Calf Survival Rates Research Articles

Estimated reproductive parameters for a vulnerable Australian humpback dolphin population

AbstractUnderstanding reproductive output and success is integral to the conservation and management of threatened species and populations. Little is known about the reproductive parameters of Australian humpback dolphins (Sousa sahulensis), a species subject to cumulative pressures from anthropogenic threats due to their coastal distribution and strong site fidelity. This study assesses several reproductive parameters, including crude birth, recruitment, fecundity, and calf survival rates, in addition to interbirth intervals of Australian humpback dolphins inhabiting the near‐urban embayment of Moreton Bay, Queensland. Between 2014 and 2020, 106 adult females were photographically identified during 222 boat surveys. Of these, 75.5% (n = 80) were observed with calves. Birth seasonality was apparent and coincided with austral autumn and winter months. Interbirth intervals ranged between 1 and >6 years, with an average of 3.1 (SD = 1.1) years if offspring survived. Findings indicate declining fecundity rates (p < .05, M = 0.12, SD = 0.02), relatively low recruitment rates (M = 0.04, SD = 0.01) and calf survival rates to 1 year of age (M = 0.63, SD = 0.15). This study provides a useful baseline that can inform viability assessments and conservation measures, for both this population and others throughout the species range.

Estimation of genetic parameters of Holstein calf survival.

Calf survival is not only an animal welfare issue but also helps to avoid huge losses in economic and genetic material due to calf mortality. Therefore, improving calf survival is essential in dairy breeding. The objective of this study was to explore the factors affecting the survival of Holstein calves in the Ningxia Region and to estimate the genetic parameters of calves using linear models and threshold models. Descriptive statistics were made for 43,847 Holstein calves born from 2018 to 2022 in Ningxia. The number of calves that died at 2-30 d was the highest, the survival rate was the lowest at 451-750 d, followed by 61-180 d and 2-30 d. Studies on the survival rates of calves born in different months have found that calves born in April have the lowest survival rates and calves born in October and December have higher survival rates. Calves born in autumn, third parity, and singleton calves are more likely to survive. The heritability of calf survival traits ranged from 0.002 ~ 0.136. Thus survival is a low heritability trait. Genetic correlation between different survival stages ranged from 0.3991 (2-30 d to 451-750 d) to 0.9985 (361-450 d to 451-750 d), the phenotypic correlation ranged from 0.1476 (2-30 d to 451-750 d) to 0.9582 (361-450 d to 451-750 d). The low genetic correlation between early and late survival suggests that survival in early and late stages may be influenced by different genetic factors. This study is helpful to understand the survival status of Holstein calves and provide a theoretical basis for improving the survival rate of calves.

Risk factors and genetic parameter estimates for preweaning survival of Fogera calves

This study utilised mortality records of 1 043 Fogera calves maintained at Andassa Livestock Research Center from 1984 to 2021 to investigate the factors that influence survival and estimate genetic parameters for the preweaning survival of Fogera calves. Survival was defined as the probability of surviving in a given length of time. Survival analysis was done using the Weibull proportional hazard model with Survival Kit version 6.1 software. Genetic variance and heritability estimates were estimated using the sire model. The proportion of right-censored calves up to 1, 4, and 8 months of age was 90.8, 87.8, and 83.5%, respectively. Around 55.8% of all deaths (16.5%) occurred up to one month of age. In addition to birth year, sex, season, and weight at birth were the most important risk factors for calf mortality. The heritability estimates for the survival of calves at 1, 4, and 8 months of age were 0.26 ± 0.14, 0.22 ± 0.13, and 0.38 ± 0.18, respectively. Moderate heritability was estimated at the age of eight months, implying that the inclusion of survival traits in the selection criteria and inclusion in the breeding goal will enhance the preweaning survival rate of calves. Similarly, higher differences in estimated breeding values of sires for survival suggest that the selection of sires with higher estimated breeding values could improve the survival potential of calves. The decreased genetic trend of 3.34% year−1 for the survival potential of Fogera calves during the study periods suggested that survival traits should be included in the breeding goal to reduce the mortality rate.

Birth date determines early calf survival in migratory caribou.

The decline of most caribou (Rangifer tarandus) populations underlines the need to understand the determinants of key demographic parameters. In migratory caribou, we have limited information on rates and drivers of pre-weaning mortality. We fitted 60 pregnant females of the Rivière-aux-Feuilles caribou herd with GPS camera collars to track the survival of calves from birth to weaning in 2016-2018. Over the three years, calf survival rate before weaning, i.e. to 01-Sep, approximately three months of age, was 0.63 (CI 0.50-0.77). Summer mortality risk was mainly influenced by calf birth date, with calves born earlier in the calving season having a lower mortality risk than those born later. Mortality also increased when calves experienced low or high temperature during calving. This study provides the first estimates of pre-weaning survival of migratory caribou calves in this herd, illustrating the value of new technologies to collect data otherwise difficult to obtain in widely distributed migratory populations. This approach can easily be extended to other large herbivores and predators. Our study brings new insights on how climate change may affect summer juvenile survival given the increased temperatures and faster changes in plant phenology expected in the future.

