A condition termed weak calf syndrome in beef

calves was first described in the 1960s. Since then,

causes have been suggested, including viral and bacterial

agents, nutritional deficiencies, toxicities, and

environmental conditions leading to stress. In retrospect,

it appears that a deficiency in the dams protein and

energy intake set the stage for the syndrome.

In April 1993, cattle producers and agricultural

diagnosticians began to speculate on another occurrence

of increased death losses in beef calves due to a weak calf

syndrome. The syndrome was defined as increased

numbers of:

• calves stillborn, or;

• calves born normally, but unable to stand and

nurse resulting in death within minutes to

hours of birth despite good mothering by the

dam, or;

• calves born normally, vigorous and nursing,

but exhibiting signs of neonatal diarrhea, respiratory disease, or navel ill resulting in death

in the first 3 days of life.

Diagnosticians have since associated a

number of infectious agents with these calves,

but a common thread with regard to infectious

agents is lacking. Many continue to suggest a

link with nutrition and weather. The scope of

the problem has been difficult to define.

Anecdotal evidence would indicate that the

distribution of the problem is spotty with some

states affected more severely than others. The

overall effect on the total calf crop has been

unknown.

As part of the National Animal Health Monitoring

Systems (NAHMS) Beef Cow/Calf Health and

Productivity Audit (CHAPA), producers were asked

about deaths among calves born in the first 6 months of

1993 and their perceptions of weak calf syndrome

occurrence on their operations. The NAHMS study was

conducted on 799 beef cow/calf operations in 18 of the

top beef states.1 Seventy percent of U.S. beef cow/calf

operations are in these 18 states.

There appears to have been regional and herd size

differences in the proportion of calves stillborn (Figures 1

and 2). A higher proportion of calves were stillborn on

No Evidence of a

New Weak Calf Syndrome

National Animal Health Monitoring System

United States

Department of

Agriculture

Animal and

Plant Health

Inspection

Service

Veterinary

Services

Figure 2

Figure 1

1 Alabama, Arkansas, California, Colorado, Florida, Georgia, Iowa, Kansas, Kentucky, Mississippi, Missouri, Nebraska, New Mexico,

Oklahoma, Tennessee, Texas, Virginia, and Wyoming.

Target population: beef cow/calf producers with 5 or more beef cows and with May 1994
Figure 3

Figure 4

Figure 5

smaller operations, while the lowest was reported by

producers with 300 or more cows. Over 7 percent of

calves born in the central region were stillborn, and the

lowest rate occurred in the western region.

Overall, cow/calf producers reported losing 2.5 percent

of the calves born alive in the first 3 days of life. These

calf death losses did not appear to be related to herd size,

except that herds with 300 or more cows seemed to have

lost smaller proportions of calves (Figure 1.) Nor were

death losses restricted to a single region of the country

(Figure 2).

Among producers who qualified to be in the study, 25.5

percent of operations reported that calf death losses in the

first 3 days of life were above a level expected in a normal

year, while 61.4 percent reported expected levels (Figure

3). When provided with the definitions described earlier

and asked if their operation had experienced cases they

would attribute to weak calf syndrome, 6.4 percent of

producers indicated that they had.

There was a strong relationship between producers

reports of weak calf syndrome and geographic region.

The largest proportion of producers who reported the

condition in their calves were from the west (20.8 percent,

Figure 4.) The southeast region was apparently spared

with only 1.3 percent of producers reporting cases.

Operations with 50 or more cows were more likely to

report weak calf syndrome than smaller operations (Figure

5). A possible influence may have been that smaller

operators were more aware of what was going on in their

herds and were less likely to attribute health events to this

generic condition.

In conclusion, it appears that the spring 1993 outbreak

of weak calf syndrome is consistent with the situation

described in the 1960s. Poor forage production in 1992

led to limited feed supplies on beef operations. Bad

weather induced early onset of the feeding period. Faced

with small forage stores and a prolonged feeding period,

producers reduced the amounts of feed to cows. The result

was cows in poor body condition as they entered the

calving season. Calves from these cows were likely

stressed due to weather conditions and suffered some

degree of failure of passive transfer of antibodies from the

dam. Failure of antibody transfer created the opportunity

for infection with common disease organisms. These

infections were responsible for diarrhea or signs of

respiratory disease in calves. More attention to colostral

management would probably have had little effect in the

outcome in such cases.

Other NAHMS collaborators included the National

Agricultural Statistics Service (USDA) and State and

Federal Veterinary Medical Officers.

For more information , contact:

Centers for Epidemiology & Animal Health

USDA:APHIS:VS, Attn. NAHMS

2150 Centre Ave., Bldg. B, MS 2E7 

Fort Collins, Colorado 80526-8117

Telephone: (970) 494-7000

NAHMSweb@aphis.usda.gov

N140.0394