Animal & Avian Sciences Theses and Dissertations

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Variations in Vocalizations of Fin Whales, Balaenoptera physalus, in the St. Lawrence River
(1980) Edds, Peggy Louise; Buchler, Edward; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)
Recordings were made of vocalizations from fin whales, Balaenoptera physalus from a fixed hydrophone in the St. Lawrence River between 28 June and 27 September 1979. Land-based observers monitored activity from a hillside hut while recordings were being made from a shoreline site. Photographs of dorsal fin variations were used to identify distinctive individuals. The 1522 sounds recorded were classified into 11 categories based on frequency and temporal characteristics. The predominant call was a descending sweep of frequencies. Parameters measured for this downsweep exhibited a dichotomy of characteristics which indicates calls with initial frequencies below 40 Hz have less variability than calls with initial frequencies above 40 Hz. In general, solitary animals produced primarily the lower frequency downsweeps. Higher frequency downsweeps were recorded from pairs or trios of fin whales. Solitary individuals did not exhibit unique variations in downsweep parameters. No clusters of values which might indicate uniquely individual ranges were consistently present in multiple animal recordings. The data suggest that the variability of fin whale vocalizations is primarily contextual rather than individual.
Infant and Juvenile-Directed Care Behaviors in Adult Toque Macaques, Macaca Sinica
(1985) Baker-Dittus, Anne; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)
The identity of care-givers, and the distribution of care to young are examined in a free-ranging polygynous primate, Macaca sinica. Care behavior is used as one measure of investment in young. There is no evidence that dominance rank influences offspring sex, but high-ranking mothers provide more care to newborn infants than do low-ranking mothers. Mothers provide more care to infant and first year sons than to daughters. This supports Dittus's suggestion (1979, 1980) that mothers should schedule care to sons and daughters differently, providing high levels of care to sons before they emigrate from the natal group. Care to daughters is low per unit time, but continues over a long period because daughters remain in the natal group. Adult females, other than the mother, tolerate, groom and support young. These behaviors are low cost, relative to the high cost behaviors of nursing and carrying, which only mothers provide. Young tend to associate with adult female relatives. Unlike male-biased maternal care, adult female care is biased towards female young; and female young return care more than do male young . Adult female rank is positively correlated with the amount of support adult females provide to female young, and the amount of grooming they receive from female young. Adult female rank has no effect on any measure of association between adult females and male young. Taken together these findings suggest that reciprocal altruism has been important in shaping adult female interactions with young. Adult and subadult M. sinica males direct the low cost, affiliative behaviors of hugging, carrying and grooming towards male infants; and direct aggressive behaviors towards female infants. I suggest that the distribution of behaviors reflects their value to male and female young. Affiliative behaviors to male infants, and aggressive behaviors to female infants serve to channel infants into association with adults from whom they can learn appropriate sex-typical behaviors, and as such benefit both male and female infants. High cost care behaviors of support in agonistic interactions, and protection are provided only by the adult male, and are provided to male and female young equally.
Habitat, home range, and population study of the eastern box turtle (Terrapene carolina)
(1986) Hallgren-Scaffidi, Lynette; Flyger, Vagn; Animal Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
This study covers the home range, population size, habitat type and components of habitat of the eastern box turtle, Terrapene carolina. The study area was within the floodplains of the Patuxent River on the grounds of Patuxent Wildlife Research Center, Laurel, Maryland. A home range and population study was conducted by Lucille Stickel in 1945 within the same study-area and provided a basis for comparative analysis including information on population trends. Mark-recapture data and a tread-trailer device were used to estimate populations, trace the daily route of eleven individual turtles, and home range size. The range length and convex polygon methods were used to calculate home range size. The average box turtles home range as calculated by the range length method was .733 hectares. In addition the average area calculated by the convex polygon method is .955 hectares for the thread-trailer technique. These home range estimates depict a small reduction in range size from Stickels original estimates Forest maturation is proposed as one of the primary factors influencing this reduction of range size. The population size of the box turtle within the study-area was ascertained by mark-recapture techniques. Using the Schnabel Method of estimating population size, an average of 8.62 (8.30 for 1984; 8.92 for 1985) turtles per hectare was determined. The total number of turtles found during the 1985 study season (58) in comparison to the total number found during the 1945 study season (284) demonstrates the declining population of the Patuxent box turtles over the las t four decades. The largest population of box turtles were found in forest habitat s or forest-field ecotones. Determination of box turtles preference for habitat types and components of habitat was emphasized in this study. Two habitat types, 'dried streambeds' and 'woods opening', encompassed the smallest areas of the study site while providing habitat for the greatest number of turtles. In addition many turtles showed preference for two components of habitats (out in the open and under a log). However, because it is easier to locate turtles out in the open, it is proposed here that the large number of turtles found in this Component of Habitat is due to bias surveying technique s and not a preference for turtles. The results also provide information for improving box turtle habitat within parklands. Changes to the study-area and surrounding ecosystems have occurred over the pa s t four decades. The fore s t has matured, upstream waters have been impounded by dams, filtration plants built and increased pollution of the Patuxent River have occurred. The decline in box turtle abundance is probably due to the frequent floods that inundate turtle eggs when upstream dams are opened.
