Parturition Date Research Articles

The effectiveness of an internal teat sealant in preventing new intra mammary infections in dairy cattle during dry period

The aim of our study was to evaluate the effect of an internal teat sealant infused upon drying off on the incidence of new intra-mammary infections (IMI) during the dry period in dairy cattle. Due to the non-availability of the product on the Indian market, the product was prepared in a laboratory using bismuth subnitrate and liquid paraffin. A total of 64 quarters free from infection on culture were selected for the study at 60 days before the expected date of parturition. The quarters were randomly divided into two groups (group A and group B), with 32 quarters in each group. The group A quarters were infused with teat sealant at the time of drying off, and the quarters in group B were kept as the control and no treatment was provided to them. Milk samples from all the selected quarters were subjected to cultural examination at the time of drying off and 1-3 days post calving. The incidence of new IMI’s between drying off and calving was significantly lower for group A quarters when compared to group B quarters (12.5% vs 34.4%). The incidence of new IMI’s in group A and group B quarters was significantly lower for Streptococcus uberis (3.13% vs 18.75%) and Streptococcus dysgalactiae (3.13% vs 12.5%). The study concluded that infusion of teat sealant at drying off is helpful in lowering the incidence of new IMI’s during the dry period.

Blood calcium dynamics in cows receiving an aqueous calcium suspension for voluntary consumption or a calcium bolus following parturition.

The form of oral calcium (Ca) supplement and the Ca source influence Ca absorption dynamics resulting in different postpartum calcemia. The objective of this study was to investigate whether an oral Ca supplement (mainly CaCO3) offered for voluntary consumption would maintain or increase postpartum blood Ca to the same degree as a Ca bolus (mainly CaCl2) providing an equivalent dose of a Ca. A total of 72 Holstein cows were blocked by expected parturition date and parity. Within each block of 3 animals, cows were randomly assigned to one of three treatments, including an oral Ca supplement offered for voluntary consumption (Ca-drink, n = 23), an oral Ca bolus (Ca-bolus, n = 24), or an untreated group (CON, n = 25). Treatments were administered once within 15 min postpartum. The Ca-drink provided 45 g of Ca (CaCO3 source) and was mixed in 20 L of lukewarm water and offered to cows for 30 min. The Ca-bolus provided 43 g of Ca (71% from CaCl2 and 29% from CaSO4) and was administered once. Both Ca-bolus and CON cows received 20-l of lukewarm water at parturition to standardize the volume of fluids (Ca-drink or 20-l lukewarm water) offered at parturition. Dairy cows offered Ca-drink had a 28% higher fluid consumption than Ca-bolus and CON cows. Milk yield and milk composition expressed in percentage protein, fat, lactose, and urea did not differ, whilst there was a small but significant increase in DMI in cows receiving the Ca-drink compared to CON, while Ca-bolus did not differ from other groups. This was consistent with reduced BW losses between week 1 and 3 in cows receiving the Ca-drink suspension. Treatment by time interactions were present for blood Ca, glucose, and urea concentrations. Blood Ca was relatively stable in Ca-drink cows, while higher fluctuations were observed in Ca-bolus cows. In Ca-bolus cows, blood Ca increased from 15 min to 6 h, decreased from 6 to 24 h, and finally increased again from 24 to 48 h. At 24 h post administration, blood Ca was greater in cows receiving the Ca-drink than cows receiving the Ca-bolus. Blood glucose was greater in Ca-bolus cows at 15 min after treatment administration compared with Ca-bolus and CON, while blood urea was higher in CON than Ca-drink and Ca-bolus throughout the sampling period. These results indicate that voluntary oral Ca resulted in a relatively stable calcemia, whereas higher fluctuations were observed in cows receiving the Ca-bolus. Due to a lack of differences between Ca-drink and Ca-bolus compared with CON, it is not possible to conclude regarding the efficacy in maintaining postpartum blood Ca.

