Beef Calf Viability: The Importance of Checking the Suck Reflex
Good neonatal viability is essential to ensure calves rapidly ingest and absorb colostrum. Many early-life losses in suckled calves are linked, directly or indirectly, to hypogammaglobulinaemia (low levels of immunoglobulins).
A University of Calgary study investigated which easily assessed newborn calf factors best predict successful colostrum intake. Two stood out:
- Dystocia score
- Suck reflex quality
Both provide highly practical, farm-friendly indicators that can help identify calves at risk of failure of passive transfer (FPT).
Dystocia: A Strong Predictor of Colostrum Intake
Calvings were categorised by the level of assistance required. The likelihood of calves failing to ingest colostrum within 4 hours rose sharply with increasing dystocia.
Colostrum Ingestion Failure by Dystocia Score
| Dystocia Score | % of Calves That Failed to Ingest Colostrum Within 4 Hours |
|---|---|
| No assistance | 14% |
| Minimal assistance | 39% |
| Significant assistance | 64% |
Dystocia alone is therefore a valuable early indicator of whether a calf may struggle to feed spontaneously.
Suck Reflex: Strongly Correlated With Colostrum Ingestion
The study also found a powerful association between a calf's suck reflex and its likelihood of consuming sufficient colostrum.
Assessing suck reflex alongside dystocia score provides a more accurate method of identifying high‑risk calves.
Dystocia + Suck Reflex Combined Risk
| Dystocia Score | Suck Reflex | % Failed to Ingest Colostrum in 4 Hours |
|---|---|---|
| No assistance | Good | 8% |
| No assistance | Poor | 78% |
| Minimal assistance | Good | 26% |
| Minimal assistance | Poor | 94% |
| Significant assistance | Good | 49% |
| Significant assistance | Poor | 98% |
Key Insight: “Unassisted” ≠ “Easy”
It is striking that 78% of calves born unassisted but with a poor suck reflex failed to ingest colostrum.
This highlights that:
- An unassisted calving may still have been prolonged or difficult
- Some calvings are unobserved, leading to delayed intervention
- Resulting hypoxia and acidosis may suppress the neonatal suck reflex
Practical tips:
- Check suck reflex on every newborn calf, regardless of calving ease
- Use dystocia + suck reflex to flag calves at highest risk of FPT
- Prioritise these calves for early colostrum support, including:
- Timely bottle feeding
- Stomach tubing if necessary
- Monitoring for vigour, temperature, and demeanour
A simple suck-reflex check can be a powerful tool in improving calf survival and reducing early-life disease linked to inadequate passive transfer.
Posted by SRUC Veterinary Services on 18/02/2026
