Effect of water trough type on the drinking behaviour of pasture-based beef heifers

The objective of this study was to investigate the effects of different trough types on the water consumption and drinking behaviour of pasture-based beef heifers. Two trials were implemented with 32 beef heifers to test two different types of water troughs, namely a rectangular concrete trough (RC) and a round polyvinyl chloride water tank (PVC). In Trial 1, both troughs were simultaneously available to groups of four animals within eight paddocks. In Trial 2, the animals were distributed in pairs throughout 16 paddocks and, in a crossover design, were exposed to one type of trough at a time. In both trials, estimated water intake was per four animals. Number of drinking bouts, time spent drinking and amount of water intake from the RC and PVC trough were recorded in both trials. Data were statistically analysed by analysis of variance. In Trial 1, group and trough effect were in the model. In Trial 2, stage, pair and trough were tested. In Trial 1, where both types of troughs were available, animals had a higher number of drinking bouts (3.32 v. 0.57 ± 0.09; P < 0.01), longer drinking periods (144.21 v. 22.81 ± 7.3 s; P < 0.01) and greater intake (160.21 v. 23.76 ± 13.06 l; P < 0.01) from the PVC water tank, compared to the RC trough. In Trial 2, all groups drank more often (5.10 v. 3.28 ± 0.32; P < 0.001), for longer periods (167.23 v. 115.23 ± 15.61 s; P < 0.02) and with higher intake (141.36 v. 118.47 ± 5.01 l; P < 0.02) from the PVC than from the RC trough. Thus, heifers not only prefer, but also drink more from a PVC water tank in comparison to a RC trough.     

Biologic data of Macaca mulatta, Macaca fascicularis, and Saimiri sciureus used for research at the Fiocruz primate center

Physiological parameters of laboratory animals used for biomedical research is crucial for following several experimental procedures. With the intent to establish baseline biologic parameters for non-human primates held in closed colonies, hematological and morphometric data of captive monkeys were determined. Data of clinically healthy rhesus macaques (Macaca mulatta), cynomolgus monkeys (Macaca fascicularis), and squirrel monkeys (Saimiri sciureus) were collected over a period of five years. Animals were separated according to sex and divided into five age groups. Hematological data were compared with those in the literature by Student's t test. Discrepancies with significance levels of 0.1, 1 or 5% were found in the hematological studies. Growth curves showed that the sexual dimorphism of rhesus monkeys appeared at an age of four years. In earlier ages, the differences between sexes could not be distinguished (p < 0.05). Sexual dimorphism in both squirrel monkeys and cynomolgus monkeys occurred at an age of about 32 months. Data presented in this paper could be useful for comparative studies using primates under similar conditions.     

Effects of positive interaction with caretakers on the behaviour of socially housed common marmosets (Callithrix jacchus)

Every aspect of the life of the captive non-human primates should be carefully attended to, as updated refinement concept recommends. Interaction with humans as environmental enrichment for these animals is believed to be of value, but it has been subject to little quantitative evaluation. This study investigates the effects of positive interaction with humans on the behaviour of a captive colony of common marmosets (Callithrix jacchus). The study was composed of two phases: baseline condition, where the interaction with humans was represented by routine care and management; and a second phase (‘Human Interaction Effects’), in which a familiar caretaker spent additional 20 min per day with each family, interacting actively and positively with the monkeys. In order to assess potential durable effects of such interaction, data were collected only when caretaker was absent. Between the two phases, a period of interaction 4 weeks long per family took place with the caretaker. The sampling method used was a 10 s scan sampling, with daily sessions 30 min long. Following the period of additional interaction with caretaker, the marmosets showed an increased level of grooming and playful activities, generally considered signs of increased level of welfare; however, they also showed lower levels of self-scratching and locomotion. A trend towards reduced contact vocalizations was also observed. These results suggest that simple, unstructured positive interactions between humans and marmoset monkeys may be part of a program aimed at maximising the level of welfare of captive non-human primates.     

Manipulating the affiliative interactions of group-housed rhesus macaques using positive reinforcement training techniques.