Blood Metabolomic Phenotyping of Dry Cows Could Predict the High Milk Somatic Cells in Early Lactation—Preliminary Results

Subclinical mastitis (SCM) is a very common disease of dairy cows. Currently, somatic cell count (SCC) is used for SCM diagnoses. There are no prognostic tests to detect which cows may develop SCM during the dry-off period. Therefore, the objectives of this study were to identify metabolic alterations in the serum of pre-SCM cows during the dry-off period, at −8 and −4 weeks before calving, through a targeted mass spectrometry (MS) assay. Fifteen cows, free of any disease, and 10 cows affected only by SCM postpartum served as controls (CON) and the SCM group, respectively. Results showed 59 and 47 metabolites that differentiated (p ≤ 0.05) CON and pre-SCM cows at –8 and −4 weeks prior to the expected date of parturition, respectively. Regression analysis indicated that a panel of four serum metabolites (AUC = 0.92, p < 0.001) at −8 weeks and another four metabolites (AUC = 0.92, p < 0.01) at −4 weeks prior to parturition might serve as predictive biomarkers for SCM. Early identification of susceptible cows can enable development of better preventive measurements ahead of disease occurrence.

Impact of adrenocorticotropin hormone administration on the endocrinology, estrus onset, and ovarian function of weaned sows.

Chronic stress affects the reproductive health of mammals; however, the impact of adrenocorticotropin hormone (ACTH) level elevation during chronic stress on the reproduction of weaned sows remains unclear. In this study, nine weaned sows with the same parturition date were randomly divided into control group (n = 4) and ACTH group (n = 5). Each group received intravenous administration of ACTH three times daily for 7 days. Blood samples were collected every 3 h after injection. A radioimmunoassay was used to measure the concentrations of cortisol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4) and estradiol-17β (E2) in the blood. Estrus was determined according to changes in the vulva and the boar contact test. The mRNA expressions of glucocorticoid receptor, FSH receptor, LH receptor (LHR) in the corpus luteum (CL) were detected by qRT-PCR. The results showed that ACTH administration substantially delayed the initiation of estrus and the pre-ovulatory LH peak. The sows of control group ovulated within 10 days and the ovulation rate was 100%, while it was 60% in the ACTH group. Two sows of ACTH group showed pseudo-estrus. The E2 concentrations significantly decreased in the ACTH group at 36 h, 42 h and 66 h of the experimental period. The P4 concentrations in the ACTH group significantly decreased at 132, 138, and 147 h of the experimental period. ACTH significantly reduced the LHR mRNA expression in CLs. In conclusion, long-term repeated ACTH administration affects the endocrinology, estrus onset, and ovarian function of weaned sows.

Pregnancy diagnosis and fetal monitoring in Yangtze finless porpoises

The Yangtze finless porpoise Neophocaena asiaeorientalis asiaeorientalis is a Critically Endangered species endemic to the Yangtze River and connecting lakes. Understanding the reproductive biology, fetal development, and physiology of this species is essential to ensure the successful development of a captive-breeding program. We studied pregnancy and fetal development in this species using endocrine monitoring and ultrasonographic imaging. Plasma progesterone concentrations increased significantly from non-pregnant (0.61 ± 0.43 ng ml-1) to pregnant (37.44 ± 16.18 ng ml-1) phases. Based on progesterone variation, we estimate gestation length to be approximately 12 mo. Fetal growth patterns are well described by linear regressions of thorax diameter, thorax circumference, and total body length plotted against days from parturition. Fetal growth models may be used to estimate fetal age and predict parturition date with more data in the future. Our findings provide fundamental information on pregnancy dynamics and fetal development in this Critically Endangered species to improve existing and benefit the establishment of new captive-breeding programs for Yangtze finless porpoises.

