BEEF HERD HEALTH

By W. Mark Hilton, DVM

 Can you have zero calf scours in 2024? Some of you will think, “no way”, others will say “we never have calves with diarrhea”. I have been a veterinarian for 40 years and have many herd owners that are in the second camp. How have they done it?

The environment is the key. If you calve out on a green grass pasture with plenty of space it is likely you never have calves with neonatal diarrhea. If you calve in the winter in a tightly confined area, sick calves are probably common. In some instances, I have had producers that changed from winter calving to calving on green grass and the result was zero calves with diarrhea. Other times for various reasons, calving ahead of grass time has not been selected.

The traditional system for calving is to have a calving lot where the cows calve and when the calf is 1-2 days of age and nursing well the pairs are kicked out to another paddock. The problem with this system is that even normal appearing calves can shed pathogens that cause scours. As the calving season progresses, the calving lot becomes more and more contaminated with these pathogens. If a healthy calf ingests a few of these organisms, he might not get sick. The problem is that if the calf ingests 100 organisms, these “bugs” multiply tremendously inside his gut and now he sheds hundreds of thousands of organisms in his manure. A cow lays down in this manure and gets thousands of pathogens on her teats. Now her calf gets dosed with a pathogen load that makes him break with disease after he nurses. This generally occurs about halfway through the calving season and just about every calf born in the lot from here on is going to get sick.

To compound this problem, calves that are slow to nurse or those with any sickness stay with their dam in the calving lot for an extended time. Both groups are more likely to be affected and then multiply the disease organisms in the environment.

The solution is to have multiple “calving lots”, and this is the concept of the Sandhills Calving System. In this system, all adult, pregnant cows start in a calving lot (all bred heifers are in a separate lot), and after 2 weeks of calving, all the pairs stay in this lot and all the cows yet to calve are moved to a new lot or paddock. This does two things. First, the next calves to be born are born in a clean, uncontaminated environment. Second, the older calves that may be shedding disease causing organisms are separated from the newborn, more susceptible calves. Now, every 7 days, pairs stay in their calving paddock and pregnant cows are moved to the next, clean paddock. This continues until calving is complete.  Have I “cheated” a bit and calved in a paddock for 10-12 days? Yes, but you should never calve for more than 14 days before moving the “heavies”. I strongly suggest you read more on this system. I have used this many times and in 100% of the cases we have either eliminated or greatly reduced calf scours.

I mentioned not having bred heifers in the same environment as the adult cows at calving time. In fact, these two age groups should be separated at the start of the winter-feeding period and not be combined until grass turn out. Studies show a three times disease rate increase in both heifers and cow’s calves when these two groups are wintered together and another three times increase in disease when they calve in the same environment. One “trick” I use so producers can reduce their number of groups being fed during the winter is to put the open replacement heifers with the bred heifers from winter feeding to grass turn-out. Their nutrient requirements are similar and the larger, bred heifers will be able to consume more feed than the smaller heifer calves. 

While addressing the environmental component to calf diarrhea is far and away the most important factor, there are other elements that will help assure you do not have neonatal diarrhea in your herd.

Cows need to be in body condition score (BCS) 5.5 - 6.0 and heifers in BCS 6.5 - 7.0 at calving. Pregnant females in adequate BCS will have improved quality and quantity of colostrum for the calf. I cannot overstate the importance of a calf quickly ingesting a belly full of colostrum on disease protection. Females that are too thin also take longer to deliver their calves and these calves are slower to get on their feet and slower to nurse. 

Studies have shown that calves with hybrid vigor jump up more quickly after calving to nurse compared to straightbred calves. Hybrid vigor comes from having crossbred calves and results in a multitude of health advances. It all starts with colostrum consumption. 

There are vaccines that can be given to pregnant females ahead of calving that contain some of the most common pathogens implicated in calf scours cases. This is a discussion you need to have with your herd health veterinarian as there are differences in the spectrum of coverage and the timing of these products.

Never buy a calf to graft onto a cow that has lost hers. This is an almost surefire way to “buy” a new disease. The same would be true for buying pairs during calving season. If you do this, the new pairs should be quarantined from the established herd for at least 30 days after purchase.

Neonatal calf diarrhea outbreaks are always frustrating. I hope the risk factors listed above will help you say to yourself, “yes, I can make that change for the benefit of my herd”.