Timing Of Breeding Research Articles

Penyuluhan Pentingnya Vaksinasi Covid 19, Pelatihan Pencegahan Deman Berdarah Dengue dan Edukasi kesehatan Gigi untuk Kader Kesehatan Kecamatan Palmerah, Jakarta Barat

In November 2021, Covid-19 vaccination coverage in the special capital area (DKI) Jakarta stage 1 (one) reached 78.1% and stage 2 (two) 60.4% for local identity cards (KTP) DKI Jakarta. Covid-19 vaccination coverage for area the Palmerah District stage 1 (one) has reached 96.56% but unfortunately for stage 2 (two) it has not met the expected target. In order to reduce the Covid-19 case, the regional administration (Pemda) of DKI Jakarta has continued given education and socialization to increase public awareness in implementing health protocols and providing Covid-19 vaccinations to the public.Another problem that occurs in the Palmerah District is the increase cases of Dengue Hemorrhagic Fever (DHF). This increase is due to the rainy season which is the breeding time for the Aedes Aegepty mosquito. DHF can be prevented through controlling the Mosquito Nest Eradication (PSN) programme. Public awareness for healthy behavior and maintaining a mosquito-free home environment is still lacking therefor counseling and training are needed for the community to prevent dengue.Since the Covid 19 pandemic, the Dental Health Education Program could not be implemented in Palmerah Health Center due to pandemic and limited resources. Providing dental health education (DHE) to health cadres will increase oral health in community. The results obtained after the training significantly increased the knowledge of the cadres and community members who participated in the event. Thus this collaboration program should continue regularly to maintain knowledge and health practice in community.

Breeding in an agricultural landscape: conservation actions increase nest survival in a ground-nesting bird

AbstractAgricultural intensification has affected wildlife across Europe, triggering steep declines and regional extinctions of farmland birds. Effective conservation activities are essential for the preservation of biodiversity in an agricultural landscape, but current efforts have not succeeded in halting these declines. Here we investigate a ground-nesting shorebird, the collared pratincole Glareola pratincola, which has shifted its habitat use in Central Europe over the last 20 years from alkaline grasslands to intensively managed agricultural fields. We show that nesting success was different between three agricultural habitat types, with the highest nesting success in fallow lands and the lowest in row crops. Nesting success was also associated with the timing of breeding and breeding density, as nests produced early in the breeding season and those in high-breeding-density areas hatched more successfully than those produced later in the season and at low density. We implemented direct conservation measures including marking nests and negotiating with farmers to avoid cultivating the field between nest markers, controlling nest predators and, most recently, creating suitable nesting sites and foraging areas for pratincoles. As a result of these conservation actions, nest survival increased from 11.2% to 83.5% and the size of the breeding population increased from 13 to 56 pairs during 2012–2021. Thus, we show that agricultural landscapes can continue to provide suitable habitats, and targeted conservation actions have the potential to reverse the declines of farmland species.

A CRISPR/Cas9-based vector system enables the fast breeding of selection-marker-free canola with Rcr1-rendered clubroot resistance.

Breeding for disease resistance in major crops is of crucial importance for global food security and sustainability. However, common biotechnologies such as traditional transgenesis or genome editing do not provide an ideal solution, whereas transgenic crops free of selection markers such as cisgenic/intragenic crops might be suitable. In this study, after cloning and functional verification of the Rcr1 gene for resistance to clubroot (Plasmodiophora brassicae), we confirmed that the genes Rcr1, Rcr2, Rcr4, and CRa from Brassica rapa crops and the resistance gene from B. napus oilseed rape cv. 'Mendel' on chromosome A03 were identical in their coding regions. We also determined that Rcr1 has a wide distribution in Brassica breeding materials and renders potent resistance against multiple representative clubroot strains in Canada. We then modified a CRISPR/Cas9-based cisgenic vector system and found that it enabled the fast breeding of selection-marker-free transgenic crops with add-on traits, with selection-marker-free canola (B. napus) germplasms with Rcr1-rendered stable resistance to clubroot disease being successfully developed within 2 years. In the B. napus background, the intragenic vector system was able to remove unwanted residue sequences from the final product with high editing efficiency, and off-target mutations were not detected. Our study demonstrates the potential of applying this breeding strategy to other crops that can be transformed by Agrobacterium. Following the streamlined working procedure, intragenic germplasms can be developed within two generations, which could significantly reduce the breeding time and labor compared to traditional introgression whilst still achieving comparable or even better breeding results.