The negative effects of cold conditions on pregnancy rates in dairy cows

This study was conducted to determine the pregnancy rate in response to two sexual synchronization protocols in 70 healthy multiparous Fleckvieh dairy cows during the cold and warm seasons. After pairing by the actual parturition date [cold seasons (-38 to 0 ºC) (Nov - Feb) vs. warm seasons (0 to 32 ºC) (Mar-Oct)], cows were randomly subjected to either Co-Synch (CoS) or double PGF2α injection (dPG) on d 35 postpartum. Data were subjected to Chi-Square (2) analysis to determine the pregnancy rate at the first service. Overall pregnancy rates (%) at the first service were 57.1 and 40.0 for Groups CoS and dPG, respectively (2 = 2.03, P = 0.15) and 35.0 and 66.7% during cold and warm seasons, respectively (2 = 6.78, P = 0.009). The protocol effect on the pregnancy rate at the first service was insignificant during cold (2 = 1.17, P = 0.28) and warm (2 = 1.62, P = 0.20) season. In summary, the cold conditions negatively affected the pregnancy rate at the first service. The synchronization protocol methods did not differ to improve the pregnancy rate at the first service when cows were exposed to cold conditions.

Birth timing after the long feeding migration in northern elephant seals

AbstractNorthern elephant seals migrate long distances from feeding grounds to raise pups during a brief period on breeding beaches. Because gestation sets a parturition date months in advance, timing of the arrival must be precise; an early arrival would waste foraging time, but a late arrival would cause parturition failure. We used satellite‐tracked animals to examine this timing, establishing arrival and birth dates in 106 migrating females and estimating how far they traveled in the days just before birth. Females arrived a mean of 5.5 days prior to birth (range 1–11, SD = 1.5), and females arriving later in the breeding season had 1.8‐day shorter prebirth intervals relative to early arrivers. There was no correlation between female body condition, nor female age, and the prebirth interval. The last 15 days prior to birth, animals traveled as far as 1,465 km. Those farthest from the colony traveled >100 km per day, three times faster than animals near the colony at the same time. Despite migrations covering several thousand kilometers while pregnant, female elephant seals were able to time their arrival within days. This allows them to maintain a precise annual birth cycle for many years consecutively.

Comparison of two-dimensional (2D) and three-dimensional (3D) ultrasonography for gestational ageing in the early to mid-pregnant bitch.

Accuracy of prediction of the day of parturition in the bitch decreases with advancing pregnancy. We hypothesized that three‐dimensional (3D) volume ultrasonography may be superior for gestational ageing than 2D measurements. Thirty‐two pregnancy examinations were performed in 25 bitches of different breeds 21–34 days after the first mating. Ovulation date from serum progesterone concentrations was estimated for 15 bitches, and parturition date was recorded for all dogs. Inner chorionic cavity (ICC) diameters and ICC length of the conceptus were measured by 2D B‐mode, and ICC volume by 3D ultrasonography (Voluson® i, GE Healthcare). Linear or exponential regressions between ICC measurements and time, i.e. days after estimated ovulation or days before parturition, were performed with significance set at p < .05. ICC volume increased exponentially over time, while ICC diameter showed a linear growth. ICC volume had similar accuracy (R 2 = .718, p < .001) to ICC diameter and ICC length (R 2 = .707 and R 2 = .728, p < .001) when analysed in relation to days after estimated ovulation or in relation to days before parturition (R 2 = .818, R 2 = .800 and R 2 = .810, p < .001 respectively). There were strong (R 2 ≥ .875) significant associations between all ICC measurements. In conclusion, ICC volume did not improve canine gestational ageing accuracy, which supports the continued use of the ICC diameter, particularly in light of the difficulty in obtaining 3D measurements. On the basis of ICC volume, the growth of the canine conceptus appeared to be exponential already during the first half of pregnancy.

