Beef Cattle Breed Season

Impact of Nutrition on a Defined Calving Season

Warm weather, green pastures, field work and turning the bulls out.  These are all parts of spring on a cattle operation.  Nutrition is the cornerstone to a successful breeding season.  Ensure you are providing the needed minerals and vitamins with Nelson Tubs supplements.

Cow BCS Implications.

When to begin the breeding season?

The Body Condition Score (BCS) of cows entering the breeding season will have the most significant impact on breeding success.  Cows need to be in a BCS of 5 or 6 for optimum pregnancy rates.  See Table 1.  If cows are under a BCS 5, supplemental nutrition will be needed and a good investment.

Table 1.  BCS of Beef Cattle Impact on Pregnancy Rate

BCS	Pregnancy Rate %
3	43
4	61
5	86
6	93

Kunkle et al., 1994

Timing the beginning of breeding season depends on when you want to market the calves, the availability of forage to meet the cow’s nutritional needs, and environmental conditions around the time of breeding and time of calving.

Two Start Dates – Cows and First Calf Heifers

Heifers having their first calf will need additional time to recover from calving to regain body condition. Heifers are still growing in addition to feeding a calf.  Starting to calve heifers one month earlier than the cows will give them additional time to recover prior to breeding.  Late calving heifers are likely to fall out of the desired calving window by their 3rd or 4th calf.  We need animals to stay in the herd for at least 4-5 calves to breakeven.

Length of Breeding Season 

Most defined breeding seasons range from 45 to 90 days.  The shorter 45-day breeding season may require some use of synchronization and either artificial insemination (AI) or extra bull power to service all the animals in 45 days.  Typical bull power is 1 bull for 20-30 head and if multiple bulls are needed in a pasture, they should be comingled prior to breeding season in order for the bulls to establish a pecking order.

Possible Benefits of a 90, 60 or 45 Day Breeding Season

• 90 Day – labor saving and better able to manage groups of cow and calves.

• 60 Day – heavier calves and more uniform groups at weaning and potential for higher price per pound.

• 45 Day – management intense but least labor at calving and most uniform in calf size.

Keeping the Breeding Season Tight With Solid Mineral and Vitamin Nutrition

The spreadsheet below shows the impact of poor conception rate on extending the calving season.  The cow gets 1 chance every 21 days to conceive, unless we are using intensive estrus synchronization.  There is an 80-day window to get the cow’s reproductive tract recovered from calving and return of the estrus cycle.  The spreadsheet depicts an operation that wants to start calving on March 1 which requires a successful first breeding on May 20th to maintain 1 calf per year.  Failing to conceive until the 3rd or 4th cycle will push the beginning of calving into April or May.

					Next Calving Date if Open	Next Calving Date if Open	Next Calving Date if Open
Calving Date	Breeding Date	Next Calving Date	Weaning Date 180 Days		2nd Cycle	3rd Cycle	4th Cycle
3/1/2025	5/20/2025	2/27/2026	8/28/2025		3/20/2026	4/10/2026	5/1/2026

Trace mineral and vitamin status of the cow will impact overall condition of the reproductive tract, egg quality and, most importantly, viability of the embryo.  Most of the potential failures happen at the cellular level and specifically the integrity of the cell wall of egg and uterine tract lining.  Nelson Tubs provide high quality bioavailable trace mineral and vitamins in a low moisture cooked tub that is very palatable and consumed each and every day. 

It is all about the Intake