Monday morning’s American Dairy Science Association “Production, Management, and the Environment I” session at this year’s Joint Annual Meeting featured 13 presentations from researchers and collaborators with the USDA – NAHMS (National Animal Health Monitoring System), a division of the USDA Animal and Plant Health Inspection Service (APHIS).
For more background on what NAHMS is and does, read this 2013 article by Jason Lombard, DVM, the NAHMS Dairy Specialist, “An overview of the USDA’s NAHMS.”
In brief, NAHMS conducts national surveys for several species. For dairy, NAHMS conducted comprehensive studies in 1996, 2002, 2007, and 2014, with a dairy heifer project in 1991-1992 and 2011.
Monday, Dr. Lombard and his colleagues presented early results of the 2014 research, focusing on milking procedures. In the first abstract, Dr. Lombard compared practices in milking parlors through the four comprehensive dairy studies, which saw herd sizes double from the first study in 1996 (70 cow average herd size) to 2014 (160 cow average herd size). The majority of the data was collected through face-to-face interviews, though some collection of samples was done.
3X milking reaches 10% of farms
According to the NAHMS data, while bulk tank somatic cell count dropped from 300,000 to 200,000 cells/mL from 1996 to 2014, parlor use grew from 28.8% to 45.7% of farms, translating to 86% of cows milking in parlors, up from 55%. Today, about 10.2% of farms milk 3X, up from 5.8% in 1996.
In the milking center, 59.1% of farms are using gloves, 71.5% are forestripping all cows, and 49.1% of farms use automatic takeoffs. Just 7% of farms use a backflush system, up 1% since 2002.
Each mastitis treatment costs $42.05
The 2014 NAHMS study found that every dairy interviewed had at least one case of clinical mastitis, with about 24% of cows affected in 2013. Of infected cows, 73% recovered, 24% were sold, and 3% died, with the cost of treatment totaling $42.05, not including milk loss.
NAHMS sent trained assessors to 192 farms to evaluate 22,773 cows between March and July 2014 to record body condition, locomotion, and lesion scores. Contrary to industry data, on their three point scale 90% of cows were considered sound, with 7% moderately lame and 3% severely lame. Over 87% of cows had no hock lesions, with 10% showing mild lesions and 2.6% experiencing severe lesions. Just 4.2% of cows were thin.
With interviews of 1,261 farms, NAHMS found 77% had at least one down cow in 2013, with an average of 2.6% of U.S. cows classified as nonambulatory. Just 23% had guidelines to handle down cows, though 57% of farms with over 500 cows had written guidelines, compared to 24% of dairies with 100 to 499 cows, and 15.5% of dairies with fewer than 100 cows.
One-third of calves experience disease event
The calf portion of the NAHMS 2014 study collected data on birthing, treatments, and blood/IgG from 851 calves on 89 farms in 12 top dairy states. Of those 851 calves, 33.4% experienced one disease event and 6.1% had more than one disease event. Of the sick calves, medications were administered to 82% of calves and electrolytes to 36%.
Only 5.4% of calves died, though 39% of those died without displaying any clinical signs of illness, dying at an average of 22.8 days of age. Serum IgG was collected with 71% excellent, 11% fair, and 17.4% a failure of passive transfer. Lombard called this area his biggest surprise.
“Frankly, we are just beginning further analysis of the data,” Lombard told Dairy Herd Management. “But the poor quality colostrum and high failure of passive transfer was probably the biggest surprise, those are really high rates. It means many farmers are still using poor quality colostrum”
Calves with failure of passive transfer experienced morbidity at 44% while those with excellent passive transfer saw only 30% morbidity.
Finally, the calf section of the study also found that 9.6% of calves received pasteurized or heat-treated colostrum, with 66.3% of colostrum IgG levels above 50 g/L. The study also evaluated digital Brix refractometers, finding they underestimated actual IgG levels in about 45% of the samples.
Tomorrow, we will cover the portion of the NAHMS study that evaluated bulk tank samples.