Changes

[[File:134957 Lat lumbar spine.jpg|200px|right|thumb|A 2 month old Great Dane puppy with a history of eating an unbalanced diet. The bone density is overall decreased with a poor corticomedullary distinction.]]

[[File:134957 Lat lumbar spine.jpg|200px|right|thumb|A 2 month old Great Dane puppy with a history of eating an unbalanced diet. The bone density is overall decreased with a poor corticomedullary distinction.]]

===Dog:===

===Dog:===

The classic syndrome of calcium deficiency in dogs is known as '''nutritional secondary hyperparathyroidism (NSHP)''', which is caused by a persistent decrease in circulating calcium in the blood (hypocalcaemia). This, in turn, stimulates the release of parathyroid hormone (PTH), which increases the reabsorption of bone to provide the calcium required to maintain a normal ionised calcium (iCa) blood concentration. The inevitable consequence is a major decrease in bone mineral content, which can lead to skeletal problems such as pathologic fractures <ref>Hazewinkel, HAW, van den Brom, WE, Vanꞌt Klooster, AT, Voorhout, G, Van Wees, A (1991). “Calcium metabolism in great Dane dogs fed diets with various calcium and phosphorus levels”. J. Nutr. 121 (suppl):S99-S106.</ref>. This is particularly serious for young puppies, where active growth of the skeleton is occurring. The condition typically results from feeding diets deficient in calcium such as those composed mainly of meats, since all meats (including offal) have a very low calcium content. The ratio of calcium to phosphorus is also important and it is the low ratio in these foods (i.e. Ca:P much less than 1:1) that contributes to the adverse effects because the '''high phosphorus level inhibits calcium absorption'''.

The classic syndrome of calcium deficiency in dogs is known as [[Hyperparathyroidism|'''nutritional secondary hyperparathyroidism (NSHP)''']], which is caused by a persistent decrease in circulating calcium in the blood (hypocalcaemia). This, in turn, stimulates the release of parathyroid hormone (PTH), which increases the reabsorption of bone to provide the calcium required to maintain a normal ionised calcium (iCa) blood concentration. The inevitable consequence is a major decrease in bone mineral content, which can lead to skeletal problems such as pathologic fractures <ref>Hazewinkel, HAW, van den Brom, WE, Vanꞌt Klooster, AT, Voorhout, G, Van Wees, A (1991). “Calcium metabolism in great Dane dogs fed diets with various calcium and phosphorus levels”. J. Nutr. 121 (suppl):S99-S106.</ref>. This is particularly serious for young puppies, where active growth of the skeleton is occurring. The condition typically results from feeding diets deficient in calcium such as those composed mainly of meats, since all meats (including offal) have a very low calcium content. The ratio of calcium to phosphorus is also important and it is the low ratio in these foods (i.e. Ca:P much less than 1:1) that contributes to the adverse effects because the '''high phosphorus level inhibits calcium absorption'''.

====Recognised Syndromes related to Calcium Deficiency====

====Recognised Syndromes related to Calcium Deficiency====

#'''Skeletal malformation''': Hazewinkel et al.<ref>Hazewinkel, HAW, van den Brom, WE, Vanꞌt Klooster, AT, Voorhout, G, Van Wees, A (1991). “Calcium metabolism in great Dane dogs fed diets with various calcium and phosphorus levels”. J. Nutr. 121 (suppl):S99-S106.</ref> described severe skeletal problems in Great Dane puppies fed diets with 0.55% calcium on a <span style="color:red">dry matter basis (DM) (hotline to definitions/glossary of terms)</span>. However Nap et al.<ref>Nap, R, Hazewinkel, HAW, van den Brom, WE (1993). “45Ca kinetics in growing miniature poodles challenged by four different dietary levels of calcium”. J. Nutr. 123:1826-1833.</ref> found no abnormalities in miniature poodle puppies (13-25 weeks) fed 0.33% calcium on DM. Nevertheless, in the same experiment<ref>Nap, R, Hazewinkel, HAW, van den Brom, WE (1993). “45Ca kinetics in growing miniature poodles challenged by four different dietary levels of calcium”. J. Nutr. 123:1826-1833.</ref>, NSHP was observed when a very low level of 0.05% calcium was fed. It is clear that giant, rapidly growing breeds are more sensitive to restrictions in dietary calcium.     

