With Proper Ventilation and Sanitation, Mob Feeders Can Do The Job

10:55AM Sep 11, 2019
cb_mob_feeding_closeup.jpg

Pam Selz-Pralle is “persnickety about sanitation,” insisting mob feeders and nipples be cleaned after each feeding.( Photo courtesy of Selz-Pralle Holsteins )

Pam Selz-Pralle was frustrated. Her calves were individually housed in a well-ventilated calf barn, but their growth wasn’t what she knew these deeply pedigreed registered Holsteins were capable of doing on twice a day feeding.

And when she and her calf crew switched to 3X feeding, daily gain increased but starter intake plummeted. Urine output, driven by the higher-solids volume of milk replacer being fed, also meant bedding was wet and a constant source of ammonia. Pneumonia sky-rocketed.

“We increased the number of fans and were moving lots of air in our naturally ventilated barn,” says Selz-Pralle, “but we just couldn’t get enough air movement at bedding level in the individual pens.

“To overcome our barn limitations, we upped our management intensity,” she says. “If there was any indication of heavy breathing or a 102.5 - 103°F temperature, we treated to prevent clinical pneumonia. Several high temperature calves were dairy occurrence.”

At one point, Selz-Pralle was treating nearly three quarters of her pre-weaned calves, and death losses climbed to 3 and 4%. And when she inventoried antibiotic usage through a University of Wisconsin study, she discovered that 41% of her entire antibiotic farm use came in the calf barn. Calf treatments alone were costing $500 per month on the 500-cow dairy she owns and manages with her husband, Scott Pralle, near Humbird, Wis. 

You’ll recognize the Selz-Pralle prefix and farm. It’s home to Selz-Pralle Aftershock 3918, the world record milk holder at 78,170 lb of milk in a 365-lactation in 2017. The 450-cow herd averages more than 31,000 lb/cow/year.

A haybarn fire a few years ago gave them some additional capital to build a new calf barn. Their dream barn was a building with group pens and an auto-feeder. But when they bid such a facility out, the price tag came in at more than $400,000, or about $6,000 per calf. “No way could our herd of 500 cows support that type of facility,” says Pam.

Plan B was a positive-pressure ventilation barn equipped with mob feeders. The entire barn, at $203,000 all inclusive, came in at less than half the cost of an auto-feeder barn.

Each of the 20 pens, 13 ½’ by 13 ½’, is sized for 4 calves. Those pen dimensions equate to about 45 square feed per calf. The base of the pens is 8 to 10” of draining rock base, covered by a landscape barrier and then overlain with 8 to 10” of limestone gravel. Straw is used for bedding. “We prefer straw because sawdust will hold ammonia,” says Pam.

Air is blown into the building through positive-pressure ventilation fans. And then circulating fans above the pens push this fresh air down to the level of the bedding where the calves breathe it in.  The system is designed to provide an exchange of air every 6 to 8 minutes at nose level, says Pam. Fencing between pens is gated pipe to facilitate air movement and ease of cleaning.

Feeding is done with a six-nipple mob feeder twice a day. New-born calves are first backgrounded individually for 10 days before they join their group of four. Since the Selz-Pralles still sell 70 bulls for breeding each year, heifers and bulls are housed together in the calf barn.

At 10 days of age, they will be offered 2.7 liters of milk replacer twice a day. At three weeks, that is upped to 3.2 liters 2X, then to 4.0 liters 2X/ at four weeks, and to 4.2 liters at seven weeks. To start weaning at 7 weeks, they are cut back to 4.2 liters 1X.

“After leaving their individual pens in the old barn, the calves took off immediately doubling their starter intake,” says Pam. “They learn from each other, and they will be eating 8 lb of starter per day at weaning.”

The results have been amazing. On 3X feeding in the old barn, average daily gain was 1.7 lb. and the cost of that gain was $2.14/lb. In the new barn, with 2X mob feeding, average daily gain has jumped to 2 lb and cost had dropped $1.16/lb. And from weaning to three months, average daily gain is 2.5 lb.

Pneumonia has also virtually disappeared. Pam and her crew are treating less than 1% of calves. And they’ve only had two calves die in a year, but those were likely due to clostridium and not pneumonia. “After moving to the new barn, calf antibiotic treatments have dropped to less than 1% of our farm usage,” says Pam.

She believes both ventilation and sanitation are key. “I like to get down to nose level where the calves lie to make sure air is fresh,” she says. “And we’re a little persnickety about sanitation.

“We wash the mob feeders after both the morning and night feedings. And we ‘floss’ each nipple after each feeding, using a narrow brush to scrub the inside of the nipple.”

When calves leave the barn at 3 ½ months, the pens are cleaned down to the limestone gravel. Gates and back wall are also scrubbed, and the pen is left empty for a week to air dry before new calves are brought in.

After a year of use, Pam is pleased with the barn’s performance. Another year will tell whether the calves first reared in the barn will push their two-year old daily milk production averge beyond the 100-pound per day mark. Pam says she can hardly wait to see if they do. 

To take a tour of the Selz-Pralle dairy, go here: https://www.facebook.com/selzpralledairy/videos/318099012326273/