Effects of Postpartum Supplemental Oral Ca for Dairy Cows Fed Prepartum Dietary Acidogenic Salts

Simple SummaryLow blood calcium after calving is problematic in dairy cows, particularly for older cows and for Jerseys vs. Holsteins. Feeding acidogenic salts before calving and oral Ca supplementation post-calving help mitigate this. We evaluated: (1) a novel approach to delivering acidogenic salts prepartum applicable to small dairies and (2) the combined effects of prepartum acidogenic salts and postpartum oral Ca supplementation for both Holsteins and Jerseys of varying parity. We found this novel approach to providing acidogenic salts to be effective. We also found preliminary evidence that shortening the time of application of this technology may enhance its beneficial effects. Responses to prepartum acidogenic salts and postpartum oral calcium supplementation were very different for second vs. greater than second parity cows. Finally, we found an increased risk of low blood calcium, particularly in older Jersey cows, when either prepartum urinary calcium excretion was low or colostrum production was high.Postpartum hypocalcemia is a problem in dairy cows. Both the Jersey vs. Holstein breed and increasing parity are known risk factors. Our objectives were: (1) to evaluate a simple approach to provide dietary acidogenic salts suitable for application on small dairies and (2) to evaluate the combined effects of degree of acidification and oral Ca supplementation along with breed and parity group on periparturient Ca status of Holstein and Jersey cows. Cows were moved weekly from the far-off dry pen at 260 days pregnant to the close-up pen, where all cows received the acidogenic diets. The diet was offered as a total mixed ration and CaCl2, and our source of acidogenic salts was top-dressed in liquid form and mixed in by hand. Thirty-six cows were blocked by parity group (parity = 2 vs. parity ≥ 3) and breed (Holstein vs. Jersey) and assigned to one of two treatments (no intervention or postpartum oral Ca bolus supplementation) in an alternating fashion, based on expected date of parturition. Urinary acidification appeared complete within 3–4 days. Increased urinary Ca excretion was >93% of maximum from 7–21 days before falling to <5% of maximum by 28 days. Serum Ca concentrations 12–24 h postpartum were lower for Jerseys vs. Holsteins and for parity ≥ 3 vs. parity = 2 cows. Serum Ca over 6–48 h postpartum decreased and increased, respectively, with oral Ca supplementation for parity = 2 and parity ≥ 3 cows. Decreased prepartum urinary Ca excretion and increased colostrum yield appear to be independent risk factors of hypocalcemia for parity ≥ 3 Jerseys.

Advanced roe deer (Capreolus capreolus) parturition date in response to climate change

AbstractIn temperate habitats, the vegetation onset in spring affects the life cycle activities of large herbivores. For one species of large herbivore, roe deer (Capreolus capreolus), parturition is tied to peak resource availability. However, recent long‐term studies of the parturition date of roe deer found only limited support for its earlier occurrence with an earlier onset of spring. In this study, data from a long‐term project (1973–2019) in southern Germany (Baden‐Württemberg; elevation 101–1036 m; 16,130 tagged roe deer fawns) were used to investigate whether the advance in the roe deer parturition date reflected different environmental conditions and was thus explained by temporal and spatial factors. Our results showed a consistent advance toward an earlier parturition date (between 0.16 and 0.33 d/yr), especially for elevations above 750 m, that coincided with an advance in plant phenology. Up to 37% of the variance of the detrended time series of the mean annual parturition was accounted for by the detrended time series of the flowering date of forsythia. Our results suggest a plasticity that allows roe deer to cope with climate‐induced changes along environmental gradients.

Testing the match-mismatch hypothesis in bighorn sheep in the context of climate change.

In species with long gestation, females commit to reproduction several months before parturition. If cues driving conception date are uncoupled from spring conditions, parturition could be mistimed. Mismatch may increase with global change if the rate of temporal changes in autumn cues differs from the rate of change in spring conditions. Using 17years of data on climate and vegetation phenology, we show that autumn temperature and precipitation, but not vegetation phenology, explain parturition date in bighorn sheep. Although autumn cues drive the timing of conception, they do not predict conditions at parturition in spring. We calculated the mismatch between individual parturition date and spring green-up, assessed whether mismatch increased over time and investigated the consequences of mismatch on lamb neonatal survival, weaning mass and overwinter survival. Mismatch fluctuated over time but showed no temporal trend. Temporal changes in green-up date did not lead to major fitness consequence of mismatch. Detailed data on individually marked animals revealed no effect of mismatch on neonatal or overwinter survival, but lamb weaning mass was negatively affected by mismatch. Capital breeders might be less sensitive to mismatch than income breeders because they are less dependent on daily food acquisition. Herbivores in seasonal environments may access sufficient forage to sustain lactation before or after the spring 'peak' green-up, and partly mitigate the consequences of a mismatch. Thus, the effect of phenological mismatch on fitness may be affected by species life history, highlighting the complexity in quantifying trophic mismatches in the context of climate change.

