L.R. McDowell

Nutrition of grazing ruminants in warm climates.

From the Preface The objective of this book is to review the basic knowledge and methodology of feeding grazing ruminants in tropical and semitropical countries. It is hoped this information will be of use to farmers, research specialists, teachers, students, extension specialists, feed manufacturers, and others throughout the world concerned with the nutrition of grazing ruminants. A unique feature is the identification of nutritional limitations of grazing ruminants in the tropics, which will be beneficial for increasing animal production efficiency through the application of improved nutrition. A large number of photographs illustrate nutritional deficiencies and conditions in tropical countries. This book contains 18 chapters concerned with the nutrition of grazing ruminants. The first chapter deals with the contributions, locations, and various types of ruminants and their importance to human welfare in the tropics and subtropics. Chapters 2 - 4 progress through nutrient requirements of grazing ruminants in warm climates, the effects of tropical heat on these requirements, and water requirements for ruminant species. Chapters 5 - 7 discuss grass and legume forage species suitable for tropical regions, pasture management procedures, and energy-protein supplementation programs needed during the extensive dry periods. The importance of tropical forages and soils toward meeting mineral requirements is discussed in Chapter 8. Chapters 9 -14 contain concise, up-to-date summaries of minerals emphasizing mineral status, incidence of mineral deficiencies and excesses in tropical regions, and benefits and methods of mineral supplementation for grazing ruminants are discussed in Chapters 15 - 17. Chapter 18 reviews vitamin nutrition considerations for ruminants consuming tropical forages.

Variation in the nutritional value of primate foods: Among trees, time periods, and areas

The study of nutritional ecology has proven to be useful for understanding many aspects of primate behavior and ecology and is a valuable tool in primate conservation. However, to date this approach has had limited application since chemical analyses of food items is very time-consuming and collections of perishable food material are often made in remote field locations. Such logistic difficulties have led to plant material being collected in a variety of fashions, and it is not known how variation in collection method might influence our understanding of the chemical basis of dietary selection. A standardization of collection methods is greatly needed to allow for direct comparison among studies. To develop an appropriate standardized method and to evaluate past research, it is necessary to understand along what dimensions plant chemistry varies. We evaluated variation in nutritional value—protein, fiber, digestibility, alkaloids, saponins, cyanogenic glycocides, and minerals—of leaf material from species eaten by red colobus (Piliocolobus tephrosceles) and black-and-white colobus (Colobus guereza) of Kibale National Park, Uganda. We consider variation at 3-levels: among trees, time periods, and areas. While there was considerable variation among species with respect to protein, digestibility, and saponins, there was also variation among individuals of the same species; in fact, individuals may vary by as much as 20%. The average coefficients of variation (CV) among individuals of the same species are 13.4 for protein, 12 for digestibility, and 43 for saponins, while the average CV among species are 35, 31.3, and 82.4, respectively. No species showed a variable response with respect to testing for the presence or absence of cyanogenic glycocides, while 2 of 11 species tested for alkaloids showed a variable response. Over 2 years there was evidence of variation among time periods in the chemical composition of the same food items. The protein-to-fiber ratio of mature leaves of the same species collected from 4 sites separated by 12 km within Kibale was also variable and in some cases the variation among sites was greater than the differences among species. For example, while Funtumia latifolia had little variation in protein-to-fiber ratio at 3 sites (0.44 at all sites), the remaining site was 28% greater. Because temporal variation is less than variation among individuals, it is likely more important to sample from multiple trees at a single point in time than to sample across time. However, the most accurate assessment of nutrient intake is obtained by collecting plant material from the specific trees selected for consumption.

Feeding minerals to cattle on pasture

Mineral deficiencies and imbalances for cattle are reported from almost all regions of the world. The mineral elements most likely to be lacking under grazing conditions for ruminants are Ca, P, Na, Co, Cu, I, Se and Zn. In some regions, under specific conditions, Mg, K, Fe and Mn may be deficient and excesses of F, Mo and Se can be extremely detrimental. In most countries of the world, the principal means by which cattle producers attempt to meet mineral requirements of their grazing herds is through use of free-choice dietary minerals. As a low cost insurance to provide adequate mineral nutrition, a modified ‘complete’ mineral supplement should be available free-choice. Calcium, Cu or Se, when in excess, can be more detrimental to cattle production than any benefit derived by providing a mineral supplement. The major disadvantage to free-choice minerals is lack of uniform consumption by animals. Factors influencing consumption of mineral mixtures include: (1) soil fertility and forage type, (2) season of year, (3) available energy and protein, (4) individual requirements, (5) salt content of water, (6) palatability of mineral mixture, (7) availability of fresh minerals and (8) physical form of minerals. Safe, biologically available and palatable forms of minerals, at a fair price, allow both the user and manufacturer to realize a profit from their use. Mineral supplements need to be evaluated for accuracy of formulation and suitability for cattle. Most studies have shown positive responses of mineral chelates and complexes when compared to inorganic sources.