Periparturient Behavior of Beef Cows and Calves
(1987) Ramli, Abdullah Sani; Stricklin, W.R.; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
Crossbred and purebred gestating Angus and Hereford cows were monitored during the 1985 and 1986 spring calving seasons (number of calvings = 375). Cows were assigned randomly to one of two treatment groups that were balanced by breed-class, age and expected date of calving. The control group was fed corn silage at 0900 hours, and hay was available free choice. The treated group was fed the same diet but at 2100 hours, and time of access to the hay was restricted to between 2100 and 0900 hours. Each group was kept in a 3.2 ha paddock and observed continuously during the 1985 calving season. During 1986 similar treatments were used, but observations were not continuous. Data recorded were behavioral signs of parturition, times and locations of parturition and behaviors of cow-calf pairs observed continuously until 8 hours post-partum. Group diurnal activity patterns were recorded over 61 consecutive days in 1985. Post-partum behavior variables of the dam were time to first standing and grooming and total time spent standing, lying, grooming, browsing and eating. Calf variables were initial standing, teat seeking, mobility, suckling, total time spent on these activities and body weight at weaning. A significant (P <.05) shift in the diurnal activity patterns of the cows occurred when the feeding schedule was altered, but treatment did not affect (P>.10) the time of day when parturition occurred. The percentage of cows calving between 0600 and 1800 hours were 55 and 60 for the control and the treated groups, respectively. During the first 8 hours post-partum, differences in the time of onset and total time spent on some behaviors were determined to be related to breed of sire and dam, parity and sex of calf. Multiple regression of weaning weight on periparturient behavioral traits resulted in R2 values of 54 and 24% for heifer and bull calves, respectively. It was concluded that night-time feeding does not result in a significant increase in day-time calvings, and there is at least a moderate relationship between cow-calf behavior in the first 8 hours after birth and the calf's weaning weight.
The Life Cycles, Ecology, and Evolution of the Witch-hazel Leaf Gall Aphid, Hormaphis hamamelidis (Fitch) (Homoptera: Aphidida)
(1987) von Dohlen, Carol Dean; Gill, Doulgas E.; Zoology; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)
Two divergent life cycles based on geographic location have been documented for the witch-hazel leaf gall aphid, Hormaphis hamamelidis (Fitch, 1851). At low elevations in northern Virginia, the aphid was found to have seven distinct generations alternating between the primary host, Witch-hazel (Hamamelis virginiana L.), and a secondary host, river birch (Betula nigra L.). These findings confirm the original published life cycle description from the same locality. A second, abbreviated life cycle consisting of only three generations restricted to witch-hazel was discovered at high (1000 m) elevations in north central and northwestern Virginia. Aphids with each life cycle were sympatric at an intermediate elevation site. Based on available life cycle and geographic data, a preliminary Phylogeny of the tribe Hormaphidini is proposed that suggests an unusual polarity in the evolution of aphid life cycles. Several features of intraspecific interactions and host-plant relations were examined in both lowland and highland populations of Hormaphis. In contrast to previous publications documenting severe competition, density effects, and habitat heterogeneity for another galling, host-alternating aphid, Pemphigus betae on Populus angustifolia, the effects of density and host-plant qualities on Hormaphis hamamelidis were fewer and more benign. Aphids did not compete for gall sites, and gall Position and final leaf area did not influence reproduction. High gall densities negatively affected gall growth and aphid fecundity. Factors accounting for the differences in Population dynamics between Hormaphis and Pemphigus are hypothesized and discussed.
