From Calf To Springing Heifer
“As an industry, people need to talk about metabolisable energy and protein intake and status relative to maintenance and stop talking about bottles, buckets, kilograms and grams of dry matter, milk, milk replacer etc” Mike Van Amburgh – Professor Animal Science, Cornell University
A blunt statement! Nevertheless, the connection between calf growth and adult performance are very strong. The first eight weeks of a calf’s life largely determines the future health status, production, reproduction and ultimately, how long she lasts in the herd – a potent economic driver.
Well documented is this connection of calf nutrition to growth, disease resistence, age of joining, milk production, fertility and most importantly, just how well she navigates her first transition to fresh heifer status. Early nutrition is the foundation of productive life. Research highlights up to 1500 lts per lactation being due to sound infant calf nutrition.
Mike Van Amburgh is quoted: “We discovered that for every 450 gm of average daily gain prior to weaning, the heifers produced 360 to 700 litres more milk”. Anything that detracts from nutrient intake pre-weaning reduces potential milk yield as an adult.
Van Amburgh states long term milk production is related to protein synthisis as a calf. This means energy intake above maintenance and adequate protein in the calf’s diet. These are responsible for “switching on” long term production responses. Protein is long overdue for discussion in calves’ development and potential, and dairy production as well. Too often we see stocky/overconditioned heifers purely from protein deficient diets. These heifers are candidates for transition problems and are certainly handicapped for life performance.
Well grown fresh heifers partition less energy to growth and more to milk production in the first 150 days of lactation. Conversely, many heifers never complete their first lactation, a very costly outcome. USA data shows 25% are culled for poor milk production, 19% for fertility reasons. I don’t have Australian data on these paradigms, but possibly worse, we hang on to low producing heifers for a second chance, or not enough replacements, however, I suspect the fertility cull rate is higher.
What we see this coming lactation in our heifers’ performance will be directly related to what we did (or didn’t do) nearly two years ago. Genetics only plays a relative small part in performance today. Fifty years ago genetics was a major contributor to heifers out-performing their dams for a multiple number of reasons. This does not negate the ongoing genetic gains from quality semen, but all too often genetics is blamed for poor first calf heifer performance (production and/or reproduction), when calf management/nutrition was the real issue.
