Degree Of Negative Energy Balance Research Articles

Factors to Concentrate on to Prevent Periparturient Disease in the Dairy Cow With Special Emphasis on Milk Fever

Efficient milk production continues to require the dairy cow to experience gestation and parturition each year. The transition from pregnant, non-lactating to non-pregnant, lactating is too often a disastrous experience for the cow. Most of the metabolic diseases of dairy cows - milk fever, ketosis, retained placenta, and displacement of the abomasum - occur within the first 2 weeks (wk) of lactation. The etiology of many of those metabolic diseases that are not clinically apparent during the first 2 wk of lactation, such as laminitis, can be traced back to insults that occurred in early lactation. In addition to metabolic disease, the overwhelming majority of infectious diseases, especially mastitis, but also diseases such as Johne's disease and Salmonellosis, become clinically apparent during the first 2 wk of lactation. The well-being of the cow and her profitability could be greatly enhanced by understanding those factors that account for the high disease incidence in periparturient cows.
 Three basic physiologic functions must be maintained during the periparturient period if disease is to be avoided. These are: 1. adaptation of the rumen to high energy density lactation diets to reduce the degree of negative energy balance experienced by the cow; 2. maintenance of normocalcemia; and 3. reducing the degree of immunosuppression that occurs around parturition. Both metabolic disease and infectious disease incidence are greatly increased whenever one or more of these physiological functions is impaired. The etiological role of each of these three physiological factors on the development of each of the common diseases encountered during the periparturient period is discussed more fully in reference.17 A brief discussion of the etiology of several important periparturient diseases is presented below.

Rate of weight loss during underfeeding: Relation to level of physical activity

The kinetics and bioenergetic-metabolic determinants of weight loss were examined in obese women ingesting 900 kcal/d for 5 weeks. The patients were assigned either to a sedentary group (n = 5) or to an exercise group (n = 6) in which the participants expended an additional ( X ± SD) 346 ± 61 kcal/d in aerobic physical activity. The percentage weight loss and the fractional rates (K1 = fast component; K2 = slow component) of weight loss were almost identical between the two groups. The failure of added exercise to increase the velocity of weight loss could not be explained by differences between the groups in any of the following: gastrointestinal energy and nitrogen (N) absorption; fractional rates of urinary urea N and total N loss; or the thermic effect of the formula diet. The cumulative and fractional rates of protein (ie N) loss were also similar between the groups. The exercise group lost more fat (5.3 ± 1.0 kg) than the non-exercise group (4.4 ± 1.6 kg, P < .001) as measured by underwater weighing. The maximum between-group difference in the rate of fat loss, as determined by energy-N balance, occurred during early underfeeding. With continuation of the 900 kcal/d diet, the between-group differences in the rate of fat loss diminished. The exercise subjects significantly lowered their resting heat losses relative to the non-exercise subjects ( P < .025). This in turn reduced the degree of negative energy balance in the more energy-deficient exercise group. While the rates of protein plus fat loss in the exercise group exceeded that observed in the non-exercise subjects, the rate of H 2O depletion was diminished in the exercise group. Hence, the combined effects of an equivalent rate of protein depletion, a decrease in the rate at which added exercise promotes fat loss over time, and a reduced rate of H 2O loss account for the failure of additional physical activity to accelerate weight loss over a 5-week underfeeding period.

Seasonal patterns of energy allocation to basal metabolism, activity and production for livestock in a nomadic pastoral ecosystem

SummaryEnergy budgets and estimates of forage intake requirements were developed for adult camels, cattle, sheep, and goats managed by nomads in the arid Turkana District of north-western Kenya. The estimates were developed by combining our field data on livestock activity patterns, diet quality, weight changes and milk yields with literature based estimates of the associated costs and efficiencies. On an annual basis, the average animal walked 17 km/day and had a total metabolizable energy (ME) allocation of 47% for basal metabolism, 16% for travel, 14% for other activities, and 23% for production. Season and species influenced patterns of energy demand and allocation. Average daily ME requirements ranged from 8·7 MJ (sheep) to 76·7 MJ (camels). ME demand for all species peaked during wet (April-May) or early-to mid-dry periods (June-October), and decreased considerably in the late-dry season (November-March). In the wet season the average sheep or goat allocated 45% of its ME budget to production of milk and gain, followed by cattle (36%) and camels (25%). All species were more similar in ME allocation for production during the late-dry season (7–13%; all to lactation), yet patterns of weight loss during this time indicated that camels experienced the lowest degree of negative energy balance. On an annual basis, camel budgets were the most deviant, as they allocated relatively more ME to activity and relatively less to basal metabolism or weight gain. Estimates of forage dry-matter intakes (per unit live weight per day) ranged from 3·8% (cattle, camels) to 4·6% (sheep, goats) throughout the year, and intakes declined for most species by an average of 50% from the wet to late-dry intervals. This approach has revealed ecological differences among livestock species that help explain the utility of multi-species holdings in this system.