Inconsistent shifts in warming and temperature variability are linked to reduced avian fitness

As the climate has warmed, many birds have advanced their breeding timing. However, as climate change also changes temperature distributions, breeding earlier might increase nestling exposure to either extreme heat or cold. Here, we combine >300,000 breeding records from 24 North American birds with historical temperature data to understand how exposure to extreme temperatures has changed. Average spring temperature increased since 1950 but change in timing of extremes was inconsistent in direction and magnitude; thus, populations could not track both average and extreme temperatures. Relative fitness was reduced following heatwaves and cold snaps in 11 and 16 of 24 species, respectively. Latitudinal variation in sensitivity in three widespread species suggests that vulnerability to extremes at range limits may contribute to range shifts. Our results add to evidence demonstrating that understanding individual sensitivity and its links to population level processes is critical for predicting vulnerability to changing climates.

Whoever their partner, female blue tits breed the same

Abstract Do females modify their reproductive investment if they do not succeed in pairing with a male that matches their preference? In a two-year experiment, we asked female blue tits (Cyanistes caeruleus) to select among six males, and then successively paired them with their preferred and their most avoided male. We monitored female reproductive investment through nest building activity, timing of breeding, size and number of eggs, number of fertilized eggs, and brood sex ratio. We found that females preferred males with a chromatic coloration (blue UV chroma of the head crown) that matched their own, but also that they preferred males with a lower achromatic coloration (less bright color of the cheeks and head crown). Although females paired with their preferred males tended to build heavier nests during the breeding season, we found no evidence of an effect of the pairing treatment on timing of breeding, or any other aspects of female reproductive investment. We however found that laying dates, clutch sizes, egg sizes, and brood sex ratio were significantly repeatable within females between the two years, despite the opposite pairing treatments. These findings show that in female blue tits, the males with which they are paired do not substantially alter their reproductive decisions.

318 The Effect of Developing Heifers to a Lower Percentage of Mature Body Weight at Breeding on Pregnancy Rates and Longevity Within the Herd

Abstract Traditional recommendations suggest that a heifer should be at 65% of her mature body weight (BW) at the time of breeding to obtain optimal production efficiency and achieve the greatest pregnancy rates. The objective of this study was to determine how developing heifers at a decreased percentage of mature BW at breeding impacts heifer performance, stayability, and calf production. Data were collected from cows and heifers (n = 1,434) from the March- and May-calving herds at the University of Nebraska Gudmundsen Sandhills Laboratory (GSL) located near Whitman, NE from 2005 through 2019. Body weights were collected from heifers and cows, percentage of mature BW of heifers was calculated using heifer breeding weight and the average MBW of cows at 5, 6, and 7 years of age. A regression analysis was conducted on percentage of estimated mature BW at breeding in heifers from 50 to 70 % of mature BW. Heifers that were 60% of mature BW at the time of breeding or greater had increased (P < 0.01) pregnancy rates compared with lighter heifers. In contrast, a greater percentage (P = 0.05) of heifers at a mature BW of 60% or less at breeding calved during the first 21 d of the calving season. Calf BW at birth was influenced (P < 0.001) by percent of mature BW at breeding with calves from greater BW heifers being heavier. Subsequent pregnancy rate as a 2-yr old was influenced (P < 0.001) by percentage of mature BW at breeding as a heifer with greater percent mature BW at breeding having greater pregnancy rates than heifers with decreased percent mature BW. However, pregnancy rate as a 3-, 4-, and 5-yr-old were not influenced (P> 0.15) by percentage of mature BW at breeding as a heifer. Overall, greater percentage of mature BW at the time of breeding increased overall pregnancy rate; however, heifers at a decreased percentage of mature BW calved at a greater percentage during the first 21-d of the subsequent calving season. In addition, longevity in the cowherd was not influenced by heifer BW at the time of breeding.

