Observed declines in body size have differential effects on survival and recruitment, but no effect on population growth in tropical birds.

Declines in body size can be an advantageous physiological response to warming temperatures, or a result of physiological and nutritional stress. Either way, studies often assume that these climate-induced trait changes have important implications for fitness and demography. We leveraged almost three decades of capture-mark-recapture data of 51 bird species in Panama to examine if body size has changed through time, how sensitive body size is to changes in weather, and if body size impacts population demography. We evaluated two metrics of body size, structural size (wing length), and body condition (residual body mass). Over the study, wing length changed in varying directions for 88% of species (23 decrease, 22 increase), but the effects were weak, and change was only significant for two species. Conversely, body condition declined for 88% of species (45), effects were stronger, and that change was significant for 22% of species (11). This suggests that nutritional stress is likely the cause of changes in body size, not an adaptive response to warming. Precipitation metrics impacted body condition across three of our four feeding guilds, while wing length was only impacted by weather metrics for two guilds. This suggests that body condition is more sensitive to change in weather metrics compared to wing length. Lastly, we found that the impact of changes in body size on survival and recruitment was variable across species, but these relationships were in the opposite direction, ultimately resulting in no change in population growth for all but one species. Thus, while different stages (adult survival and recruitment) of populations may be impacted by body size, populations appear to be buffered from changes. The lack of an effect on population growth rate suggests that populations may be more resilient to changes in body size, with implications for population persistence under expected climate change.

Phenotypic homogenization and potential fitness constraints following non-native introgression in an endemic sportfish.

Introgressive hybridization may lead to contrasting evolutionary outcomes that are difficult to predict, since they depend on the fitness effects of endogenous genomic interactions and environmental factors. Conservation of endemic biodiversity may be more effective with require direct measurement of introgressed ancestry and fitness in wild populations, especially for keystone taxa at risk of hybridization following species introductions. We assessed the relationship of non-native ancestry with growth and body condition in the basin-restricted Neosho Bass (Micropterus velox; NB), focusing on two streams in the NB native range that are admixed extensively with non-native Smallmouth Bass (M. dolomieu; SMB). We quantified genetic composition of 116 fish from Big Sugar Creek (N=46) and Elk River (N=70) at 14 microsatellite loci. Using back-calculated total length-at-age estimated from sagittal otoliths, we assessed whether genetic ancestry explained variation in von Bertalanffy growth model parameters, accounting for sex and stream effects. We then assessed the relationship of ancestry and body condition. We found no differences in growth parameters by sex, stream, or ancestry, suggesting phenotypic homogenization which could be mediated by selection on body size. We found a negative correlation between SMB ancestry and condition, including lower condition in Big Sugar Creek, possibly reflecting a trade-off between maximum length and condition with respect to overall fitness. We show that ongoing non-native introgression, which may be augmented by anthropogenic SMB introductions, may attenuate evolutionary differentiation between species and directly influence fitness, possibly having critical implications for long-term persistence and management of adaptive potential in a popular and ecologically important endemic sportfish.

Do sexual differences in life strategies make male lizards more susceptible to parasite infection?

Female and male hosts may maximise their fitness by evolving different strategies to compensate for the costs of parasite infections. The resulting sexual dimorphism might be apparent in differential relationships between parasite load and body condition, potentially reflecting differences in energy allocation to anti-parasitic defences. For example, male lacertids with high body condition may produce many offspring while being intensely parasitised. In contrast, female lacertids may show a different outcome of the trade-offs between body condition and immunity, aiming to better protect themselves from the harm of parasites. We predicted that females would have fewer parasites than males and a lower body condition across parasitaemia levels because they would invest resources in parasite defence to mitigate the costs of infection. In contrast, the male strategy to maximise access to females would imply some level of parasite tolerance and, thus, higher parasitaemia. We analysed the relationship between the body condition of lizards and the parasitemias of Karyolysus and Schellackia, two genera of blood parasites with different phylogenetic origins, in 565 females and 899 males belonging to 10 species of the Lacertidae (Squamata). These lizards were sampled over a period of 12 years across 34 sampling sites in southwestern Europe. The results concerning the Karyolysus infections were consistent with the predictions, with males having similar body condition across parasitaemia levels even though they had higher infection intensities than females. On the other hand, females with higher levels of Karyolysus parasitaemia had lower body condition. This is consistent with the prediction that different life strategies of male and female lacertids can explain the infection patterns of Karyolysus. In contrast, the parasitaemia of Schellackia was consistently low in both male and female hosts, with no significant effect on the body condition of lizards. This suggests that lizards of both sexes maintain this parasite below a pathogenic threshold.