Vertical Resource Partitioning and Sexuality of Three Sympatric Species of Red Sea Sandfishes (Xyrichtys melanopus, Labridae; Trichonotus nikii, Trichonotidae; Gorgasia sp., Congridae)
(1988) Krall, Marianne Martha; Clark, Eugenie; Zoology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
Three species of marine sandfishes were studied from 1984 to 1986. Their inter- and intraspecific behavior was monitored during the daylight hours to examine interactions that could result in the vertical stratification of the species over the sandy bottom within the fringing and patch reefs in the north Red Sea. Horizontal plankton tows were taken at three heights and three times a day. These samples were compared to stomach contents of the fishes to determine the trophic relationships in the community and their affects on spatial relations between the species . Prey specificities of the fishes were determined by using an electivity measure. Using paraffin histology, Xyrichtys melanopus was determined to be a monandric protogynous hermaphrodite and Trichonotus nikii, a gonochorist. Previous work on the mating systems and territoriality of all three sandfish species helped in part to explain the vertical spatial arrangement of the sandfish species within the community. Effects of pollution on the b iota of the Northern Gulf of Aqaba are noted.
Physiological and Behavioral Effects of Handling and Restraint of the Ball Python (Python regius) and the Blue-Tongued Skink (Tiliqua scincoides)
(1992) Kreger, Michael Douglas; Mench, Joy A.; Poultry Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
Reptiles are handled during transport, veterinary care, education programs, and as companion animals. This study investigated corticosterone levels (CS), heterophil/lymphocyte ratio (H/L), and behavioral responses to routine handling in the ball python (Python regius) (n=4) and the blue-tongued skink (Tiliqua scincoides) (n=3). We validated the RSL I125 Corticosterone Kit for rodents for parallelism and recovery, and found this to be a precise and highly specific means of CS measurement in reptiles. To determine the optimal blood sampling time, animals were sampled throughout a 24-hour cycle under two different light regimens, one a 12L:12D and one in which a red light was on during the dark period. The diurnal pattern of CS did not differ as a result of light regimen. Python peak CS levels occurred at 2400 hours during the peak locomotor activity period and at 1200 hours when body temperature was highest, while skinks showed no significant CS rhythm. Heterophil/lymphocyte ratio values indicated that cardiac puncture did not cause chronic stress although it may be an acute stressor. Animals were then handled gently, manually, or were container restrained (CR) for 10 minutes. Although skink CS was unaffected by treatment, CR caused an elevated level of CS in pythons which may indicate short-term stress. There were no differences in H/L ratio or changes in activity level in either species. Brief periods of routine handling of the study species in captivity thus did not cause chronic stress as measured by CS, H/L ratio, and activity parameters.
The interaction between a parasitic barnacle, Loxothylacus panopaei (Cirripedia, Rhizocephala), and three of its crab host species (Brachyura, Xanthidae) along the east coast of North America.
(1993) Alvarez, Fernando; Reaka-Kudla, Marjorie; Animal & Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)
Rhizocephalan barnacles parasitize primarily decapod crustaceans (Bocquet-Vedrine 1968, Overstreet 1983). The principal effect of the parasites is often the permanent sterilization of the hosts (Bocquet-Vedrine 1972, O'Brien & Van Wyk 1984). Regardless of the processes involved, the end result of the infection is the creation of non-reproductive individuals that will use resources that otherwise would be available to the healthy traction of the host population. The potential impact on the host population then resides in the accumulation of sterile resource-using individuals in each generation. Prevalences of barnacles on anomuran and brachyuran crabs have been reported in a number of studies (e.g., Walker 1985, Hawkes et al. 1986, Johnson et al. 1986, Wardle & Tirpak 1991 ). Rhizocephalan infections can reach very high levels locally, suggesting that entire host populations may have a greatly reduced reproductive capacity. However, in most host species, the pattern of distribution of parasites is not uniform throughout the host's range. I examined the crab-rhizocephalan interaction using the system composed by the barnacle Loxothylacus panopaei and three of its crab host species: Panopeus lacustris, Eurypanopeus depressus, and Rhithropanopeus harrisii, occurring along the east coast of the North America. Through experimental infections conducted in the laboratory, it was determined that B. harrisii of a wide range of sizes could be infected by L. panopaei. The complete life-cycle of the parasite was manipulated in the laboratory. Neither host molting frequency nor host molt increments differed significantly between parasitized and control crabs. Host survival was significantly reduced during the parasite's developmental period; the heaviest mortality of the host occurred in the megalopal stage.