Acceleration of wheat breeding: enhancing efficiency and practical application of the speed breeding system

BackgroundCrop breeding should be accelerated to address global warming and climate change. Wheat (Triticum aestivum L.) is a major food crop. Speed breeding (SB) and speed vernalization (SV) techniques for spring and winter wheat have recently been established. However, there are few practical examples of these strategies being used economically and efficiently in breeding programs. We aimed to establish and evaluate the performance of a breeder-friendly and energy-saving generation acceleration system by modifying the SV + SB system.ResultsIn this study, a four-generation advancement system for wheat (regardless of its growth habits) was established and evaluated using an energy-efficient extended photoperiod treatment. A glasshouse with a 22-hour photoperiod that used 10 h of natural sunlight and 12 h of LED lights, and minimized temperature control during the winter season, was successful in accelerating generation. Even with one or two field tests, modified speed breeding (mSB) combined with a speed vernalization system (SV + mSB) reduced breeding time by more than half compared to traditional field-based methods. When compared to the existing SV + SB system, the SV + mSB system reduced energy use by 80% to maintain a 22-hour photoperiod. Significant correlations were found between the SV + mSB and field conditions in the number of days to heading (DTH) and culm length (CL). Genetic resources, recombinant inbred lines, and breeding materials that exhibited shorter DTH and CL values under SV + mSB conditions showed the same pattern in the field.ConclusionsThe results of our SV + mSB model, as well as its practical application in wheat breeding programs, are expected to help breeders worldwide incorporate generation acceleration systems into their conventional breeding programs.

Earlier springs increase goose breeding propensity and nesting success at Arctic but not at temperate latitudes.

Intermittent breeding is an important tactic in long-lived species that trade off survival and reproduction to maximize lifetime reproductive success. When breeding conditions are unfavourable, individuals are expected to skip reproduction to ensure their own survival. Breeding propensity (i.e. the probability for a mature female to breed in a given year) is an essential parameter in determining reproductive output and population dynamics, but is not often studied in birds because it is difficult to obtain unbiased estimates. Breeding conditions are especially variable at high latitudes, potentially resulting in a large effect on breeding propensity of Arctic-breeding migratory birds, such as geese. With a novel approach, we used GPS-tracking data to determine nest locations, breeding propensity and nesting success of barnacle geese, and studied how these varied with breeding latitude and timing of arrival on the breeding grounds relative to local onset of spring. Onset of spring at the breeding grounds was a better predictor of breeding propensity and nesting success than relative timing of arrival. At Arctic latitudes (>66° N), breeding propensity decreased from 0.89 (95% CI: 0.65-0.97) in early springs to 0.22 (95% CI: 0.06-0.55) in late springs, while at temperate latitudes, it varied between 0.75 (95% CI: 0.38-0.93) and 0.89 (95% CI: 0.41-0.99) regardless of spring phenology. Nesting success followed a similar pattern and was lower in later springs at Arctic latitudes, but not at temperate latitudes. In early springs, a larger proportion of geese started breeding despite arriving late relative to the onset of spring, possibly because the early spring enabled them to use local resources to fuel egg laying and incubation. While earlier springs due to climate warming are considered to have mostly negative repercussions on reproductive success through phenological mismatches, our results suggest that these effects may partly be offset by higher breeding propensity and nesting success.

Spring departure date, not en route conditions, drive migration rate and arrival timing in a long-distance migratory songbird

