CAC CAC Livestock & Animal Science 1 — Questions and Answers
Question 1: Which body condition score (BCS) range is generally considered optimal for beef cows at calving?
- 1–2
- 3–4
- 5–6 (Correct answer)
- 7–8
Correct answer: 5–6
A BCS of 5–6 at calving ensures adequate energy reserves for milk production and rebreeding.
Question 2: The gestation length for a beef cow is approximately how many days?
- 200 days
- 245 days
- 283 days (Correct answer)
- 310 days
Correct answer: 283 days
The average gestation period for beef cattle is approximately 283 days.
Question 3: Which of the following vaccines is part of a standard pre-breeding vaccination program for beef heifers in the US?
- Rabies only
- IBR/BVD/PI3/BRSV (modified live) (Correct answer)
- Foot-and-mouth disease
- Equine influenza
Correct answer: IBR/BVD/PI3/BRSV (modified live)
Modified live IBR/BVD/PI3/BRSV vaccines are routinely used to protect breeding heifers from reproductive diseases.
Question 4: What is the primary purpose of synchronizing estrus in a beef cow herd?
- Increase milk production
- Compress the calving season for management efficiency (Correct answer)
- Reduce feed costs
- Prevent dystocia
Correct answer: Compress the calving season for management efficiency
Estrus synchronization tightens the calving window, allowing producers to manage labor, creep feeding, and weaning more uniformly.
Question 5: Expected Progeny Differences (EPDs) are used by beef producers primarily to:
- Calculate feed conversion ratios
- Predict the genetic potential of offspring for specific traits (Correct answer)
- Determine vaccination schedules
- Estimate land carrying capacity
Correct answer: Predict the genetic potential of offspring for specific traits
EPDs express the expected difference in performance of a sire's offspring compared to the breed average for traits like birth weight and weaning weight.
Question 6: Which internal parasite most significantly impacts weight gain in stocker cattle on US pastures?
- Liver fluke (Fasciola hepatica)
- Barber pole worm (Haemonchus contortus) (Correct answer)
- Tapeworm (Moniezia spp.)
- Lungworm (Dictyocaulus spp.)
Correct answer: Barber pole worm (Haemonchus contortus)
Haemonchus contortus is a blood-sucking abomasal parasite that causes significant production losses and anemia in grazing cattle.
CAC CAC Livestock & Animal Science 1
Which body condition score (BCS) range is generally considered optimal for beef cows at calving?