Los machos y hembras pueden maximizar su eficacia biológica mediante la evolución diferencial de estrategias que compensen los costes asociados con las infecciones parasitarias. Por ejemplo, los machos con una alta condición corporal pueden producir muchas crías aun estando altamente parasitados. Mientras que es común que las hembras inviertan más energía en protegerse frente a los parásitos, lo que podría comprometer el mantenimiento de su condición corporal. Nuestra hipótesis es que las diferencias sexuales en la asignación de energía pueden quedar de manifiesto al analizar la relación entre la intensidad de infección con la condición corporal. También esperamos que las hembras tengan menos parásitos que los machos y que su condición corporal esté correlacionada negativamente con su carga parasitaria. Por el contrario, esperamos que los machos tengan más parásitos en parte porque su estrategia implicaría cierto nivel de tolerancia si con ello pueden incrementar su inversión reproductiva. Hemos analizado la relación entre la condición corporal y las parasitemias de Schellackia y Karyolysus, dos parásitos sanguíneos, en 565 hembras y 899 machos de 10 especies de la familia Lacertidae (Squamata) durante 12 años en 34 localidades en el suroeste de Europa. El patrón para Karyolysus fue coherente con las predicciones, ya que la condición corporal de los machos no se correlacionó con su parasitemia, a pesar de que estas fueron mayores que en las hembras. Mientras que la relación fue negativa en las hembras. Por lo que el patrón de infección de Karyolysus concuerda con las diferentes estrategias de inversión energética en machos y hembras. Sin embargo, en el caso de Schellackia las parasitemias fueron más bajas en hospedadores de ambos sexos y su parasitemia no se correlacionó con la condición corporal. Este resultado sugiere que Schellackia es mantenido en umbrales subpatogénicos.

First evidence of age-dependent decreases in non-persistent pesticide mixtures in nestlings of a farmland raptor.

Intensive use of synthetic pesticides in conventional agriculture may harm non-target organisms through sublethal effects on life-history traits. Farmland birds are exposed throughout their life cycle, but the fate of non-persistent pesticide mixtures in wild birds remains unknown. In this study, we investigated changes in pesticide contamination levels in Montagu's harrier (Circus pygargus) nestlings during their growth. In total, 35 chicks were sampled twice during the rearing period, and blood was tested for 116 pesticides to assess pesticide load through two proxies; the number of pesticides detected and the sum of pesticide concentrations. Body mass and tarsus length were also measured to estimate body condition. Across the two sampling times, nine herbicides, five insecticides and four fungicides were detected. Contamination levels decreased significantly with nestling age irrespective of sampling date, and there was no relationship between pesticide load and body condition. Moreover, concentrations of chlorpyrifos-methyl, fenpropidin, metamitron, picloram and S-metolachlor, all detected throughout the rearing period, were unrelated to any of the explanatory variables. However, ethofumesate concentrations decreased significantly with chick age. This study provides the first evidence that non-persistent pesticide mixtures can decrease with age in wild nestlings. This has implications for understanding how chicks are contaminated and provides new insights on pesticide fate within organisms.

Consistent Negative Correlations between Parasite Infection and Host Body Condition Across Seasons Suggest Potential Harmful Impacts of Salmincola markewitschi on Wild White-Spotted Charr, Salvelinus leucomaenis.

Assessing the impacts of parasites on wild fish populations is a fundamental and challenging aspect of the study of host-parasite relationships. Salmincola, a genus of ectoparasitic copepods, mainly infects salmonid species. This genus, which is notorious in aquaculture, damages host fishes, but its impacts under natural conditions remain largely unknown or are often considered negligible. In this study, we investigated the potential impacts of mouth-attaching Salmincola markewitschi on white-spotted charr (Salvelinus leucomaenis) through intensive field surveys across four seasons using host body condition as an indicator of harmful effects. The prevalence and parasite abundance were highest in winter and gradually decreased in summer and autumn, which might be due to host breeding and/or wintering aggregations that help parasite transmissions. Despite seasonal differences in prevalence and parasite abundance, consistent negative correlations between parasite abundance and host body condition were observed across all seasons, indicating that the mouth-attaching copepods could reduce the body condition of the host fish. This provides field evidence suggesting that S. markewitschi has a potential negative impact on wild white-spotted charr.

Effects of a physical exercise programme on bodyweight, body condition score and chest, abdominal and thigh circumferences in dogs.

BACKGROUND: Research on the effects of physical exercise on canine body composition is limited. The aim of this study was to investigate the effects of a physical exercise programme on bodyweight, body condition score (BCS) and chest, abdominal and thigh circumferences in dogs. Twenty-one healthy dogs of different breeds exercised together with their owners during an eight-week programme consisting of jogging and strength exercises. Standardised measurements were performed in triplicates with a measuring tape on standing dogs. Chest circumference was measured at three anatomical locations, abdomen at two and thigh at one. Data on bodyweight, BCS (9-point scale) and circumferences were analysed with mixed model repeated measures analyses to evaluate changes after the programme and effects of target distance. RESULTS: Seven dog owners choose a target distance of 2 km and 14 owners choose 5-10 km. Mean BCS decreased (P = 0.007) after the programme (5.1 ± 0.9 vs. 4.7 ± 0.6) but there was no effect of target distance. Almost all chest and abdominal circumference measurements decreased (P ≤ 0.007) with the 2 km group driving the reduction in chest circumference and the 5-10 km group driving the reduction in abdominal circumference. In contrast, thigh circumference (28.8 ± 0.4 vs. 30.2 ± 0.4) increased (P = 0.007) while bodyweight was maintained. There were positive correlations between BCS and abdominal/chest ratios before and after the programme (Pearson correlation; R square ≤ 0.43, P ≤ 0.0012) but the mean ratio remained constant. CONCLUSIONS: Results indicated a redistribution between total body fat and muscle mass in body composition of normal weight to slightly overweight dogs after the physical exercise programme. The use of bodyweight alone was not a reliable evaluation method to complement the BCS assessment. However, repeated measurements of chest, abdominal and thigh circumference might aid in the assessment of body composition in dogs performing physical exercise. Further research should include a control group and objective evaluations of total body fat and lean mass, in order to investigate the effectiveness of physical exercise as a freestanding method for decreasing BCS and increasing muscle mass in overweight dogs.

