Effect of long-term cold storage of the predatory mite Neoseiulus californicus at high relative humidity on post-storage biological traits

The present study investigated whether long-term cold storage at high relative humidity (RH) affected the quality of the predatory mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) in terms of its survival and reproduction. For this purpose, we examined biological traits at the end of storage and during the post-storage period. Mated females three?days after adult emergence were stored individually in 1.5-ml vials for 15, 30, 45, 60, or 75?days at 5.0?±?0.3°C and RH of 99?±?0.1% under continuous darkness. At the end of the storage period, 94–100% of females had survived when the storage period was ≤30?days, but percent survival decreased with longer storage. After storage, female survival and oviposition rates were equivalent to un-stored females at 24?±?1°C, RH of 93?±?2%, and a photoperiod of LD 16:8?h. The quality of progeny (hatchability, survival to adulthood, and sex ratio) of stored females was not affected by storage periods as long as 60?days. These results indicate that storage using the tested method can preserve N. californicus for at least 30?days without any degradation.     

Seasonal reproductive costs contribute to reduced survival of female greater sage‐grouse

Tradeoffs among demographic traits are a central component of life history theory. We investigated tradeoffs between reproductive effort and survival in female greater sage‐grouse breeding in the American Great Basin, while also considering reproductive heterogeneity by examining covariance among current and future reproductive success. We analyzed survival and reproductive histories from 328 individual female greater sage‐grouse captured between 2003 and 2011, and examined the effect of reproductive effort on survival and future reproduction. Monthly survival of females was variable within years, and this within‐year variation was associated with distinct biological seasons. Monthly survival was greatest during the winter (November–March; Φ_W= 0.99 ± 0.001 SE), and summer (June–July; Φ_S= 0.98 ± 0.01 SE), and lower during nesting (April–May; Φ_N= 0.93 ± 0.02 SE) and fall (August–October; Φ_F= 0.92 ± 0.02 SE). Successful reproduction was associated with reduced monthly survival during summer and fall, and this effect was greatest during fall. Females that successfully fledged chicks had lower annual survival (0.47 ± 0.05 SE) than females who were not successful (0.64 ± 0.04 SE). Annual survival did not vary across years, consistent with a slow‐paced life history strategy in greater sage‐grouse. In contrast, reproductive success varied widely, and was positively correlated with annual rainfall. We found evidence for heterogeneity among females with respect to reproductive success; compared with unsuccessful females, females that raised a brood successfully in year t were more than twice as likely to be successful in year t+ 1. Female greater sage‐grouse incur costs to survival associated with reproduction, however, variation in quality among females may override costs to subsequent reproductive output.     

Comparison of occupancy modeling and radiotelemetry to estimate ungulate population dynamics

Radiotelemetry and unmarked occupancy modeling have been used to estimate animal population growth, but have not been compared for ungulates. We compared white-tailed deer (Odocoileus virginianus) population growth estimates from radiomarked individuals and occupancy modeling of unmarked individuals and evaluated advantages and disadvantages of each method. Estimates of population growth were obtained using remote camera (N = 54/year) detection/non-detection occupancy surveys of unmarked deer and from survival and recruitment data of radiomarked adult females (N = 87) and neonate fawns (N = 127) in a predominantly forested region of the Upper Peninsula of Michigan, USA, 2009–2011. We hypothesized that occupancy models and radiotelemetry data would have similar population growth trends because both methods sampled the same temporally closed population. Percent changes in camera trap data generally reflected finite population growth (λ) of radiomarked deer which increased (λ = 1.10 ± 0.01) from 2009 to 2010, but decreased (λ = 0.87 ± 0.02) from 2010 to 2011. Also, unmarked adult female abundance and fawn:adult female ratios generally reflected trends in radiomarked deer survival and recruitment. Royle–Nichols occupancy model abundance estimates had wide confidence intervals, which may preclude using this method from accurately estimating deer population growth. Radiotelemetry provided more precise population growth estimates, while allowing collection of vital rates and location data. However, the Royle–Nichols occupancy model may be preferred to radiotelemetry because it reflected yearly variation in population growth with reduced labor and no invasive marking. Researchers should consider the objectives and logistics of their study when choosing a specific method.     

