VET ON CALL: Yes, love your cows, but don’t be fond of them

I met an interesting case last week that involved a first-time calving heifer with high promise of milk yield. The mother used to give 36 litres of milk per day and the father, otherwise called sire, was recorded to have had daughters that gave 40 litres daily.

The owner, therefore, had a scientifically sound expectation of the heifer to produce 30 to 40 litres of milk per day in the second or third lactation. I received the phone report from Kimani, the farm manager, saying the heifer had calved the previous day but was only producing milk from the left hind quarter.

The rest of the udder was heavily swollen but with normal temperature, according to his feel of the palm. The animal’s rectal temperature was within the normal range. “What kind of mastitis would this be doctor?” Kimani wondered?

The description necessitated me to examine the cow physically. The animal was happy and eating well when I arrived on the farm. It had already been restrained at the milking parlour. I noticed the right eye was infected but that had nothing to do with the milk issues. I made a note to give an eye ointment.

The temperature and other vital parameters were normal. Upon examining the udder, it was heavily swollen with the back part being reddened and containing some fluid. It would form the impressions of my fingers on pressure but was not painful.

Pregnancy oedema

I concluded that was due to pregnancy oedema, a condition characterised either by swelling on the udder or lower side of the abdomen next to the udder and umbilicus. The swelling is caused by heavy supply of blood to the udder, which increases pressure and causes fluid to leave the blood vessels and be retained in the tissues.

Physiological oedema is normal and resolves a few days after calving. If it is excessive, reabsorption of the fluid in the tissues can be accelerated by massaging the udder with warm water twice a day to enhance blood flow. This causes the fluid to move back into the blood vessels and reduce the swelling.

“Kanini’s swelling is due to the pregnancy and retention of milk but we shall know the issue with milk release once I examine the teats,” I told Kimani as I started washing them. I first milked the left hind teat and the milk flowed freely.

All the other three teats became heavily engorged with milk and they stuck out of the udder turgidly as though they were daring me to milk them.

When I squeezed each of them, two produced tiny milk drops. The milk inside the teats felt fully fluid and the cow definitely enjoyed my attempts at stripping out the milk. She was very quiet and cooperative.

The last teat produced no milk but the contents inside felt normal. I informed Kimani there was a problem with the structures of the teat canals of the three teats.

Teat cistern

Using a sterile canula, I probed the teat canal through the teat opening right into the cistern. A teat canula is a metal or plastic tube instrument with a hole on both ends. It is used to drain milk from the udder in case of milking difficulties.

The teat cistern is the empty space running the inside length of the teat. Its function is to hold milk once it is released from the udder before it is stripped out or suckled by the calf.

The teat canal is a short channel running from the opening of the teat to the valve mechanism that closes the teat canal from the outside environment. The valve is also called the teat sphincter.

From two of the teats, the milk flowed freely once the canula entered the teat cistern. I could feel the cow’s relief as the pressure in the udder eased. Finally, I tried the canula on the fourth teat but it could not go beyond the teat opening.

Teat canal

When I palpated the last 5 millimetres of the teat, I felt solid tissue filling the teat canal. This teat had an imperforate teat canal and could not produce milk. The formation of the canal had malfunctioned during development of the foetus and the milking channel was filled with tissue.

When I removed the teat canula from the other two teats, they could not allow milk to pass. This meant there was a structural abnormality that made the teat sphincter to occlude the teat canal.

Such occurrences are called developmental abnormalities that occur as the foetus grows in the uterus. In this case, I diagnosed an inward orientation of the teat sphincter that prevented the valve from opening when milking pressure was applied on the teats. This is called inversion of the teat sphincter.

There was a possibility of milking the two teats using teat canulas. However, such milking is likely to result in persistent mastitis. I advised Kimani to dry the three deformed teats and fatten the cow for culling once milking stopped.

Love the animals but do not get emotionally attached

I could not help but empathise with him as I saw the disappointment written all-over his face. This was one of the farm’s best heifers that were coming into production for the first time. He really had high hopes on her. Unfortunately, the trickery of biological systems had dashed the farm’s hopes.

In farming we say, “Love the animals but do not get emotionally attached to any because culling is a constant but unpleasant activity.”
Inversion of the teat sphincter is a genetic abnormality that can occur in any species. Animals showing the trait should be culled to avoid propagating the defect. Fortunately for farmers, the defect has a rare occurrence in cattle. In the course of my more than 30 years of veterinary practice, I was only seeing my second case.