Macronutrient composition of milk from captive southern pig-tailed macaques (Macaca nemestrina).

Milk composition is a fundamental aspect of mammalian reproduction. Differences in milk composition between species may reflect phylogeny, dietary ecology, lactation strategy, and infant growth patterns, but may also vary within a species due to maternal body condition. This study presents the first published data on milk macronutrient composition of southern pig-tailed macaques (Macaca nemestrina) and compares the results with data on two other Cercopithecine species. Milk samples were obtained from five dams at 10- and 14-weeks postparturition. Macronutrient composition was determined at the Smithsonian's National Zoo and Conservation Biology Institute using proven methods developed over 30 years. On average (±SEM), the milk contained 83.9 ± 0.4% water, 6.7 ± 0.4% fat, 7.6 ± 0.1% sugar, 1.8 ± 0.1% protein, and 0.22 ± 0.01% mineral content. The Ca:P ratio was 1.8; concentrations of Ca and protein were correlated. Mean gross energy was 1.02 ± 0.03 kcal/g with most of the energy coming from fat (59.6 ± 1.5%), followed by sugar (29.9 ± 1.4%) and protein (10.5 ± 0.5%). The milks at 14 weeks of infant age were higher in energy than the milks at 10 weeks, with an increase in energy from fat (p = 0.005) and decrease in energy from sugar (p = 0.018). The energy from protein did not change (p = 0.272). Compared to captive rhesus macaque (Macaca mulatta) and olive baboon (Papio anubis) milk assayed by identical methods, captive pig-tailed macaque milk was higher in energy, but after accounting for the higher milk energy there was no difference in the proportions of milk energy from protein, fat, and sugar. The captive pig-tailed dams were significantly heavier than reported values for wild pig-tailed macaques, suggesting high body condition. High body condition in captive Cercopithecines appears to result in milk higher in energy, with more energy coming from fat and less from sugar. However, variation in the proportion of milk energy from protein in captive Cercopithecine milks appears relatively constrained.

Association Between Household Location (Urban versus Rural) and Fundamental Care Provided to Domestic Dogs (Canis Familiaris) in Northern Ireland.

This study aimed to generate information regarding living conditions (e.g. indoors and outdoors, living space available), fundamental care (e.g. feeding and exercise) and owners' perceptions of dog's preferences (e.g. living conditions) in the urban and rural areas of Northern Ireland via a cross-sectional survey questionnaire. The responses were collected from May to August 2022, at 24 locations across Northern Ireland, including 15 agricultural shows and livestock markets and nine large supermarkets (single supermarket chain) located in an area of the show or market grounds. In all, 548 questionnaires were collected and after exclusion of questionnaires with missing or incomprehensible responses, 507 questionnaires were included in the final database. Out of 507 questionnaires, 264 respondents resided in a city while 243 respondents resided on farms. The majority of respondents from the city locations perceived their dogs as pets, while those living on farms regarded their dogs as working animals. The populations of dogs in the city locations and on the farms in this study were similar regarding the age range and numbers of the animals, but more female dogs were spayed in the city locations than on the farms. Most respondents in this study, regardless of their household location, declared that they did not monitor their animal's body weight or body condition. When feeding their dogs, the respondents from the city locations were predominantly following veterinary advice or instructions on food labels. On the other hand, the respondents from farm locations mostly reported that they fed their dogs based on 'a visual inspection of dog condition'; this type of feeding was associated with a certain type of household occupancy (more frequent in single and adults only households) and respondents' employment status (more frequent by retired and those managing the home). The living conditions of dogs in city and farm locations in this study were different, namely dogs in the city were kept predominantly indoors with access to outdoors while dogs from farm locations were kept predominantly outdoors. The dogs were reported to be walked daily for a shorter time (up to 1 h/day) in the city locations and longer on the farm locations (1-2 h/day). Regardless of household location (city versus farm) respondents believed that exercise needs depend on animal age, body condition and medical condition, that dogs need to be kept active by owners to keep them fit, that dogs cannot self-regulate the amount of food they eat daily, and finally that walking with a dog a few times a day is difficult due to other commitments. On the other hand, the respondents from farm locations more often believe that dogs can get all the exercise they need by themselves if kept outdoors and they are happier with living outdoors, while the respondents from city locations believed that dogs are happier with living indoors. In conclusion, the results of this study have shown a number of differences in basic care and perception of dogs kept in city locations and on farm locations. Further studies are required to understand the provision of health care and fulfilments of all welfare needs of the dogs kept on farms.

Relationship between skin and body condition in three species of baleen whales.

The assessment of free-ranging cetacean health through the study of skin conditions using photographs has gained prominence in recent years. However, little attention has been given to the relationships between cetacean skin conditions, species, and body condition. To explore this relationship among baleen whale species along the northwestern coast of Spain, we employed a non-invasive method involving photograph analysis. In this study, we examined skin conditions (including injuries, epizoites and ectoparasites, pigmentation disorders, skin lesions, and anatomical malformations) and body condition (overall physical contours and form, as an indicator of nutritional status and health) in 3 species of whales (blue, fin, and minke whales). This methodology facilitated the identification of 29 subcategories of distinct skin conditions and an assessment of body condition over a 5 yr period (2017 to 2021). In our study, we present evidence linking hypopigmentation, protruding pieces of tissue, and tattoo-like lesions to 'Poor' body condition in the 3 baleen whale species. Fin whales exhibited a higher susceptibility to mottling (prevalence = 17.7%), while blue whales were more prone to starbursts (prevalence = 90.5%). Additionally, we found a significant relationship between skin condition diversity and individual body condition. Our findings contribute valuable information to the broader understanding of the health status of baleen whales. Further investigations are necessary to delve into the etiology of the documented skin conditions and their potential implications for individual survival. This study serves as a foundation for ongoing research aimed at advancing our comprehension of these findings.