Physiological Parameters to Identify Suitable Blood Donor Cows for Preparation of Platelet Rich Plasma.

Simple SummaryPlatelet rich plasma is a biological product obtained from blood and used for regenerative treatments of different pathologies. It is characterized by a high concentration of platelets (at least 3 times the physiological level) containing many growth factors with anti-inflammatory, bactericidal and regenerative properties. In human medicine, PRP is used in an autologous way, it means that the blood donor is also the recipient. In veterinary medicine, PRP is used to treat different diseases or lesions and in bovine species to treat mastitis. In this context, the opportunity to have PRP ready to use, stored from donor cows of the same farm where it will be used, would be very useful in treating this pathology immediately when it occurs. For this purpose, the present research aimed to detect parameters useful to identify the most suitable cows to be used as blood donors to obtain the highest yield of PRP (milliliters of PRP obtained with respect to milliliters of initial blood). Our results showed that blood collection from the mammary vein within three months of parturition, from nonpregnant cows at 5 years of age, but not the blood collection season, were associated with a high yield of PRP.Platelet rich plasma (PRP) has been shown to be beneficial in the treatment of bovine mastitis, with an action comparable to that of antibiotics. Autologous treatment is feasible in experimental conditions but is difficult to apply in field conditions, particularly in acute mastitis. The ideal scenario would be to have heterologous PRP stored on every farm so that it is readily available when needed. In this paper, we analysed data collected during bovine mastitis treatment with heterologous PRP produced by casual donor cows on several farms. We tried to identify parameters which might be useful to identify the most suitable cows to be used as blood donors, to obtain the highest yield of PRP. Variables considered for each animal were the age, the parity, the date of the last parturition, the season of blood collection, the site of blood collection (jugular or mammary vein) and the reproductive status e.g., pregnant or not pregnant. There were statistically significant differences for all the variables considered from the 135 blood cows, except for the blood collection season. The highest yield of PRP was associated with nonpregnancy blood collection within three months of parturition, parity 3 or 4, and blood collection from the mammary vein.

Warm Springs Are Associated with Early Births in Three Montane Rattlesnake Species

A warming climate is correlated with phenological shifts in many taxa. We analyzed data from two long-term field studies of three viviparous viperid snakes to examine correlations between temperature and parturition dates. We studied Rock Rattlesnakes (Crotalus lepidus) and Ridge-Nosed Rattlesnakes (Crotalus willardi) over a 31-yr period and Twin-Spotted Rattlesnakes (Crotalus pricei) over a 23-yr period. On average, a 1°C increase in mean daily maximum temperature during mid-April to June, the probable gestation period, was associated with C. lepidus litters being found 6.0 ± 0.84 days earlier and C. willardi litters being found 5.7 ± 1.79 days earlier. We were more likely to find C. pricei neonates during surveys in late July following warm springs and pregnant females in late July following cool springs. Although earlier parturitions could potentially increase maternal survival and improve lifetime reproductive output, warmer temperatures during embryo development could cause unviability or neonate abnormalities. Neonate survival would probably be negatively affected if births occurred before the onset of the summer monsoon rains. Populations of these species that inhabit the highest elevations of mountain ranges will be unable to shift their distributions to maintain the thermal conditions under which they evolved.