Vitamin E supplementation for the ruminant

Vitamin E is essential for such body functions as growth, reproduction, prevention of various diseases, and for integrity of tissues. The most significantly important result of selenium and vitamin E deficiency is tissue degeneration (e.g. white muscle disease). Vitamin E does not cross the placenta in any appreciable amounts; however, it is concentrated in colostrum. Supplemental vitamin E can greatly increase colostral tocopherol. The importance of providing colostrum rich in vitamin E is essential as both calves and lambs are born with low levels of the vitamin. Vitamin E has been shown to increase performance of feedlot cattle and to increase immune response for ruminant health, including being beneficial for mastitis control. Vitamin E given to finishing cattle at higher than National Research Council (NRC) requirements dramatically maintained the red color (oxymyoglobin) compared with the oxidized metmyoglobin of beef. It appears that supplementation of 500 IU vitamin E per head daily for 84–126 days yields tissue α-tocopherol that would maintain a favorable level of oxymyoglobin in meat, thus increasing its value. Vitamin E nutritional status is commonly estimated from plasma concentration, with a high correlation between plasma and liver levels of α-tocopherol. The NRC estimates for vitamin E requirements of beef cattle, dairy cattle and sheep to range from 15 to 40 mg kg−1; however, higher levels will likely improve performance, and megadose levels will improve carcass quality.

Mineral Resource Availability and Consumption by Colobus in Kibale National Park, Uganda

Very little information exists on mineral nutrition of tropical, forest-dwelling species, yet minerals are critical to growth, reproduction, and survival. We examined the mineral resources available to and consumed by colobus in Kibale National Park, Uganda. We combined behavioral data on black-and-white (Colobus guereza) and red colobus (Piliocolobus tephrosceles) in a section of unlogged forest, a heavily logged area, and a forest fragment with mineral analysis of their foods to estimate the proportion of the diet containing specific minerals (mineral content). We compared mineral content of colobus foods (natural and crops) across plant parts and among plant species. Additionally, we estimated mineral intake of frugivorous primates in Kibale from published dietary data and our estimates of mineral content of foods. Dietary mineral content for all colobus groups and frugivorous species is similar despite significant differences in the mineral content of foods. Ripe and unripe fruits are lower in mineral content than most foods. Foods rarely consumed, such as bark, petioles, and caterpillars have high levels of some minerals. The mineral content of crops is low in comparison to that ofnatural foods. For all colobus groups of both species, sodium content of foods was extremely low and iron content was generally low, suggesting that intake isbelow suggested requirements, though current suggested iron requirements may overestimate physiological needs. Copper content was marginal and deficient seasonally for most colobus groups. Despite a sodium-limiting environment, only one of 8 colobus groups appeared to select sodium; however, this may be due to a lack of variation in sodium content among plant species and a positive correlation between high plant sodium content and secondary compounds. Despite the lack of selection for sodium by colobines, some behaviors point to a potential sodium deficiency, including urine drinking, consumption of high-sodium swamp plants, and use of mud-puddles.

Geophagy in the African Elephant in Relation to Availability of Dietary Sodium

Abstract We studied the use of mineral licks by African elephants (Loxodonta africana) during the dry season in a Kalahari-sand habitat in Hwange National Park, Zimbabwe, to investigate the role of geophagy as a mechanism for supplementing low Na+ levels in browse and natural water supplies. Plant, water, and soil macrominerals were measured to evaluate mineral availability for elephants during the dry season. Elephant behavior was monitored at licks to investigate the intensity of geophagy (measured by number of mouthfuls of soil consumed) in relation to fecal-Na+ loss. Female elephants, which probably had greater requirements than did males because of pregnancy and lactation, consumed more mouthfuls of soil and spent a greater part of their activity budget feeding on soil than did males, suggesting that geophagy may be driven by a nutritional requirement. We found the following consistent with the Na+-supplementation hypothesis: 1) unlike other minerals, Na+ in woody plants and natural water supplies may be inadequate to meet the minimum requirements of elephants during the dry season; 2) soils consumed by elephants differed from other soils primarily in their high Na+ content; 3) intensity of geophagy was negatively correlated with fecal Na+; and 4) elephants in non–Kalahari-sand habitats do not appear to create or use licks, probably because they are able to meet their Na+ requirements from ubiquitous Na+-rich water supplies, which do not occur naturally in Kalahari-sand habitats.

