An examination of a compensatory relationship between food limitation and predation in semi-domestic reindeer

A central issue in ecology is to what extent food limitation and predation affect animal populations. We studied how survival and reproductive success was related to the female's size in a population of semi-domesticated reindeer during 2 years where there was a large difference in snowfall during winter. The females were kept within a predator-free enclosure for about 5 weeks during the calving period and thereafter released to their natural summer pastures. Small females were more likely to fail to reproduce and they produced smaller calves than large females. Additionally, small females were more likely to loose their calves due to starvation within the predator-free enclosure and to predators outside the enclosure. Food limitation during the harsh winter appeared to be the major cause of deaths. However, food limitation interacted with predation and led to high calf losses when the females experienced low food availability during the harsh winter. In contrast, predators killed no calves after the mild winter. Apparently, the interaction between predation and food limitation is due to small females favouring their own growth and survival over calf production in summers following harsh winters with food shortage. Our results indicate that a compensatory relationship exists between mortality due food limitation and predation. Thus, the impact of calf predation on reindeer demography and population dynamics may be limited.     

Nursing behavior and early development of impala at San Diego Wild Animal Park

Because impala are commonly exhibited and handreared in zoos and their natural nursing behavior had not previously been studied, we examined nursing and early development in five impala calves housed in a large, naturalistic enclosure. Calves were observed for the first 5 weeks of life during 12-hr continuous watches and 20-min focal animal samples. Total daily suckling time decreased while time grazing and feeding on concentrates increased from 1–5 weeks of age. An increasing proportion of nursing bouts were terminated by the dam as calves matured, with dams terminating almost 70% of bouts during the first week. Suckling success and maternal grooming also decreased after week I, suggesting that impala mothers cut back early on nursing and grooming of offspring. Rapid decline in mother-young spatial proximity and a concomitant increase in calf association with age-mates over time suggests that the mother-young bond is weak and ephemeral in impala. An example of the implications of our results for improving handrearing programs would be that newborn calves should be started on a daylight feeding schedule of one bottle-feeding every three hours, and that they not be allowed to gorge themselves at any one of these feedings.     

Aggression and Nearest Neighbour Distances in Female Reindeer during the Rut

Data on nearest neighbours and aggressive behaviour were collected within rutting groups of semi-domesticated reindeer (Rangifer t. tarandus L.) in a 1300-ha pasture in Finnish Lapland, and wild forest reindeer (Rangifer t. fennicus Lönnb.) in a 15-ha enclosure in Central Finland. Adult cows of forest reindeer charged yearling males, yearling females and calves in that order of decreasing frequency. Semi-domesticated reindeer cows rushed yearling females more often than they did one another. One suggested influence of antagonism by cows were the observed intragroup associations of yearling females. Cows were tolerant toward their own yearling females, but not toward their own yearling males. Although no maternal aggression toward calves was found, male calves moved away more often from their mothers than did female calves during the post-rut period.     

Domestic Calves (Bos taurus) Recognize their Own Mothers by Auditory Cues

The goal of this study was to determine if auditory cues are important in maternal recognition by domestic cattle calves, Bos taurus. Cows and their calves were separated and the vocalizations of the mothers were recorded. During experimental playbacks in a test enclosure, each calf (n = 9) was given a choice between a tape-recorded vocalization of its mother and that of a strange mother. Calves significantly preferred their own mother's vocalization as compared to the vocalization of the unfamiliar mother. Calves spent significantly more time near the speaker that played their own mother's call, and approached significantly closer to their mother's speaker. These results demonstrate that 3–5-wk-old calves can recognize their mothers by auditory cues alone. Visual inspection of audiospectrograms of the cows' vocalizations suggests that there are individual differences among cows.     

Pharmacokinetics and effect of intravenous meloxicam in weaned Holstein calves following scoop dehorning without local anesthesia