MOLECULAR ANALYSIS OF CYCLOPHILIN FUNCTION IN THE YEAST SACCHAROMYCES CEREVISIAE
(1994) Davis, Edward S.; Brennan, Miles S.; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)
The cyclophilins are a family of proteins first identified as receptors for cyclosporin A (CsA), a cyclic peptide of fungal origin. CsA inhibits T-lymphocyte activation, and is thus a potent immunosuppressant. Although cyclophilins are ubiquitous, and highly conserved, among eukaryotes, their normal physiological functions are unknown. As the receptors for CsA, cyclophilins might be involved in regulating signal transduction pathways. Cyclophilns also have peptidyl-prolyl, cis-trans isomerase (PPIase) activity in vitro, suggesting a role in protein folding in vivo. While CsA inhibits cyclophilin's PPIase activity, this inhibition is insufficient to account for the pharmacological activity of CsA. Therefore, previous results cannot be readily synthesized into a model for cyclophilin function. The goal of this project was to define and characterize physiological roles of cyclophilins using the yeast S. cerevisiae. Three S. cerevisiae cyclophilin genes were cloned and inactivated by insertional mutagenesis. I demonstrated that one, CPR3, is necessary for the efficient metabolism of non-fermentable carbon sources. The CPR] gene product, Cpr3, is localized to the mitochondrial matrix, and a truncated version of Cpr3 expressed in bacteria binds CsA. CPR3 inactivation does not significantly compromise the induction of transcription of two nuclear cytochrome genes. Thus, Cpr3 is not necessary for the signal transduction pathway governing cytochrome gene expression. To identify biochemical targets of Cpr3, I demonstrated that inactivation of a mitochondrial lactate dehydrogenase is insufficient to account for the growth defect of cpr3 mutants. An exhaustive search for high-copy suppressors of the growth defect of cpr3 mutants led to the identification of a novel gene, JEN1, that suppresses the growth defect at elevated temperature. JEN1 encodes a protein that is probably a lactate transporter, and thus not a direct biochemical target of Cpr3. A dominant mutation in a nuclear gene, JEN2, suppresses the growth defect of cpr3 mutants on lactate at 30°C and 37°C. JEN2 might encode a direct biochemical target of Cpr3. In summary, the cyclophilin, Cpr3, plays a general role in the efficient function of yeast mitochondria, and presents an excellent model system for studying cyclophilin function.
Dietary Control of Cystinuria in Maned Wolves (Chrysocyon Brachyurus)
(1998) Boniface, Jennifer; Soares, Joseph H., Jr.; Avian and Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
The maned wolf (Chysocyon brachyurus) is an endangered South American species of canid, whose numbers in both the wild and captivity are threatened in part by a condition called cystinuria. In humans and rats, cystinuria is caused by mutations of the rBAT gene, expressed in intestinal mucosal cells and renal tubules. In dogs, only renal tubules are affected. Cystinuric individuals exhibit impaired capacity for reabsorption of the sulfur amino acid cystine. Consequently, excess cystine accumulates in the urine. In acidic conditions, cystine may precipitate into uroliths, potentially obstructing the urethra and ultimately causing bladder rupture or kidney damage. Treatments include medical management and dietary modification. Test diets differing only in levels of cystine were fed to 15 maned wolves in a cross-over design. Apparent digestibility calculations suggest the diets were well received, well utilized and improved fecal quality. The low cystine diet significantly reduced urinary excretion of cystine (P<0.05). Mean urinary concentrations of cystine were 341±45.87 mg/L or 2.78±0.326% total urinary nitrogen for the low cystine diet; and 475.8± 47.80 mg/L or 4.01± 0.342% for the high cystine diet. Water balance studies was determined three maned wolves, using orally administered deuterium oxide. Urine samples were collected daily for seven days, purified by sublimation, and analyzed by infrared spectrometry. It was determined that total body water, water turnover rate and body composition were 17.2 L, 2.3 L/d, and 20.5% fat; 79.5% lean, respectively. These results are comparable to published values for dogs.