Nutritional ecology of elephants in Kibale National Park, Uganda, and its relationship with crop-raiding behaviour

This study investigated the nutritional ecology of forest elephants in Kibale National Park, Uganda relative to crop-raiding behaviour, and examined nutritional differences between crops and food consumed by wild elephants. An index of dietary nutrient concentration was determined by quantifying the species and parts of plants consumed along feeding trails, collecting food items, and analysing foods for energy, fibre, protein, minerals and secondary compounds. Frequency of crop raiding was quantified over 13 mo. Energy and protein concentration was within suggested levels, but concentrations of several minerals, particularly sodium, were low relative to requirements based on captive elephants and values reported for other wild populations. The very low sodium concentrations of Kibale elephant diets and low availability of alternative sodium sources, such as soil or water, suggest that sodium drive is very likely in this population. Crops consumed by Kibale elephants had higher Na concentrations and lower concentrations of fibre and secondary compounds than wild diets. The known attraction of elephants to mineral sources throughout their range and the low mineral concentration of leaves, fruits, bark, and stems consumed by forest elephant in this study suggest that mineral nutrition is likely to be an important factor driving elephant behaviour and patterns of habitat use.

Monthly variation of forage and soil minerals in Central Florida. II, Trace minerals

Abstract A two‐year study was conducted to determine the trace mineral status of cattle grazing forages (bahiagrass) and soils on a ranch in central Florida. Forage and soil samples were collected every month for two years. Month effect (P 0.05) in forage trace mineral concentrations. Few and low correlation coefficients were observed between and within soil and forage trace minerals concentrations. Percentages of total forage collected with trace minerals below critical values (in parentheses) and suggestive of deficiency...

Effects of pasture‐applied biosolids on forage and soil concentrations over a grazing season in north Florida. II. microminerals

Abstract The experiment rationale was to determine forage micromineral concentrations as effected by biosolids fertilization. We determined the effects of two exceptional quality biosolids on bahiagrass trace mineral concentrations as related to beef cattle requirements. Twenty‐five 0.8‐ha pastures were divided into five blocks. Two biosolids were applied as normal and double agronomic rates. The control received NH4NO3. Forages were analyzed for total copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), molybdenum (Mo), cobalt (Co), and selenium (Se), and soils were analyzed for Mehlich I extractable Cu, Mn, and Zn. Some significant increases (P<0.05) in forage Co, Cu, Fe, Zn, and Se were observed at various sampling times, but the increases were generally small and biologically insignificant. Although forage Mo samples from pastures with the Tampa biosolids applied were consistently higher than the control (P<0.05), at no time did they approach levels considered toxic. Similar results were seen in forage Mn concentrations, with treatment Baltimore‐2X elevating (P<0.05) Mn concentrations as well. Deficiencies of Co, Cu, Zn, and Se are common in this Florida region and slight elevations due to biosolids treatment could be beneficial. Biosolids applied at the highest rates improved soil Cu and Zn concentrations above control soils and soil Mn was increased over the control at both sampling times for Baltimore‐2X. In relation to beef cattle requirements, the majority of forages were deficient in Co, Cu, Se, and Zn. In summary, biosolids fertilization slightly improved the micromineral status of forage and soil, without creating toxicity.

Seasonal variation of soil and forage mineral concentrations in north Florida

Abstract A two‐year study was conducted in north Florida on two farms located near Bronson and Williston for beef cattle grazing bahiagrass pastures. Soil concentrations of Ca, P, Mg, Na, and Cu were similar for both locations and seasons for either year. At Bronson soil, Se was higher than at Williston in 1988, but in 1989, soil Se at Williston was higher in the late than in the main grazing season. All soil salnples analyzed were deficient in K and Se, and over 63% of samples were found deficient for Mg, Zn, P, Cu, and Mn. Acidity did not appear to be a problem in soil mineral availability, since mean pH was 5.5 and higher. Forage concentrations of Ca, Na, Fe, Co, Mo, and protein were similar for all seasons and locations during 1988; however, greater (P < 0.05) concentrations of P, K, Cu, and Zn were found in June than in October. In 1989, forage concentrations of Ca, K, Na, Zn, Co, Mg, and Cu were higher in the early grazing season (March‐May) than during the rest of the year; however, concentrations ...