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Submitted to: Western Beef Producer
Publication Type: Popular Publication Publication Acceptance Date: 2/1/1998 Publication Date: N/A Citation: N/A Interpretive Summary: This is a review paper covering factors during the peripartum period that affect calf survival. Nutrition of the pregnant dam must be adequate in both energy and protein since deficiencies in energy result in high incidences of scours. Protein deficiencies result in symptoms typical of Weak Calf Syndrome. The transition the calf makes from the uterine environment to exposure to an often hostile external environment requires metabolic heat production that prevents hypothermia. Heat produced during this time period is from shivering (muscle activity) and nonshivering thermogenesis. Nonshivering thermogenesis results from metabolism of brown adipose tissue (BAT) which can account for up to 22% of the cardiac output and produce 40% of the heat produced in the neonate. Development of BAT can be affected by the gestation diet of the dam with feeding fat containing a high percentage of linoleic fatty acid showing the greatest effect. Slow or difficult parturition results in varying degrees of anoxia. This condition reduces calf survival through changes induced in blood parameters, delayed suckling, reduced intake of colostrum and lowered levels of circulating antibodies in the calf. Body temperature of the dam drops 10 to 18 hours prepartum. This drop may protect the calf from hyperthermia during parturition and may also act as a mechanism of heat transfer to the calf which aids in the temperature transition made at parturition. Technical Abstract: This is a review paper covering factors during the peripartum period that affect calf survival. Nutrition of the pregnant dam must be adequate in both energy and protein since deficiencies in energy result in high incidences of scours. Protein deficiencies result in symptoms typical of Weak Calf Syndrome. The transition the calf makes from the uterine environment to exposure to an often hostile external environment requires metabolic heat production that prevents hypothermia. Heat produced during this time period is from shivering (muscle activity) and nonshivering thermogenesis. Nonshivering thermogenesis results from metabolism of brown adipose tissue (BAT) which can account for up to 22% of the cardiac output and produce 40% of the heat produced in the neonate. Development of BAT can be affected by the gestation diet of the dam with feeding fat containing a high percentage of linoleic fatty acid showing the greatest effect. Slow or difficult parturition results in varying degrees of anoxia. This condition reduces calf survival through changes induced in blood parameters, delayed suckling, reduced intake of colostrum and lowered levels of circulating antibodies in the calf. Body temperature of the dam drops 10 to 18 hours prepartum. This drop may protect the calf from hyperthermia during parturition and may also act as a mechanism of heat transfer to the calf which aids in the temperature transition made at parturition. |