ABSTRACT: BACKGROUND: Dehorning is a common practice involving calves on dairy operations in the United States. However, less than 20% of producers report using analgesics or anesthetics during dehorning. Administration of a systemic analgesic drug at the time of dehorning may be attractive to dairy producers since cornual nerve blocks require 10 -- 15 min to take effect and only provide pain relief for a few hours. The primary objectives of this trial were to (1) describe the compartmental pharmacokinetics of meloxicam in calves after IV administration at 0.5 mg/kg and (2) to determine the effect of meloxicam (n = 6) or placebo (n = 6) treatment on serum cortisol response, plasma substance P (SP) concentrations, heart rate (HR), activity and weight gain in calves after scoop dehorning and thermocautery without local anesthesia. RESULTS: Plasma meloxicam concentrations were detectable for 50 h post-administration and fit a 2-compartment model with a rapid distribution phase (mean T1/2alpha = 0.22 +/- 0.087 h) and a slower elimination phase (mean T1/2beta = 21.86 +/- 3.03 h). Dehorning caused a significant increase in serum cortisol concentrations and HR (P < 0.05). HR was significantly lower in the meloxicam-treated calves compared with placebo-treated calves at 8 h (P = 0.039) and 10 h (P = 0.044) after dehorning. Mean plasma SP concentrations were lower in meloxicam treated calves (71.36 +/- 20.84 pg/mL) compared with control calves (114.70 +/- 20.84 pg/mL) (P = 0.038). Furthermore, the change in plasma SP from baseline was inversely proportional to corresponding plasma meloxicam concentrations (P = 0.008). The effect of dehorning on laying behavior was less significant in meloxicam-treated calves (p = 0.40) compared to the placebo-treated calves (P < 0.01). Calves receiving meloxicam prior to dehorning gained on average 1.05 +/- 0.13 kg bodyweight/day over 10 days post-dehorning compared with 0.40 +/- 0.25 kg bodyweight/day in the placebo-treated calves (p = 0.042). CONCLUSIONS: To our knowledge, this is the first published report examining the effects of meloxicam without local anesthesia on SP, activity and performance of calves post-dehorning. These findings suggest that administration of meloxicam alone immediately prior to dehorning does not mitigate signs of acute distress but may have long term physiological, behavior and performance effects.     

Ultrasound-guided transvaginal oocyte collection in prepubertal calves

The present study was designed to develop a technique for oocyte collection using an ultrasound-guided transvaginal approach in prepubertal calves too small to accommodate manual transrectal manipulation. A commercially available, 5 MHz, convex-array ultrasound transducer designed for intravaginal use in women was custom-modified for use in calves. In Experiment 1, calves 10 to 16 wk old (n = 10) were restrained in the standing position in an adjustable squeeze chute with regional anesthesia. In Experiment 2, the follicle aspiration procedure was performed in 6 wk-old calves (n = 20) in dorsal recumbency after tranquilization and caudal epidural anesthesia. Ovarian superstimulation was induced in half of the calves using 750 IU eCG (Experiment 1) or 200 mg Folltropin (Experiment 2). Consistent visualization of both ovaries using the transvaginal approach was accomplished after considerable practice. Two methods of ovarian immobilization were attempted, but both interfered with the ultrasound image and were consequently abandoned. The inability to immobilize the ovary resulted in attempts to spear the intended follicle "free-hand." The contents of follicles >or= 6 mm in diameter were aspirated, filtered, and oocytes were located using a stereomicroscope. Although ovarian superstimulation did not resolve the problem of ovary movement, the number of follicles of adequate size to aspirate was dramatically increased. Extremely sharp needles were found to be very important in the free-hand technique. A total of 232 follicles was aspirated, and 100 oocytes were collected (43%). In summary, a transvaginal ultrasound-guided technique for oocyte collection was developed for young calves in a standing position (10 to 16 wk of age) and dorsal recumbency (6 wk of age). Results demonstrate the potential utility of this approach for deriving oocytes from young calves.     

Suckling behavior of eland antelopes (Taurotragus spp.) under semi-captive and farm conditions

Mother–offspring interactions soon after parturition play a key role in the survival of mammals. We investigated the suckling behavior of semi-captive Western Derby eland (Taurotragus derbianus derbianus) in a 60-ha enclosure covered by dense savanna vegetation in Senegal and farmed Common eland (T. oryx) on an open 2-ha pasture in the Czech Republic. We hypothesized that the basic pattern of suckling bout duration and mother–offspring interactions would be similar between species, but would vary in response to the environmental conditions and breeding system. During three calving periods, we observed the suckling of 27 and 23 calves of Derby and Common elands, respectively, between the ages of 1–5 months, and the interactions between mother and calf before and during suckling. Suckling bout duration increased with the age of the calves for both elands. However, in Derby elands we recorded longer suckling bouts in male than female calves and shorter suckling bouts in primiparous mothers than multiparous ones; no differences were found in farmed Common elands. The animals’ active approach to mother–offspring contact, for example naso–anal contact, and initiation and termination of suckling, resulted in longer suckling bouts in Derby elands. The results suggest that Derby elands that range over a large enclosure with dense vegetation cover adjust their maternal behavior in compliance with potential predator risk, facing a trade-off between nursing and vigilant behavior in the wild. The suckling behavior of farmed elands, on the other hand, reflects the conditions of captivity without predators and with the small available area enabling permanent visual contact of animals.     