Social housing, whether continuous, intermittent, or partial contact, typically provides many captive primates with opportunities to express affiliative behaviors, important components of the species-typical behavioral repertoire. Positive reinforcement training techniques have been successfully employed to shape many behaviors important for achieving primate husbandry goals. The present study was conducted to determine whether positive reinforcement training techniques could also be employed to alter levels of affiliative interactions among group-housed rhesus macaques. Twenty-eight female rhesus were divided into high (n = 14) and low (n = 14) affiliators based on a median split of the amount of time they spent affiliating during the baseline phase of the study. During the subsequent training phase, half of the low affiliators (n = 7) were trained to increase their time spent affiliating, and half of the high affiliators (n = 7) were trained to decrease their time spent affiliating. Trained subjects were observed both during and outside of training sessions. Low affiliators significantly increased the amount of time they spent affiliating, but only during nontraining sessions. High affiliators on the other hand, significantly decreased the amount of time they spent affiliating, but only during training sessions. These data suggest that positive reinforcement techniques can be used to alter the affiliative behavior patterns of group-housed, female rhesus monkeys, although the two subgroups of subjects responded differently to the training process. Low affiliators changed their overall behavioral repertoire, while high affiliators responded to the reinforcement contingencies of training, altering their proximity patterns but not their overall behavior patterns. Thus, positive reinforcement training can be used not only as a means to promote species-typical or beneficial behavior patterns, but also as an important experimental manipulation to facilitate systematic analyses of the effects of psychosocial factors on behavior and potentially even immunology.     

Assessment of circadian rhythms throughout the menstrual cycle of female rhesus monkeys

Reproductive cyclicity has a significant influence on the regulation of circadian rhythms in rodents. Studies have suggested that there are changes in body temperature rhythms between the follicular and luteal phases in human females. This study examined the effects of menstrual cyclicity on physiological and behavioral circadian rhythms in female rhesus monkeys (Macaca mulatta), an acknowledged biomedical model. Seven unrestrained subjects were implanted with a biotelemetry transmitter to measure body temperature and heart rate and an accelerometer was used to measure physical activity. Water was available ad libitum and drinking was measured via an electronic circuit attached to a water lixit. A video-based task system, the Psychomotor Test System, provided environmental enrichment and delivered a pelletized diet. Mean, phase, and amplitude of each rhythm were calculated. Estrogen and progesterone conjugates were assayed and quantified from daily urine samples to identify follicular and luteal phases of the menstrual cycle. Average circadian variables were then compared between these phases. Heart rate was significantly (P< or =0.05) delayed in the luteal phase. Albeit non-significant, analysis showed a trend toward decreased circadian amplitude of body temperature in the luteal phase.     

Effect of inhibition of estrogen synthesis during the luteal phase on function of the corpus luteum in rhesus monkeys

It has been hypothesized that estrogen synthesized by the corpus luteum initiates luteal regression during the nonfertile menstrual cycle in primates. To study the role of endogenous estrogens in functional regression of the monkey corpus luteum, we administered the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD) to rhesus monkeys during the luteal phase of the menstrual cycle. Twice-daily oral administration of ATD suppressed systemic and intraluteal estrogen levels by 80-90%. The midluteal phase rise in estradiol concentrations that occurs in rhesus monkeys was completely abolished by ATD treatment. Despite suppression of estrogen synthesis during the luteal phase, mean menstrual cycle length and length of the luteal phase were not different than in control monkeys treated with vehicle only. Progesterone levels were lower in the ATD-treated group on the second and third day of treatment, but did not differ from control levels during the remainder of the cycle. These data suggest that elevated estrogen synthesis during the luteal phase of the menstrual cycle is not a prerequisite for spontaneous luteolysis in rhesus monkeys.     

Induction of relaxin secretion in rhesus monkeys by human chorionic gonadotropin: dependence on the age of the corpus luteum of the menstrual cycle

Peripheral concentrations of immunoreactive relaxin are undetectable in primates during the nonfertile menstrual cycle, but become measurable during the interval when chorionic gonadotropin (CG) rises in early pregnancy. The objectives of the current study were to determine if exogenous CG, administered in a dosage regimen which invoked patterns and concentrations resembling those of early pregnancy, would induce relaxin secretion in nonpregnant rhesus monkeys, and whether the induction was dependent on the age of the corpus luteum (CL) at the onset of treatment. Female rhesus monkeys received twice-daily i.m. injections of increasing doses of human CG (hCG) for 10 days beginning in the early (n = 4), mid (n = 6) or late (n = 4) luteal phase of the menstrual cycle [5.3 +/- 0.3, 8.3 +/- 0.5, and 12.0 +/- 0.4 days after the midcycle luteinizing hormone (LH) surge, respectively; means +/- SEM]. Whereas immunoreactive relaxin was nondetectable in the luteal phase of posttreatment cycles, detectable levels of relaxin were observed in 2 of 4, 5 of 6, and 3 of 4 monkeys during hCG treatment in the early, mid and late luteal phase, respectively. Although CG treatment rapidly enhance progesterone levels, the appearance of relaxin was deferred; relaxin was first detectable 9.0 +/- 1.0 and 4.7 +/- 1.9 days after the onset of CG treatment at early and late luteal phases. Patterns of relaxin concentrations differed among groups (P less than 0.05, ANOVA; split plot design) and relaxin levels were lowest (P less than 0.01) in monkeys treated during the early luteal phase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Discrete or graded variation within rhesus monkey screams? Psychophysical experiments on classification