Long-distance avian migrants are threatened by a rapidly changing environment, which can induce a mismatch between favorable environmental conditions and the timing of breeding. Therefore, migratory birds must rely on phenotypic plasticity within migration timing to remain synchronized with earlier occurring resources over the shorter term. However, how this plasticity responds to en route environmental factors and whether or not it may allow migratory birds to remain synchronized with advancing springs is largely unknown. The objective of this study was to investigate how extrinsic factors, such as those related to the weather (e.g., temperature, precipitation, and wind speed) and daylength experienced along spring migration routes, and intrinsic factors, such as sex and age, migration departure date from wintering grounds, and migration destination (i.e., breeding site), influence the migration rate and spring arrival date at breeding grounds in purple martins (Progne subis). We investigated arrival timing and rate using 307 individual migration tracks sampled across the birds’ eastern breeding range. We found that the departure date and total stopover time explained most of the variation in migration rate, with birds departing later traveling faster but taking more stopover days, leading to a slower overall migration rate. To a lesser extent, facilitating southern winds and lower precipitation also induced a faster migration rate. We found that birds with a faster migration rate arrived earlier at their breeding sites. We also found that female birds traveling to more northern breeding sites arrived earlier than male birds, and that they migrated at a faster rate. Overall, our results suggest that the migration rate may be most impacted by intrinsic factors tied to spring departure dates that are aligned with the phenology of breeding sites rather than by conditions experienced en route. These findings support growing evidence that selection for spring departure date may be needed for the advancement of spring arrival date to match advancing springs with climate change. Future research investigating how environmental conditions at stopovers contribute to the overall migration rate would provide further insight into the factors influencing migration timing.

Breeding biology of the grey-browed brushfinch Arremon assimilis (Aves: Passerellidae) in the Eastern Andes of Colombia

ABSTRACT The timing of breeding is a key component of the life history of birds. In the tropics, where avian diversity is higher and environmental variability is less predictable than in temperate latitudes, breeding phenology patterns are poorly understood, and many other life-history traits remain largely unstudied. We describe the nest, egg, juvenile plumage, and breeding phenology of a population of the grey-browed brushfinch (Arremon assimilis assimilis, Passerellidae) from the Eastern Andes of Colombia. We found a single bluish-white unmarked egg in a cup-shaped nest. We also examined the relationship between photoperiod and precipitation with breeding phenology by monitoring 44 territorial pairs between 2017 and 2018. Arremon assimilis has two breeding peaks associated with the onset of rainfall in prior months: the first peak extends from mid-May to September, and the second from November and December to January. We also update a recent review of breeding biology data in Arremon and discuss how life-history traits may have evolved in light of the relationships among sparrows in this genus. Our study, one of few analyses of the breeding biology of a population in a montane species from the Andes, highlights the importance of such studies to further comprehend the general mechanisms that shape the breeding biology of tropical birds.

Evaluation of breeding distribution and chronology of North American scoters

North America's scoter species are poorly monitored relative to other waterfowl. Black Melanitta americana, surf M. perspicillata, and white‐winged M. deglandi scoter abundance and trend estimates are thus uncertain in many parts of these species' ranges. The most extensive source of waterfowl abundance and distribution data in North America is the Waterfowl breeding population and habitat survey (WBPHS). Although the WBPHS effectively monitors most species, both its timing and geographic coverage may preclude accurate scoter monitoring. Therefore, our goal was to better define when and where scoters breed to help interpret survey results and optimize potential supplemental survey efforts for scoters. We integrated satellite telemetry tracking data from scoters marked at multiple molting, staging, breeding, and wintering areas along the Atlantic and Pacific coasts to quantify continent‐wide breeding chronology and distribution. We also examined possible drivers of variation in timing of arrival, length of stay, and departure at nesting locations. We documented a northwest to southeast distribution of estimated breeding sites across Alaska and Canada. On average, scoters arrived at nest sites on 1 June. Surf scoters and Pacific black scoters arrived earliest and departed earliest. Pacific‐wintering black and white‐winged scoters began breeding earlier than Atlantic‐wintering birds. Additionally, birds arrived at nesting locations earlier in years with earlier snowmelt, and later snowmelt reduced lengths of stay for males. Breeding chronology also varied by age group, with adults arriving earlier than subadults. Our study is the first to comprehensively describe spatial variation in timing of breeding of both Atlantic and Pacific populations of all three scoter species across North America. Our results increase our understanding of how current surveys enumerate scoters and will inform possible supplemental efforts to improve continental monitoring of scoter populations.