Corticosterone treatment results in fat deposition and body mass maintenance without effects on feeding behaviour or immunity in female lizards (Tropidurus catalanensis).

Throughout life, animals must maintain homeostasis while coping with challenging events. The period after reproduction can be challenging for oviparous females to maintain homeostasis since they direct most of their energy stores to vitellogenesis, possibly increasing the vulnerability to stressors. Changes in glucocorticoids' (GC) secretion promote various behavioural and physiological adjustments daily and to restore balance after facing stressors. However, when GC are elevated for extended periods, which usually occurs in response to chronic exposure to stressors, they can affect feeding behaviour and suppress the immune function. We aim to elucidate the effects of chronic corticosterone (CORT) exposure on feeding behaviour, body condition and immune function in female lizards, Tropidurus catalanensis, in the post-reproductive period. Thirty animals were divided into three groups: 1. Control (no experimental procedure performed); 2. Empty Implant (animals implanted with empty silastic tube); and 3. CORT Implant (animals implanted with silastic tube filled with CORT, with a chronic continuous release for at least a week). CORT plasma levels feeding behaviour, body condition (body index [BI] and fat index [FI]), leukocyte count, and several immune function variables (bacterial killing ability [BKA], hemagglutination titer, phytohemagglutinin [PHA] immune challenge and leukocyte count) were evaluated. After implantation, CORT treated animals maintained stable body mass through the experiment, while Control and Empty Implant groups displayed weight loss. In the CORT treated animals, there was also a positive relation between BI and FI, and higher FI when compared to groups 1 and 2. No effects of CORT were observed on feeding behaviour nor on the immune function.

Association between body condition profiles, milk production and reproduction performance in Holstein and Normande cows.

Body-condition dynamics are known to affect the different steps of reproduction in cattle (cyclicity, estrus expression, fertilization, embryo development). This has led to a widespread idea that there is an ideal-target optimal body condition, but no clear profile has yet been identified. Here we investigated the relationships between body condition score (BCS) profiles and reproductive performance in dairy cows. Data were from Holstein or Normande herds in 6 French experimental farms. In the Holstein breed, we discriminated 4 BCS profiles based on combining BCS at calving (Low: around 2.6 points, or High: around 3.3 points) with BCS loss after calving (Moderate (M): ≤ 1.0 points, or Severe (S): > 1.0 points). The Low-M profile mostly included multiparous cows with higher milk yield and lower reproductive performance than cows in the 3 other profiles. Low-M cows that experienced abnormal ovarian activity had lower reproductive performance than their profile-mates. Moreover, 67% of Low-M cows kept the same profile at the following lactation. The High-S profile mostly included primiparous cows with lower milk yield and higher reproductive performance than cows in other profiles. In High-S cows, higher milk yields correlated to higher risk of failure to calf on first insemination. Moreover, 38% of High-S cows kept the same profile at the following lactation, and none changed to Low-M. The other 2 BCS profiles (Low-S and High-M) were intermediate in terms of milk yield and reproductive performance. In Normande, we discriminated 3 BCS profiles based on combining BCS at calving (Low: around 2.6 points, or High: around 3.5 points) with BCS loss after calving (Flat (F): flat with no loss, Moderate (M): around 0.5 points, or Severe (S): around 1.0 point). The Low-M and High-S profiles included cows with similar performance, even though High-S-profile cows showed better but not significantly different milk yield and reproduction performance. The High-F profile included cows that were more likely to experience abnormal ovarian activity and fail at first insemination than cows in other profiles. More than 50% of Normande cows with 2 successive lactations kept in the same BCS profile at the next lactation. Even though a low BCS at calving combined with severe BCS loss (more than 1 point) after calving was found to increase reproductive failure, there was no evidence of an optimal BCS profile for reproduction in dairy cows, and reproductive success or failure is multifactorial.

Liver transcriptome profiles of dairy cows with different serum metabotypes.