Gouzoules et al. (1984, Animal Behaviour,32, 182-193) presented evidence that semifree-ranging rhesus monkeys, Macaca mulatta, produce acoustically distinctive classes of scream vocalizations that carry different functional messages. To determine the perceptual validity of these vocal classes, we conducted psychophysical experiments on captive rhesus monkeys. We trained two monkeys to maintain contact with a metal response cylinder during presentation of nontarget stimuli, and to release the cylinder to report detection of target stimuli. For one subject, tonal screams served as nontarget stimuli and arched screams served as targets. These conditions were reversed for a second subject. Once natural exemplars were correctly discriminated, both subjects correctly generalized to synthetic targets. Variability in responses to nontarget stimuli, however, suggested that scream categories were not well defined following training. This result suggests that rhesus monkeys do not perceive categorical distinctions between arched and tonal screams, at least under the testing conditions implemented. Rather, our results provide evidence for a graded category. To explore which acoustic features are most important for classifying novel exemplars as tonal or arched screams, we ran several follow-up experiments with novel scream exemplars. Generalization trials suggested that variation in rate of frequency change, maximum frequency of the fundamental and harmonic structure may be important to the discrimination of screams.     

人工饲养条件下死亡实验恒河猴肠道病理改变特点分析

目的观察人工饲养条件下实验恒河猴肠道病理改变,探讨实验猴肠道疾病分布规律和病理改变特点,丰富实验猴自发病变基本研究资料。方法对1998-2008年云南地区饲养的自然死亡的155只恒河猴（年龄2-20岁）的肠道进行病理检查,按年龄分为幼年组、成年组、老年组,并对观察结果进行统计学分析。结果155例恒河猴中58例检出肠道病变,有慢性肠炎、急性肠炎、黏膜充血水肿、出血、糜烂、溃疡、穿孔、寄生虫共8种主要病变,出现率最高的为急性肠炎（20．00％）。实验猴不同年龄组肠道病变类型分布基本相同,肠道病变率随年龄增长而增高,不同年龄组间统计学分析差异无显著性。结论人工饲养条件下死亡实验猴肠道病变检出率较高,急性肠炎是实验猴的主要致死原因之一,实验猴肠道病理改变随年龄增长而病变加重。对实验猴饲养和研究时,应重视肠道病变因素,尤其是急性肠炎。死亡实验猴肠道病变研究对实验猴的质量控制和相关动物实验有重要指导价值。     

Stereotypic and self-injurious behavior in rhesus macaques: a survey and retrospective analysis of environment and early experience

Abnormal behavior in captive rhesus monkeys can range from active whole-body and self-directed stereotypies to self-injurious behavior (SIB). Although abnormal behaviors are common in singly-housed rhesus monkeys, the type and frequency of these behaviors are highly variable across individual animals, and the factors influencing them are equally varied. The purpose of this investigation was to survey abnormal behavior in a large population of rhesus macaques, to characterize the relationship between stereotypies and self-injury, and to identify potential risk factors for these aberrant behaviors. Behavioral assessments of 362 individually housed rhesus monkeys were collected at the New England Regional Primate Research Center (NERPRC) and combined with colony records. Of the 362 animals surveyed, 321 exhibited at least one abnormal behavior (mean: 2.3, range: 1-8). The most common behavior was pacing. Sex differences were apparent, with males showing more abnormal behavior than females. SIB was also associated with stereotypies. Animals with a veterinary record of self-injury exhibited a greater number of self-directed stereotypies than those that did not self-injure. Housing and protocol conditions, such as individual housing at an early age, longer time housed individually, greater number of blood draws, and nursery rearing, were shown to be risk factors for abnormal behavior. Thus, many factors may influence the development and maintenance of abnormal behavior in captive primates. Some of these factors are intrinsic to the individual (e.g., sex effects), whereas others are related to colony management practices, rearing conditions, and research protocols.     