Mothers' Movements: Shifts in Calving Area Selection by Partially Migratory Elk

ABSTRACTLoss of migratory behavior or shifts in migratory ranges are growing concerns to wildlife managers. How ungulates prioritize safety from predators at the expense of high‐quality foraging opportunities during calving may be key to understanding these shifts and long‐term reproductive success. We compared trade‐offs in selection for forage and predation risk by elk (Cervus canadensis) following 3 migratory tactics (western and eastern migration and resident) during 2 time periods in a declining (by almost 70% from 2002–2016), partially migratory elk population adjacent to Banff National Park in Alberta, Canada. We hypothesized that regardless of migratory tactic, maternal elk would show stronger trade‐offs between high‐quality foraging associated with higher predation risk and forage resources of lower‐quality yet lower risk on calving ranges than on ranges used during summer because of vulnerability of their offspring. Additionally, we hypothesized these trade‐offs would occur at high (2002–2006) and low (2013–2016) elk population sizes. We used a machine‐learning algorithm to predict dates of parturition based on global positioning system (GPS) movements of elk equipped with vaginal implants (n = 60) and predictions were within 1.43 ± 0.85 (SE) days of the known date. We applied the model to an additional 58 GPS‐collared elk without vaginal implants. Based on changes in localized movements, we defined calving areas as the 26 days post‐parturition and compared habitat characteristics of calving areas to 10 similar‐sized areas centered on random locations during summer for the same individual in a latent selection framework. Across the 2 time periods, parturition occurred from 8 May–11 July with median parturition dates differing among migratory tactics and residents shifting towards an earlier parturition date in the later period. All elk, regardless of migratory tactic and time period, selected calving areas with greater forage resources than were available on areas used during summer, with no evidence for greater selection of areas that reduced predation risk at the expense of higher‐quality foraging. Calving season selection for areas with abundant forage exposed western migrants to high risk of bear (Ursusspp.) predation, residents to high risk of wolf (Canis lupus) predation, and eastern migrants to low risk of bear and wolf predation. Patterns in exposure to predation risk during calving between migratory tactics were consistent with the recent decline in western migrants and increase in eastern migrants, implying that conditions on calving areas contributed to observed changes in the number of elk following these tactics. © 2021 The Wildlife Society.

Oxidative status in dairy goats: periparturient variation and changes in subclinical hyperketonemia and hypocalcemia

BackgroundA better comprehension of the redox status during the periparturient period may facilitate the development of management and nutritional solutions to prevent subclinical hyperketonemia (SCHK) and subclinical hypocalcemia (SCHC) in dairy goats. We aimed to evaluate the variation in the redox status of dairy goats with SCHK and SCHC during their periparturient periods. Guanzhong dairy goats (n = 30) were assigned to SCHK (n = 10), SCHC (n = 10), and healthy (HEAL, n = 10) groups based on their blood β-hydroxybutyrate (BHBA) and calcium (Ca) concentrations. Blood were withdrawn from goats every week from 3 weeks before the expected parturition date to 3 weeks post-kidding. On the same day, the body condition scores (BCS) were evaluated, and the milk yield was recorded for each goat. The metabolic profile parameters and the indicators of oxidative status were determined by using the standard biochemical techniques.ResultsIn comparison with the HEAL goats, SCHK and SCHC goats presented with a more dramatic decline of BCS post-kidding and a significant decrease in the milk yield at 2- and 3-weeks postpartum, ignoring the obvious increase at 1-week postpartum. The levels of non-esterified fatty acids (NEFA) peaked at parturition, exhibiting significantly higher levels from 1-week prepartum to the parturition day in the SCHK and SCHC groups. The malondialdehyde (MDA) concentration was increased in the SCHK goats from 1-week antepartum until 3-weeks postpartum, with its concentration being significantly higher in the SCHC goats at parturition. The hydrogen peroxide (H2O2) concentration was significantly lower in the SCHK and SCHC goats from 2-weeks antepartum to 1-week post-kidding. The total antioxidant capacity (T-AOC) and the superoxide dismutase (SOD) level were decreased at 1-week antepartum in the SCHK and SCHC goats, respectively. The glutathione peroxidase (GSH-Px) level was increased in the SCHK and SCHC goats during the early lactation period.ConclusionsThe SCHK and SCHC goats exerted more efforts to maintain their redox homeostasis and to ensure the production performance than the HEAL goats during their periparturient period, probably owing to more intense fat mobilization and lipid peroxidation in the former.