In a previously established animal model, 38 multiparous Holstein cows were assigned to 2 groups fed different diets to achieve either a normal (NBCS) or high (HBCS) body condition score (BCS) and backfat thickness (BFT) until dry-off at -49 d before calving (NBCS: BCS <3.5 [3.02 ± 0.24) and BFT <1.2 cm [0.92 ± 0.21]; HBCS: BCS >3.75 [3.82 ± 0.33] and BFT >1.4 cm [2.36 ± 0.35], mean ± SD). The groups were also stratified for comparable milk yields (NBCS: 10,361 ± 302 kg; HBCS: 10,315 ± 437 kg; mean ± SD). The cows were then fed the same diet during the dry period and subsequent lactation, maintaining the differences in BFT and BCS throughout the study. Using the serum metabolomics data, we created a classification model that identified different metabotypes. Machine learning classifiers revealed a distinct cluster labeled HBCS-PN (HBCS predicted normal BCS) among over-conditioned cows. These cows showed higher feed intake and better energy balance than the HBCS-PH (high BCS predicted high BCS) group, while milk yield was similar. The aim of this study was to investigate the changes in the hepatic transcriptome of cows differing in serum-metabotype postpartum. We performed hepatic transcriptome analysis in cows from 3 metabolic clusters: HBCS-PH (n = 8), HBCS-PN (n = 6), and normal BCS predicted normal BCS (NBCS-PN, n = 8) on d 21 (±2) postpartum. Liver tissue from cows expressed a total of 13,118 genes aligned with the bovine genome. A total of 48 differentially expressed genes (DEG; false discovery rate ≤0.1 and fold-change >1.5) were found between NBCS-PN and HBCS-PH cows, whereas 24 DEG (14 downregulated and 10 upregulated) were found between HBCS-PN and HBCS-PH cows. The downregulated DEG (n = 31) in NBCS-PN cows compared with HBCS-PH cows are involved in biosynthetic processes such as lipid, lipoprotein, and cholesterol synthesis (e.g., APOA1, MKX, RPL3L, CANT1, CHPF, FUT1, ZNF696), cell organization, biogenesis, and localization (e.g., SLC12A8, APOA1, BRME1, RPL3L, STAG3, FBXW5, TMEM120A, SLC16A5, FGF21), catabolic processes (e.g., BREH1, MIOX, APOBEC2, FBXW5, NUDT16), and response to external stimuli (e.g., APOA1, FGF21, TMEM120A, FNDC4), whereas upregulated DEG (n = 17) are related to signal transduction and cell motility (e.g., RASSF2, ASPN, SGK1, KIF7, ZEB2, MAOA, ACKR4, TCAF1), suggesting altered metabolic adaptations during lactation. Our results showed 24 DEG between HBCS-PN and HBCS-PH in the liver. The expression of SLC12A8, SLC16A5, FBXW5, OSGIN1, LAMA3, KDELR3, OR4X17, and INHBE, which are responsible for regulating cellular processes was downregulated in HBCS-PN cows compared with HBCS-PH cows. In particular, the downregulation of SLC12A8 and SLC16A5 expression in HBCS-PN cows indicates lower metabolic load and reduced need for NAD+ biosynthesis to support mitochondrial respiratory processes. The upregulation of MAOA, ACKR4, KIF27, SFRP1, and CAV2 in the liver of HBCS-PN cows may indicate adaptive mechanisms to maintain normal liver function in response to increased metabolic demands from over-conditioning. These molecular differences underscore the existence of distinct metabolic types in cows and provide evidence for the role of the liver in shaping different metabolic patterns.

Development and validation of a fully automated 2-dimensional imaging system generating body condition scores for dairy cows using machine learning.

Monitoring body condition score (BCS) is a useful management tool to estimate the energy reserves of an individual cow or a group of cows. The aim of this study was to develop and evaluate the performance of a fully automated 2-dimensional imaging system using a machine learning algorithm to generate real-time BCS for dairy cows. Two separate datasets were used for training and testing. The training dataset included 34,150 manual BCS (MAN_BCS) assigned by 5 experienced veterinarians during 35 visits at 7 dairy farms. Ordinal regression methods and deep learning architecture were used when developing the algorithm. Subsequently, the testing dataset was used to evaluate the developed BCS prediction algorithm on 4 of the participating farms. An experienced human assessor (HA1) visited these farms and performed 8 whole-milking-herd BCS sessions. Each farm was visited twice, allowing for 30 d (±2 d) to pass between visits. The MAN_BCS assigned by HA1 were considered the ground truth data. At the end of the validation study, MAN_BCS were merged with the stored automated BCS (AI_BCS), resulting in a testing dataset of 9,657 single BCS. A total of 3,817 cows in the testing dataset were scored twice 30 d (±2 d) apart, and the change in their BCS (ΔBCS) was calculated. A subset of cows at one farm were scored twice on consecutive days to evaluate the within-observer agreement of both the human assessor and the system. The manual BCS of 2 more assessors (HA2 and HA3) were used to assess the interobserver agreement between humans. Finally, we also collected ultrasound measurements of backfat thickness (BFT) from 111 randomly selected cows with available MAN_BCS and AI_BCS. Using the testing dataset, intra- and interobserver agreement for single BCS and ΔBCS were estimated by calculating the simple percentage agreement (PA) at 3 error levels and the weighted kappa (κw) for the exact agreement. A Bland-Altman plot was constructed to visualize the systematic and proportional bias. The association between MAN_BCS and AI_BCS and the BFT was assessed with Passing-Bablok regressions. The system had an almost perfect repeatability with a κw of 0.99. The agreement between MAN_BCS and AI_BCS was substantial, with an overall κw of 0.69. The overall PA at the exact, ± 0.25-unit, and ± 0.50-unit BCS error range between MAN_BCS and AI_BCS was 44.4%, 84.6%, and 94.8%, respectively, and greater than the PA obtained between HA1 and HA3. The Bland-Altman plot revealed a minimal systematic bias of -0.09 with a proportional bias at the extreme scores. Furthermore, despite the low κw of 0.20, the overall PA at the exact and ± 0.25-unit of BCS error range between MAN_BCS and AI_BCS regarding the ΔBCS was 45.7 and 88.2%, respectively. A strong linear relationship was observed between BFT and AI_BCS (ρ = 0.75), although weaker than that between BFT and MAN_BCS (ρ = 0.91). The system was able to predict single BCS and ΔBCS with satisfactory accuracy, comparable to that obtained between trained human scorers.

Derivation of the maintenance energy requirements in Jersey cows differing in body condition score.

