The future vitality of the dairy industry depends on getting calf rearing right, world-renowned calf-rearing expert Dr Bob James told the Dairy Research Foundation's 2018 Symposium.
Dr James, professor emeritus of Dairy Science at Virginia Tech University, challenged farmers to stop thinking about how much calf rearing costs overall but to think about it in terms of cost per unit of weight gain.
He also challenged farmers to think about the overall lifetime production and performance of the cow in the herd when assessing calf-rearing success.
He outlined some of the latest research to provide a thought-provoking address. Dr James spoke about: Getting the environment right. The importance of colostrum. Feeding regimes and its impact on weaning weights and lifetime performance. Group housing. The use of automatic feeders. Facility and people management.
Right environment Dr James said doing the right job with calf rearing started with the environment in which the calf was born.
When a calf was born in a poor, dirty environment, it became a race between the bacteria from that environment and the antibodies in the colostrum to see which would be absorbed by the calf first.
Dr James said farms needed an optimum calving area. "When I go to a farm, the first thing I want to see ... is where your cows freshen," he said. "I want to see something that is the cleanest place on your farm.
"I want all of you to think about that calf the same way you think about your child — because biologically they are no different. And would you let your child be born and exposed to an environment like that?"
Importance of colostrum Dr James said colostrum contained a raft of components that were important to the calf and should be fed for longer than previously recommended. All the focus had been on one component in colostrum — Immunoglobulin G or IgGs or antibodies. These were important and the transfer of those particular antibodies needed to happen quickly.
But the other components in colostrum, including second and subsequent milking colostrum, particularly when it was compared to whole milk (see Table 1) played an important role, which research was starting to unlock.
These other components included cytokines, which are small molecular proteins involved in cell signalling, immune system and growth, and hormones, which are involved in metabolism, growth and cell function.
"We are just discovering the role of these two in the development of the intestine of that young calf," Dr James said.
European research showed calves fed colostrum for the first four days of life had significantly higher long-term glucous absorption and better developed small intestine villi than calves fed calf milk replacer for the same period.
Dr James said he liked to see transition milk fed to the youngest calves for as long as possible. Farmers needed to work out a way to do that that fitted into their calf-rearing management system.
If the farm or herd had a risk of infectious disease, colostrum should be pasteurised. But he did point out that would reduce the transfer of immunity from the cow to the calf. Research at West Virginia Tech had shown calves fed fresh colostrum had a higher immune response to vaccinations than those fed defrosted colostrum that had been flash pasteurised before being frozen.
"If you just can't (feed unpasteurised colostrum because of disease risk), that's a compromise you have to make," he said.
But regardless of disease risk, it was vital to ensure milking equipment and storage vessels used for colostrum were clean.
"Again, think about the milk that you ship, if it had a high bacteria count, it would be taken off the market," he said.
"The same thing applies to this colostrum. If fresh cows are milked into dirty pails, it is going to grow bacteria every 20 minutes, the bacteria count is going to double at temperature. Pretty soon, you have bacterial soup.
"I want to cool that colostrum or feed it as soon as possible to minimise that bacterial growth, and that doesn't mean taking the bottle and putting it in an old refrigerator you have at the barn, because it may take eight hours to cool."
Putting a bottle of frozen water into the bucket of colostrum would cool it within 20 minutes.
Dr James said good dry cow nutrition was also important for producing quality colostrum. It was also vital to milk fresh cows as soon as possible after calving. If farmers chose to milk fresh cows only at certain times of the day, that might fit into their management system but they needed to realise they were making a sacrifice on the colostrum quality.
Feeding regimes need to change Dr James called for farmers to completely rethink their approach to feeding calves.
He challenged them to think about what they fed, how much they fed, how often they fed it and how they assessed the success of their calf-feeding systems.
Dr James said he wanted farmers to feed calves to their biological potential for growth. "That means feeding a higher quantity of high-quality solids," he said. The research was conclusive that what happened pre-weaning had a huge impact on the health and later performance of cows.
It was vital to feed calves high-quality milk or calf-milk replacer. Some waste milk was not suitable for feeding. "Is this something you would feed to your children — some of it is not too bad, some of it is pretty nasty," he said.
He also counselled against assessing calf-milk replacer solely on cost. Cheaper products might contain vegetable proteins or lower levels of protein and energy, which meant calves would not gain weight as readily when fed them.
It was also important to use a quality calf starter. "If you have a really good textured starter that's great, if you have a good quality pellet that doesn't fall apart, that's great," he said.
He also advised including some chopped straw in calf starter — something he said he would never have recommended five years ago. But recent research had shown a small amount helped promote cud chewing.
Farmers also needed to rethink the quantities of milk fed to calves. "Why did we feed four litres a day," he said. "Well in the US, we had gallon (4L) jugs."
But Dr James said looking at research with beef animals, it was clear calves needed more than that. "An Angus calf will drink six litres by the end of week one, and Angus are smaller than Holsteins," he said. "They (Angus calves) will drink 10 litres by the end of week six."
