Steven M. Parish

Food Intake and Foraging Energetics of Elk and Mule Deer

The energetic cost of grazing was measured using indirect calorimetry with a tracheotomized elk (Cervus elaphus nelsoni). The cost of eating herbaceous forage averaged 0.32 kcal/kg body weight/ hour, an energetic increment of 26% over standing costs. Forage intake was quantified using esophageal fistulated elk and mule deer (Odocoileus hemionus hemionus). Dry matter consumption rate and mean bite size increased curvilinearly as functions of forage biomass for both species. Asymptotic grass intake rates were 2.22 and 14.04 g dry matter/minute for deer and elk, respectively. Consumption rate and bite size were greater in shrub-forb communities than on grass pastures of comparable biomass. Biting rate ranged from about 15 to 60 bites/minute and was inversely related to bite size. Rate of travel during foraging decreased exponentially with increasing forage availability. A computer model was constructed to evaluate the interaction of time and energy constraints on foraging ungulates. The effects of variation in forage quality, forage abundance, and snow cover on the ability of animals to meet daily energy requirements are discussed. J. WILDL. MANAGE. 48(4): 1285-1301 Foraging is the dominant activity of free-ranging ungulates. Wild ungulates typically devote 40-60% of each day to finding and consuming food (Craighead et al. 1973; White et al. 1975; Schwartz 1977; Belovsky and Jordan 1978; Collins et al. 1978; Owen-Smith 1979, 1982; Gates 1980; Hanley 1982). The energetic cost of these activities represents an important component of the animals energy budget (Young 1966, Osuji 1974, Chappel and Hudson 1978). However, in spite of the significance of foraging in the life strategy of wild ungulates, relatively little is known about the energetics of this behavior. The literature is replete with food habits information, but such observations are of limited value without an understanding of the efficiency with which the animal harvests the food resource and extracts energy from its environment. This study was undertaken to quantify the cost-benefit functions of foraging by captive elk and mule deer relative to food availability. Specific objectives were to: (1) determine forage intake rate as a function of the biomass of acceptable food items; (2) determine the relationship of intake rate to mean bite size and biting rate to better understand the behavioral adjustments that regulate energy intake; (3) quantify locomotion rate during foraging relative to food availability; (4) measure the energetic cost of eating as distinct from expenditures for standing and locomotion; and (5) model the effects of variation in forage quality and abundance on the ability of free-ranging cervids to meet daily energy requirements. This project was funded by the U.S. For. Serv. and Washington State Univ. We thank K. L. Parker for support and assistance in data collection and M. A. Reisenauer for the care of experimental animals. L. D. Bryant and J. W. Thomas provided facilities at the U.S. For. Serv. Range and Wildl. Habitat Lab. in La Grande, Oregon. J. Wildl. Manage. 48(4):1984 1285 This content downloaded from 157.55.39.29 on Tue, 12 Apr 2016 10:03:48 UTC All use subject to http://about.jstor.org/terms 1286 INTAKE AND FORAGING ENERGETICS OF ELK AND DEER * Wickstrom et al. METHODS AND MATERIALS Elk calves and mule deer fawns were bottle-raised and habituated to the experimental protocol. Training included acceptance of gentle restraint with a head halter, manipulation of the esophageal and tracheal cannulae, and transport in a trail-

Bovine neonatal immunology.

Early fetal immune development occurs independent of antigen exposure, whereas later development depends on exposure to specific antigens. Although neonates are immunocompetent at birth, they are clearly immunonaive and dependent on passively acquired maternal immunoglobulins, immune cells, and other substances from colostrum for protection. Neonates that suffer failure of passive transfer of maternal immunoglobulins may be at increased risk for disease; however, many other factors interact in conjunction with the level of passively acquired immunoglobulin to determine the occurrence of disease.

Preclinical detection of PrPSc in nictitating membrane lymphoid tissue of sheep

observed in donkeys infected by larvae of Rhinoestrus usbekistanicus (Kaboret and others 1996). The pathology is probably caused by permanent antigenic stimulation during the infection. In both of these myiases, considerable numbers of eosinophils and mast cells have been observed in the lung parenchyma, mainly in the peribronchial region. In the absence of any other lung parasite and any cause of allergic pneumonia it is presumed that aspirated larval antigen induces pulmonary sensitisation. It has recently been suggested that mast cells could induce lung fibrosis; histamine and serotonin stimulate the growth factor for fibroblasts in vitro and in vivo. In vitro co-cultivation of fibroblasts and mast cells resulted, first, in the maturation of mast cells which, in turn, stimulated the growth of fibroblasts and the synthesis of collagen (Tunon de Lara and others 1996). The same hypothesis could possibly explain the development of interstitial pneumonia in oestrosis in both sheep and donkeys.

