Replacement and first-calf heifers need extra management, but producers can take different paths to get to the same destination.
Beef producers like Alberta’s Darren Bevans, Tyler Fulton in Manitoba, and Murray Shaw in Ontario know replacement and first-calf heifers need some extra attention heading into winter, but that doesn’t mean over-the-top management.
Bevans and Fulton manage heifers separately in order to give them extra feed, while Shaw moves the whole herd on to a Total Mixed Ration (TMR) in early December. The hay and corn silage ration may be a bit more than the mature cows need, but adequate to meet heifer requirements.
Heifers aren’t as competitive as cows especially in limit feeding situations on swaths, corn grazing, or bale grazing. Even in drylots, competition can be an issue around feed bunks and round-bale feeders. And when the weather gets particularly cold, it is important to meet the energy requirements of these young females to ensure their body condition doesn’t slip. For every 1 C drop in temperature below 0 C, the beef cow’s TDN (Total Digestible Nutrients) energy maintenance requirements increase by about two per cent. Nutritional requirements, just due to the demands of cold temperatures, increase by 25 to 30 per cent over winter.
For optimum reproductive performance, research has found beef heifers should be at 60 to 65 per cent of their mature weight at about 14 months of age; at 65 to 70 per cent of mature weight at time of first breeding (15 months of age); and 85 to 90 per cent of mature weight at time of calving (24 months of age). Heifers continue to grow even through to their second calving.
The December to March period is probably one of the toughest and most expensive times to try to get skinny or poor-condition animals back into condition. Poor condition leads to more calving difficulties, weaker and low-vigour calves, and extra costs in getting those mothers back into condition for the next breeding season. Some research showed cattle with the mid-range (recommended) body condition score versus a low body condition score, had 10 per cent more live calves; their calf weaning weights the next fall were 26 per cent higher; and the pregnancy rate came in at 92 per cent (versus 79 per cent for lower-condition females).
Heifers aren’t just young cows, said Bart Lardner, senior research scientist at the Western Beef Development Centre in Saskatchewan.
“Bred and first-calf heifers are still growing themselves,” said Lardner. “So they shouldn’t be managed the same as mature cows.”
Heifer management is actually a three-year project, he said.
“Sometimes producers will manage those replacement heifers really well from weaning until the time they are bred, and as soon as they have that first calf they get moved into and managed with the cow herd,” says Lardner. “But that heifer herself is still growing so has higher feed requirements. She needs to be managed properly right through until that second calving.”
Ideally producers should apply Body Condition Scoring (BCS) to the entire beef herd, he added.
Canada has a five-point BCS scale — one being thin and five being fat. (Some producers use the U.S. system that has a scale from one to nine.)
Older research suggested cows and heifers should be fed to maintain at 2.5 to 3.0 score on the Canadian BCS (five on U.S. scale) heading into and during winter. More recent research, which studied more than 100 herds across Western Canada, found open rates were lowest in females with a BCS of 3.0 to 3.5 on the Canadian scale.
The challenge with feeding bred and first-calf heifers is that they require more energy, protein and other nutrients comparatively to mature cows, yet have about 20 per cent less dry matter capacity. Often they can’t physically eat enough poor-quality feed to meet their needs.
“If a mature animal is being maintained on a ration containing eight to 10 per cent protein, for example, the bred heifers and first-calf heifers are going to need about 20 per cent more,” said Susan Markus, beef research scientist with Alberta Agriculture and Forestry. “And energy requirements will be similar. If the cow ration has 55 per cent TDN, the heifer ration needs to be in 60 to 65 per cent TDN range.”
Poorer-quality, high-fibre forage may fill cattle up but still not meet their nutrient requirements, said Markus, who also recommends cattle be provided a well-balanced mineral mix. Cereal-based feeds, for example can be high in potassium, which can adversely affect calcium levels.
More feed is needed to improve body condition of a beef animal in winter, so it makes economic sense to have replacement and first-calf heifers in good shape heading into winter. For example, a 1,200-pound mature animal requires about 160 pounds of weight gain to improve body condition score by one point (on the Canadian scale).
Depending on summer and fall pasture quantity and quality, it may make sense to wean first-calf heifers and nursing heifers also pregnant with their second calf about a month early,” he said. “But there is no reason these systems can’t work, maintain cattle in good body condition, and in fact we have seen situations where they actually gain weight while winter grazing.”
The first step is to have a feed test analysis before cattle start grazing. Many forages saved for winter feed might look good but could be low on protein or energy, said Lardner. Also, remember cows and heifers need to be on a higher plane of nutrition during the last trimester of pregnancy.
“If you have different qualities of stockpiled feed, put them on the lower-quality feed, such as straw or chaff, earlier in the winter grazing period and then switch them over to higher-quality feed as they approach calving.”
If animals are underconditioned, feeding lower-quality feed earlier in the winter is not a good option. Adjustments to the feeding program should be made no later than 60 days before calving.
When swath grazing, animals given free range will eat the seed heads first and be left with nothing but stems and stalks later in the winter when it’s colder and nutrient requirements are higher, so cross-fencing and restricting access are critical (and also reduces wastage).
Lardner also recommends first- and second-calf heifers be fed separately from mature cows.