The Perfect Protein. Egg protein is often referred to as the perfect protein, being the standard for evaluating proteins for much of the 20th century. Their amino acid content and digestibility are the reference against which all other protein sources are compared.
Estimates of amino acid requirements for young calves indicate that lysine and methionine + cystine are first and second limiting amino acids (Davis and Drackley, 1998). The following table shows how the amino acid percentages of egg proteins stack up to whey proteins, demonstrating that eggs provide more key amino acids
Amino Acid Profiles
(Percentage of Protein)
|
| Amino Acid |
Egg Protein |
Whey Protein |
| Lysine |
7.2 |
7.7 |
| Methionine + Cystine |
5.4 |
3.1 |
| Isoleucine |
5.4 |
5.4 |
| Leucine |
8.6 |
10.4 |
| Arginine |
6.0 |
2.3 |
| Valine |
6.1 |
5.4 |
| Tryptophan |
4.1 |
2.8 |
| Histidine |
2.4 |
1.7 |
| Phenylalanine + Tyrosine |
9.4 |
5.9 |
|
Two research trials were conducted at Merrick's research facility to evaluate calf performance when fed a 20-20 milk replacer formulated with milk and egg proteins . Results of the first trial (shown below) indicate better performance when proteins are derived from both milk and egg sources than when derived from milk sources alone.
| Egg Protein
Feed Trial 1
(All Milk Protein vs.
Milk Protein + Egg) |
Better Average Daily Gain (ADG): |
Calves fed milk replacer containing egg had significantly higher ADG than calves fed all milk protein milk replacer |
| More Starter Consumption: |
Calves on egg treatment tended to consume more starter than other calves |
Egg Protein Feed Trial 2
(All Milk Protein vs.
Milk Protein + Egg) |
Average DailyGain : |
No significant differences in weight gain were observed between calves receiving either milk protein or milk & egg protein |
| Starter Consumption: |
No significant differences observed between treatments |
| Scours: |
Fecal scores were excellent with no signifcant differences between treatments |
Results demonstrate that calves receiving milk replacer containing milk and egg proteins perform as well as or better than calves receiving milk replacer with only milk proteins. Formulating milk replacers with both milk and egg proteins reduces ingredient cost while maintaining superior product quality and animal performance.