Correction to: The biotic and abiotic drivers of timing of breeding and the consequences of breeding early in a changing world

Correction to: The biotic and abiotic drivers of timing of breeding and the consequences of breeding early in a changing world

The interplay among breeding timing, brood size, food quantity, and nestling growth rate in the Eurasian eagle owl (Bubo bubo)

Abstract Optimal clutch size theory predicts a trade-off between egg number and fledgling body mass, potentially affecting their survival rate. Yet, only a few studies have directly linked clutch or brood size to energy (food), nestling growth rate, and timing of breeding. We studied the relationship among all these variables in the Eurasian eagle owl. Of 150 eggs laid in 48 nests, 119 hatched and 117 nestlings fledged, indicating low nestling mortality. The number of eggs, hatchlings and fledglings (possibly indicating territory quality) decreased with ordinal date. The total amount of food brought to the nest increased with brood size, but the average amount per nestling decreased. Nestling growth rate (and thus probably fledgling body mass) was negatively correlated with brood size. A trade-off between brood size and fledgling survival may lessen the benefit of occupying food-rich territories. However, we suggest that fledglings from large broods, despite their relatively low body mass, may have higher survival rates owing to their relatively early fledging. This may be due to: (1) higher prey abundance in late spring compared with late summer and (2) a longer period before entering the cold season. Variation in brood size may therefore represent a set of strategies linked to prey abundance.

Phenotypic plasticity in reproductive and somatic efforts of female Columbian ground squirrels

Phenotypic plasticity of life-history traits is well known among vertebrate species. We estimated reproductive and somatic efforts of female Columbian ground squirrels ( Urocitellus columbianus (Ord, 1815)) to test for plasticity of these important resource allocations. We examined a 27-year dataset of life-history traits on these long-living (8–10 years), hibernating, montane-living mammals. Environmental variation was estimated from two important traits of mothers, their relative timing of breeding and spring maternal body mass (initial “capital” for use in subsequent reproduction). Results from 183 known-aged mothers and 508 litters revealed considerable variation in the relative timing of breeding, initial maternal mass, and reproductive and somatic efforts, as well as significant variation among ages and years. Results from 125 mothers that reproduced more than once (and 450 litters) revealed significant plasticity of reproductive and somatic efforts with respect to relative timing of breeding and spring maternal mass. A within-subject centering statistical approach showed that phenotypically plastic reproductive and somatic efforts were due to variation within individuals, but were not always reflected by the pattern of responses among individuals in the population. The plastic responses of different mothers appeared to be similar in strength.

Temporal and Environmental Dynamics of Fish Stocks in the Marine Protected Area of the Artificial Reef of Kitros, Pieria (Northern Greece, Mediterranean Sea)

The impact of temporal factors and physiochemical properties on the quantities and biomass of fish in the Thermaikos Gulf and adjacent habitats around the Pieria artificial reef complex in Northern Greece was evaluated. Data were collected from edge habitats of an artificial reef made of submerged concrete blocks located offshore of Kitros. Between 2015 and 2017, sampling excursions took place in the spring, summer, and fall of each year. The artificial reef complex is positioned 11.5 km offshore from Kitros, near the delta of the Aliakmonas River, and is influenced by freshwater from the Axios, Aliakmonas, Ludias, and Gallikos Rivers. To estimate the biomass and numbers of the primary benthopelagic commercial fish in the region, nine experimental samples were taken from 2015 to 2017, employing a bottom trawl with a mesh size of 10 mm. Each trawl sample lasted for 30 min to reduce the environmental impact of fishing in the areas under study. The sampling schedule was aligned with factors like the breeding times of the dominant species and the seasonal changes in the thermocline zone. Analysis showed seasonal differences in average abundance and biomass values across the 3 years of the study. Mullus barbatus, recognized as the most commercially significant species caught, demonstrated the greatest abundance and biomass during the second sampling season. Conversely, Pagellus erythrinus, the second most vital commercial species caught, exhibited its highest abundance in the first season and reached its peak biomass during the third sampling season. Hierarchical cluster analyses showed that the two major resulting clusters of species proliferated in numbers over the 3-year period, while undergoing a concurrent reduction in their individual sizes.