Vasoactive intestinal polypeptide and endometrial blood flow in the goat

Endometrial blood flow was measured in seven goats twice before, once during, and twice after the close intra-arterial infusion of 300 pmol/min of vasoactive intestinal polypeptide (VIP). A saline solution of ⁸⁵krypton was injected intra-arterially and local blood flow calculated from the disappearance rate of the isotope from tissue surrounding a miniature Geiger-Müller probe in the uterine lumen. Initial blood flows (median and range) in animals pretreated with oestradiol-17β (N = 4) or with a regimen of oestradiol-17β and progesterone (N = 3), respectively, were 0.21 (0.11–0.35) and 0.20 (0.06–0.27) ml min^?1 g^?1. No significant change in endometrial blood flow occurred during or after the infusion of VIP, although the dose was sufficient to increase heart rate from 2.14 ± 0.15 to 2.32 ± 0.16 Hz (P < 0.001). The results indicate that VIP, in a dose known to increase myometrial blood flow in goats, is unable to evoke vasodilatation in the endometrium of this species. Since there is a corresponding variation in the density of nerve fibers containing VIP, it is suggested that VIP may play a role in regulating the partition of uterine blood flow in goats.     

Relationship between survival rates and numbers of natural teeth in an elderly Japanese population

Objectives: The objective of this study was to assess whether elderly people with 20 or more natural teeth were more likely to live longer than a cohort with less than 20 teeth. Materials and methods: Groups of elderly people over 80 years of age (24 males and 35 females) with 20 or more teeth (≥20 group) were compared with elderly people (24 males and 35 females) with less than 20 teeth (<20 group). Follow‐up studies were conducted at regular intervals for 10 years from July 1992 to July 2002. The cumulative survival rate of the ≥20 group (average ± SE tooth number of teeth – males, 23.9 ± 0.6; females, 23.8 ± 0.4) was compared with the <20 group (average number of teeth – males, 3.8 ± 1.1; females, 2.6 ± 0.8). The multivariate Cox proportional hazard models with the number of teeth in a group (≥20 group or <20 group). Smoking status and alcohol intake as covariates were used to adjust the cumulative survival rate. Results: The male participants in the ≥20 group had a significantly higher cumulative survival rates (p < 0.05) than the <20 group at 18 and 21 months from baseline. There were no significant differences in survival rates between the female groups. Adjusted cumulative survival rate was significantly different at 72, 75 and 78 months between the ≥20 group and <20 group for males but not for females. Conclusion: Having 20 or more natural teeth was associated with increased survival rate in elderly males, but not among the elderly females.     

Repeatable nest defense behavior in a wild population of Eastern bluebirds (Sialia sialis) as evidence of personality

Consistent individual differences in behavior, or personality, have been demonstrated in a variety of species other than humans, including mammals, birds, and invertebrates. Behavioral consistency has been shown to affect dispersal, foraging, exploration, and antipredator responses, which may have an impact on parental and offspring survival. Despite increasing research in behavioral consistency, the repeatability of nest defense behavior has rarely been assessed in wild bird populations. Furthermore, previous studies investigating nest defense behavior have utilized laboratory studies or mounted predators to elicit defensive behavior. It is important to assess personality in wild populations to fully understand the fitness consequences of behavioral consistency across natural contexts and to utilize live predators or competitors for accurate assessment of defensive behavior. We used an ecologically relevant, live, invasive, nest site competitor, the house sparrow (Passer domesticus), to elicit nest defense behavior in a wild population of Eastern bluebirds (Sialia sialis) to determine if nest defense behavior is repeatable within and between years for males and females (males: 2009, N?=?17; 2010, N?=?18; both years, N?=?9. Females: 2009, N?=?22; 2010, N?=?15; both years, N?=?11). We also determined if individual behavior changes as a function of season, parental age, brood size, or the number of house sparrows around the nest site. We found that females demonstrated repeatable behavior both within and between years. Male nest defense behavior was only repeatable in 1 year and was influenced by season in the other year. Parental age, brood size, and the number of house sparrows around the nest site did not affect nest defense behavior. We conclude that Eastern bluebirds demonstrate consistent nest defense behavior, or personality, although males are more plastic than females.     