Whole milk contained high levels of nutrients, particularly fat and protein. "So why does the cows' milk have so much fat and protein — is mother nature countering for changes in the environment with a margin of safety?," Dr James said.
He also dismissed the idea of restricting milk intake to force young calves to eat more concentrates or calf starter to aid early rumen development. "Our industries and universities have supported the idea of limited feeding and early weaning and some still do — I used to teach this," he said.
But research showed there was no lifetime benefit to early rumen development. Calves fed a restricted milk diet consumed more grain before eight weeks of age but by 12 weeks of age, they were consuming less grain and were smaller than calves fed a higher milk diet.
Calves fed higher quantities of milk were also healthier. Dr James said body condition was important to calves. "I like to look at a four-week-old calf and see them start to deposit body fat over their hips," he said.
When a calf became sick, it stopped eating but its energy requirements increased. If the calf had no reserves of fat, it started breaking down protein to survive, compromising critical organs.
He also challenged the idea that feeding more milk or calf-milk replacer caused calves to scour.
"Calves don't have well-formed stools," he said. "If you feed calves more milk, there's going to be more coming out the other end — then people say that calf's got diarrhoea. No, it doesn't. It is probably fairly normal."
Farmers also needed to think about how often calves were fed. A calf fed only at 8am and 4pm was going to be really hungry at 3am, Dr James said.
Dr James said farmers needed to follow the same logic for feeding calves that they followed with cows. They needed to plan the calf diet taking into account the nutrient requirements for maintenance, body weight gain and environment.
Calves needed to be fed more when it was colder — their feed requirements for maintenance increased as temperatures fell (see Table 2).
Feed cost needed to be assessed per unit of production. "So what is unit of production for calves — it is their weight gain," Dr James said.
Farmers needed to measure the weight gain to assess the effectiveness of their system.
Dr James said there would be little gain in week one, but in weeks 2-4, there should be gains. "I don't want to see four weeks where they hardly gain at all and if they are still alive, then they start growing. That's not what I want," he said.
The aim was to achieve a low cost per kilogram of gain and optimum lifetime profit with higher production from those calves when they entered the herd.
Dr James said he did not like the term accelerated feeding. "I want to banish that from your memories — I like to call it biological normal feeding," he said. "This is the way it supposed to be — it is not accelerated, it is not intensive, it is normal."
Automatic feeders Dr James said smart calf-rearing systems with automatic feeders provided the opportunity to mimic nature. They also provided a raft of data to help management and assess performance.
He said he originally had some doubts about automatic feeding systems. "I remember the first day I walked out to the pad when we had our automatic calf feeders, and all the calves were laying there and I looked at them and I said 'oh gosh what have we done'," he said.
"Then I realised they were just sleeping. Some of them woke up and meandered over and started eating. Very different behaviour.
"It is not normal behaviour for calves to get excited when you come out to them in the morning — they are doing that because they are looking for food."
Automatic feeders allowed calves to be fed regular amounts of milk more frequently. They allowed the farmer to work out a feeding plan — the amount per meal, the amount per day and the percentage solids for each calf. They also allowed for gradual weaning.
Dr James said automatic feeder provided reports on how much each calf was eating and the number of visits it made to the feeder. Some also measured drinking speed. These were indicators for calves there were getting sick.
Many had automatic or semi-automatic cleaning and calibration.
Research was showing major benefits of more natural calf-feeding behaviour that appeared when those animals entered the milking herd. Slug feeding type behaviours might be learned — so teaching a calf to eat twice a day could lead to more slug feeding later in life.
Other options for smart calf-rearing systems that were being developed or available now included: Activity boxes on automatic feeders that showed how aggressively a calf was feeding. Neck bands that measured activity. Water stations that measured water intake and incorporated weighing stations. Flashing lights on calves that are triggered by certain alarms so the farmer can easily locate any calf that requires treatment.
Group housing Dr James said group housing of calves in smart calf-rearing systems also created benefits. Although some veterinarians were concerned about the disease risks with these systems, Dr James said housing calves individually still involved risks. "There are risks in everything we do — we have to manage them," he said.
Calves housed in groups showed less indication of stress, showed improved immune function, were more docile and were an earlier age at first breeding. It also promoted solid intake — as the calves taught each other where the calf starter was located.
They also showed improved lactation performance. "It is a delayed response, but I can tell you in the field trials I have done with dairy producers they can tell you when those first group-fed animals came into the milking system because they notice the productivity difference," he said,
Dr James said the key to achieving optimum calf management was getting the facility and people management right.
Facility planning meant looking at the flow of animals, milk and people and ensuring that these were connected. It meant planning to milk fresh cows as soon as possible and having a commitment to sanitation.
The right people were critical. "I want people committed to that process," he said. "This is where it all begins — if you don't get this right you are always playing catch up. "You need the right people and protocols. You have some people who should never be close to a calf — they wouldn't know a calf was sick if it died right in front of them.
"Having people who can detect some changes in behaviour are priceless." D