Does early spring arrival lead to early nesting in a migratory shorebird? Insights from remote tracking

Advancing breeding phenology is a commonly observed response to climate warming among bird species, potentially in response to shifts in the phenology of key resources. However, for migratory birds breeding at high latitudes, their capacity to breed earlier may be constrained by the time available between arrival on the breeding grounds and nesting, especially for later‐arriving individuals. This may have consequences for productivity, as early laying is often linked to higher breeding success, particularly in such seasonal environments. We investigated how migratory arrival timing influences subsequent timing of breeding, in particular whether the time between arrival and laying (arrival–laying gap) varies with arrival date, and if later‐arriving individuals are able to catch up with early‐arriving conspecifics. We tracked individual Icelandic Black‐tailed Godwit Limosa limosa islandica with GPS and PTT tags for one to two complete breeding seasons between 2013 and 2022. After arrival in Iceland, most Godwits visited their breeding territory within 5 days, though this interval was longer for earlier‐arriving birds. The total gap between arrival and laying was also longer for earlier‐arriving birds, such that laying date did not vary significantly with arrival date. These results suggest that, despite individual consistency in migratory phenology, subsequent timing of nesting is probably influenced by other factors, such as mate arrival timing and/or annual variation in environmental conditions. Regular pre‐nesting visits to the breeding territory may indicate that Godwits are able to monitor such factors closely and to nest early when conditions allow, but a larger sample of individuals and years is needed to assess whether early‐arriving individuals contribute disproportionately to population‐level advances in breeding phenology. Widespread tracking with high temporal and spatial resolution helps improve our understanding of phenological variation during the breeding season and its consequences for productivity and variation in juvenile phenology.

Genome-wide association study of anogenital distance and its (co)variances with fertility in growing and lactating Holstein-Friesian dairy cattle

Anogenital distance (AGD) is a moderately heritable trait that can be measured at a young age that may provide an opportunity to indirectly select for improved fertility in dairy cattle. In this study, we characterized AGD and its genetic and phenotypic relationships with a range of body stature and fertility traits. We measured AGD, shoulder height, body length, and body weight in a population of 5,010 Holstein-Friesian and Holstein-Friesian × Jersey crossbred heifers at approximately 11 mo of age (AGD1). These animals were born in 2018 across 54 seasonal calving, pasture-based dairy herds. A second measure of AGD was collected in a subset of herds (n = 17; 1,956 animals) when the animals averaged 29 mo of age (AGD2). Fertility measures included age at puberty (AGEP), then time of calving, breeding, and pregnancy during the first and second lactations. We constructed binary traits reflecting the animal's ability to calve during the first 42 d of their herd's seasonal calving period (CR42), be presented for breeding during the first 21 d of the seasonal breeding period (PB21) and become pregnant during the first 42 d of the seasonal breeding period (PR42). The posterior mean of sampled heritabilities for AGD1 was 0.23, with 90% of samples falling within a credibility interval (90% CRI) of 0.20 to 0.26, whereas the heritability of AGD2 was 0.29 (90% CRI 0.24 to 0.34). The relationship between AGD1 and AGD2 was highly positive, with a genetic correlation of 0.89 (90% CRI 0.82 to 0.94). Using a GWAS analysis of 2,460 genomic windows based on 50k genotype data, we detected a region on chromosome 20 that was highly associated with variation in AGD1, and a second region on chromosome 13 that was moderately associated with variation in AGD1. We did not detect any genomic regions associated with AGD2 which was measured in fewer animals. The genetic correlation between AGD1 and AGEP was 0.10 (90% CRI 0.00 to 0.19), whereas the genetic correlation between AGD2 and AGEP was 0.30 (90% CRI 0.15 to 0.44). The timing of calving, breeding, and pregnancy (CR42, PB21, and PR42) during first or second lactations exhibited moderate genetic relationships with AGD1 (0.19 to 0.52) and AGD2 (0.46 to 0.63). Genetic correlations between AGD and body stature traits were weak (≤0.16). We conclude that AGD is a moderately heritable trait, which may have value as an early-in-life genetic predictor for reproductive success during lactation.