The age-related immunity in cattle to Babesia bovis infection involves the rapid induction of interleukin-12, interferon-gamma and inducible nitric oxide synthase mRNA expression in the spleen.

Young calves possess a strong innate immunity against Babesia bovis infection that lasts for approximately 6 months after birth and is abrogated with the removal of the spleen. This immunity is characterized as cellular involving a soluble mediator. Nitric oxide has been implicated by virtue of its babesiacidal affects in vitro, but questioned to be as effective in vivo, due to its ability to downregulate type‐1 immunity. Spleen cells were obtained from 4‐month‐old calves and adult steers and processed for monitoring cytokine and inducible nitric oxide synthase (iNOS) mRNA expression during the response to initial B. bovis infection. The data provided evidence of a transient role for nitric oxide in innate immunity, characterized by brief iNOS induction in the spleen of calves that was not detectable in the spleens of adults. The iNOS message followed the early induction of interleukin (IL)‐12 and interferon (IFN)‐γ message in calves. The induction of IL‐12 and IFN‐γ message in adults was delayed until IL‐10 message was induced. Transformation growth factor‐β mRNA expression levels were greater in spleen cells from adults early in infection and then declined, whereas expression levels increased in spleen cells from calves later in the infection process. Together, the data support the concept of ‘first come, first serve’ cytokine influence over cellular activities, the importance of a type‐1 response in the control of an initial infection and the need for tight regulation in order to prevent pathology associated with over production of nitric oxide and inflammatory cytokines.

Molecular and Biological Characterization of a Newly Isolated Anaplasma Marginale Strain

Anaplasma marginale, a rickettsial hemoparasite of cattle and other ruminants, results in significant economic losses worldwide. Distinct strains of A. marginale have been identified based on differences in tick transmissibility, molecular size of surface proteins and DNA restriction fragments, and reactivity to a panel of monoclonal antibodies. These different strains vary considerably in their virulence, antigenic composition, and ability to protect against heterologous challenge. In this paper, we report on the molecular characterization of a newly isolated strain of A. marginale, designated St. Maries, recovered from an acutely infected cow in northern Idaho. Dermacentor andersoni ticks taken from the infected animal were tested for infection by RNA probe analysis. The infection rate of male ticks (as determined by midgut infection) was 100%, and the infection rate of female ticks was 83%. Infected male ticks were able to transmit the St. Maries strain to a susceptible calf. The high infection rate in male ticks may be particularly relevant, given that male ticks are believed to be epidemiologically important in transmission of A. marginale because of their intermittent feeding behavior, which promotes interhost transfer. The newly isolated strain differs from other US strains, including strains previously isolated in Idaho and Washington, based on reactivity to a panel of monoclonal antibodies and restriction fragment length polymorphisms. These results imply that antigenically distinct strains of A. marginale may arise within the same region. However, because epitopes previously demonstrated to be conserved in other A. marginale strains were also present in the St. Maries strain, it is possible to develop diagnostic tests against conserved epitopes that could be used for early identification of infected cows or ticks.

Disseminated Bovine viral diarrhea virus in a persistently infected alpaca (Vicugna pacos) cria.

Bovine viral diarrhea virus (BVDV) is an emerging infectious pathogen of concern to the alpaca industry. A 4-month-old, intact, male alpaca cria was diagnosed as persistently infected with BVDV on the basis of repeated positive antemortem polymerase chain reaction (PCR) and virus isolation (VI) assays and negative serologic titers to BVDV. Immunohistochemistry, real-time reverse transcription PCR, and VI performed on tissues collected at necropsy demonstrated disseminated BVDV-1b infection. Virus was detected in multiple tissues, including parotid salivary gland, testes, prostate, kidneys, skin, and gastrointestinal tract. Demonstration of BVDV in previously unreported tissues suggests additional potential routes of BVDV transmission in alpacas.