Long-term implications of feed energy source in different genetic types of reproductive rabbit females: III. Fitness and productivity

The specialization process associated with genetic selection could be associated with functional disorders, affecting the reproductive success of females (fitness). We hypothesized that by modulating energy acquisition and allocation of females we could balance productivity and reproductive success. To test this hypothesis, we used 203 rabbit females belonging to three genetic types: H (n=66) maternal line specialized in prolificacy, LP (n=67) generalist maternal line, R (n=70) paternal line specialized in growth rate. We fed each genetic type with two diets specifically designed to promote milk yield (AF) or body reserves recovery (CS). We controlled females between their first and fifth reproductive cycles, recording traits related with productivity and fitness of females. H females fed CS had on average 11.2±0.43 kits with an individual weight of 54±1.2 g at birth and 525±11 g at weaning. Their conception rate when multiparous was 44% and their survival rate at the end of the experiment 30%. When they were fed AF, the individual weight of kits was 3.8 g heavier (P<0.05) at birth and 38 g heavier at weaning (P<0.05), the conception rate when multiparous increased 23 percentage points (P<0.05) and the survival rate at the end of the experiment 25 percentage points (P<0.05). LP females fed CS had on average 10.8±0.43 kits with an individual weight of 52±1.2 g at birth and 578±11 g at weaning. Their conception rate when multiparous was 79% and their survival rate at the end of the experiment 75%. When they were fed AF, it only increased individual weight of kits at weaning (+39 g; P<0.05). R females fed CS had on average 8.4±0.43 kits with an individual weight of 60±1.2 g at birth and 568±11 g at weaning. Their conception rate when multiparous was 60% and their survival rate at the end of the experiment 37%. When they were fed AF, they presented 1.4 kits less at birth (P<0.05) but heavier at birth (+4.9 g; P<0.05) and at weaning (+37 g; P<0.05). Therefore, we observed that genetic types prioritized different fitness components and that diets could affected them. In this sense, seems that more specialized genetic types, were more sensitive to diets than the more generalist type.     

Endocrinology of oviposition in the tuatara (Sphenodon punctatus)—II. Plasma arginine vasotocin concentrations during natural nesting

• 1.1. Plasma concentrations of the neurohypophysial arginine vasotocin (AVT) were measured during three stages of natural nesting [nest digging (N = 16), oviposition (N = 6), nest guarding (N = 6)] in the rare New Zealand reptile, the tuatara (Sphenodon punctatus).
• 2.2. Nest digging females (X ± 1 SE: 134.9 ± 15.0 pg/ml) exhibited elevated but significantly lower concentrations of plasma AVT compared to those observed during oviposition (216.0 ± 28.1 pg/ml). Nest guarding females (54.6 ± 29.8 pg/μl) had plasma AVT concentrations significantly lower than other stages.
• 3.3. These data are similar to those reporting elevated plasma AVT concentrations during oviposition in sea turtles but tuatara exhibit significantly lower plasma AVT values (10-fold difference). Plasma AVT concentrations reported for tuatara and birds are comparable.

     

Feral goat home range: Influence of social class and environmental variables

The daily range of feral goats varied in relation to social class and environmental variables. Mean daily ranges for 5 social classes were: male herd, 3.52 × 10⁵ m²; female herd, 2.12 × 10⁵ m²; composite herd, 1.86 × 10⁵ m²; stayer female, 0.57 × 10⁵ m²; creche group, 0.39 × 10⁵ m². Total recorded home range was male herd 14.8 × 10⁵ m² and female herd 9.65 × 10⁵ m². Female herd daily range varied seasonally in terms of size, location and habitat utilization. Female herd daily range area was correlated significantly with number of days since rain (r = 0.412), amount of rain in the past 30 days (r = ?0.296), maximum daily temperature (r = ?0.409), and minimum daily temperature (r = ?0.523), but not with wind velocity in the morning (r = ?0.064) or afternoon (r = ?0.137).     

