2002 

Part I: Reference of Dairy Health and Management 

in the United States, 2002. 

• The majority of cows were culled for udder 

health and reproductive problems, 26.9 

percent and 26.5 percent, respectively. Poor 

production from an unknown cause 

accounted for 19.3 percent of culled cows 

(Figure 1). 

________________________________________________________ 

Figure 1. Percent of Dairy Cows Culled, by 

Producer-reported Reason for Culling. 

________________________________________________________ 

• Clinical mastitis, infertility problems, and 

lameness were the conditions reported most 

commonly for all operations, with 14.7 

percent, 11.9 percent, and 11.6 percent of 

cows reported to have experienced these 

conditions, respectively. 

• Overall, 8.7 percent of dairy heifers born 

alive died before weaning. Nearly 2 percent 

of weaned heifers died between weaning 

and calving, and 4.8 percent (as a 

percentage of the January 1, 2002, cow 

inventory) of cows died during 2001. 

• Overall, 15.2 percent of operations used 

bovine Somatotropin (bST), and 22.3 

percent of cows received the hormone. 

• Preventive practices for dairy replacement 

heifers were very common. Only 5.1 percent 

of operations representing just 2.5 percent 

of heifers did not use any preventive 

practices. 

• A total of 98.1 percent of producers reported 

that heifers were born and raised on their 

operation, accounting for 89.5 percent of 

dairy heifers. Heifers were born on the 

operation but raised elsewhere on 3.6 

percent of operations, accounting for 7.2 

percent of dairy heifers. 

• During winter, deer had contact sometimes 

or most of the time with cattle pasture (78.1 

percent of operations), hay (55.1 percent of 

operations), or water sources (39.7 percent 

of operations). 

• During summer, deer had contact 

sometimes or most of the time with cattle 

pasture (93.5 percent of operations), hay 

(69.7 percent of operations) or water 

sources (58.9 percent of operations). 

• Rendering was the most common method of 

disposal for dead calves (43.8 percent of 

operations) and dead cows (62.4 percent of 

operations). Burial was the second most 

prevalent method, followed by composting. 

• The rolling herd average (RHA) was 18,235 

pounds of milk per cow (averaged across all 

operations) per year. RHA increased as 

herd size increased. 

Udder/mastitis problem

26.9%

Lameness/injury

16.3%

Disease

6.0% Aggresiveness/belligerence

0.9%

Reproductive problems

26.5%

Poor production*

19.3%

Other

4.1%

*Unrelated to the other listed problems
0

20

40

60

80

100

Small Medium Large All Operations

Herd Size

Percent

36.6

78.3

90.2

47.0

7.1

13.7

25.6

12.8

3.2

3.6

55.7

0 10 20 30 40 50 60

Percent

Chlortetracycline (CTC)

Oxytetracycline (OTC)

Oxytetracycline with Neomycin

Decoquinate

Lasalocid

Other

Any

Medication

• Operations with on-farm computer 

record-keeping systems had a higher RHA 

(20,024 pounds of) than operations with offfarm computer record-keeping systems 

(19,631 pounds) and operations with no 

computer record-keeping systems (16,371 

pounds). 

• The majority (90.2 percent) of large 

operations (500 or more cows) fed a total 

mixed ration (TMR), while 78.3 percent of 

medium operations (100 to 499 cows) and 

36.6 percent of small operations (less than 

100 cows) fed a TMR (Figure 2). 

________________________________________________________ 

Figure 2. Percent of Operations that Fed a Total Mixed 

Ration, by Herd Size. 

________________________________________________________ 

• Oral drenching with an energy source at the 

time of calving may be effective in reducing 

energy deficits and improving milk 

production (Stokes, et. al.). Overall, 20.1 

percent of operations reported drenching, 

with 28.9 percent of cows receiving an oral 

drench at the time of freshening. 

• Waste milk was fed to dairy heifer calves on 

87.2 percent of operations but was 

pasteurized prior to feeding on only 1.0 

percent of operations. 

• A total of 55.7 percent of operations used 

milk replacer that contained medication. 

Oxytetracycline with neomycin was the 

medication most common (25.6 percent of 

operations) in medicated milk replacers 

(Figure 3). 

________________________________________________________ 

Figure 3. Percent of Operations that Fed Medicated Milk 

Replacer to Dairy Heifer Calves During 2001, by 

Medication Used. 

________________________________________________________ 

For more information, contact: 

USDA:APHIS:VS:CEAH 

NRRC Building B., M.S. 2E7 

2150 Centre Avenue 

Fort Collins, CO 80526-8117 

970.494.7000 

E-mail: NAHMSweb@aphis.usda.gov 

www.aphis.usda.gov/vs/ceah/cahm

#N384.1202 

_______________________________________________________________ 

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