Activity of various rumen organisms results in accumulation of various volatile fatty acids (normally, mostly acetic, propionic, and butyric acids), which are partially dissociated. Although some lactate is normally produced in the rumen, it is normally metabolized by such organisms as Megasphaera elsdenii and, to a lesser extent, Selenomonas ruminantium and some other organisms. With high grain consumption, the concentration of dissociated organic acids can become quite high, resulting in rumen pH dropping below 6. Within this lower pH range, Lactobacillus spp. (producing lactate and hydrogen ions) are favored, and M. elsdenii and S. ruminantium are inhibited, tending to result in a considerable rise of lactate and hydrogen ion concentrations in the rumen fluid. The pKa of lactic acid is low, about 3.9, versus, for example, 4.8 for acetic acid; this contributes to the considerable drop in rumen pH which can occur.Because of the high solute concentration of the rumen fluid under such conditions, considerable water is translocated from the blood to the rumen along the osmotic potential gradient, resulting in dehydration which cannot be relieved by drinking, and which can ultimately lead to hypovolemic shock. As more lactate accumulates and rumen pH drops, the ruminal concentration of undissociated lactic acid increases. Undissociated lactic acid can cross the rumen wall to the blood, where it dissociates, lowering blood pH.
Smith–Magenis Syndrome (SMS), also known as 17p- syndrome, is a microdeletion syndrome characterized by an abnormality in the short (p) arm of chromosome 17. It has features including intellectual disability, facial abnormalities, difficulty sleeping, and numerous behavioral problems such as self-harm. Smith–Magenis syndrome affects an estimated between 1 in 15,000 to 1 in 25,000 individuals. Signs and symptoms
Facial features of children with Smith–Magenis syndrome include a broad and square face, deep-set eyes, large cheeks, and a prominent jaw, as well as a flat nose bridge (in the young child; as the child ages it becomes more ski-jump shaped). Eyes tend to be deep-set, close together and upwards-slanted. Eyebrows are heavy with lateral extension. The mouth is the most noticeable feature; both upper and lower lips are full, and the mouth is wide. The mouth curves downwards and the upper lip curves outwards, due to a fleshy philtrum. These facial features become more noticeable as the individual ages, as Mandible growth outstrips that of the maxilla leading to a clear midface hypoplasia. There is also a mild brachycephaly.Disrupted sleep patterns are characteristic of Smith–Magenis syndrome, typically beginning early in life. Affected individuals may be very sleepy during the day, but have trouble falling asleep and awaken several times each night, due to an inverted circadian rhythm of melatonin.People with Smith–Magenis syndrome have engaging personalities, but all also have a lot of behavioral problems. These behavioral problems include frequent temper tantrums, meltdowns and outbursts, aggression, anger, fidgeting, compulsive behavior, anxiety, impulsiveness, and difficulty paying attention.