Resting habits of Zebu cattle in a nocturnal enclosure

Over a period of one year, resting habits in a nocturnal enclosure were studied in a cattle herd consisting of cows with their calves and one bull. Individual preferences for particular resting areas were found in all members of the herd; in some cases such habits could be traced throughout 12 months. Local preferences, climatic changes, disturbances and/or personal associations with certain group members determine an animal's resting habits. The degree of consistency with which an animal lies on its resting place is independent of its dominance status. It was concluded that an animal's individual resting habit raises no competitive situation with other herd members.     

Peyer’s Patches and the Follicle-Associated Epithelium in Diarrheic Calves

Twelve 2–5-week-old calves affected with a spontaneous intestinal disorder were examined; 8 had diarrhea and 4 were convalescents. In all the affected calves the “pseudovilli” (syn. domes or lymphoid villi) over Peyer’s patches seemed atrophic and appeared enclosed within the mucosa, owing to fusion of ordinary villi with “pseudovilli”. Morphometric examination showed a decrease of lymphoid follicle length in the affected calves as compared with controls (P &lt; 0.01). Convalescents showed longer follicles than diarrheic calves (P&lt;0.05). Often cytoplasmic acid phosphatase of the follicle-associated epithelium (FAE) in affected calves did not show the marked basal-apical decrease along “pseudovillus”, typical of the controls. Scanning electron microscopy revealed sparse development of concentric folds in the luminal plasma membrane of the enclosed FAE, contrasting with their abundance in the normal FAE. Transmission electron microscopy showed that the “pseudovilli” had increased numbers of ordinary villous epithelial cells. Affinity of chlamydia for FAE was shown. It is suggested that the sparse occurrence of surface folds in the FAE and the change in acid phosphatase distribution indicate diminished endocytosis of antigenic material, probably resulting from the enclosure of “pseudovilli”. The atrophy of lymphoid follicles may be another expression of the probable decreased contact with the intestinal contents.     

Survival of Oocysts of Eimeria alabamensis on Pastures under Different Climatic Conditions in Sweden

The extent to which oocysts of the coccidian parasite Eimeria alabamensis can survive the winter and cause clinical coccidiosis in different parts of Sweden was investigated. Fecal samples were collected between May and July 1993 from calves on 59 farms where calves had grazed the same pasture for at least 5 consecutive years. The farms were situated in 9 regions of Sweden with different climatic conditions in the winter. On each farm, 5 samples of feces were collected from the floor of the calf-house before the calves were turned out in the spring, and again from the pasture on days 4 or 5, 8 or 9 and 10 or 11 after they were turned out. Overwintering of oocysts of E. alabamensis was considered to have occurred if an increase in the excretion rate of oocysts of this species could be demonstrated 8 to 11 days after calves had been turned out to pastures that had not been grazed since the previous autumn. Oocysts were shown to have overwintered on 27 farms, representing all 9 regions. Samples from 20 (34%) of the farms representing all the climatic regions contained more than 850000 oocysts per g of feces. This was comparable with the numbers found in animals with clinical coccidiosis due to E. alabamensis. Delaying turnout until the beginning of July did not affect the infection rate of the calves. However, calves which were turned out to pastures that had been grazed by older cattle or horses, either earlier in the spring or in previous years, excreted significantly fewer oocysts than calves which were turned out to pastures that had been grazed only by calves. A questionnaire answered by 321 dairy farmers revealed that of the 298 farmers who turned their first-season grazing cattle out to traditional pastures, 179 (60%) had used the same pasture for at least 5 years. These 179 farmers had experienced a significantly higher incidence of diarrhoea in their calves during the first 2 weeks at pasture than those farmers who had used different pastures.     

The Distribution of O-antigen Types of Escherichia coli in Normal Calves, compared with Man, and their R plasmid Carriage

The distribution of O-antigen types of Escherichia coli in calves over a ten-month period has been determined. A total of 400 calves from separate farms located over a wide area of England and Wales have been surveyed. Of the 148 O-types recognized, 93 were found in calves, compared with 107 in a previous survey in man; 42 of these were common to both hosts. In calves 60% of isolates were resistant to at least one antibiotic. Of these, 71% belonged to ten O-types, 9 of which were found in man. It is concluded that calves form a potential reservoir of R plasmid carrying E. coli .     

