• Nutritional Demands During Breeding Season: Cows face significant demands during breeding season, needing to support calf growth (lactation) and repair reproductive tracts within 90 days post-calving for a yearly calving interval. Quality and quantity of forage, and suitable supplements, are essential to meet these demands.
• Evaluating Forage Quality and Quantity: Understanding forage availability and quality, especially during drought, helps determine if supplementation is necessary. Native forage quality peaks in June and declines through November, which impacts breeding-season nutritional planning.
• Strategic Supplementation Needs: Lactating cows have high nutrient demands, often requiring supplements if forage lacks protein and energy. Protein sources, especially those high in rumen undegradable protein (RUP), can increase pregnancy rates, calf weight, and reproductive cycling, particularly in younger cows.
• Focus on First-Calf Females: Younger cows with high lactation and growth needs may benefit most from early post-calving supplementation, with a recommended diet of at least 62% total digestible nutrients (TDN) and 10-11% crude protein (CP).
• Alternative Management Options: If forage is insufficient, early weaning or confined feeding can reduce forage demand. Early weaning cuts daily forage needs by 5 pounds per cow and 10 pounds per weaned calf, helping to conserve resources during limited forage availability.
How weather affects breeding success for cattle
• Heat Stress on Fertility: Heat stress can reduce fertility in beef cattle by affecting oocyte viability and fertilization, particularly during the critical 10 days before conception through 20 days post-conception.
• Temperature and Humidity Impact: High temperatures and humidity during early breeding season can reduce conception rates; each degree Fahrenheit above normal reduces conception by about 1%, and prolonged heat can continue to impact breeding success.
• Optimal Conditions for Conception: Ideal conditions for conception include average daily minimum temperatures between 55-60°F and a temperature-humidity index (THI) between 64-68. Deviations increase pregnancy loss by 1.5-2% per THI unit.
• Regional Differences in Nebraska: Eastern Nebraska faces higher humidity and heat, increasing reproductive challenges compared to western regions, though adverse weather affects herds statewide.
• Management Practices: Producers can mitigate heat stress by minimizing cattle movement, working cattle early, providing water and shade, controlling flies, and keeping bulls cool to help maintain conception rates.
FAQ: Breeding Health
What effect does dry-lotting breeding cows have on conception rates and fertility in general?
We can't find data where they have drylotted cows and bred for an entire breeding season. There are data where they have drylotted cows and AI'ed then turned to pasture and natural bred. The conception rate to AI (AI'ed once) in these experiments was in the 60% range which would be pretty typical. Following are my comments in regard to advantages and disadvantages of dry-lotting beef cows.
As pasture prices continue to increase, producers will look for ways to lower production costs, especially feed cost, and dry-lotting cows may be an option. If you do dry-lot cows, it would be important that the lot be big enough or you have an adjacent pasture that can be used as an exercise lot.
When you indicate dry-lotting cows, I assume that cows may have calves at their side and breeding may occur in the lot.
Herd health issues to address or be aware of include:
- Cows could have more feet and legs problems.
- Calves need to be able to get away from the cows, especially during the breeding season.
- Producers need to be good at managing the diet.
- Bulls need to be observed frequently during the breeding season for injury.
Disadvantages:
- Labor and feeding equipment is needed to deliver a ration.
- Feed bunks are needed, with 24 to 36 inches of bunks space per head.
- Hay needs to be ground so you can mix in low quality forages to make the diet more economical.
- A more intensive herd health program is needed for both cows and calves.
Advantages:
- May reduce total production costs and work in a system where cows are able to graze low cost crop residue during the fall and winter.
- Producers can use low quality forages and mix in ethanol by-products or grain and supplements to meet the needs of the herd.
- Calves are ready eat out of a bunk once they are weaned - bunk broke.
- Artificial insemination may be easier because cows are probably close to a chute and working facility.
- Cows will have lower nutrient/energy requirements than in a pasture setting due to less exercise occurring in a dry-lot environment
Is there any reason that heifers cannot be fed MGA for 14 days then take them off, let them cycle once, then breed them on the next cycle? My thinking is that they will be grouped within 3 to 4 days, which I could live with.
Breeding should occur when the heifer reaches puberty. Puberty is a function of breed, age, and weight. Most heifers will reach puberty and be bred by 12 to 14 months of age and will be between 55% and 65% of their mature weight when they first begin to exhibit estrous cycles. Higher growth heifers and heifers that have a breed composition that is a high percentage bos indicus (Brahman) are later maturing and are older at puberty.
There are, in some cases, beef females that will cycle at less than a year of age and become pregnant. This is called precocious puberty. These females may be still nursing their dams. This doesn't happen often, but can happen. This is too young for a beef female to become pregnant because at calving these females tend to have difficult births as the birth canal is not fully developed.
Can cows give off a false heat after they are bred?
The primary hormone of pregnancy for beef females is progesterone. Progesterone is produced by the corpus luteum that is on the ovary. Progesterone does not allow the cow to cycle.
During mid- to late-gestation, there are hormones produced that come from the placenta. Some of those hormones are estrogen or estrogen-like.
So the answer to your question is yes, cows that are pregnant may have some riding activity caused by hormones that are estrogen-like that are being produced by the placenta.
At what age is it safe to breed a heifer?
Breeding should occur when the heifer reaches puberty. Puberty is a function of breed, age, and weight. Most heifers will reach puberty and be bred by 12 to 14 months of age and will be between 55% and 65% of their mature weight when they first begin to exhibit estrous cycles. Higher growth heifers and heifers that have a breed composition that is a high percentage bos indicus (Brahman) are later maturing and are older at puberty.
There are, in some cases, beef females that will cycle at less than a year of age and become pregnant. This is called precocious puberty. These females may be still nursing their dams. This doesn't happen often, but can happen. This is too young for a beef female to become pregnant because at calving these females tend to have difficult births as the birth canal is not fully developed.