Effect of area specific mineral mixture supplementation on milk production, biochemical and blood mineral status of Black Bengal goats

This study was conducted to find out the effect of area-specific mineral mixture (ASMM) supplementation on production performances, the biochemical and mineral profile of Black Bengal does during the peripartum period. For this purpose, 20 pregnant does were made into two groups according to the bodyweight viz., Control-T 0 (n=10) and Treatment-T 1 (n=10) and supplemented with 0 and 6 g ASMM/animal/day, respectively starting from 3 months before the expected date of parturition to till the onset of the first post-partum estrus. Overall mean milk fat, total ash, total solids, solids not fat, milk crude protein and milk yield, blood glucose, non-esterified fatty acids, α-amino nitrogen, phosphorus and serum glutamic pyruvic transaminase concentration were non-significant (P&gt;0.05) between the groups. The overall mean of serum glutamic oxaloacetic transaminase, calcium, copper, and zinc concentration in control (T 0 ) and treatment (T 1 ) groups were127.05±1.27 vs.132.73±1.26 IU/L, 7.83±0.08 vs. 8.19±0.08 mg/dl, 0.66±0.02 vs. 0.94±0.02 ppm, 0.69±0.01 vs. 0.97 ± 0.02 ppm, respectively, and differed significantly (P&lt; 0.05) between the groups. So by the findings of this study, it is concluded supplementation of the area-specific mineral mixture@ 6 g/day during the peripartum period had a significant effect on blood biochemical parameters in Black Bengal does.

Comparative Reproductive Ecology of Two Subspecies of Pacific Marten (Martes caurina) in California

Accurate information on reproductive ecology is necessary to develop conservation actions for at-risk wildlife species. Our objective was to describe female reproductive parameters and den use of two subspecies of wild, untrapped Pacific martens (Humboldt marten, Martes caurina humboldtensis; Sierran marten, M. c. sierrae) of conservation interest in California. We used radio telemetry and remotely triggered cameras to monitor 10 Humboldt martens (2014 to 2016) and six Sierran martens (2016 to 2017) over 23 total denning periods. For Humboldt martens, mean parturition date was 13 April, proportion of adult females reproducing was 80% (n = 12 of 15), and mean litter size was 1.8 ± 0.6 kits (x̄ ± SD). For Sierran martens, mean parturition date was 29 April, proportion of adult females reproducing was 87% (n = 7 of 8), and mean litter size was 1.9 ± 0.7 kits. Humboldt and Sierran marten dens were predominantly located in woody structures, with live trees, snags, and logs comprising 91% and 79% of dens, respectively. Although reproductive ecologies of Humboldt and Sierran martens were largely similar, Sierran marten parturition dates were significantly later. We compare our study populations to other North American marten populations and examine factors that could influence consistency or variability in reproductive parameters between populations.

Migration distance and maternal resource allocation determine timing of birth in a large herbivore.