The Characterization and Cryopreservation of Striped Bass (Morone saxatilis) Semen
(1999) Jenkins, Karen; Curry Woods III, L.; Department of Avian and Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
Quantification of fatty acids over the gametogenic cycle of striped bass (Morone saxatilis) with varying dietary levels of DHA, EPA and AA
(2000) Dickey, Lisa Ann; Woods, L. Curry III; Animal and Avian Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
The purpose of this thesis was to investigate the effects of dietary treatments on the fatty acid composition of striped bass (Marone saxatilis) blood, liver and ovary over the course of the gametogenic cycle. Striped bass were fed experimental diets in which docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (AA) were increased in a stepwise fashion progressing from diets 1-4 respectively. A significant difference was seen in the tissues between fish from dietary treatment group 1 when compared to those fish from dietary treatment group 4 suggesting a direct impact on the tissues by the fatty acid composition of the diet. The second purpose of this thesis was to explore the use of a novel method of fatty acid extraction from fish tissues. This method was compared (UMD method) was compared to the well-known Bligh and Dyer method commonly used for fatty acid extraction. The UMD method proved to be superior quantitatively in terms of fatty acid extraction when compared to the Bligh and Dyer method. The UMD is also more cost affective and leaves less room for human error.
NUTRITIONAL AND ENVIRONMENTAL IMPLICATIONS OF STARCH DEGRADABILITY AND NITROGEN FERTILIZATION OF ORCHARDGRASS SILAGE IN TOTAL MIXED RATIONS FED TO LACTATING COWS
(2003) Woodward-Greene, Mary Jennifer; Erdman, Richard; Animal & Avian Sciences; University of Maryland, College Park, Md.; Digital Repository at the University of Maryland
The objectives of this research were to determine the effect of starch and nitrogen (N) availability on microbial protein production and N efficiency, ruminal N efficiency and ammonia, and to assess forage fertilization and grain selection decisions. Diets were incubated in vitro batch culture, and fed in a 6 x 6 Latin square in vivo digestion trial. Total mixed rations (TMR) contained 50:50 forage:concentrate (dry matter (DM) basis) of second-cutting orchardgrass silage fertilized with 200 (OG200) or 400 (OG400) pounds per acre N, plus concentrate mixes using high to low rumen available starches: barley, corn, and milo. TMR crude protein (CP) was 17% and 18% for in vivo, and 20% and 21% for in vitro OG200 and OG400 diets, respectively. Synchronous diets were low:low or high:high rumen starch availability:diet N (corn or milo withOG200, and barley with OG400). No effects on ruminal microbial protein synthesis and flow, N flow, or milk production were observed. DM, organic matter (OM) (P<0.01), N, and neutral detergent fiber (NDF) (P<0.02) total digestibilities increased with synchronous diets. N digestibility was depressed in diets of low:high rumen starch availability:diet N, due to increased hindgut fermentation adding microbial protein to the feces (P<0.001). All OG400 diets had higher fecal N percentage (P<0.001). OG400 had higher ruminal ammonia both in vitro and in vivo (P<0.05), and higher total in vivo volatile fatty acid (VFA) concentration (P<0.001), but rumen pH was stable due to increased recycling of urea. Orchardgrass fertilized at high N can be digested as well as lower N fertilized forages when combined with a rapidly available ruminal starch such as barley, and decrease outputs of fecal DM by up to 401.5 and N by nearly 22 kilograms per year per cow. Crop fertilization and grain selection decisions affect forage composition, rumen fermentation, ration digestibility, and fecal DM and N output.
