Category Archives: reproduction
Cattle A.I. School, Burns, Oregon
Learn cattle reproductive anatomy and physiology, heat detection, estrus synchronization, semen handling, gestational nutrition, and sire selection in the classroom and practice artificial insemination with reproductive tracts and live animals.
When: March 27-29, 2019
Where: Eastern Oregon Agricultural Research Center, Burns
Cost: $375
Class size is limited; register ASAP to secure a spot. For full details and registration information, click on the flyer link below.
A.I. School for SE Oregon and SW Idaho
Learn cattle reproductive anatomy and physiology, heat detection, semen handling, artificial insemination technique, and sire selection in the classroom and on live animals.
When: February 26-March 1, 2019
Where: Owyhee County Extension Office, Marsing, Idaho
Cost: $325 for entire school or $125 for “tune-up” session
Languages: English, Spanish
For full details and registration information, click on the flyer link below.
AI School on OSU Campus
Artificial Insemination in Dairy Cattle
This three-day program includes both indoor and outdoor instruction and practice on the skill of artificial inseminating cows. The class also provides instruction on cow and herd management for efficient, successful reproduction. A certificate of achievement is given upon successful completion of the course.
- January 5, 6, 7, 2018 (Fri-Sat-Sun)
- Inside instruction – Oldfield Teaching Center (on west side of OSU campus), 3521 SW Campus Way, Corvallis, OR 97333
- Outside instruction – OSU Dairy, Corvallis
- Cost $500 per person
- Instructors
- Kathryn Younger, OSU Dept. of Animal and Rangeland Sciences
- Steve Gosse, Genex
- Contact Shelby Filley, Regional Livestock and Forage Specialist, OSU Extension Service at 541-236-3016/Shelby.filley@oregonstate.edu for registration information.
The Target for Age at First Calving
When heifers calve very young, there is a greater risk of stillbirth and lower first-lactation milk production. When heifers are old at calving, their fertility may be negatively affected and it raises their culling risk. Plus, there is the cost of feeding them to that age before you get any return. So what is the sweet age for first calving to maximize average lifetime production? To answer that question, researchers at USDA analyzed production, reproduction, and lifetime data along with genetic (relationship) data from 13.9 million Holstein, 1.2 million Jersey, and 90,400 Brown Swiss cows. (Isn’t the national dairy database great? That’s just cows who first calved from 1997 through 2015!) Genomic data from about 205,000 of those animals were also used.
One of the first interesting results of this study was documentation of the significant trend toward younger ages at first calving (see Table 1). It’s been most pronounced for Jerseys.
Table 1. Percentages falling into each age-at-first-calving (AFC) category in 1997 and 2012. (Data condensed from Hutchison et al. 2017.)
AFC (months) | Holstein
1997 2012 |
Jersey
1997 2012 |
Brown Swiss
1997 2012 |
|||
18–22 | 7.9 | 33.5 | 18.5 | 65.2 | 3.0 | 12.8 |
23–27 | 66.8 | 58.3 | 64.2 | 31.1 | 53.5 | 59.2 |
28–35 | 25.3 | 8.2 | 17.3 | 3.7 | 43.5 | 28.0 |
Age at first calving may serve as an indirect indicator of general productivity and survivability, as lower ages at first calving correlate with higher lifetime production and fertility. That is, heifers capable of getting pregnant at younger ages may just be more robust animals in general. In order to capitalize on those individuals, one shouldn’t start breeding too late. The data support a target age of 21-22 months for Holsteins and Brown Swiss to deliver their first calves and 20-21 months for Jerseys. However, breeding at ages younger than 11-13 months is not recommended because younger heifers are more likely to have stillborn calves. The authors of the study suggest that AFC be incorporated in bull selection indexes, which would enable population-level selection for an AFC that increases profitability.
the article: Hutchison et al. Genomic evaluation of age at first calving. Journal of Dairy Science. August 2017. 100:6853–6861.
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