Adjustment of the ME requirement for maintenance by body condition score as influenced by previous nutritional plane

After a limited nutritional plane, growth by other ruminant species can be more rapid or efficient than expected based on nutrient intake, because of increased feed intake and(or) efficiency of metabolism (NRC, 2000). NRC (2000) suggested that compensatory growth in cattle may occur for 2-3 month and that the ME requirement for maintenance could be decreased by 20% during this time, depending on the severity of restriction (e.g., level and length), with the reduction decreasing as the period of realimentation advances. Compensatory growth has also been observed in goats. But, there has not been enough research conducted to develop a system based directly on research findings to predict the ME requirement for maintenance after a low plane of nutrition. Nonetheless, because it is known to occur, it seems logical to present a possible system for use until a better alternative is available. To develop a system to predict an adjustment factor to be multiplied by the ME for maintenance requirement, body condition score (BCS; 1 - 5 with 0.5 increments; 1 = extremely thin and 5 = extremely fat) was employed. This adjustment or multiplication factor is applied to the ME for maintenance requirements in MJ/kg body weight (BW)0.75 or MJ/day, and are not applied to the actual amount of dietary ME used for maintenance in scenarios in which BW change is negative. The following table presents values predicted with the calculation method.
 Week after low nutritional plane stops and adequate nutritional plane starts
BCS 1 2 3 4 5 6 7 8 9 10 11
1.0 0.800 0.820 0.840 0.860 0.880 0.900 0.920 0.940 0.960 0.980 1.000
1.5 0.850 0.869 0.887 0.906 0.925 0.944 0.963 0.981 1.000 1.000 1.000
2.0 0.900 0.917 0.933 0.950 0.966 0.983 1.000 1.000 1.000 1.000 1.000
2.5 0.950 0.962 0.975 0.987 1.000 1.000 1.000 1.000 1.000 1.000 1.000
3.0 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
3.5 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
4.0 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
4.5 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
5.0 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000

As an example, if the calculated ME requirement of a goat in a BCS of 1.0 after a severe and long period of nutrient restriction is 10.0 MJ/day, the requirement in the subsequent first, fifth, and tenth week is 8.0 (10.0 MJ × 0.80), 8.80 (10.0 MJ × 0.88), and 9.8 MJ (10.0 MJ × 0.98), respectively. There would be no adjustment in the eleventh week.

1. Enter week after low nutritional plane stops and adequate nutritional plane starts
(enter 1 if during the period of the low nutritional plane)
2. Enter  
(To view photo depictions and to read descriptions for body condition scores, please click on the above button.)

    

Adjustment (multiplicative) of the ME requirement for maintenance by body condition score as influenced by previous nutritional plane:

Sources used (discussion and recommendations) for this calculation method are:

NRC. 2000. Nutrient Requirements of Beef Cattle, Update 2000. National Academy Press, Washington, DC.

Sahlu, T., A. L. Goetsch, J. Luo, I. V. Nsahlai, J. E. Moore, M. L. Galyean, F. N. Owens, C. L. Ferrell, and Z. B. Johnson. 2004. Nutrient requirements of goats: developed equations, other considerations and future research to improve them. Small Ruminant Research 53:191-219.