FUNCTIONAL STUDIES OF INFECTIOUS PANCREATIC NECROSIS VIRUS PROTEINS AND MECHANISM OF VIRUS-INDUCED APOPTOSIS
(2003-12-04) Song, Haichen; Vakharia, Vikram N; Animal Sciences
Infectious pancreatic necrosis virus (IPNV) encodes a 12 or 15-kDa nonstructural protein, known as VP5. To study the function of VP5, we generated three recombinant viruses rNVI15, rNVI15-15K, and rNVI15-ΔVP5, which could encode either 12-kDa VP5, 15-kDa VP5 or be deficient in VP5, respectively. VP5 was detected in rNVI15 and rNVI-15K infected cells but not in the cells infected with rNVI15-ΔVP5. However, the opal stop codon at nucleotide position 427 in rNVI15 virus was read-through, giving rise to a 15-kDa VP5 that is expressed poorly than rNVI15-15K virus-infected cells. All three recombinant viruses show similar replication kinetics in both Chinook salmon embryo (CHSE-214) and rainbow trout gonad (RTG-2) cells. Moreover, in Sp strains, IPNV segment A could encode a novel, putative 25-kDa protein from another ORF. This 25-kDa protein could not be detected in virus-infected cells, however, we could recover a mutant virus lacking this ORF, indicating that it is not essential for virus replication. To assess the molecular basis of virus adaptation in the cell culture, virulent rNVI15 was serially passaged in CHSE cells nine times to obtain a tissue-culture adapted virus, rNVI15TC. Comparison of the deduced amino acid sequences showed only one amino acid substitution at position 221 (Ala → Thr) in VP2. However, this adaptation mutation is only acquired in CHSE cells but not in RTG-2 cells. Two chimeric viruses, rNVI15ΔVP2 and rNVI15-15KΔVP2 were also generated, in which the residues at positions 217 and 247 in VP2 of the rNVI15 and rNVI15-15K viruses were replaced by the corresponding residues of an attenuated strain, Sp103. These two viruses have similar replication kinetics as Sp103, which replicates faster than rNVI15 in vitro, indicating that residues at positions 217 and 247 of VP2 may be the important markers for virus adaptation and attenuation in vitro. By generating a reassortant virus between rNVI15-15K and Sp103, we also demonstrate that VP1 is not involved in virus cell adaptation. The signal pathways and nature of IPNV-induced apoptosis were investigated in RTG-2 cells. IPNV-induced apoptosis occurs at the late stage of viral life cycle. Caspase-3 is activated during virus infection, and inhibition of caspase-3 could partially inhibit virus-induced apoptosis. Moreover, NF-κB activation is essential for IPNV-induced apoptosis, and it is involved in interferon-induced antiviral state. Both the NF-κB inhibitor and the antioxidant could inhibit NF-κB activity and apoptosis induced by IPNV infection, but they do not affect viral replication.
The effect of agonistic encounters on aggressive response in socially isolated Siamese fighting fish, Betta splendens
(2003-12-16) Charles, Debbie; Halperin, Janet R.P.; Estevez, Inmaculada; Animal Sciences
Male Siamese fighting fish were held for 7 to 10 weeks either in visually-social conditions (interact aggressively with a mirror image for 2 min, three times a week) or as visually-isolated fish (no aggression, saw only the back of a mirror). Phase I of this experiment investigated whether visually-isolated fish became hyper-aggressive, compared to visually-social fish. Aggression levels were tested with a series of models and mirrors. Social isolation did not affect duration or frequency of specific agonistic behaviors, nor of pooled behavioral categories (ANOVA, P > 0.05) within aggression tests. Phase II was to determine if aggression levels re-adjusted in visually-isolated fish experiencing live encounters among groups of 4 fish in naturalistic environments. Data was not significant unlike in previous isolation experiments (ANOVA, P > 0.05). However, several behavioral trends were observed that were consistent with previous isolation studies.
