Stocking Replacement Heifers – Canadian Cattlemen

Growing heifers is expensive due to feed and time requirements, and weaned calves usually have narrow margins. If the average cow needs the first five calves to pay for itself, it is clearly useless to cull her before she is seven years old. Having the majority of cows weaned each year under your management and environment for many years is a major factor affecting profitability.

Read also

Animal husbandry in a difficult environment

It’s party night at the Canadian Beef Industry Conference (CBIC) in Penticton, BC Cowboy hats are found …

But it is difficult to know which heifer calves will become profitable cows. Unprofitable candidates are more obvious. Heifers that are small for their age or born late in the breeding season, mated with bulls, have obvious conformation problems, or are temperamental daughters are best sent to the feedlot. But who should be chosen from the rest?

[RELATED] Feeding 101 for replacement heifers

Some producers use a carefully guarded magic equation to identify promising heifers, and their strategy probably works like the secret formulas of their neighbors. Other producers cull the heifers that are clearly not performing, keep the rest, subject them to a very short breeding season, sell the yearlings as feed, and keep the pregnant heifers.

Dr. John Basarab and Cameron Olson (University of Alberta) studied whether feed intake characteristics in weaned heifers help predict their performance as mature cows (Phenotypic and Genetic Correlations of Cow Performance and Lifetime Performance of Feeding Behavior, Feed Intake and Feed Efficiency of Beef Replacement Heifers; DOI: 10.1111/jbg.12522).

What did they do?: This study used lifetime records of 1,145 Angus-cross heifers born between 2005 and 2017 at the AAFC’s Lacombe Research and Development Center and the University of Alberta’s Roy Berg Kinsella Research Station. At both locations, weaned heifers were dry-housed and fed silage until mid-May. Individual weights, back fat, feed intake and residual feed intake (feed intake adjusted for size and back fat) were measured for at least 70 days. Heifers were pastured from mid-May to October and exposed to bulls for 45 days (late May to mid-June).

At Lacombe, a group of cows were dry-fed silage from mid-October to April. The other group was grazed from mid-October to February/March (conditions permitting) and then fed indoors through calving. All cows were put out to pasture in mid-May and exposed to bulls for 63 days (early June to early August). Kinsella’s cows were left on pasture and supplemented with grass all winter. At the beginning of the breeding season, cow weight and back fat are measured, and calf birth and weaning weights are collected. Heifers and cows were culled if they failed to reproduce (re-)breed, lost foals or had poor temperament, performance, conformation or udder structure.

Each cow’s days in the herd (from first breeding to slaughter) and total lifetime productivity (total kilograms of calves weaned in its lifetime) were calculated and the relationship between its feed intake and its performance as a heifer and subsequent performance as a cow was determined. Pedigree information has been used to reveal the effect of genetics (as opposed to environment and management) on cow performance.

[RELATED] Don’t leave money on the table when selling livestock

What They Learned: Genetics played a very small role in determining how long cows stayed in the herd (four percent) or overall lifetime productivity (six percent). This means that environmental influences and management practices accounted for the other 96 percent (days in herd) or 94 percent (total lifetime productivity).

Genetics played a larger role in feed intake (23 percent) and residual feed intake (43 percent) in heifers, so they calculated genetic correlations between these feed intake traits in heifers and their reproductive performance as cows. Heifers with a genetic predisposition to eat more tended to stay in the herd longer (13% of the same genes affected both traits), but cows that gave birth to and weaned slightly larger calves gained slightly more weight.

In contrast, heifers with a genetic predisposition to higher residual feed intake (ie, less efficient heifers that ate more than average but did not grow faster) had higher lifetime fertility (14 percent of the same genes affected both traits), and cows slightly became fatter (but not heavier), with no change in calf birth or weaning weights.

So What Does It Mean?: Your environment and management are the main factors affecting a cow’s longevity and productivity, and the two go hand in hand. It’s about doing the little things right. Things like working with a nutritionist to test the feed you’re raising (and sometimes your water) and supplementing as needed to ensure your herd is getting the nutrients it needs to grow, maintain body condition, carry and deliver a healthy calf, produce adequate colostrum, and feed. to breed again. Things like talking to your veterinarian to make sure your vaccination and other preventative herd health management practices are appropriate for diseases prevalent in your area.

Genetic selection—selecting the daughters of the most fertile cow to replace them—is a very slow way to improve reproductive performance. Crossbreeding is the best genetic strategy to improve reproductive performance and longevity in commercial cows. Many breeders carry more than one breed. If you have used the same mother breed for several generations, a reputable breeder can help you identify a genetic, environmental and management-friendly fit.

Funded by the Beef Cattle Research Council Canadian Beef Cattle Inspection. BCRC partners with Agriculture and Rural Development Canada, provincial beef industry groups and governments to develop research and technology transfer that supports the Canadian beef industry’s vision of being recognized as the preferred supplier of healthy, high-quality beef, cattle and genetics .

Leave a Comment