Discover how lung consolidation at weaning impacts the growth of beef × dairy calves. Can early health issues affect long-term growth? Read the Penn State study insights.
Have you ever wondered how lung consolidation could affect the growth of calves? A recent study conducted by I.L.B. Fernandes and fellow students at Penn State University has revealed that lung consolidation at weaning significantly impacts the short-term growth of beef × Holstein calves. This study, which evaluated the average daily gain (ADG) of 145 calves, was presented at the 2024 Tri-State Dairy Conference. The findings highlight the importance of monitoring lung health during the crucial weaning period to ensure optimal calf growth.
Study Overview
The calves were sourced from two dairies and raised in three cohorts. Calf health—specifically diarrhea and bovine respiratory disease—was assessed at various stages:
- After arrival (1 to 4 days of age)
- At 61 ± 14 days (4 days post-weaning)
- At 83 ± 21 days
- At 238 ± 21 days
Calves received a thoracic ultrasonography scan (TUS) during the first period to assess lung consolidation (TUS+ ≥ 1 cm in one lobe) and lung consolidation severity (LCS; none, 1 to 2 cm, or 3 cm).
Feeding and Weaning Process
During their early life stage, calves were nourished with a daily milk replacer intake of 0.84 kg. In addition to this, they had unrestricted access to starter feed and water, provided in buckets. After reaching 4 ± 2 days post-weaning, the calves were transitioned to a different rearing facility.
To meticulously monitor the growth progress, the Average Daily Gain (ADG) of the calves was divided into three distinct periods:
- Period 1: From arrival weight to weaning weight per day
- Period 2: From weaning weight to 83-day weight per day
- Period 3: From 83-day weight to 238-day weight per day
Statistical Model and Results
The statistical model used in the study considered period and sire breed as fixed effects, while serum total protein and birthweight were included as covariates. Calf nested within the cohort served as a random effect. The study sample consisted of 36 TUS+ calves and the following lung consolidation severity (LCS) outcomes:
- 109 healthy calves
- 10 calves with 1 to 2 cm consolidation
- 26 calves with 3 cm consolidation
A significant TUS+ × period interaction was observed (P ≤ 0.001). During Period 1, there was no significant difference in ADG between healthy calves (0.57 ± 0.02 kg/day) and TUS+ calves (0.56 ± 0.03 kg/day) (P = 0.99). However, in Period 2, healthy calves grew 0.13 (± 0.04) kg/day more than TUS+ calves (P < 0.01). No significant differences in ADG were detected for Period 3 (healthy 1.20 ± 0.02 kg/day, TUS+ 1.28 ± 0.03 kg/day, P = 0.14).
Key Takeaways:
- Lung consolidation at weaning has a temporary negative impact on calf growth, primarily in the short term.
- No significant difference in growth rates was observed between healthy and TUS+ calves in the early (Period 1) and final (Period 3) stages.
- The most notable adverse effect on growth was seen in Period 2, where healthy calves gained significantly more weight than those with lung consolidation.
- Despite initial setbacks, lung-impaired calves demonstrated compensatory growth by the end of the study period.