Birth timing is a key life‐history characteristic that influences fitness and population performance. For migratory animals, however, appropriately timing birth on one seasonal range may be constrained by events occurring during other parts of the migratory cycle. We investigated how the use of capital and income resources may facilitate flexibility in reproductive phenology of migratory mule deer in western Wyoming, USA, over a 5‐yr period (2015–2019). Specifically, we examined how seasonal interactions affected three interrelated life‐history characteristics: fetal development, birth mass, and birth timing. Females in good nutritional condition at the onset of winter and those that migrated short distances had more developed fetuses (measured as fetal eye diameter in March). Variation in parturition date was explained largely by fetal development; however, there were up to 16 d of plasticity in expected birth date. Plasticity in expected birth date was shaped by income resources in the form of exposure to spring green‐up. Although individuals that experienced greater exposure to spring green‐up were able to advance expected birth date, being born early or late with respect to fetal development had no effect on birth mass of offspring. Furthermore, we investigated the trade‐offs migrating mule deer face by evaluating support for existing theory that predicts that births should be matched to local peaks in resource availability at the birth site. In contrast to this prediction, only long‐distance migrants that paced migration with the flush of spring green‐up, giving birth shortly after ending migration, were able to match birth with spring green‐up. Shorter‐distance migrants completed migration sooner and gave birth earlier, seemingly trading off more time for offspring to grow and develop over greater access to resources. Thus, movement tactic had profound downstream effects on birth timing. These findings highlight a need to reconsider classical theory on optimal birth timing, which has focused solely on conditions at the birth site.

Support vector regression algorithm modeling to predict the parturition date of small - to medium-sized dogs using maternal weight and fetal biparietal diameter

Background and Aim:Fetal biparietal diameter (BPD) is a feasible parameter to predict canine parturition date due to its inverted correlation with days before parturition (DBP). Although such a relationship is generally described using a simple linear regression (SLR) model, the imprecision of this model in predicting the parturition date in small- to medium-sized dogs is a common problem among veterinarian practitioners. Support vector regression (SVR) is a useful machine learning model for prediction. This study aimed to compare the accuracy of SVR with that of SLR in predicting DBP.Materials and Methods:After measuring 101 BPDs in 35 small- to medium-sized pregnant bitches, we fitted the data to the routine SLR model and the SVR model using three different kernel functions, radial basis function SVR, linear SVR, and polynomial SVR. The predicted DBP acquired from each model was further utilized for calculating the coefficient of determination (R2), mean absolute error, and mean squared error scores for determining the prediction accuracy.Results:All SVR models were more accurate than the SLR model at predicting DBP. The linear and polynomial SVRs were identified as the two most accurate models (p<0.01).Conclusion:With available machine learning software, linear and polynomial SVRs can be applied to predicting DBP in small- to medium-sized pregnant bitches.

A standardised biologging approach to infer parturition: An application in large herbivores across the hider‐follower continuum

Abstract The timing of birth has a predominant influence on both the reproductive success of the mother and the life‐history trajectory of her offspring. Because early growth and survival are key drivers of population dynamics, there is an urgent need to understand how global change is affecting reproductive phenology and performance. However, identifying when and where birth occurs is often difficult in the wild due to the cryptic behaviour of females around parturition, although this information may also help managers to protect reproductive females and newborn against human disturbance. While several approaches to identify parturition based on movement metrics derived from GPS monitoring have previously been proposed, their performance has not been evaluated over a range of species with contrasted movement characteristics. Here, we present a novel approach to detect parturition by combining data on animal movements, activity rate and habitat use. Using machine learning approaches, we evaluated the relative and combined performance of each category of metrics in predicting parturition for three large herbivores with contrasted life histories: a hider‐type species, the roe deer Capreolus capreolus and two follower‐type species, the Mediterranean mouflon Ovis gmelini musimon × Ovis sp. and the Alpine ibex Capra ibex. We first showed that detection of parturition was much improved when birth‐related modifications in the habitat use and activity rate of the mother were considered, rather than relying on movement metrics only. We then demonstrated that our approach was highly successful (76%–100% of events correctly identified) in detecting parturition in both follower and hider species. Furthermore, our approach generated estimates for peak birth date and the proportion of parturient females that were comparable with those based on direct observations at the population scale. Finally, our approach outperformed the most commonly employed methods in the literature which generally failed to identify non‐reproductive females for the three studied species, and provided birth timing estimates that only poorly match the true parturition date. We suggest that by combining sources of information, we have developed a standardised methodological approach for inferring parturition in the wild, not only for large herbivores but also for any species where parturition induces marked behavioural changes in the mother.