Effectiveness of Information Acquisition via the Internet in Standardizing the Use of Antimicrobials by Hog Farmers: Insights from China

Antimicrobial residues and resistance caused by farmers’ overuse of veterinary antimicrobials have seriously threatened food safety, the ecological environment, and public health. With the popularization of the Internet in rural areas, especially in developing countries, the constraints of obtaining agricultural technical information provided by governments or organizations are greatly eased, farmers’ knowledge and skills are significantly improved, and the agricultural standardized production system is effectively constructed. However, there is still a research gap on whether information acquisition via the Internet (IAI) can induce farmers to standardize the use of antimicrobials. Using the data of 675 hog farmers in the Hebei, Shandong, Henan, and Hubei provinces, China, the IV-Heckman and mediating effect models were used to analyze the phenomenon empirically. The main findings revealed that the IAI had exerted a significant influence on the standardized use of veterinary antimicrobials by hog farmers, i.e., the IAI not only helped farmers to decide to standardize the use of antimicrobials but also reduced the amount of investment in the standardized use of antibiotics. Moreover, information-sharing and feedback mechanisms partially mediated the relationship between the IAI and farmers’ standardized use of antimicrobials. Finally, considering the heterogeneity of individual endowments, the study further revealed that the IAI significantly impacted the standardized use of antimicrobials for farmers below the age of 36 years. However, the IAI was found to positively and significantly promote farmers’ standardized-use decisions only if they had less than five years of breeding time.

Effect of dietary energy source on pregnancy rates and reproductive physiology of pastured beef heifers

Proper production of steroid hormones, such as progesterone (P4), is essential for maintenance of pregnancy. Provision of gluconeogenic substrates from the diet may alter postabsorptive energy supplies and associated hormone signaling in a manner supportive of elevating P4 concentrations. Crossbred Angus heifers (n=27) were balanced for pre-trial bodyweight (BW) and body condition score (BCS), then assigned to isoenergetic diets leveraging starch (ES) or fat (EF) as the primary source of energy (45.7% starch vs 11.5% fat). The heifers were placed on the assigned diets 8 days prior to the initiation of estrous synchronization and continued the diets through the second pregnancy diagnosis, 52 days after the initial insemination. On day 28 post-breeding, pregnancy status was diagnosed via ultrasonography. Measurements of follicle size and number were collected via rectal palpation and ultrasonography on days −10, −8, −4, and day 0 relative to breeding. Blood samples were collected on days −10, 1 through 7, 10, 14, 18, 21, 24, and 28 to analyze plasma for P4 concentrations and placental-associated glycoprotein (PAG) concentrations. Data were analyzed using a linear mixed effects model with a fixed effect for treatment and a random effect for pen. Observations collected over time were analyzed using a repeated measures approach with fixed effects for treatment, time, initial condition, and a random effect for pen. Interactions between treatment and pregnancy status were also tested for PAG and P4 concentrations. No treatment differences were observed in final BCS (P=0.12) and total dry matter intake (DMI; P=0.51), though heifers on the ES treatment tended to reach an increased BW (P=0.10). Although heifers fed ES diets had numerically higher conception rates compared to heifers fed EF diets (71.4% vs. 66.7%), there was no statistically significant difference. Furthermore, there were no significant differences observed among diets in terms of pregnancy outcomes, follicle size, or number. A treatment by pregnancy status interaction was detected for both PAG and P4 concentrations. These results suggest that short-term dietary starch supplementation provided around the time of breeding can result in shifts to reproductive hormone abundance that may be conducive for pregnancy establishment.

Census counts of Common Murres adjusted for timing of breeding are more accurate than counts based on calendar dates

Abstract Climate change has resulted in a marked advancement in the breeding phenology of many bird species. Since the timing of many monitoring programs is based on calendar dates, changes in the timing of birds’ breeding seasons may result in a mismatch with the census period. Using data from a long-term population study of Common Murres (Uria aalge; Common Guillemots in Europe) on Skomer Island, Wales, together with simulations, we show that the 2-week advance in the timing of breeding in Common Murres between 1973 and 2020 has serious implications for the timing of census counts. We show that because censuses have traditionally been conducted during the same fixed calendar period each year, the size of the breeding population has been underestimated. We recommend that censuses of breeding seabirds be made relative to the median egg-laying date rather than on specific calendar dates. Since climate change has resulted in a widespread advance in the timing of birds’ breeding seasons in the northern hemisphere, our results may be relevant to Common Murres at other colonies, and to other bird species worldwide.