Some statistics say that on earth there are approximately 5500 mammal species.I have seen a video of Mother Cape Buffalo protecting it's calf from being eaten by predative animals.Like Mother Cape Buffalo,do remaining mammal mother species also try to protect their babies from being eaten by predative animals?
There is quite a bit of evidence showing that mothers of a number of mammalian species will sometimes kill and eat their own young. E.g. https://www.nationalgeographic.com/news/2014/3/140328-sloth-bear-zoo-infanticide-chimps-bonobos-animals/
It's a hard question to answer definitively, because it's almost a black-swan problem. By definition, all mammal species secrete some form of milk to nourish their offspring (to my knowledge there are no known exceptions to this) [See "Mammalogy: Adaptation, Diversity, Ecology" by Feldhammer et al.]. It could be argued that the mere proximity of smaller young to their larger mothesr would deter some predators who might otherwise prey on those young. So, from a behavioral perspective, it's difficult to completely separate parental feeding from other protective parenting behaviors.
If you are only interested in more specific exceptions, it's not uncommon for some mammals to reject and abandon their offspring, or even cannibalize their young. But these behaviors are generally based on situational or environmental cues, like whether the mother has enough nutrients available to raise the young.
If you think about the evolutionary implications, it seems fairly straight forward why this is the case. Most mammals give live birth. For all parenting bahavior to completly vanish from a given population, there would have to be a greater fitness advantage for offpring of mothers who completly abandon their young at birth compared to those who provide nourishment and therfore (arguably) protection from predators.