Abundance and demographic parameters of humpback whales from the Gulf of Maine, and stock definition relative to the Scotian Shelf

The Gulf of Maine is one of the principal summer feeding grounds for humpback whales (Megaptera novaeangliae) in the North Atlantic, and was one focus of effort in an ocean-basin-wide study known as the Years of the North Atlantic Humpback (YoNAH) project. Data from that project and from subsequent surveys were used to assess stock boundaries, abundance and demographic parameters for Gulf of Maine humpbacks. Surveys on the Scotian Shelf in the summers of 1998 and 1999 produced the first substantial dataset of identified individual humpbacks observed in this region, which lies between the well-studied areas of the Gulf of Maine and Newfoundland. The results gave a match rate of approximately 27% (14 of 52 individuals) between the Scotian Shelf and the Gulf of Maine, with evidence that many of the matched whales were transient in the Gulf of Maine; there were no matches to any other location in the North Atlantic. These data suggest that the range of most whales from the Gulf of Maine usually does not extend as far east as the Scotian Shelf or Newfoundland. Only one whale was observed on the Scotian Shelf in both the 1998 and 1999 surveys, and another seen in 1998 had also been sighted there in 1994. This low inter-annual match rate suggests that the abundance of humpback whales on the Scotian Shelf is larger than previously recognised. Three different but overlapping estimates of abundance for the Gulf of Maine population were calculated. Mark-recapture data from 1992/93 gave an estimate of abundance of 652 (CV = 0.29); however, this estimate is likely biased because of heterogeneity in sampling and in animal distribution. Photo-id data also provided a minimum population estimate of 497 humpbacks known to be alive in 1997; this estimate is also likely to be negatively biased because of heterogeneity. Finally, line-transect surveys conducted in 1999 yielded estimates of 816 (CV = 0.45) or 902 humpback whales (CV = 0.41, including a portion of the eastern Scotian Shelf stratum); these transect-based estimates are more consistent with the number of humpbacks (1,273, including dead animals) in the current photo-id catalogue for the Gulf of Maine. Overall, the size of the Gulf of Maine population is likely to be in the high hundreds, but no more precise estimate can be calculated at this time. The growth rate for the Gulf of Maine population was estimated using an interbirth interval method using data from 1992-2000. The estimate was either 1.00 (for a calf survival rate of 0.51) or 1.04 (for a calf survival rate of 0.875). Although confidence limits are not available (because maturation parameters could not be estimated), both estimates of population growth rate are outside the 95% confidence intervals of the previous estimate of 1.065 for the period 1979-1991 (Barlow and Clapham, 1997). It is unclear whether this apparent decline is an artefact resulting from a shift in distribution or is a real phenomenon; if the latter, it may be related to known high mortality among young-of-the-year whales in the waters of the US mid-Atlantic states. However, calf survival appears to have increased since 1996, presumably accompanied by an increase in population growth.

Long-term increase in mortality of Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River Estuary following anthropic activities: Evidence from the stranded dolphin mortality analysis from 2003 to 2017

With the dramatic increase in anthropogenic threats to the Pearl River Estuary (PRE), the population size of the Indo-Pacific humpback dolphins (Sousa chinensis) has significantly decreased over the past decade. To understand the impact and potential risks of intense human activities on these dolphins, factors related to the mortality of humpback dolphins in the PRE were investigated by a detailed examination of 343 dolphin specimens stranded during 2003–2017. There was a significant (p < 0.01) increasing trend for humpback dolphin stranding, reflecting the accelerating rate of the population decline. A large proportion of strandings (35.88%) were neonates. A low recruitment rate implies slow population growth, and hence, limited capacity to resist anthropogenic stress. The most commonly diagnosed causes of death were vessel collision and net entanglement. The concentrations of trace metals, polychlorinated biphenyl (PCB) congeners, dichlorodiphenyltrichloroethane, polycyclic aromatic hydrocarbons, and most of per- and polyfluoroalkyl substances (PFASs) in the dolphin samples were greater than those previously reported in cetaceans globally. Furthermore, Cu, PCB77, PCB169, PCB81, PCB37, and PFASs (excluding PFBA, PFPeA, PFHxA, PFHxDA, and PFODA) were the major pollutants accumulated in neonates. 67% of PCB, 78% of Cu, and 100% of perfluorooctane sulfonate concentrations in the neonates exceeded the threshold for toxicological effects in marine mammals, suggesting that these compounds could be important factors contributing to the low survival rate of calves in this area. This study revealed that vessel transportation, fishing activities, and pollutant bioaccumulation are the three major causes of humpback dolphin mortality in the PRE. These results highlight the need for more efforts to restrict anthropogenic activities, especially vessel traffic, the catching of these marine animals and fishing, and pollutant discharge, in order to prevent vulnerable species from continuous population decline and further extinction.