Changes in blood chemistry and hematology variables during aging in captive rhesus macaques (Macaca mulatta)

Identifying changes with age in physiological variables of captive nonhuman primates will aid in the proper treatment and clinical diagnosis of these animals, as well as enhance our understanding of nonhuman primate models for human aging. Information for 33 physiological variables was obtained from the Primate Aging Database, a multi-centered database being developed for clinical and research use. Using multiple regression analyses, we investigated the relationship of age to hematological variables, blood chemistry and body weight in 345 captive rhesus monkeys (age range 7-30 years) from three different primate research facilities. The analyses revealed that 15 of these variables show a significant relationship with chronological age and are altered in older as compared with adult animals. Here we present the first phase of a project that will: a) identify changes with age in physiological variables among adult captive rhesus macaques; and b) characterize normative values for the aging rhesus population.     

A test of the randomness of paternity of members of maternal sibships in six captive groups of rhesus monkeys (Macaca mulatta)

Results of previous studies have shown that in captive groups of rhesus monkeys (Macaca mulatto)fathers associate more frequently with their own offspring than with those of other males and that mothers are most permissive of physical contact between their own infant and a juvenile when that juvenile shares the same father with her infant. These two observations suggest that the identity of offspring born in captive groups of rhesus monkeys is recognized by at least some adult members of the group. Consistent patterns of mating among mating seasons might explain this apparent recognition of offsprings’ paternity. Fathers, for example, might regularly associate with young who maintain a close relationship with females with whom they have previously mated, and mothers might selectively permit juveniles who maintain a close relationship with males with whom they have previously mated to associate with their infants. This hypothesis is tested in this paper by comparing the observed distribution of 70 maternal sibships, members of which were fathered by the same or by different adult males over a 4-year period in six captive groups of rhesus monkeys, with that distribution expected based on random mating from season to season. Seasonal mating patterns were found to be random. Preparations are now underway to test this hypothesis in several free-ranging groups.     

Does intermale mounting function as a dominance demonstration in rhesus monkeys?

The relationship between dominance and intermale mounting was analyzed in two troops of captive rhesus monkeys (Macaca mulatta). The data did not support the assumption that mounting among males functions as a dominance demonstration as described in the literature because mounting commonly (63% of 65 dyads) occurred in a bidirectional fashion, and mounting not only was performed by dominant males but also was shown with regularity (36% of 521 cases) by subordinate males. Intermale mounting was often (37% of 521 cases) associated with amicable interactions--commonly preceding them--but it was only rarely (2%) associated with dominance-subordination behaviors. It was concluded that intermale mounting may serve as a socially cohesive behavior in rhesus monkeys by promoting nonagonistic contact.     

Altruistic interference shown by the alpha-female of a captive troop of rhesus monkeys

Interferences in aggressive disputes were recorded in a captive troop of rhesus monkeys (Macaca mulatta) comprising 19 mature females, 2 mature males and 12 immatures. The top ranking animal - the oldest female, Alpha, 23 years of age - was the only one who consistently interfered in favor of victims, never of aggressors. This protective, dispute-breaking strategy was distinguished by the following facts: None of the supported monkeys shared genes with Alpha; Alpha had no preference for aiding particular individuals; Alpha's high-risk interference (against aggressors) was never reciprocated; and (4) there was no evidence that Alpha's strategy aimed at the improvement of dominance standing. It was concluded that Alpha's behavior may represent an example of altruism.     

Natural and experimental simian cytomegalovirus infections at a primate center

Simian cytomegalovirus infections were studied in captive, naturally infected primates and in experimentally infected rhesus monkeys. Neutralizing antibody to simian cytomegalovirus was prevalent in selected species of Old World Monkeys. Naturally infected, rhesus monkeys shed virus in their urine during the entire two-year period of study. Similarly, experimentally infected rhesus monkeys showed neutralizing antibody and viruria for more than two years. The indirect fluorescent antibody procedure was found more sensitive than the neutralization antibody technique but appeared less specific for antibody to cytomegalovirus strains.     

Hormonal effects of early rearing conditions in the infant rhesus monkey

Mother-reared and nursery-reared rhesus monkeys were evaluated during the first month of life to assess the effects of early rearing on endocrine status in infancy. Plasma cortisol and growth hormone (GH) levels were measured in two conditions: (1) basal and (2) 30 min following removal from either the mother or the nursery. Nursery-reared infants had lower basal GH levels and higher cortisol levels than did mother-reared infants. Both GH and cortisol levels rose significantly following separation and reached similar levels in the mother-reared and nursery-reared infants. Mother-reared animals exhibited higher GH levels in response to a pharmacological GH-stimulation test. Thus nursery rearing of primate infants significantly affected the baseline secretion of two important endocrine systems, but did not appear to alter markedly the acute endocrine response to a psychological stressor.     

Designing Better Water Troughs: Does Trough Color Influence Dairy Cows’ Preference?

