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Abstract
An experiment was conducted to determine the effects of feeding supplemental fat in calf milk replacers during periods of cold stress. Holstein bull calves (n=60), less than 7d of age were purchased from an area sale barn. Using a randomized complete block design, calves were assigned by weight to diets of 1) all milk protein milk replacer (MR; 20%CP and 20% fat from DM); 2) MR plus a fat supplement (MR+, 7% protein, 60% fat from DM or 3) high fat milk replacer (HFMR; 17% CP and 28% fat from DM). Solids for each diet were: MR fed at 454 g/d (2088 kcal); MR+ fed at 454 g/d of MR and 56.7g per feeding of the fat supplement when the outside temperature at feeding was below 0oC (2840 kcal); and HFMR fed at 567.5 g/d (2840 kcal). Calves were fed 1.9 L of milk replacer twice daily. During the trial, 75% of feedings occurred at temperatures below 0o0C. Calves were housed in individual hutches with water available free choice from d 0. A high quality, commercial calf starter was available free choice beginning at d 7. Feed intake, incidence of scours and antibiotic treatments were recorded daily. Calves were weighed weekly. Calves were weaned at a minimum of 42 d with weaning dependent on the calf eating a minimum of 454 g of calf starter for 3 consecutive d. Calves fed higher amounts of dietary fat (MR+, HFMR) had consistently greater weekly weight gains throughout the study. On day 14 calves fed MR were on average 1.35 kg lighter than calves fed MR+ and HFMR. This difference increased to 2.25 kg on d 21. Total weight gains were also greater for MR+ and HFMR diets (47.4, 47.5, 45.7 kg respectively for MR+, HFMR and MR). Additionally, average daily gains were greater for MR+ and HFMR (849, 849, 817 g/d for MR+, HFMR, and MR respectively). Overall, health of the calves was excellent with only 3.3% mortality and no significant differences in number of days scoured or number of medical treatments. These results indicate that increasing the level of dietary fat fed to calves during periods of cold stress may help maintain or improve calf growth.
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Introduction
Colder environmental temperatures during winter strongly affect a calf's nutrient requirements. During periods of cold stress, energy becomes the limiting factor in a calf's ability to grow. The purpose of this study was to determine the effect of feeding additional fat during cold weather as either an additive or a complete milk replacer on calf growth and performance.
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Objective
To determine the effects of feeding supplemental fat in calf milk replacers during periods of cold stress.
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Materials and Methods
Trial Design:
- Randomized complete block design
Animals and housing:
- 60 Holstein Bull calves, from an area sale barn
- Calves were housed in individual hutches
Feeding
- Milk Replacer:
- Control (MR)
20% CP, 20% Fat
Fed at 454g/d, reconstituted to 12% DM
- Fat Supplement (MR+) :
20% CP, 20% Fat (MR)
Supplemented with a 7% CP, 60% Fat additive when the temperature at feeding was below 0°C
Fed at 454g/d of MR, reconstituted to 12% DM plus 56.7g of supplement when applicable
- High Fat Milk Replacer (HFMR)
17% CP, 28% Fat
Fed a 567.5 g/d, reconstituted to 15% DM
- Calf Starter:
- Fed free choice beginning on d 7
- Water
- Fed free choice beginning on d 0
- Weaning
- Calves were weaned at a minimum of 42 d with weaning dependent on the calf eating a minimum of 454g for 3 consecutive d.
Data Collection
- Weights recorded weekly
- Serum IgG levels collected on d0
- Fecal scores recorded daily on a scale of 1 to 4
1 = very firm, 4 = extremely watery
- Antibiotic treatments recorded daily
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Table 1
Table 1. Treatment means of growth, feed intake and health for calves fed a control diet (20% CP, 20% fat, 454g/d MR), MR plus fat supplement diet ( 20%CP, 20% fat, 454g/d plus 57.6g of supplement, MR+) or high fat diet (17%CP, 28%fat, 567g/d, HFMR).
| Treatment |
| Item |
MR |
MR+ |
HFMR |
| ADG, kg |
0.81 |
0.84 |
0.84 |
| Total Weight Gain, kg |
45.7 |
47.4 |
47.5 |
| Feed Efficiency, kg/kg |
0.55 |
0.54 |
0.47 |
| Total Starter Intake, kg |
77.44 |
77.98 |
75.25 |
| Scours, d |
0.40 |
0.61 |
0.65 |
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Figure 1
Effect of Milk Replacer Diet on Average Daily Feed Intake
| Figure 1. Average weekly feed intakes (g) for calves fed a control diet (20% CP, 20% fat, 454g/d MR), MR plus fat supplement diet ( 20%CP, 20% fat, 454g/d plus 57.6g of supplement, MR+) or high fat diet (17%CP, 28%fat, 567g/d, HFMR). |
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Figure 2
Effect of Milk Replacer Diet on Average Weekly Weight Gain
| Figure 2. Average weekly weight (kg) for calves fed a control diet (20% CP, 20% fat, 454g/d MR), MR plus fat supplement diet ( 20%CP, 20% fat, 454g/d plus 57.6g of supplement, MR+) or high fat diet (17%CP, 28%fat, 567g/d, HFMR). Weights were collected on arrival and then once weekly. |
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Summary and Conclusions
Summary
Calves fed higher amounts of dietary fat (MR+, HFMR) had consistently higher weekly weight gains.
On day 14, calves fed MR were on average 1.35kg lighter than calves fed higher amounts of dietary fat and 2.25kg by day 21.
Total weight gains were greater for calves fed higher amounts of dietary fat in cold weather.
Average daily gains were greater for calves fed higher amounts of dietary fat in cold weather.
Conclusion
Increasing the level of dietary fat fed to calves during periods of cold stress may help maintain or imporve calf growth.
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