Feeding Cull Beef Cows
Questions often arise regarding optimal rations and expected performance when feeding cull beef cows. A study published in the Journal of Animal Science evaluated growth, carcass characteristics, and implant response in thin cull cows fed high‑concentrate diets for short-term feeding periods.
Study Details
- Animals: 60 non‑pregnant British-bred cows
- Age: Over 5 years
- Initial Body Condition Score (BCS): 3–4 (scale 1–10)
- Weight Groups:
- Light: 386–454 kg
- Heavy: 454–522 kg
- Feeding Periods: 28 or 56 days
- Implant Treatments:
- No implant
- Trenbolone acetate (TBA)
- Synovex H (TEB)
- TBA + TEB
- Cows received a 7‑day warm-up ration (56% concentrate), followed by an 80% concentrate finishing diet.
Ration Composition (Dry Matter Basis)
Table 1. Diet Composition (%)
Ingredient |
Warm-up Diet |
High-Concentrate Diet |
Rolled corn |
23.90 |
56.00 |
Sorghum silage |
72.20 |
39.30 |
Soybean meal (44% CP) |
3.04 |
3.67 |
Limestone |
0.55 |
0.66 |
Salt |
0.19 |
0.23 |
Urea |
0.08 |
0.09 |
Trace mineral premix |
0.03 |
0.03 |
Rumensin 60 |
0.00025 |
0.00025 |
Performance and Carcass Results
Table 2. Performance and Carcass Data
Trait |
0 Days |
28 Days |
56 Days |
ADG (kg/day) |
— |
2.12 |
1.99 |
DMI (kg/day) |
— |
11.8ᵃ |
13.3ᵇ |
Feed:gain |
— |
5.57ᵃ |
6.68ᵇ |
Dressing % |
52.1ᵇ |
50.6ᵃ |
54.0ᶜ |
Hot carcass wt (kg) |
238.2ᵃ |
262.3ᵇ |
308.7ᶜ |
Adj. fat thickness (cm) |
0.43ᵃ |
0.73ᵇ |
1.10ᶜ |
LM area (cm²) |
66.8ᵃ |
74.9ᵇ |
80.0ᶜ |
Superscripts (a, b, c) indicate statistically significant differences within rows.
Key Findings
1. Effects of Feeding Duration
- 28 days on feed improved:
- Quality grade
- Longissimus muscle (LM) area
- Sensory traits (flavour, tenderness, juiciness)
- 56 days on feed further improved:
- LM lean colour
- Carcass fat colour
- Both feeding durations increased:
- Carcass weight
- Carcass soft tissue
- Fat deposition
2. Implant Response
- All implant treatments:
- Increased average daily gain (ADG)
- Improved feed efficiency
- Enhanced carcass performance
- Best response: Combination of TBA + TEB
- Implants also improved juiciness and tenderness.
Practical Implications for Producers
- Short-term feeding (28–56 days) of thin cull cows on high-concentrate diets can substantially increase carcass value.
- Implanting—especially with combination treatments—improves both performance and meat quality attributes.
- Longer feeding increases carcass weight but also fat thickness; producers should balance desired endpoint with cost of gain.