Pedigree and herd characterization of a donkey breed vulnerable to extinction

Most donkey and local horse breeds are vulnerable to extinction as mechanization of agriculture progress throughout the world. The present study analyzed the pedigree and herd records of the donkey Asinina de Miranda breed (RAM), identifying genealogical and human factors that may affect the breed genetic diversity in the future and suggesting suitable strategies to breed preservation, early on the conservation program. The breeding rate was very low, with a ratio of foaling/live animals of 0.23 (178/760). The estimated number of founders and ancestors contributing to the reference population was 128 and 121. The number of founder herds in the reference population was 64, with an effective number of founder herds for the reference population of 7.6. The mean age of herd owners was 65.50±0.884 years, with a negative association among the herd size and owner’s age (P<0.001). In contrast, the size of the herd and the ownership of a male were both positively associated (P<0.001) with the herd number of in-born foals. Both the owners’ age and the herd location (RAM home region v. dispersal region) were negatively associated with the foaling number (P<0.001). The main identified risk factors were: low breeding rates; low number of males and their unequal contribution to the genetic pool; unequal contribution of the herds to genetic pool; and advanced age of herd owners.     

Survival,Birth Characteristics,and Cause-Specific Mortality of White-Tailed Deer Neonates

ABSTRACT Understanding survival of and factors that may predispose newborn deer (Odocoileus spp.) to mortality contribute to improved understanding of population dynamics. We captured free-ranging white-tailed deer neonates (n = 66) of radiocollared females that survived severe (Winter Severity Index [WSI] = 153) and mild (WSI = 45) winters 2000–2001 and 2001–2002. Mean dates of birth (26 May ± 1.7 [SE] days and 26 May ± 1.3 days) and estimated birth-masses of 2.8 ± 0.1 kg and 3.0 ± 0.1 kg were similar between springs 2001 (n = 31) and 2002 (n = 35), respectively. Neonate survival was similar between years; pooled mortality rates of neonates were 0.14, 0.11, and 0.20 at 0–1 weeks, 2–4 weeks, and 5–12 weeks of age, respectively, and overall survival rate for neonates to 12 weeks of age was 0.47. Predation accounted for 86% of mortality; the remaining 14% of deaths were attributed to unknown causes. Black bears (Ursus americanus) were responsible for 57% and 38% of predation of neonates in springs 2001 and 2002, respectively, whereas bobcats (Felis rufus) accounted for 50% in 2002. Wolves (Canis lupus) accounted for only 5% of predator-related deaths. Low birth-mass, smaller body size, and elevated concentrations of serum urea nitrogen (26.1 ± 2.6 mg/dL vs 19.3 ± 0.8 mg/dL) and tumor necrosis factor-α (82.6 ± 78.6 pg/mL vs. 2.3 ± 0.5 pg/mL) were associated with neonates that died within 1 week of birth. Even though we did not detect a direct relation between winter severity and birth or blood characteristics of neonates, evidence suggests that birth-mass and key serum indices of neonate nutrition were associated with their early mortality. Thus, managers can make more informed predictions regarding survival and cause-specific mortality of fawns and adjust management strategies to better control deer population goals.     

Reproductive Ecology and Cub Survival of Florida Black Bears

Abstract: We investigated reproductive ecology and cub survival of Florida black bears (Ursus americanus floridanus) in Ocala National Forest and the adjacent residential area of Lynne, Florida, USA, 1999-2003. We documented production of 81 cubs from 39 litters. Average litter size was 2.08 ± 0.11 (SE) cubs. The mean age of first reproduction was 3.25 ± 0.27 years. Excluding females that reproduced in consecutive years due to litter loss, interlitter interval was 2.11 ± 0.11 years. The mean annual fecundity rate was 0.57 ± 0.06. We used expandable radiocollars to monitor the fate of 41 bear cubs. The probability of cubs surviving to 9 months of age was 0.46 ± 0.09 and did not differ between cohorts or study locations. The most important causes of cub mortality included infanticide and mortality caused directly or indirectly by collisions with vehicles. Our results indicate that reproductive rates of female black bears in the Ocala study area are comparable to those reported for other black bear populations from eastern United States, but cub survival rates are lower than those reported for most black bear populations. Management of Florida black bears should emphasize strategies to reduce the mortality of cubs.     

