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Managing calves to avoid a summer slump

There are three phases in a calf’s life that are all equally important to reach targets —  the ‘nursery phase’ for the first 60 days, the ‘transition phase” from 60 to 90 days and the ‘grower phase’ from 3 to 8 months onwards. It is important to focus on strategies to keep calves growing quickly, efficiently and consistently in all three phases in order to hit targets without checks or catch up needed later.

The transition phase should maintain gains made during the nursery phase and is dependent on adequate calf size, a functioning and healthy rumen, a low-stress environment and adequate access to clean water and high-quality feed.

Spring-born calves are still transitioning into the grower phase and are sensitive to environmental and nutritional challenges that can produce growth checks. Lost gain in beef cattle may mean they have to be carried on longer and may miss optimum markets. Heifers need to meet their weight targets to trigger the brain to start the puberty cycle and then get in calf quickly.

Many hormones that are influenced by nutrition carry out important roles in reproduction; dominant heifers that get the best tucker will always reach targets earlier (by more than two  weeks) than shyer or compromised heifers. During the summer months, heat stress and drought can limit intake and pasture quality. When I have weighed mobs it is clear that calves that have rarely reached targets will barely be gaining weight and may even be in a maintenance period. Helping the lightest quartile is especially important.

Heifers that reach targets in the first 15 months generally have good frame size and stature. Heifers whose growth was checked during this time will be stunted and have potential calving problems as small-framed heifers and subsequently, may struggle to get pregnant. Heifers must attain enough weight to reach their first estrous cycle before the onset of the breeding season. If they reach puberty by 13 months and are at 63–65 percent of mature weight this will help raise the fertility level of cows in the herd.

Holstein heifers mature at an older age than Jersey heifers so may need extra help. There is an opportunity during the first summer to achieve higher growth rates by very good stock and pasture management and if necessary, with higher energy supplementary feed. Pasture and straights may not deliver all the minerals that growing stock require so mineralised feed may be beneficial.

Having a summer feed pinch strategy to ensure targets are hit may give your replacements the advantages of an extra estrous cycle before breeding time, greater first lactation potential and future reproductive efficiency.

Work with your local NRM Nutrition Specialist, vets and use your previous farm records to better understand the development of your calves.

Give some thought to the grower phase and if your weighing scales need upgrading talk to your local Farmlands Technical Field Officer. You may be surprised by the opportunities you find and the long-term production gains.

For further information, contact your Farmlands Technical Field Officer or the friendly team at your local Farmlands store.

Article supplied by Karen Fraser,
NRM Technical Specialist.