IMPLICATIONS OF DIVERGENT CORTISOL STRESS RESPONSIVENESS IN MALE STRIPED BASS (MORONE SAXATILIS)
(2003-12-18) Castranova, Daniel Anthony; Woods III, Lewis C; Animal Sciences
The aim of this study was to identify whether differences exist in reproductive and growth performance of male striped bass selected for high cortisol stress responsiveness (HCR) and low cortisol stress responsiveness (LCR), when exposed to standardized stress challenges before and during the spawning season. HCR (n=10) and LCR (n=10) were identified out of a population of 67 three-year-old striped bass males. Although no significant differences in weight, length, or coefficient of condition were found between HCR and LCR, HCR had a significantly greater specific growth rate when compared to LCR. Circulating levels of testosterone and 11-ketotestosterone were significantly higher in HCR than in LCR before and during the spawning season. HCR also had more fish spermiating across all sample dates compared to LCR. These results suggest that striped bass selected for high cortisol stress responsiveness have better reproductive and growth performance than fish selected for lower cortisol stress responsiveness.
Quantitative Trait Loci and Promoter Analysis of the Bovine Butyrophilin Gene
(2004-01-27) Zegeye, Abiy; Mather, Ian H; Animal Sciences
The butyrophilin gene (BTN1A1) has been described in all mammalian species so far investigated. BTN1A1 is a likely QTL candidate that affects an economically important trait in dairy animals because it is specifically expressed in lactating mammary tissue and the gene product BTN1A1 may function in the secretion of milk lipid. Five PCR-RFLP intragenic markers were identified. Three of the five markers are bi-allelic, however, the two 5'-most markers may be multiallelic loci. The markers were further used to conduct a QTL analysis to examine any allelic substitution effects on economically important milk production traits, namely, total protein, percent protein, total fat, percent fat, somatic cell score, herd life, and milk yield. One significant effect was detected for percent protein. Other effects were not significant, but this could possibly be due to the skewed allelic frequency distribution, or because the variable nucleotides were either intronic or coded for a conservative amino acid substitution. The 5' flanking region of bBTN was cloned and sequenced. Computational and transient transfection assays were conducted to identify regions of bBTN that are important for its expression. A computational analysis was conducted to compare and analyze the 5' flanking region of cow, goat, human and mouse sequences. Several regions of homology were identified that code for shared binding motifs. However, neither the transcription start site (TSS) nor the other segments of similarity in the proximal promoter region were analogous to other 'milk protein genes' such as the caseins and α-lactalbumin, and other widely studied non-mammary-specific genes. Transient transfection assays in HC11 cells indicate the region from -1kb to -0.45 kb is sufficient to drive the expression of a reporter gene. bBTN appears to contain a novel set of elements that define the (TSS) and proximal promoter modules. A more incisive examination will circumscribe the major cis-acting elements.
EFFECTS OF MILK UREA NITROGEN AND OTHER FACTORS ON PROBABILITY OF CONCEPTION OF DAIRY COWS
(2004-04-01) Guo, Kejun; Kohn, Richard A; Erdman, Richard A; Douglass, Larry; Varner, Mark A; Animal Sciences
The objective of the present study was to evaluate the relationships among milk urea nitrogen (MUN) and other factors with the probability of conception in dairy cows. A total of 713 dairy herds and 10,271 dairy cows were included in the study. Logistic regression was used to determine the effects of MUN, milk production, lactation number, and breeding season on the probability of conception for each of three services. Within herds, MUN displayed a slight negative association with probability of conception at first service. In among-herd regression analysis, there was no effect of MUN on probability of conception. These results suggest that MUN may be related to conditions affecting reproduction of individual cows within a herd. Diet formulation usually would affect MUN equally among all cows at a similar stage of lactation in a herd. Since there was no effect of MUN among herds, diet formulation to meet the protein requirements did not appear to affect conception rate.