Protein profile and alpha-lactalbumin concentration in the milk of standard and transgenic goats expressing recombinant human butyrylcholinesterase

The expression of recombinant proteins of pharmaceutical interest in the milk of transgenic farm animals can result in phenotypes exhibiting compromised lactation performance, as a result of the extraordinary demand placed on the mammary gland. In this study, we investigated differences in the protein composition of milk from control and transgenic goats expressing recombinant human butyrylcholinesterase. In Experiment 1, the milk was characterized by gel electrophoresis and liquid chromatography/mass spectrometry in order to identify protein bands that were uniquely visible in the transgenic milk and/or at differing band densities compared with controls. Differences in protein content were additionally evaluated by computer assisted band densitometry. Proteins identified in the transgenic milk only included serum proteins (i.e. complement component 3b, ceruloplasmin), a cytoskeleton protein (i.e. actin) and a stress-induced protein (94 kDA glucose-regulated protein). Proteins exhibiting evident differences in band density between the transgenic and control groups included immunoglobulins, serum albumin, β-lactoglobulin and α-lactalbumin. These results were found to be indicative of compromised epithelial tight junctions, premature mammary cell death, and protein synthesis stress resulting from transgene expression. In Experiment 2, the concentration of α-lactalbumin was determined using the IDRing^® assay and was found to be significantly reduced on day 1 of lactation in transgenic goats (4.33 ± 0.97 vs. 2.24 ± 0.25 mg/ml, P < 0.01), but was not different from non-transgenic controls by day 30 (0.99 ± 0.46 vs. 0.90 ± 0.11 mg/ml, P > 0.05). We concluded that a decreased/delayed expression of the α-lactalbumin gene may be the cause for the delayed start of milk production observed in this herd of transgenic goats.     

The ovulatory and LH responses to the male effect in dominant and subordinate goats

The objective of this study was to evaluate the LH and ovulatory response of dominant and subordinate dairy does following the introduction of males. A behavioral study was carried out to determine the individual success index (SI) of 35 anestrous does according to their ability to dominate other females. The 8 highest-ranking (highest SI) and the 8 lowest-ranking does (lowest SI) in terms of dominance were separated from the rest of the herd and placed together in the same pen, where a male was later introduced. Blood samples for plasma LH determinations were obtained from the 16 females at 30 min intervals from 0 to 6, 12 to 18 and 33 to 39 h after the introduction of the male, using an intravenous catheter. After day 8, plasma progesterone was also measured daily in order to determine the occurrence of ovulation. None of the does showed LH pulses during the sampling period prior to the introduction of the male. The dominant does showed significantly (p < 0.05) more LH pulses (2.0 ± 0.18 ng/ml vs. 1.2 ± 0.25 ng/ml) and a higher mean plasma LH concentration (0.25 ± 0.03 ng/ml vs. 0.14 ± 0.03 ng/ml) than the subordinate goats during the first 6 h of exposure to the male. There were no differences in LH pulsatility or concentrations at other times. The frequency of goats that ovulated tended to be greater in high-ranked than low-ranked does (87% vs. 37%). It could be concluded that the immediate LH response to the presence of the male (number of LH pulses) is higher in the dominant, compared to the subordinate goats, and this is associated with a higher number of dominant goats ovulating in response to the male effect.     

Undernutrition reduces the body weight and testicular size of bucks exposed to long days but not their ability to stimulate reproduction of seasonally anestrous goats