Research in a variety of species including cattle has suggested energy required for maintenance may be affected by body condition. The objective of this study was to use indirect calorimetry and total fecal and urine collections to estimate maintenance energy and fasting heat production (FHP) of cows differing in BCS. Twelve multiparous nonpregnant and nonlactating Jersey cows were randomly assigned to one of 2 treatment groups. To construct these groups, cows were fed 2 different TMR in a preexperimental period for 84 d resulting in a BCS of >5 (HiBCS) and a BCS <3 (LoBCS), and no difference was observed in initial BW or BCS between treatments, averaging 509 ± 26.0 kg and 4.1 ± 0.23. To begin the experiment all animals were fed at maintenance [NELmaint, (Mcal/d) = 0.10 × metabolic BW (BW0.75)] for 24 d followed by 4 d of data collection for energy balance, cows were then fasted of 96 h with data collection for energy balance once again taken over the final 24 h. During the maintenance collection period, differences in BW and BCS existed (439 and 566 ± 19.0 kg BW, and 3.0 and 5.0 ± 0.13 BCS) for LoBCS and HiBCS, respectively. Heat production increased with increasing BCS (13.1 to 16.2 ± 0.55 Mcal/d), but when expressed per unit of BW0.75 no difference was observed (0.14 ± 0.002 Mcal/d per BW0.75). When fasted, BW loss did not differ averaging 28.9 ± 0.181 kg. The FHP did not differ, averaging 0.10 ± 0.004 Mcal/d per BW0.75 and resulted in the following representation of maintenance: [NELmaint, (Mcal/d) = 0.10 ± 0.004 × BW0.75]. During fasting the nitrogen free respiratory quotient tended to differ (0.69 and 0.73 ± 0.014) and O2 consumption and CO2 production for protein oxidation differed for LoBCS and HiBCS (5.44 and 2.35 ± 0.988 O2 and 4.52 and 1.95 ± 0.821 CO2 L/BW0.75). Overall, FHP increased with increasing BCS, but FHP per unit of BW0.75 did not differ. Although BW change was similar during fasting, differences O2 consumption and CO2 production per unit of BW0.75 used for protein oxidation may indicate differences in the nature of body tissue utilization in cows differing in BCS.

The association between calf birth weight and the postcalving performance of its dairy dam in the absence of dystocia.

The objective of the study was to quantify the association between the birth weight of a calf and the subsequent performance of its dairy dam in the absence of any recorded calving assistance. A total of 11,592 lactation records from 4,549 spring-calving dairy cows were used. The association between a series of quantitative cow performance metrics (dependent variable) and calf birth weight (independent variable) was determined using linear mixed models; logistic regression was used where the dependent variable was binary. Nuisance factors in the models were calf sex, heterosis coefficient of both the cow and calf, dry period length immediately before the birth of the calf, cow age at calving relative to the median cow age per parity, breed proportion of the cow, cow live weight between 100 and 200 d of lactation relative to the mean cow weight per parity, and contemporary group. Calf birth weight was included in the model as either a continuous or a categorical variable. Primiparous and multiparous cows were analyzed separately. Mean (SD) calf birth weight was 36.2 (6.8) kg. In primiparous cows, calf birth weight was associated with milk yield in the first 60 d of lactation, calving to first service interval, calving body weight (BW), and both nadir BW and body condition score (BCS). In multiparous cows, calf birth weight was associated with total milk, fat, and protein yield in the first 60 and 305 d of lactation, peak milk yield, total milk solids, both calving and nadir BW, and BCS loss from calving to nadir. Relative to primiparous cows that gave birth to calves weighing 34 to 37 kg (i.e., population mean), their contemporaries who gave birth to calves that weighed 15 to 29 kg produced 9.82 kg more milk in the first 60 d of lactation, had a 2-d shorter interval to first service, and were 8.08 kg and 5.51 kg lighter at calving and nadir BW, respectively; the former was also 0.05 units lower in BCS (5-point scale, 1 = emaciated and 5 = obese) at nadir. Relative to multiparous cows that gave birth to calves that were 34 to 37 kg birth weight, multiparous cows that gave birth to calves that were 15 to 29 kg yielded 59.63 kg, 2.44 kg, and 1.76 kg less milk, fat, and protein, respectively, in the first 60 d of lactation; produced 17.69 kg less milk solids throughout the 305-d lactation; and were also 10.49 kg lighter at nadir and lost 0.01 units more BCS to nadir. In a separate series of analyses, sire breed was added to the model as a fixed effect with and without calf birth weight. When calf birth weight was not adjusted for, 60-d milk yield for multiparous cows who gave birth to calves sired by a traditional beef breed (i.e., Angus, Hereford) produced 59.63 kg more milk than multiparous cows who gave birth to calves sired by a Holstein-Friesian. Hence, calf birth weight is associated with some subsequent dam performance measures; however, where associations do exist, the effect is biologically small.

Bile acid profiles and mRNA abundance of bile acid-related genes in adipose tissue of dairy cows with high versus normal body condition.