#'''Skeletal malformation''': Hazewinkel et al.<ref>Hazewinkel, HAW, van den Brom, WE, Vanꞌt Klooster, AT, Voorhout, G, Van Wees, A (1991). “Calcium metabolism in great Dane dogs fed diets with various calcium and phosphorus levels”. J. Nutr. 121 (suppl):S99-S106.</ref> described severe skeletal problems in Great Dane puppies fed diets with 0.55% calcium on a <span style="color:red">dry matter basis (DM) (hotline to definitions/glossary of terms)</span>. However Nap et al.<ref>Nap, R, Hazewinkel, HAW, van den Brom, WE (1993). “45Ca kinetics in growing miniature poodles challenged by four different dietary levels of calcium”. J. Nutr. 123:1826-1833.</ref> found no abnormalities in miniature poodle puppies (13-25 weeks) fed 0.33% calcium on DM. Nevertheless, in the same experiment<ref>Nap, R, Hazewinkel, HAW, van den Brom, WE (1993). “45Ca kinetics in growing miniature poodles challenged by four different dietary levels of calcium”. J. Nutr. 123:1826-1833.</ref>, NSHP was observed when a very low level of 0.05% calcium was fed. It is clear that giant, rapidly growing breeds are more sensitive to restrictions in dietary calcium.     

#'''[[Hypocalcaemia#Eclampsia|Eclampsia]]''': Also called ''lactation tetany'' or ''milk fever'', eclampsia is a disease occurring during the later stages of pregnancy or soon after parturition (1-3 weeks postpartum). It is characterised by '''loss of consciousness, convulsions or both and is associated with severe hypocalcaemia''', although its aetiology is not completely understood. Proposed mechanisms include poor dietary intake, excessive calcium losses during lactation and abnormal parathyroid gland function<ref>Schenck, PA, Chew, DJ, Nagode, LA, Rosol, TJ. (2012). “Disorders of Calcium: Hypercalcemia and Hypocalcemia. In: Fluid, Electrolyte, and Acid-Base Disorders, 4th Edition. Dibartola SP (Editor). Sanders Elsevier St Louis, MO pp 120-194.</ref>. In addition, there may be a predisposition of this condition in toy breeds<ref>Austad, S, Bjerkas, E (1976). “Eclampsia in the bitch”. J. Small Anim. Pract. 17:793-798.</ref>. Clinical signs in dogs are typically not seen until total calcium concentration drops below 1.6 mmol/L [6.5 mg/dL] or iCa drops below 0.7 mmol/L [2.8 mg/dL].

#'''[[Hypocalcaemia#Eclampsia|Eclampsia]]''': Also called ''lactation tetany'' or ''milk fever'', eclampsia is a disease occurring during the later stages of pregnancy or soon after parturition (1-3 weeks postpartum). It is characterised by '''loss of consciousness, convulsions or both and is associated with severe hypocalcaemia''', although its aetiology is not completely understood. Proposed mechanisms include poor dietary intake, excessive calcium losses during lactation and abnormal parathyroid gland function<ref>Schenck, PA, Chew, DJ, Nagode, LA, Rosol, TJ. (2012). “Disorders of Calcium: Hypercalcemia and Hypocalcemia. In: Fluid, Electrolyte, and Acid-Base Disorders, 4th Edition. Dibartola SP (Editor). Sanders Elsevier St Louis, MO pp 120-194.</ref>. In addition, there may be a predisposition of this condition in toy breeds<ref>Austad, S, Bjerkas, E (1976). “Eclampsia in the bitch”. J. Small Anim. Pract. 17:793-798.</ref>. Clinical signs in dogs are typically not seen until total calcium concentration drops below 1.6 mmol/L [6.5 mg/dL] or iCa drops below 0.7 mmol/L [2.8 mg/dL].

===Cat:===

===Cat:===

The effects of calcium deficiency in cats are broadly similar to those in dogs in terms of effects on bone formation, although there is little if any breed variation. This is to be expected given the much narrower bodyweight range in the cat. As with dogs, the calcium requirement of kittens decreases with increasing age<ref>Pastoor, F, Opitz, A, Vanꞌt Klooster, AT, Beynen, A (1994) “Dietary calcium chloride vs. calcium carbonate reduces urinary pH and phosphorus concentration, improves bone mineralization and depresses kidney calcium level in cats”. J. Nutr. 124:2212-2222.</ref>. Cats can also suffer from eclampsia but this is not as common as in dogs.

The effects of calcium deficiency in cats are broadly similar to those in dogs in terms of effects on bone formation, although there is little if any breed variation. This is to be expected given the much narrower bodyweight range in the cat. As with dogs, the calcium requirement of kittens decreases with increasing age<ref>Pastoor, F, Opitz, A, Vanꞌt Klooster, AT, Beynen, A (1994) “Dietary calcium chloride vs. calcium carbonate reduces urinary pH and phosphorus concentration, improves bone mineralization and depresses kidney calcium level in cats”. J. Nutr. 124:2212-2222.</ref>. Cats can also suffer from eclampsia but this is not as common as in dogs.