Research, development and adoption for the north Australian beef cattle breeding industry: an analysis of needs and gaps

This review seeks to analyse and prioritise needs and gaps in research and development (R&amp;D) for the north Australian beef cattle breeding industry, and to advise on options to increase rates of adoption and successful implementation of this R&amp;D. The material reviewed includes the peer-reviewed literature as well as industry reports and other relevant publications in three targeted areas of R&amp;D deemed to be important by industry leaders and supporting scientists: (i) breeding herd management, (ii) feedbase management, and (iii) management of environmental sustainability. For breeding herd management, the need for uniform definition and consistent utilisation of appropriate productivity metrics is highlighted, with emphasis on assessment of maternal reproductive efficiency in terms of weaning (or branding) rates. Priority is given to the urgent need for reliable means of remotely assessing causes of neonatal calf mortality to enable the development and application of management interventions that improve calf survival rates. The highest priority for feedbase management is to increase producer awareness and willingness to adopt stocking rates that are appropriately matched to the long-term carrying capacity of native rangeland pastures that predominate in northern Australia. Other opportunities include increasing the use of perennial, tropically adapted legumes, where conditions permit, to improve soil fertility and nitrogen intake of cattle, and devising strategies to overcome widespread phosphorus deficiency through diagnosis and supplementation, especially in the wet season. In order to enhance environmental sustainability in the face of climate change, priorities include improving producer awareness and use of increasingly robust tools for predicting key weather events, as well as developing genetic strategies to increase heat tolerance of cattle and evaluating management interventions to mitigate heat stress. Conclusions drawn from these sections are summarised and used to make recommendations on priorities for increasing adoption of existing research-proven practices and technologies, and for further R&amp;D on selected topics.

Growth Performance and Survival Rate of Fogera and Their Crossbred Calves at Government Ranches in Ethiopia

The economic benefit of dairy products can be enhanced by increasing the efficiency of growth and survival rate of calves. The objective of the study was to evaluate the effects of non-genetic factors on pre- and post-weaning growth traits and mortality rate of pure Fogera and their F1 cross Fogera × Holstein Friesian calves at the Andassa and Chagni Cattle Breeding and Improvement Ranch. Retrospective types of study design and direct measurement were used to collect the data. A total of 3,626 for pre-weaning weight records and 107 for post-weaning measurements were used for analysis. Genotype, sex, dam parity, year of birth, the season of birth, and location were the considered production factors. The overall least square means (LSM ± SE) of birth weights were 22.33 ± 0.12 and 24.56 ± 0.11 kg for Fogera and their crosses, respectively. The overall LSM ± SE of weaning weights were 93.25 ± 0.85 and 111.63 ± 0.84 kg for Fogera and their cross calves, respectively. The overall post-weaning weight for Fogera and their cross calves were 101.02 ± 1.62 and 111.08 ± 2.65, respectively. All variables considered in the model, except dam parity, significantly (P &amp;lt; 0.05) affected post-weaning weight. The overall recorded mortality rate was 3% which was nearly the optimum that many scholars agreed to successful rearing practices.

The challenges of a small population exposed to multiple anthropogenic stressors and a changing climate: the St. Lawrence Estuary beluga

Until 2012, the St. Lawrence Estuary beluga population was considered stable with about 1100 individuals. An abnormally high number of calves reported dead that year triggered a population status reassessment. This review article summarizes the findings from this reassessment and various studies subsequent to it and provides an updated analysis of carcass recovery rates up to 2019. The 2013 review indicated a decreased incidence of cancer in adults, suggesting positive impacts from the regulation of toxic substances (e.g., PCBs and PAHs). However, the review also revealed that the population initiated a decline of ca. 1% per year in the early 2000s and had reached a size of ca. 900 individuals by 2012. This decline was accompanied by high inter-annual variability in calf survival and pregnancy rates and by more frequent peripartum complications among dead females. The change in population dynamics coincided with a shift in the St. Lawrence ecosystem structure and warmer environmental conditions, suggesting a link through effects on reproductive success and adult female body condition. This was supported by the continued high calf mortality after 2012 and a documented decline of fat reserves in beluga blubber from 1998 to 2016. Other factors, such as the exposure to chronic vessel noise, increasing whale-watching activities, high contaminant levels and episodic harmful algal blooms, may also be contributing to the long-term non-recovery and current decline of the population. The strong natal philopatry and complex social system of the beluga likely increase its vulnerability to extinction risk by limiting dispersal.

