The simple solution to boosting dairy cattle conception rates (CR) is to improve reproductive management and cow environment, as these two general categories account for 96 percent of CR variation.
More specifically, nutrition (e.g., energy and mineral balance and feed molds and mycotoxins), animal health (e.g., metabolic disorders and reproductive system soundness), reproductive practices (e.g., heat detection and insemination practices) and data management influence most of the reproduction puzzle.
What else influences CR? Genetics, with 3 percent attributed to the cow and 1 percent to the service bull.
Let’s take a closer look at how dry period, close-up period, calving, post-calving, estrus synchronization, insemination, mastitis and data management/evaluation influence CR.
Dry period
Cows with short dry periods (30 to 40 days) experience an earlier first ovulation and improved fertility at first and second insemination. Excessively long dry periods (beyond 100 days) may lead to poorer reproductive performance. As the dry period lengthens, cow fertility decreases in the next reproductive cycle.
Close-up period
During the close-up period, strive to maximize dry matter intake by feeding a balanced ration with nutrients, such as calcium, at the proper dietary cation-anion difference, along with proven feed ingredients that include essential fatty acids. Feed the close-up ration for a minimum of 14 days.
Calving
To enhance transition period and future CR success, provide cows with a clean and dry calving area with minimal stress. Inferior conditions and calving assistance may lead to dystocia, retained placenta, metritis or endometritis. Researchers showed cows with dystocia and clinical endometritis were 67 and 55 percent, respectively, more likely to lose their pregnancies during the first 60 days of gestation compared with healthy cows.
Post-calving
Metabolic disorders influence CR. To help cows experiencing subclinical ketosis, consider giving them oral propylene glycol. A study found this protocol reduced the development of a displaced abomasum. Cows were less likely to be removed from the herd during the first 30 days in milk and more likely to conceive to the first service.
Estrus synchronization
It probably goes without saying but, as a friendly reminder, strict compliance with injection and hormonal management protocol is crucial for carrying out a successful synchronization program. Variations from protocol explain the outcomes of timed-A.I. programs. Poorer-than-expected performance is almost always attributed to compliance issues at the farm level.
Insemination
Just like milking procedures, evaluate individuals’ heat detection, semen handling and breeding techniques on a regular basis. Check for compliance with established procedures. Similarly, follow industry guidelines for proper semen handling, semen thawing and cleaning breeding implements. While speediness is often admired, don’t let speed get in the way of effectively getting cows bred.
Data management
Data can be your friend in evaluating technicians and protocols. For example, DairyComp 305 allows you to evaluate CR through many traits. Using the evaluation by heat interval (Bredsum\I) is one way to evaluate CR at four to 17 days since last A.I.
A reduced CR in this segment will show inseminators are breeding cows that are not in heat or the heat detection process is not accurate. To avoid breeding cows and heifers in this heat interval range, provide the inseminator a daily updated breeding list.
Mastitis
While fertility and udder health may seem like vastly different health challenges, research continues to show a strong correlation. Researchers estimated the cost of each incident of clinical mastitis occurring in the first 30 days of lactation at $444. Part of this amount considers the negative effects of mastitis on overall reproductive performance.
The presence of endotoxins produced by the mastitis pathogen induces the release of chemical neurotransmitters and hormones responsible for local responses, such as redness, swelling, pain and function loss. These mediators and hormones can affect reproductive performance and pregnancy loss.
Researchers found the time when clinical mastitis occurs can extend days open from 85 days in an uninfected cow to 106 days if the infection occurs before first service and up to 143 days if the infection occurs between first service and pregnancy diagnosis. A significant CR reduction also occurs.
A study demonstrated the occurrence of mastitis is associated with a prolonged interval to first postpartum A.I.
Stats evaluation
Evaluating reproductive performance encompasses several factors, so avoid just looking at a single performance measure or statistic. Monitor several factors, such as CR, pregnancy risk, days in close-up pen, calving difficulty, days dry and heat interval. These measurements provide valuable information that can be used to find opportunities to improve procedures and protocols that influence outcomes.
High-risk cow list
Establish fresh cow protocols, including procedures for cows that didn’t have a textbook lactation or dry period (e.g., extended days in milk, too short/long dry period, calving difficulty). Giving a little extra attention to high-risk cows will help prevent challenges in the next lactation.
Daily, use your dairy software to print a high-risk fresh cow list and proactively manage these cows. For example, give propylene glycol, if appropriate, to prevent the effects of subclinical ketosis. Work with your herd veterinarian and nutritionist to develop management protocols.
Taking advantage of farm information can be an excellent strategy to proactively work with specific cows, if all information is accurate and gathered correctly.
Regular CR evaluation by heat interval and cows with high somatic cell count offers an excellent opportunity to reduce the negative effects of these health challenges on CR. To improve CR, reduce culling rates and lower the incidence of metabolic disorders, develop a proactive fresh cow protocol for cows in the high-risk group. 
References omitted but available upon request. Click here to email an editor.
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Christian A. Rippe
- Veterinarian
- Church & Dwight
- Email Christian A. Rippe
