Influence of the proportion protein/fat of the substitute for milk during lactation, on some zootechnical parameters in the upbringing of Holstein calves replacement, in a suckling dairy herd in northern Mexico.
*Ibarra, S., *Leyva, O.C.
Evaluate the growth parameters with different levels of protein and fat with a substitute (22-20% against Celtic Milk 26-15%) in the food ration for calves in the stage of growth.
Materials and methods
For the realization of this experiment, we randomly selected 100 suckling dairy calves, during the peak of deliveries from a dairy herd in northern Mexico that after weighing and receive its colostrum according to the practices of the region, were randomly assigned to two experimental groups: G1 warning light (n= 50) received 4 liters of milk substitute official whose proportion was 22%/20%, for protein/fat respectively. This substitute is the that is commonly used for the breeding of dairy calves in the north of Mexico. The calves of G2 (Treaty) (n=50) received the same daily amount of a substitute for milk, but in proportion of 26%/15% for protein/ fat respectively. All the calves were placed in individual cages, separated according to the zootechnical applied. They carried out three weights and measurements at the following times: at birth, per month and at weaning (two months). Measures that were compared in the two experimental groups and statistically analyzed by the computational package SYSTAT version 10.
For the obtaining of measures were used digital scales of 100 kg for the mediated linear, a tape measure, liquids mixer which performs the preparation of the milk substitutes 250 lt. capacity and buckets of 5 lt. of capacity to provide the substitute for the calves.
For all the parameters evaluated the substitute for milk with content 26%/15% for protein and fat respectively to be offered to the calves in the treated group was significantly higher (p<0.05) in the control group.
The following comparative graphs, present the most relevant results from each of the evaluated variables, for each experimental group.
Fig. 1 Weight at weaning of calves of both experimental groups
A, B Letters, in the same category, indicate significant differences (P<0.05). As can be seen the calves of the treated group had 9.978 kg higher than the control group. Regarding to the size of the suckling dairy calves valued by the cross wing height can be seen also that the calves treated with substitute for milk containing 26% protein and 15% fat, had a height at the withers of 2.94 cm higher in the control group this behavior can be observed in the following figure.
Fig. 2 Height of the cross to the suckling dairy calves of both experimental groups
A, B Letters in the same category indicate significant differences (P<0.05) when analyzed the length of the suckling dairy calves which consumed the milk substitute for with higher levels of protein and less fat percentage we can observe a gain of 3.89 cm, vs the control group.
Fig. 3 Length of the suckling dairy calves of the experimental groups
A, B different letters in the same category indicate significant differences (P<0.05).
With regard to the width of pelvis milk substitute 26- 15 protein and fat respectively obtained an advantage of 0.54 cm with respect to substitute for milk of lesser amount of protein and greater amount of grease.
Fig. 4. Width of pelvis of calves of both experimental groups.
A, B Different letters in the same category indicate significant differences (P<0.05), these results are consistent with the above with Drackley (2002), which found that the average daily weight gains and the growth of the calves improved much more when increased the protein content of the substitute, determining that by increasing the amount of protein in the substitute, provides a more stable growth in stature and muscle; complemented with what was said by (Elorduy ,1989) that determines that calves fed with milk substitutes highly energetic (with higher levels of fat) tend to consume initiators to a later age, those who consume milk substitutes of low energy, delaying the rumen development and also the level of growth of suckling dairy calves
On the basis of the analysis of the results obtained, it can be concluded that with the increase of up to 26% of protein and the decrease in the percentage of fat in up to 15% with respect to the standards used for breastfeeding substitutes of calves in the region (22%/20%) for protein and fat respectively, significantly enhance the daily weight gain and consequently the weaning weight, as well as the size (length and height) and the width of the pelvis of the calves fed with substitutes containing in its composition the proportion 26 per cent/15 %, for protein and fat respectively.