This month we look at feeding and some of the choices farmers make in rearing healthy calves to go on to be productive herd members. Based on their calf rearing research, AgResearch scientists Dr Sue McCoard, Dr Ajmal Khan and Dr David Pacheco provided some guidelines on calf feeding and management.
The best milk
Just as “breast is best” for human babies, cows produce the best-quality first food for calves. While the comparative cost of calf milk replacers (CMR) to the milksolids payout, and availability of whole milk may sway some farmers to feeding CMR, the lifetime health and production benefits of feeding whole milk, and lots of it, to dairy replacements, should not be underestimated.
“To develop a CMR that is as good as whole milk, it would take more research to understand some of the properties of milk that are not understood at this stage,” Pacheco said.
This is because it is becoming clearer that the performance of the rearing system goes beyond just bodyweight gain of the calf. It is about her survival, health and performance in the milking herd.
“Don’t just think about cost,” McCoard said.
“Look at early feeding as an investment in the animal, to set her up for lifetime performance. So you might spend more on whole milk or more milk replacer”.
“The advantage CMR may have over whole milk is that it can be manipulated,” Khan said.
“In whole milk there is a very specific amount of nutrients. With CMRs, nutrient ratios can be manipulated and other ingredients like additives and nutrients from plant origin can be added”.
CMRs are either casein-based or whey-based.
“Research should focus on how CMRs can best mimic or have an advantage over whole milk,” Pacheco said.
“The basics of protein, lactose, and fat are well understood in whole milk, but there are so many other things in very small quantities in whole milk that scientists have not paid much attention to. This is becoming more evident now. Farmers wonder why they do not get the same results with some CMRs as whole milk. This is where we are now, trying to work out what are the less obvious components in cows’ milk that make calves grow well.”
There are variations in commercial CMRs. Curd formation is important for the calf to digest milk and CMR. CMR should be best quality available and based on milk. Fortifying whole milk with CMR should only be done after five weeks on cows’ milk. It is important the addition rate is the same every feed.
Milk volume is best reduced after feeding calves 15-20% of their body weight for their first eight weeks. After this, switching to hard feed could be cheaper and more convenient than CMR.
Milk additives and complementary products
There have been 50-60 trials of significance on probiotics, with varying results.
“There is not conclusive evidence that there will always be growth or health benefits as the strains of probiotics vary, the calf feeding regime for the first week or so will interact with the probiotic strains, and the addition rate made by the farmer may vary,” Khan said.
Colostrum, milk feeding rate and calf handling will also affect the efficacy of probiotics, and probiotics may have a more significant effect where feeding or management practices are lacking. So trial data supporting the addition of probiotics should be scientifically based and involve large numbers of calves.
When pressed on additives McCoard said “Do the basics well. Collect calves twice a day. Feed them first colostrum within 12 hours of life. Spray the navel with iodine. Put them into a clean, warm, dry environment – no overcrowding, no draughts. Basic husbandry skills are really critical. Don’t put newborn calves in with older calves that will trample over them. Look after them. Put them into a nursery environment. That’s the best investment you can make. If you don’t get that right, you’re setting them up for all sorts of complications. This is the critical first investment. Think about the feeding regime or additives after that. Feed them high levels of milk for at least eight weeks”.
Hard feeds
Solid feeds like pellets and texturised calf starter should be introduced to calves at about one week old, and fed ad lib. Forage sources like good quality chopped grass hay should be fed independently to pellets or meal.
Most commercially available feeds in NZ are good quality, but farmers should look for good quality ingredients like soya bean meal which is palatable and has a good balance of amino acids, compared to other ingredients like palm kernel. Energy level should be at least 10.5 MJ/kg, and the feed should contain coccidiostat.
Meal and pellets should be clean, and kept where it cannot be contaminated. Changing feed every second day keeps it fresh and clean. Look for mould growth and discard any contaminated feed. Calves should be eating a minimum of 1.5kg of meal/calf/day when milk is stopped.
Ajmal Khan has the final word.
“When you are thinking of investing on your farm, think of the first few days of your calves’ lives, as this is an investment in the lifetime performance of your herd. Bring in additional labour if needed, invest in time in colostrum, and don’t skimp on the milk.”
Bas Schouten, veterinarian and well-known calf-rearing guru, promotes feeding silage to calves from about one week old, in conjunction with pellets or meal, as a cost-effective means for growth and rumen development.
“Grass silage works extremely well, is palatable, and costs around 30c/kg DM, compared with about $1/kg DM for traditional calf meals and pellets, so is a good way to reduce rearing costs,” Schouten says.
“It must be grass, not maize silage, and good quality. Silage is about 40% drymatter compared to about 90% for calf feeds, and you can only stuff so much into a calf’s rumen. So the water content and the rumen size of a young calf are the two limiting factors in silage feeding. Silage fed in conjunction with a good quality hard feed, means the rumen develops pretty fast.”
He warns about feeding palm kernel to young calves.
“It’s not very palatable, has high energy but low carbohydrate content, no coccidiostat, no balanced minerals and vitamins, and causes respiratory problems.”
Feed volume
Low- and high-volume whole milk feeding regimes for dairy replacements have been compared at Massey University’s Dairy 1, led by senior lecturer in dairy production Dr Penny Back.
The low-volume group was fed a total of four litres a day in two feeds. The high-volume group was started on the same regime, then it was increased to six and then eight litres a day in two feeds. Growth rate and hard feed consumption were monitored. These calves will be followed through to their first year’s production in the herd. The research group will also carry out genetic analysis of the calves’ growth rates.
Growth rates between the two groups were closer than expected, with the mean weaning weights for the high and low groups being 97.1kg and 95.6kg respectively. The low-volume group ate an average of 25kg of meal, while the high-volume group ate an average of 13kg through to weaning.
Calf shed space is limited at Dairy 1, so calves are put outside when two to three weeks old. This is often the case too on commercial dairy farms, while calf-rearing enterprises tend to have more shed space, the calves are inside longer, eat more hard feed, and grow quicker. When calves are put outside at two to three weeks old, it can be very difficult to meet an eight-week target weaning weight of 80-100kg (breed-dependent), because they will preferentially eat pasture rather than meal.
“The key to calf rearing where shed space is limited is having sheltered paddocks with a constant supply of fresh, good-quality pasture”, Back said.
“And they are better off outside in these conditions than squashed into pens that get damp and dirty because they are considered too young to put outside. I think people expect calves to graze down lower than they should, which restricts their intake. Their eating behaviour is quite different to that of cows. People try to push them to graze as low as cows do but that restricts their intake and their growth suffers. You see a lot of calves being fed in the same muddy paddocks for too long. They grow well in sheltered paddocks on fresh pasture.”
Grazing behaviour studies have shown calves are very selective, so they were shifted at 2000kg/ha DM. When the pasture dried out, post-weaning, they were shifted at 1800kg/ha DM.
The Massey group have found strip-grazing bigger paddocks works well. They use a sheep electric fence system with three or five hot wires. While this means more work, once the system is set up it isn’t too time-consuming.
Once they reached four to five weeks old, the calves were shifted every couple of days on to fresh pasture. Under this regime, their meal intake was minimal.
After weaning, the calves were either kept on pasture or put on to a herb mix (chicory-plantain-red and white clover). They prefer clover, then chicory, and then eat the plantain if they have to.
Cows will hoover up the lot in a single pass, while calves keep going back to the areas they like and keep grazing them down.