Eighteen lactating dairy cows were used to elucidate their preference for green, grey, or red troughs. The herd was managed under a rotational grazing system with ad-libitum access to water until 11:30 h. For 9 days, all cows were tested individually following the afternoon milking. Cows drank similar quantities, spent a similar amount of time drinking, and took a similar number of sips from the 3 trough colors (p > .05). In 75% of the tests, cows drank more than 95% of the test period from the same trough. Within this time, the percentage of choices did not differ among colors (33.3% green, 39.0% grey, and 27.7% red). When they chose the red trough, cows spent less time drinking (p ≤ .05) and tended to take fewer sips (p = .07), which could suggest a partial aversion to this color. Suboptimal water trough design may have long-term negative effects on both the production and welfare of dairy cattle; however, the results suggest that color does not play a major role in the drinking behavior of dairy cows.     

The relationship between aggressive behavior and menstrual cycle stage in female rhesus monkeys (Macaca mulatta)

The aggressive behavior of eight adult female rhesus monkeys, living in a captive social group, was studied prior to and during a breeding season extended by vasectomizing all the adult males in the group. Female reproductive status was ascertained by: recording all adult female-adult male copulations, detecting menstruation by vaginal swabbing, and analyzing serum progesterone levels by radioimmunoassay. Females were more aggressive during the follicular stage of their menstrual cycle than the luteal stage or during the period prior to the onset of seasonal ovarian activity. Increases in aggression were limited to increases in the milder forms of agonistic behavior, primarily threatening gestures. Although the females showed their highest rates of noncontact aggressive response categories during the follicular stage, several showed highest rates of contact aggressive response categories in the precycling period.     

Effects of infant-infant separation of young monkeys in a free-ranging natural environment

Five infant rhesus monkeys reared togather in free-ranging natural environment for about eight months were subjected to peer separation. Separation of an infant was inflicted by way of removing all the other infants from their home range. The infants so separated showed exceedingly high levels of locomotion and vocalizations in the beginning of separation phase, but their such excited behaviour did not last for more than a day, and during the remaining separation period they appeared to be quite depressed as mainly indicated by their reduced range of locomotion, reduced motivation for food and water, and reduced level of vocalization and environmental exploration. Thus, the animals showed a biphasic response to separation, which was characterized by an initial phase of ‘protest’ followed by a ‘despair’ stage, basically similar to what has been reported in infant rhesus monkeys subjected to peer or mother separation under laboratory conditions. The main project of which this research was a part is being financed by Indian Council of Social Science Research (ICSSR).     

Differential effects of N-methyl-D-aspartate receptor stimulation on growth hormone secretion at specific stages of postnatal development of the male rhesus monkey

The present study attempts to examine the role of N-methyl-D-aspartate (NMDA) receptor in the central regulation of growth hormone (GH) secretion during specific stages of pubertal development of the male rhesus monkey (Macaca mulatta). Infantile (n=4), prepubertal (n=5), peripubertal (n=5) and adult (n=5) intact male rhesus monkeys were given an agonist of NMDA receptor, N-methyl-D,L-aspartate (NMA) (15 mg/kg BW) through a teflon cannula implanted in the saphenous vein. Blood samples were collected 20-60 min before and 40-80 min after the injection of the drug at 10-20 min intervals. NMA was dissolved in normal saline immediately before use and passed through a 0.22 microm filter at the time of injection. All bleedings were carried out under ketamine hydrochloride anesthesia (initial dose 5 mg/kg BW, im followed by 2.5 mg/kg at 30 min intervals). The plasma levels of GH and testosterone (T) were determined by using specific assay systems. The hypothalamic-somatotrope activity under basal conditions was studied by averaging all the GH concentrations obtained before NMA injection, whereas the sensitivity of NMDA receptor to NMA stimulation was determined by comparing basal GH levels immediately before NMA injection at 0 min and GH concentrations obtained 10 min after the injection. The mean basal plasma concentrations of GH in the four groups of animals showed marked age-related differences. The levels of GH were found to be higher in infantile and peripubertal monkeys as compared to those of prepubertal and adult animals. A single iv injection of NMA produced differential effects on GH secretion during specific stages of postnatal development depending upon the level of GH secretion under basal conditions. Whereas NMA had no demonstrable effect on GH secretion in infantile and peripubertal animals in which the basal GH levels were high, it produced pronounced effects on GH secretion in prepubertal and adult monkeys wherein baseline GH concentrations were low. In conclusion, the present study suggests that the glutamatergic component of the control system that governs GH secretion by utilizing NMDA receptor may participate in regulation of age-related changes in the secretion of GH in the male rhesus monkey.