Table 9.
Economic marginal return to cost of feed ratio of 5 strains of broilers fed control or amino acid–reduced diet (with digestible lysine, TSAA, and threonine being 20% lower than the control diet), with or without woody breast loss considered.
| Treatment |
Economic return: feed cost on day 42 processing |
Economic return: feed cost on day 56 processing |
|||
|---|---|---|---|---|---|
| Strain | Diet | WB was not considered2 | Severe WB considered3 | WB was not considered2 | Severe WB considered3 |
| Strain 1 | 1.695b | 1.662 | 1.372a | 1.284 | |
| Strain 2 | 1.746a,b | 1.597 | 1.355a,b | 1.187 | |
| Strain 3 | 1.617b | 1.599 | 1.365a,b | 1.283 | |
| Strain 4 | 1.617b | 1.590 | 1.239b | 1.196 | |
| Strain 5 | 1.837a | 1.726 | 1.412a | 1.207 | |
| SEM1 | 0.0337 | 0.0400 | 0.0327 | 0.0312 | |
| Control | 1.684 | 1.590b | 1.335 | 1.200b | |
| Reduced | 1.721 | 1.680a | 1.362 | 1.263a | |
| SEM | 0.0213 | 0.0253 | 0.0207 | 0.0197 | |
| Strain 1 | Control | 1.650 | 1.609 | 1.391a,b,c | 1.335 |
| Strain 1 | Reduced | 1.740 | 1.716 | 1.352a,b,c | 1.234 |
| Strain 2 | Control | 1.725 | 1.529 | 1.253b,c | 1.117 |
| Strain 2 | Reduced | 1.767 | 1.666 | 1.458a,b | 1.257 |
| Strain 3 | Control | 1.605 | 1.587 | 1.341a,b,c | 1.238 |
| Strain 3 | Reduced | 1.629 | 1.611 | 1.389a,b,c | 1.328 |
| Strain 4 | Control | 1.607 | 1.552 | 1.216c | 1.149 |
| Strain 4 | Reduced | 1.627 | 1.627 | 1.261a,b,c | 1.243 |
| Strain 5 | Control | 1.833 | 1.674 | 1.476a | 1.161 |
| Strain 5 | Reduced | 1.842 | 1.778 | 1.349a,b,c | 1.254 |
| SEM | 0.0476 | 0.0566 | 0.0463 | 0.0441 | |
| P-value | Strain | <0.0001 | 0.084 | 0.006 | 0.062 |
| Diet | 0.226 | 0.015 | 0.367 | 0.026 | |
| Strain × diet | 0.924 | 0.884 | 0.012 | 0.070 | |
a–cMeans in a column not sharing a common superscript were different (P < 0.05).
The value of parts was calculated by breast wt. × $0.9459 + tender wt. × $1.6429 + wing wt. × $1.7522 + drumstick wt. × $0.3063 + thigh wt. × $ 0.4308.
Feed cost on day 41 was calculated by (feed price day 0–14 × FI day 0–14 + feed price day 14–28 × FI day 14–28 + feed price day 28–41 × FI day 28–41)/average BW of each pen on day 41 × average BW for processing on day 41.
Feed cost on day 55 was calculated by (feed price day 0–14 × FI day 0–14 + feed price day 14–28 × FI day 14–28 + feed price day 28–41 × FI day 28–41 + feed price day 41–55 × FI day 41–55)/average BW of each pen on day 55 × average BW for processing on day 55.
The prices for the diets are listed in Table 1.
n = 16, 40, and 8, respectively, for treatments of strain, diet, and interaction of strain and diet.
Economic marginal return = value of the cut-up parts (skinless and boneless breast, tender, wing, drumstick, and thigh) – cost of feed to produce the cut-up parts.
The value of breast with severe woody breast myopathy was calculated at half price of normal breast price of $0.9459.