Mercifully, the spring calving suckler herds seem to have dodged too many of the Schmallenberg cases we feared may have been looming after the high incidence among the early lambers. Instead, we have a few farms that have been reporting an entirely different type of birth deformity, interestingly both are very close to each other geographically. For both farms, this is a new issue, and we would be really interested to hear from anybody else who has experienced similar calves in the last few years.

The condition has many names, Dwarfism being the easiest to pronounce, but also goes by Long Bone Chondrodystrophy or Long Bone Deformity. Affected calves are usually born with shortened limbs, often with thickened joints, but a normal torso and head size. Their fetlock joint (the last joint before the foot starts) can be very loose and bendy, making it difficult or impossible for the calves to stand and suck. Calves may have an underbite with the upper jaw being shorter than the lower jaw. Calves can show varying degrees of these abnormalities, with the less severe ones potentially surviving long enough to grow out of it to a small degree, though most will need euthanizing.

This is normally a sporadic issue where farmers may get one or two in a year and then possibly never again, with the cause never really being established. This year however, there are apparently an increase in the case numbers reported to Starcross and on one of our farms, they have had some degree of dwarfism in well over half of their calves born so far.

Although there can be a genetic element in some cases, more often than not, the condition is caused by a complicated and not fully understood form of manganese deficiency. This is particularly important when it occurs from around month four to six of pregnancy, where the lack of available manganese prevents normal growth of the “long bones” of the leg as they turn from cartilage into bone, leaving them abnormally shortened. It is unclear whether this is due to a primary manganese deficiency in the soil/forage, or whether some other element, such as high iron, may interfere with its uptake mechanism in the gut.

The following feeding practices seem to increase the risk of this occurring:

• Feeding very high-quality silage to suckler cows, such as well-made clamp silage or maize silage. Also, silage with a high red clover content may increase the risk.

• Feeding more than 75% of their daily dry matter intake (DMI) as silage (especially the above types), especially if only silage is fed. Ensuring straw makes up at least 25% of their daily DMI will reduce the risk.
• Feeding silage with a higher than normal soil content, especially in areas with high iron content in the soil. Iron and manganese are thought to share the same uptake channel in the gut, so when dietary iron intake is high, these channels can close to protect the cow from iron poisoning. Unfortunately, this also shuts out the manganese, which might lead to secondary deficiency.

If these symptoms are ringing any bells with anyone, please do get in contact with Charlie or Pip at the practice! No Snow White jokes, please.