It depend by which animal we are talking. Metabolism or simply put body size is obviously very important : a mouse body condition can change in a week while in a camel take several months. Obviously the physiological status play an important role : body condition changes in a lactating animal take much longer time (if at all) then a castrate adult, in a weaned calf much more then a suckling calf .  

It depends completely on the energy balance over time. Animals that are losing a large amount of stored body energy and protein for a function such as producing milk without having sufficient energy intake to meet that need will lose body condition score quickly. Mature animals that are not "growing" or "lactating" will lose body condition score slowly, even with restricted energy intake. Animals with a very high metabolic rate, such as humming birds, may live only a few day without adequate food intake because of loss of body energy. Some species, such as seals and certain bears, will store a lot of energy and then may go for months without consuming any food while their body condition declines naturally. So there is not easy rule to answer your question.

It depends on animal species, body condition status and age. I increased the body condition of  ewes from 2 to 3 in 35 days by feeding a diet 2.65 Mcal ME/kg at 85g per Metabolic weight. Raising condition from 3 to 3.5 needs same time. This is for a medium framed breeds.

The body condition score indicates fatness of an animal, so the score is dominantly linked to the fact content. For sheep the relationship between fat content and body condition score can be found from Rusell et al. 1969, J Agri Sci Camb 72: 451-454. in that paper. An change in bod fat content can be estimated from estimated daily energy balance. Based on the change of daily fat content, you can estimate the duration required for a detectable change in body condition score.  

thank you for all

I ask about the condition score in dairy cattle...after application of management technique (not feeding regime)

Hello Naglaa Abdel Azeem, you need to elaborate on the management technique so that we can reason accordingly, some techniques are feed-based while some are health-based, physiological effects on your animals, welfare, e.t.c

further clarification to my previous answer. The impact of management techniques aiming at "improving body conditions" differ widely if you are targeting lactating cattle or young growing animal or adult males or castrates. Body conditions of a lactating cow are difficult to modify rapidly once the lactation has started. The same slow response is present in fully mature males or castrates. In my experience body conditions can be RAPIDLY modified: improved, mainly in young,weaning or growing animals.    

thank you