The effects of twinning on mother—Offspring behavior in range beef cattle

Methods to increase the productivity of beef cattle include induced twinning and multiple fostering of calves on nurse cows, but little is known about the capacity of cows to rear more than one calf in a rangeland environment.Eight single and 14 twin calves and their mothers were studied in a 30.4-ha enclosure in a California rangeland environment from 2 to 20 weeks following parturition. Data were obtained on ingestive, grooming, agonistic, play and sexual behaviors, as well as spatial proximity of calves to mothers and peers.Initially, twins spent more time suckling their mothers than did single calves (presumably due to insufficient milk intake), but later adapted by utilizing natural forage and obtaining milk from alien cows. By 15–20 weeks of age, twins were suckling their dams for less than one-quarter of the time spent at 3–6 weeks, whereas the suckling time of single calves did not decline. Thus, twins may experience a natural early weaning from mother's milk.The hypothesis that mother—Offspring bonds are weaker with twins than with singles was supported by the fact that mothers bearing twins groomed their offspring less than mothers with singles, and twins were normally found at greater distances from their mothers than singles.Most long-distance cow—Calf separations resulted from the cow moving to feed or to obtain water. Reunion of mother and young depended on auditory communication; the calf normally traversed most of the intervening distance.     

Embryo transfer as a means of controlling viral infections. VI. Bluetongue virus-free calves from infectious semen

Four Holstein heifers were superovulated and inseminated with infectious semen from a bull experimentally infected with type 17 bluetongue virus (BTV). A total of 20 embryos were collected at donor slaughter and transferred to 16 recipients. Ten recipients became pregnant of which one subsequently aborted, one gave birth to twins which died at birth, one was killed at term because of dystocia, and 7 gave birth to live calves one of which died perinatally. All animals were tested for BTV antibodies at the time of slaughter which was at least 30 days post partum for surviving heifers and calves. Two of the four donor heifers were retrospectively determined to have been infected by the semen (viremia demonstrated) and their embryos accounted for 9 of the 10 pregnancies including the six surviving calves. None of the recipients or calves developed BTV antibody by the termination of the experiment. This study suggests that BTV-free calves can be readily obtained from the use of BTV-positive semen.     

Feeding and survival of Culicoides sonorensis on cattle treated with permethrin or pirimiphos-methyl

The persistence of permethrin (5% a.i.) and pirimiphos-methyl (27% a.i.), applied to the dorsum of calves in the field against Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae), was estimated using a hair-blood-feeding bioassay in the laboratory. Hair clippings were taken before treatment and 3, 7, 14, 21, 28, 42 and 56 days after treatment from the dorsum, side and belly of treated and control calves. Laboratory-reared insects were allowed to feed through thin hair layers and a parafilm membrane on sheep blood warmed using a water-jacketed feeder. Some intoxication after exposure to hair was noted up to 28 days after treatment with permethrin and up to 14 days after treatment with pirimiphos-methyl. Hair from the dorsum caused more intoxication for a longer period than hair from other body regions. Permethrin and pirimiphos-methyl applied to the back did not significantly reduce overall engorgement (body regions pooled) after treatment. Permethrin residues on hair remained far higher on the back than other body regions and were related to insect intoxication and reduction in engorgement in the laboratory. Residues on belly hair never exceeded 12p.p.m. and did not result in significantly reduced feeding at any time. Engorged insects that exhibited sublethal intoxication from feeding through permethrin-treated hair did recover and matured numbers of eggs comparable to controls. Field trials using treated and control calves and enclosure nets showed that dorsal applications of 5% permethrin were not effective in reducing engorgement, despite some intoxication. Vacuum samples from a calf showed that C. sonorensis fed primarily on the belly. A 0.2% permethrin application on the belly (250 ml) did result in > 80% reduction of C. sonorensis in the enclosure nets at 3 and 7 days after treatment, but activity had subsided by 10 days after treatment. The utility of insecticidal treatments for suppression of this vector is discussed.     

Behaviour of nilgai (Boselaphus tragocamelus) antelope in captivity

The behaviour of captive nilgai (Boselaphus tragocamelus) was studied at Whipsnade Wild Animal Park, Bedfordshire, UK, by the method of focal animal sampling. There were four principal feeding periods: at dawn, in the morning, in the afternoon and during the evening. The activity pattern of the male differed significantly from that of the females but otherwise the various age/sex classes behaved similarly. There were significant associations between the classes and significant differences in the mean distances to the nearest neighbour. Play fighting, in the form of neck wrestling, occurred in the calves, mainly the males. The adult male revealed signs of territoriality and the females showed evidence of the existence of social hierarchy. Blackbuck (Antelope cervicapra) sharing the enclosure reacted with the nilgai as if they were conspecifics but other ungulates present ignored them. The area of the enclosure appeared to be adequate and it is concluded that the animals are being managed correctly.     