Besides their lipid-digestive role, bile acids (BA) influence overall energy homeostasis, such as glucose and lipid metabolism. We hypothesized that BA along with their receptors, regulatory enzymes, and transporters are present in subcutaneous adipose tissue (scAT). In addition, we hypothesized that their mRNA abundance varies with the body condition of dairy cows around calving. Therefore, we analyzed BA in serum and scAT as well as the mRNA abundance of BA-related enzymes, transporters, and receptors in scAT during the transition period in cows with different body conditions around calving. In a previously established animal model, 38 German Holstein cows were divided into either a high (HBCS; n = 19) or normal BCS (NBCS; n = 19) group based on their BCS and back-fat thickness (BFT). Cows were fed different diets to achieve the targeted differences in BCS and BFT (NBCS: BCS <3.5, BFT <1.2 cm; HBCS: BCS >3.75, BFT >1.4 cm) until dry-off at 7 wk antepartum. During the dry period and subsequent lactation, both groups were fed the same diets according to their energy demands. Using a targeted metabolomics approach via liquid chromatography-electrospray ionization-MS /MS, BA were analyzed in serum and scAT at wk -7, 1, 3, and 12 relative to parturition. In serum, 15 BA were observed: cholic acid (CA), chenodeoxycholic acid (CDCA), glycocholic acid (GCA), taurocholic acid (TCA), glycochenodeoxycholic acid (GCDCA), taurochenodeoxycholic acid, deoxycholic acid (DCA), lithocholic acid, glycodeoxycholic acid (GDCA), glycolithocholic acid, taurodeoxycholic acid, taurolithocholic acid, ß-muricholic acid, tauromuricholic acid (sum of α and ß), and glycoursodeoxycholic acid, whereas in scAT 7 BA were detected: CA, GCA, TCA, GCDCA, taurochenodeoxycholic acid, GDCA, and taurodeoxycholic acid. In serum and scAT samples, the primary BA CA and its conjugate GCA were predominantly detected. Increasing serum concentrations of CA, CDCA, TCA, GCA, GCDCA, DCA, and ß-muricholic acid with the onset of lactation might be related to the increasing DMI after parturition. Furthermore, serum concentrations of CA, CDCA, GCA, DCA, GCDCA, TCA, lithocholic acid, and GDCA were lower in HBCS cows compared with NBCS cows, concomitant with increased lipolysis in HBCS cows. The correlation between CA in serum and scAT may point to the transport of CA across cell membranes. Overall, the findings of the present study suggest a potential role of BA in lipid metabolism depending on the body condition of periparturient dairy cows.

Bile acid profiles and messenger RNA expression of bile acid-related genes in the liver of dairy cows with high versus normal body condition.

Bile acids (BA) play a crucial role not only in lipid digestion but also in the regulation of overall energy homeostasis, including glucose and lipid metabolism. The aim of this study was to investigate BA profiles and mRNA expression of BA-related genes in the liver of high versus normal body condition in dairy cows. We hypothesized that body condition and the transition from gestation to lactation affect hepatic BA concentrations as well as the mRNA abundance of BA-related receptors, regulatory enzymes, and transporters. Therefore, we analyzed BA in the liver as well as the mRNA abundance of BA-related synthesizing enzymes, transporters, and receptors in the liver during the transition period in cows with different body conditions around calving. In a previously established animal model, 38 German Holstein cows were divided into groups with high body condition score (HBCS; n = 19) or normal body condition score (NBCS; n = 19) based on BCS and backfat thickness (BFT). Cows were fed diets aimed at achieving the targeted differences in BCS and BFT (NBCS: BCS <3.5, BFT <1.2 cm; HBCS: BCS >3.75, BFT >1.4 cm) until they were dried off at wk 7 before parturition. Both groups were fed identical diets during the dry period and subsequent lactation. Liver biopsies were taken at wk -7, 1, 3, and 12 relative to parturition. For BA measurement, a targeted metabolomics approach with liquid chromatography electrospray ionization MS/MS was used to analyze BA in the liver. The mRNA abundance of targeted genes related to BA synthesizing enzymes, transporters, and receptors in the liver was analyzed using microfluidic quantitative PCR. In total, we could detect 14 BA in the liver: 6 primary and 8 secondary BA, with glycocholic acid (GCA) being the most abundant one. The increase of glycine-conjugated BA after parturition, in parallel to increasing serum glycine concentrations may originate from an enhanced mobilization of muscle protein to meet the high nutritional requirements in early lactating cows. Higher DMI in NBCS cows compared with HBCS cows was associated with higher liver BA concentrations such as GCA, deoxycholic acid, and cholic acid. The mRNA abundance of BA-related enzymes measured herein suggests the dominance of the alternative signaling pathway in the liver of HBCS cows. Overall, BA profiles and BA metabolism in the liver depend on both, the body condition and lactation-induced effects in periparturient dairy cows.

Association between prepartum body condition score and prepartum and postpartum dry matter intake and energy balance in multiparous Holstein cows.