In semiarid conditions, feed is often scarce and variable with underfeeding being common; these factors can potentially induce fertility reductions in both sexes. Sexually active bucks are able to very efficiently fertilize out-of-season goats, but we do not know whether underfeeding would reduce the ability of bucks to fertilize goats during these periods. Two experiments were conducted to determine (i) testicular size and change of odor intensity of undernourished bucks exposed to long days and (ii) the ability of these bucks to stimulate reproductive activity in seasonally anestrous goats. In experiment 1, bucks (n = 7) were fed 1.5 times the normal maintenance requirements from September to May and formed the well-fed group. Another group of bucks (n = 7) were fed 0.5 times the maintenance requirements and formed the undernourished group. All bucks were subjected to artificially long days from 1 November to 15 January; this period was followed by a natural photoperiod until 30 May. Body weight, scrotal circumference and male odor intensity changes were determined every 2 weeks. In experiment 2, two groups of female goats (n = 26 each) were exposed to well-fed (n = 2) or undernourished bucks (n = 2) on 31 March. Ovulations and pregnancy rates were determined by transrectal ultrasonography. In experiment 1, a treatment by time interaction was detected for BW, scrotal circumference and odor intensity changes (P < 0.001). The BWs of well-fed bucks were greater than those of the undernourished bucks from October to May (P < 0.01), as were the scrotal circumferences from December to March (P < 0.05) and odor intensities from February to May (P < 0.05). In experiment 2, the proportions of females that ovulated at least once (100% v. 96%) or those that were diagnosed as pregnant (85% v. 77%; P > 0.05) did not differ significantly between the goats exposed to well-fed or undernourished bucks. The interval between the introduction of bucks and the onset of estrous behavior was shorter in goats exposed to well-fed bucks compared to the interval for those goats exposed to undernourished bucks (2.5 ± 0.2 v. 9.5 ± 0.6 days; P < 0.05). We conclude that undernourishment reduces the testicular size and odor intensity responses in bucks exposed to long days, but that undernourished bucks are still able to stimulate reproductive activity in seasonally anestrous goats, as is also the case for well-fed bucks.     

Efficiency and demographics of a high-yield dairy ewe farm with two managing systems involving five or 10 lambings per year

This study assessed milk productivity, demographic characteristics and workload distribution on a single high-yield dairy ewe farm in Spain (Avila, Spain; continental climate, latitude of 40.90 N, altitude of 900 m) over a 7-year period considering a transition from a herd management system involving five lambings per year (5LY) to a system involving 10 lambings per year (10LY). The 5LY system was practiced on the farm from 2010 to 2012 and the 10LY system from 2014 to 2015, with 2009 and 2013 being considered transition years. During this period, 27 415 lactations were recorded from an average of 3746 Lacaune sheep/year. Several productivity parameters were higher in 2014 to 2015 than in 2010 to 2012: milk yield/lactation (370±156 v. 349±185 l), lactation length (218±75 v. 192±75 days) and dry period length (53.5±38.3 v. 69.1±34.8 days) (all P<0.0001). During 2014 to 2015, investment in new lambing facilities was possible, workload was distributed more uniformly throughout the year, workload per worker was smaller, rate of ewe culling was lower (35.39±0.53% v. 42.51±7.51%), ewe longevity was greater and higher-order lactations were more numerous (P<0.0001). On the other hand, during 2010 to 2012, daily production was higher (1.73±1.66 v. 1.70±0.62 l/day; P=0.038), the interlambing period was shorter (283±50 v. 302±44 days; P<0.0001) and lambings/ewe per year were greater (1.42±0.01 v. 1.30±0.01; P<0.05). These results suggest that a 10LY herd management system can be compatible with profitability, productivity and good animal and worker’s welfare on a high-yield dairy farm, and may even be associated with better outcomes than a 5LY system.     

Social ranking and plasma progesterone levels in goats

Progesterone is essential for maintaining pregnancy in goats, and embryonic losses may be a consequence of the reduction in circulating progesterone levels close to the time of implantation. Some evidence exists regarding social dominance affecting the plasma progesterone levels in several species—where dominant females conceive earlier. The objective of this research was to determine whether serum progesterone levels differ in goats of different social status. A behavioural study was conducted for 10 days in a herd of 57 does and an individual success index (SI) was calculated according to the result of aggressive interactions. Goats were classified as high (SI: 1–0.67), medium (SI: 0.66–0.34) and low-ranking (SI: 0.33–0.0). Ovulation was synchronized using two injections of prostaglandin 11 days apart, and the plasma progesterone levels determined daily for a period of 20 days. The area under the plasma progesterone curve during the entire study was greater in the high than in the medium and low-ranking does (96.2 ± 5.8, 79.5 ± 5.3 and 81.3 ± 5.3 ng/ml, respectively, P < 0.05). During days 11–17 following prostaglandin synchronization, the plasma progesterone levels were higher in the high-ranking (P < 0.05), compared to the low-ranking does. Plasma progesterone levels were significantly correlated with SI at days 14 and 15 (r = 0.26; P < 0.05). Results suggest a relationship between social ranking of goats and the plasma progesterone production from the corpus luteum and other possible sources.     