Neuronal Activation Following Cohabitation in the Prairie Vole (Microtus ochrogaster)
(2004-04-29) Hazelton, Julie Louise; Ottinger, Mary A; Hoffman, Gloria E; Keefer, Carol L; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Sexually naïve female prairie voles require exposure to a novel male to activate the neural circuits involved in the formation of stable pair bonds and to stimulate sexual receptivity. The objective of our study was to investigate the neural pathways involved in the formation of pair bonds. Cushing et al. (2003) studied neuronal activation in selected brain regions, as expressed by c-Fos immunoreactivity (ir), during the first hour of cohabitation in prairie voles. In the present study, we extend the findings of this study to examine neuronal activation associated with cohabitation to include 2, 6 and 12 hr. In addition, we examined the potential colocalization of luteininzing hormone releasing hormone (LHRH) and c-Fos to determine if this is a system activated during the initial stages of pair bond formation. The selected time periods include the initiation of sexual activation of the female and pair bond formation. Expression of c-Fos as analyzed in three regions that play a role in early social encounters. These areas included: (1) the sociosexual behavior circuit, (2) the reward pathway, and (3) nuclei whose peptides regulate the actions of those networks. Based on the previous data, increased c-Fos expression was predicted in the social behavior circuit, including the medial amygdala, bed nucleus of the stria terminalis, medial preoptic nucleus, and ventromedial nucleus of the hypothalamus. The lateral septum was examined due to its role in the social behavior circuit and in the process of pair bond formation. Next, we predicted that increased c-Fos activity would be observed over time in regions that did not show increases during initial contact, but are involved in pair bond formation. These regions include two components of the reward pathway: the nucleus accumbens and the ventral pallidum. Finally, nuclei known to regulate both the social behavior and reward circuits were examined and included the supraoptic nucleus and the pariventricular nucleus, which produce oxytocin and vasopressin. These neuropeptides are critical in social behavior and the formation of pair bonds. Immediately following the period of cohabitation (0, 1, 2, 6 or 12 hour in length) animals were separated and brains fixed. Fixed brains were sectioned at 30μm and stained with c-Fos and LHRH antibodies using double label immunocytochemistry (ICC) (Berghorn et al., 1994). Significant colocalization of LHRH and c-Fos was not observed in the first twelve hours in either sex of cohabitated prairie voles. Additionally there was no difference in number of LHRH ir neurons between sex or treatments. LHRH ir neurons in male and female prairie voles were predominantly located in the diagonal band of broca, preoptic area, lateral hypothalamus and supraoptic decussation. Individual LHRH neurons that did express c-Fos were predominantly located in the POA and LH. We observed a sexually dimorphic temporal pattern in c-Fos ir in the circuitry involved in pair bond formation in prairie voles. This pattern suggests that incoming information is first sorted through the social-sexual circuit and continues to be processed as information is received by nuclei of the reward pathway a short time later in both sexes. An increase in immediate early gene (ieg) immunoreactivity in the social behavior network is reported concurrently with peak activation of the reward circuit. During the same time period, an increase in c-Fos ir is reported in the nuclei involved in the endocrine control of partner preference and pair bond formation. Together these data suggest that in prairie voles, both the social and reward circuits interact early in cohabitation prior to reproductive activation to establish a heterosexual bond and that both circuits may be regulated by neuropeptides produced by the PVN and SON. This research was conducted by funding from the following: NSF IBN-9817024 (MAO), NIH HD 38490 (CSC, GEH, BSC, MAO) and MH 01992 (BSC). Subject Category: Neuronendocrine Activation following cohabitation Keywords: LHRH, social behavior, reward pathway, c-Fos, neuronal activation
FORAGING STRATEGIES, USE OF SPACE AND AGGRESSIVE BEHAVIOR OF DOMESTIC FOWL (Gallus gallus domesticus)
(2004-05-03) Hoerl, Erin Natalie; Estevez, Inma; Animal Sciences
Domestic fowl were tested in three experiments, all investigating the mediating effects of three group sizes of 5, 10, and 20 individuals, on behavioral responses under varying environmental conditions. The first experiment investigated social spacing and aggressive behavior in the presence or absence of cover panels. Smaller group sizes were more affected by cover panels than larger group sizes. In the second and third experiments patchy environments were used to test optimal foraging strategies. In the second experiment, smaller group sizes were more affected by patch locations than larger ones. In the third experiment birds were presented with patches varying in quality. Birds in all group sizes were able to immediately discern patch quality and preferred patches of higher quality. Despite generations of artificial selection pressure domestic fowl continue to forage optimally in patchy environments, and adopt flocking strategies predicted by behavioral ecology theory.