The objectives of this retrospective observational study were to investigate the association between BCS at 21 d before calving with prepartum and postpartum DMI, energy balance (EB), and milk yield. Data from 427 multigravid cows from 11 different experiments conducted at the University of Florida (Gainesville, FL) were used. Cows were classified according to their BCS at 21 d before calving as fat (BCS ≥ 4.00; n = 83), moderate (BCS = 3.25-3.75; n = 287), and thin (BCS ≤ 3.00; n = 57). Daily DMI from -21 to -1 and from +1 to +28 DIM was individually recorded. Energy balance was calculated as the difference between net energy for lactation consumed and required. Dry matter intake in fat cows was lower than that in moderate and thin cows both prepartum (fat = 9.97 ± 0.21, moderate = 11.15 ± 0.14, and thin = 11.92 ± 0.22 kg/d) and postpartum (fat = 14.35 ± 0.49, moderate = 15.47 ± 0.38, and thin = 16.09 ± 0.47 kg/d). Dry matter intake was also lower for moderate cows compared with thin cows prepartum, but not postpartum. Energy balance in fat cows was lower than in moderate and thin cows both prepartum (fat = -4.16 ± 0.61, moderate = -1.20 ± 0.56, and thin = 0.88 ± 0.62 Mcal/d) and postpartum (fat = -12.77 ± 0.50, moderate = -10.13 ± 0.29, and thin = -6.14 ± 0.51 Mcal/d). Energy balance was also lower for moderate cows compared with thin cows both prepartum and postpartum. There was a quadratic association between BCS at 21 d before calving and milk yield. Increasing BCS from 2.5 to 3.5 was associated with an increase in daily milk yield of 6.0 kg and 28 d cumulative milk of 147 kg. Increasing BCS from 3.5 to 4.5 was associated with a decrease in daily milk yield of 4.4 kg and 28 d cumulative milk of 116 kg. In summary, a moderate BCS at 21 d before calving was associated with intermediate DMI and EB pre- and postpartum but greater milk yield compared with thinner and fatter cows. Our findings indicate that a moderate BCS is ideal for ensuring a successful lactation.

Effect of postpartum body condition score change on the pregnancy outcomes of lactating Jersey cows inseminated at first service with sexed Jersey or conventional beef semen after a synchronized estrus versus a synchronized ovulation.

Our objective was to compare insemination rate and pregnancies per artificial insemination (P/AI) of lactating Jersey cows inseminated at first service with sexed Jersey or conventional beef semen after submission to a Double-Ovsynch protocol for timed artificial insemination (TAI) versus a protocol to synchronize estrus at similar days in milk (DIM). Secondary objectives were to determine the effect of protocol synchrony and postpartum body condition score (BCS) change on P/AI. Lactating Jersey cows (n = 1,272) were allocated by odd versus even ear tag number, which was randomly allocated within the herd, within parity and semen type for submission to a Double-Ovsynch protocol (DO; n = 707) or a protocol to synchronize estrus (ED; n = 565). All ED cows detected in estrus were inseminated (EDAI; n = 424), with undetected cows receiving TAI after an Ovsynch protocol (EDTAI; n = 141). There was a treatment by parity interaction on insemination rate with 100% of DO cows receiving TAI, but a tendency for fewer primiparous ED cows to be detected in estrus and AI than multiparous cows (69.5% ± 0.04% vs. 77.1% ± 0.02%, respectively). For cows inseminated with sexed Jersey or conventional beef semen, DO cows tended to have and had more P/AI than EDAI cows (sexed, 49.2% ± 0.03% vs. 43.6% ± 0.03%; beef, 64.2% ± 0.04% vs. 56.3% ± 0.05%, respectively) and had more P/AI than EDAI+EDTAI cows (sexed, 49.1% ± 0.03% vs. 40.6% ± 0.03%; beef, 65.5% ± 0.04% vs. 56.2% ± 0.04%, respectively). Overall, 29.1% of DO cows expressed estrus with 5.0% and 24.2% of cows detected in estrus ≥24 h before and at TAI, respectively, and there was no difference in P/AI 61 ± 4 d after AI based on expression of estrus at TAI. The synchronization rate was greater for DO than EDAI cows (92.1% ± 0.01% vs. 79.2% ± 0.02%, respectively); however, synchronized DO cows had more P/AI than synchronized EDAI cows (55.0% ± 0.02% vs. 49.2% ± 0.03%, respectively). There was an interaction between BCS change from 7 to 39 ± 2 DIM and treatment on P/AI 61 ± 4 d after AI with no difference between DO and EDAI cows that lost = 0.25 (49.8% ± 0.04% vs. 51.0% ± 0.05%, respectively) or maintained or gained (55.6% ± 0.04% vs. 50.8% ± 0.05%, respectively) BCS, but within cows that lost ≥0.5 BCS, DO cows had more P/AI than EDAI cows (54.1% ± 0.04% vs. 36.1% ± 0.04%, respectively). In conclusion, submission of lactating Jersey cows to a Double-Ovsynch protocol for first insemination increased insemination rate and fertility to first insemination compared with AI after a detected estrus regardless of semen type and expression of estrus, particularly for cows with excessive postpartum BCS loss.

Relationship among thermal environment, stage of lactation, body characteristics, yield and milk constituents of dairy Gyr cows managed on pasture.

Our aims were to evaluate changes in body characteristics, milk yield and milk constituents as well as to determine the relationship between the thermal environment and production characteristics during the first lactation of dairy Gyr cows managed on pasture. Between 2013 and 2015, forty-five primiparous dairy Gyr cows were evaluated from prepartum to 10 months of lactation in Southeast of Brazil. Body weight, body condition score (BCS), subcutaneous fat thickness (SFT), milk yield (305 d), and milk constituents were collected monthly and progesterone was collected weekly. Additionally, we determined the temperature humidity index (THI) based on microclimate data. Overall, the cows lost body weight until six months of lactation and there was a progressive decrease in BCS, SFT, milk yield and milk lactose as the months in lactation progressed. In contrast, there was an increase in milk fat, milk protein and milk solids. The thermal environment did not pose a consistent heat challenge, nevertheless, we found a positive correlation between the average THI two days before milk collection with milk yield, fat and lactose contents, but in contrast a negative correlation was found with total solids and protein. In conclusion, the THI and months of lactation affected the yield and constituents of milk. However, more studies are necessary to understand the impacts of body characteristics and thermal environment on yield and milk constituents throughout the productive life of Gyr dairy cows.