Serum LH,FSH, estradiol-17β and progesterone profiles of native and crossbred goats in a tropical semiarid zone of Venezuela during the estrous cycle

The patterns of serum luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone and estradiol-17β during the estrous cycle of six crossbred (Alpine × Nubian × Native) and six native goats showing a 21 day estrous cycle in a semiarid zone of Venezuela are presented. In the crossbred goats, FSH had two significant peaks on Days 19 and 0 (33 ± 8.6 ng ml⁻¹ and 25 ± 6 ng ml⁻¹, respectively); in contrast, native goats only had one significant peak on the day of estrus (22 ± 2 ng ml⁻¹), with the increase beginning on Day 17. During the follicular phase of crossbred goats, estradiol-17β and LH increased to 28 ± 6 pg ml⁻¹ and 23 ± 6.9 ng ml⁻¹, respectively, on Day 0. Prior to Day 0, LH increased to 10.0 ± 4.9 ng ml⁻¹ on Day 18, decreasing to 1.5 ng ml⁻¹ on Day 19, while estradiol-17β was increasing. This relationship between estradiol-17β and LH was not found to exist in native does, which presented a LH peak on Day 0 (30 ± 8 ng ml⁻¹ and 35 ± 10 ng ml⁻¹ in first and second estrus, respectively). LH basal levels were notably higher in native does. The highest concentrations of progesterone (10 and 12 ng ml⁻¹) were detected on Days 12 and 15 in crossbred and native females, respectively. In conclusion, the relationship between estradiol-17β and gonadotropins during the follicular phase in crossbred goats suggests negative and positive feedback effects on both LH and FSH. Serum concentrations of LH were higher in native than in crossbred goats, whereas concentrations of FSH were higher in crossbred does. Thus, genetic factors need to be taken into account when comparing blood levels of gonadotropins in goats raised in tropical semiarid zones.     

Comparative age-related responses to serological and faecal tests directed to Mycobacterium avium paratuberculosis (Map) in French dairy goats

The objectives of the present study were to estimate sensitivity and specificity of 6 different tests directed to Mycobacterium avium paratuberculosis (faecal culture, microscopic examination, Agar Gel Immunodiffusion (AGID) and 3 commercial ELISA tests, named A, B and C) in different age categories and to assess the degree of agreement between responses thus obtained. The study was carried out in 12 French commercial dairy herds, which were selected in a population of herds with unknown paratuberculosis status. In each herd, a sample of goats without clinical signs was randomly selected according to 4 age categories. Responses of 412 goats with concomitant results for the 6 tests were analysed. In the 4 age categories, the specificity and the sensitivity of the 6 tests were estimated using Bayesian methods with conditional dependence between tests. Agreement among the results obtained for these tests was determined by calculating the kappa statistic.With the exception of AGID, the proportions of positive responses for each test differed significantly between herds (range 0–27.5%). With the exception of scopy, the proportions of positive responses for each test differed significantly between age categories. Sensitivities and specificities of the 6 tests were very different according to age categories. Specificities were higher than sensitivities. The highest values in sensitivity were obtained in goats between 2 and 3 years, with the best value for ELISA C (76.6%, 95% CI of 46.1–96.1%). In the other age categories, sensitivities of the 6 tests were too low to have practical use. Only scopy, faecal culture and ELISA B have positive responses in category 1 (goats of less than 1 year). Agreements between the different pairs of tests were low, except between the 3 ELISA tests which were in “good” or “quite good” agreement.This study showed that detection of infection with Map was efficient only in goats between 2 and 3 years, with an ELISA test. For goats in other age categories, no test was sensitive enough to detect goats infected with Map. In a Map infection control program, ELISA tests, performed on goats between 2 and 3 years, can be used to define herd status and to estimate prevalence but they should not be used at goat level to select goats for culling, due to the low positive predictive value.