Sensory reinforcement and illumination preference in sheep and calves

The preferences of sheep or calves for light or darkness have been examined by placing animals in light-proof chambers in which they could turn the lights on or off by interrupting an infrared beam switch with their muzzles. Sheep spent an average of 77% of each 24 h period in light while the calves spent an average of 67% of each 24 h in light. The experiments show that sheep and calves prefer light to darkness. The strength of their motivation for light was examined by means of an operant task in which they were rewarded with only 40 s of light for each interruption of the i.r. beam. Sheep then obtained an average of 1.5 h of light per 24 h and calves 1.0 per 24 h. Finally, the animals were subjected to a situation in which the light only remained on for as long as the i.r. beam was interrupted. In this experiment sheep obtained 4.8 min of light per 24 h and calves 3.2 min per 24 h. Quantitative operant methods can provide an objective means for measuring environmental preferences in farm animals.     

Acid-base state of blood in calves with dyspepsia treated using different therapeutic approaches

As a result of our investigations it has been found, that the state of sub-compensated respiratory-metabolic acidosis with gradual recovery of electrolytic composition of blood serum was observed in calves which have had dyspepsia by the 30th day of life. At the same time in calves, which obtained milk phospholipids in a form of biologically active additive FLP-MD, more rapid recovery of acid-base balance of blood was diagnosed. The mentioned above was proved by the presence of compensated metabolic acidosis with simultaneous stabilization of blood serum electrolytic composition in calves which obtained biologically active additive FLP-MD.     

Chromosome studies in bovine quintuplets

Chromosome analysis has been carried out on the four surviving calves of a bovine quintuplet set. Blood samples from all calves exhibited lymphocyte chimerism with greater percentages of male cells. Chromatid breaks and the presence of a hypodiploid cell carrying a metacentric marker were noted in varying proportions in all four calves. The possible relationship between chromosome abnormalities and immunological diversity between the calves have been discussed.     

Maternal strategies in sable antelope,Hippotragus niger: Factors affecting variability in maternal retrieval of hiding calves

Maternal behavior of wild ungulates has long been considered relatively invariant, yet recent reports from both wild and captive populations indicate considerable variability. Maternal behavioral tactics associated with the “hider” developmental strategy were investigated in six mother-infant pairs of sable antelope, Hippotragus niger, at the National Zoological Park's Conservation and Research Center near Front Royal, Virginia. When a calf moved away from its mother to hide, the mother tended to be 10 or more body lengths away and facing away from the calf. The presence of maternal vocalizations and the mother's ability to orient to the calf's resting site prior to calf activity periods were dependent on the age of the calf and whether the calf was lying alone or with other calves. The presence of maternal vocalizations and the ability of a mother to orient toward her calf were negatively related, with the mother vocalizing only when her calf could not be located visually. Variability in maternal behavior when searching for hidden calves was best explained by differences in calf conspicuousness. A mother apparently remembered only the general area in which her calf was lying, and not the precise location. Comparison of this study with previous studies of captive sable antelope suggests that mother-infant interactions are strongly influenced by enclosure size and the availability of tall vegetation; therefore, behaviors of individuals observed in small captive enclosures lacking tall vegetation may not be representative of those in the wild. © 1996 Wiley-Liss, Inc.     

Inbreeding and population dynamics of the Chillingham cattle (Bos taurus)

The Chillingham herd of white cattle has been isolated and confined in a park in northern England for several centuries. Blood grouping confirmed the cattle to be remarkably homozygous. Random fixation of harmful alleles and consequent extinction have presumably been prevented by selection, and this paper discusses possible selective processes and the ways in which these have changed over the last hundred years. Herd records from 1862 to 1899 and 1953 to 1985 show that, in the former period, but not the latter, culling and castration took place. In both periods, breeding was not seasonal. Herd fertility (calves born per female) was higher in the latter period. Between 1953 and 1985, calves which survived for at least 12 months had a median date of birth (25 June) a month later than that of calves which did not survive. Conception intervals were rather longer and fecundity lower than those observed in commercial cattle. K-factor analysis showed mortality to differ in its causes between the sexes. A multiple regression model showed January-May rainfall, and population size on 1 January to influence mortality rate of the January-May period. The Chillingham cattle have evidently been, and continue to be, subjected to rigorous selection and this presumably underlies the survival of this herd.