Effect of feed availability on post-milking standing time in dairy cows

Control programmes for contagious mastitis pathogens, primarily Streptococcus agalactiae and Staphylococcus aureus , consisting of milking hygiene, treatment or isolation of infected cows and post-milking teat disinfection are relatively effective (McDonald, 1970; Natzke, 1977; Fox & Gay, 1993). Similar control programmes are often ineffective in the prevention of intramammary infections caused by environmental bacteria (Eberhart, 1977; Smith et al . 1985; Erskine et al . 1991; Smith & Hogan, 1993). This disparity of success relates to the fact that the principal source of environmental mastitis pathogens is the cows environment, rather than another cow with an intramammary infection (Eberhart, 1977; Smith et al . 1985). Infections of environmental origin are particularly noteworthy because they may remain common in well managed herds, and these infections often cause severe clinical signs and high case fatality rates (Eberhart, 1977; Smith et al . 1985; Erskine et al . 1991; Smith & Hogan, 1993). Control programmes for environmental mastitis usually include premilking teat disinfection, decreased use of water in udder preparation, increased concentrations of dietary vitamin E and selenium, improved sanitation of the environment and modification of cow behaviour in the post-milking period (Eberhart, 1977; Smith et al . 1984, 1985; Weiss et al . 1990; Erskine et al . 1991; Smith & Hogan, 1993). Environmental infections are thought to result when bacteria lacking specific virulence factors penetrate the teat sphincter (Eberhart et al . 1979; Smith et al . 1985). The bulk of these exposures are thought to occur between milkings. Control of these infections is problematic because the cows teat sphincter remains open after mechanical milking (McDonald, 1975 a ). Presumably, cows are predisposed to intramammary infections when the open teat sphincter is exposed when cows lie down. Hence, dairy managers are advised to offer fresh feed to cows immediately after milking to increase the likelihood that the teat sphincter will close at least partly before cows become recumbent. The purpose of this study was to determine the effect of feed availability on post-milking behaviour in dairy cows. Specifically, the measured dependent variable was the length of time that cows remained standing after leaving the milking parlour.

Nutritional Investigations and Management of Captive Moose

Historically, moose have been difficult to maintain in captivity when on diets of grass or legume hays and grain due to enteritis that frequently leads to chronic diarrhea/wasting disease. The development of wood-fiber diets has increased the lifespan of moose in captivity, but these diets do not completely prevent chronic wasting. Purina Mills (St. Louis, MO) hypothesized that captive moose are unable to digest starch that escapes the rumen, and therefore abnormal bacterial fermentation in the hindgut causes chronic diarrhea. An earlier study found no evidence of a digestive problem, so we tested the hypothesis that moose have difficulty metabolizing excess propionate produced from the fermentation of starch found in traditional cervid rations and high-grain wood-fiber diets. When challenged with an i.v. propionate load, moose metabolized propionate similar to healthy mule deer and domestic livestock. We then tested the hypothesis that grass forage is an initiating factor to chronic diarrhea/wasting and further hypothesized that grass, alfalfa, and other agriculture-based forages in association with an anaerobic bacteria produce inflammatory bowel disease (IBD) in moose. Captive moose that had ad libitum access to a wood-fiber pelleted moose diet and grazed in grass pastures developed chronic wasting symptoms at 2–4 years of age and died at 4.7 ± 0.3 years unless restricted from grass before the development of advanced symptoms. We isolated Bacteroides vulgatus in the feces and successfully treated a moose with chronic diarrhea/wasting disease with long-term metronidazole therapy, suggesting that the chronic enteritis causing wasting disease arises from a bacteria-associated defective immunosuppressive response similar to IBD in other species. Further support for the IBD cause of wasting in moose is that this animal will relapse within hours if the metronidazole treatment is discontinued even after many months. We developed a highly palatable high-fiber, low-starch moose ration that can be fed as the sole source of nourishment, although additional research and dietary improvements are required. Zoo Biol 16:479–494, 1997.

Ash-free indigestible acid detergent fiber as an internal marker to estimate digestibility with grazing ruminants.

Two experiments with wethers and one with steers were conducted to compare extraction methods of ash-free indigestible acid detergent fiber (IADF) from feed, and to determine variation across days in fecal IADF content. In trial I, 4 wethers were fed 4 maturities of intermediate wheatgrass (Agropyron inm (2) pepsin-HCI digestion then a 96hour in vitro incubation; and (3) 96hour in vitro incubation. Method of IADF extraction and fecal IADF recovery were not affected by, and did not interact (JP.1) with wheatgrass maturity. Fecal IADF reeovery averaged 96.6,80.6, and 77.2% for extraction Methods 1,2, and 3, respectively, and Method 1 differed from Method 2 (P<l and 3 (K.05). Four steers were fed 6 maturities of fresh bromegrass in a repeated measures design with a factorial arrangement in the subplot. Main effects were method of IADF extraction (1,2, or 3) and endpoint of the incubation (96 or 120 h). No main effect of endpoint was detected. Method 1 differed (P<.Ol) from Method 3, but not Method 2, in forage IADF content and fecal recovery of IADF. Organic matter digestibility determined by total collection differed (P<.Ol) from that calculated from feed to feces ratio using IADF extracted by Method 3, but not by Methods 1 and 2. In a grazing trial, fecal IADF content varied little among sampling days within a period. Ash-free IADF extracted from feed by Method 1 appeared to be a suitable internal marker to calculate digestibility by forage-fed or graxing ruminants.

Progressive hindlimb paraparesis in a goat associated with a vascular hamartoma

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