Evaluation of survival rate of fogera calves and their crossbred at Chagni Cattle breed improvement and andasa livestock research centres

Evaluation of survival rate of fogera calves and their crossbred at Chagni Cattle breed improvement and andasa livestock research centres

Accessibility to Reproductive Technologies by Low-Income Beef Farmers in South Africa.

This study address historical legacy of South Africa that has dual economies resembling low and high income beef sectors. Low-income herds are farmed mainly under communal village or land reform farms. The study focused on providing assisted reproductive technologies (ARTs) to the low-income sector including finding challenges to its implementation and adoption. The study was conducted in Limpopo, Mpumalanga and KwaZulu-Natal provinces using mixed methods that looked at cows and sectors stakeholders. Data collected and evaluated on cows included breed type, frame size, body condition, age parity, and lactation status. Cows were exposed to ART through synchronisation, oestrus detection, fixed time artificial insemination and pregnancy diagnosis. Qualitative data was collected to study perception of key stakeholders on ART implementation and adoption. Chi-Square Test was computed to determine the association among cow factors. Qualitative data was collected, coded and managed into themes using Nvivo Version 11. Themes that emerged were interpreted using critical social and systems thinking. Conception rate was not independent of provinces (P < 0.05), cow body condition score (BCS) and body frame size. KwaZulu-Natal cows had the highest conception rate at 66% (P < 0.05) than Limpopo (44%) and Mpumalanga (60%) provinces. Cows with a BCS higher than 3.5 had higher conception rate (P < 0.05) than those with BCS of <2.5 and 3. Interestingly, large framed cow size had higher conception rate than medium and small framed (P < 0.05) cows. The study achieved a 100% calf survival rate. Calving rate was influenced by body BCS, province and district (P < 0.05). Calving rate of 58% in Mpumalanga and 54% in KwaZulu-Natal was higher than that recorded in Limpopo at 36% (P < 0.05). Interestingly, cows with BCS of <2.5 had a higher calving rate than those with a higher body condition score of 3 (P < 0.05). Perception study results revealed many factors that could affect the adoption and implementation of ART in the study areas. The high success rate and above average reproductive performance led to North West and KwaZulu-Natal provinces adopting ART as part of their low-income beef sector support.

Socially Defined Subpopulations Reveal Demographic Variation in a Giraffe Metapopulation

ABSTRACTPopulations are typically defined as spatially contiguous sets of individuals, but large populations of social species can be composed of discrete social communities that often overlap in space. Masai giraffes (Giraffa camelopardalis tippelskirchi) of Tanzania live in distinct social subpopulations that overlap spatially, enabling us to simultaneously explore environmental and social factors correlated with demographic variation in a metapopulation of &gt;1,400 adult females and calves. We considered statistically distinct communities in the social network as subpopulations and tested for variation among the 10 subpopulations in adult female survival, calf survival, and reproductive rate (calf‐to‐adult female ratio). We then related variation in demographic rates among subpopulations to differences in vegetation, soil type, proximity to 2 types of human settlements, local giraffe population density, and social metrics of relationship strength and exclusivity among adult females. We did not find any among‐subpopulation effects on adult female survival, suggesting adult female survival is buffered against environmental heterogeneity among subpopulations. Variation in calf demographic rates among subpopulations were correlated with vegetation, soils, anthropogenic factors, and giraffe population density but not with adult female relationship metrics, despite substantial spatial overlap. Subpopulations with more dense bushlands in their ranges had lower calf survival probabilities, and those closer to human settlements had higher reproductive rates, possibly because of spatial gradients in natural predation. Reproductive rates were higher in subpopulations with more volcanic soils, and calf survival probabilities were greater in subpopulations with higher local adult female densities, possibly related to higher‐quality habitat associated with fertile soils or lower predation risk, or to greater competitive ability. The variation in fitness among subpopulations suggests that giraffes do not move unhindered among resource patches to equalize reproductive success, as expected according to an ideal free distribution. The differences in calf survival and reproductive rates could rather indicate intercommunity differences in competitive ability, perception, learning, or experience. Our approach of comparing demography among spatially overlapping yet distinct socially defined subpopulations provides a biologically meaningful way to quantify environmental and social factors influencing fine‐scale demographic variation for social species. © 2021 The Wildlife Society.

Effects of β-Mannanase and Bacteriophage Supplementation on Health and Growth Performance of Holstein Calves.

Simple SummaryFor sustainable animal agriculture, we need to find ways to increase growth efficiency without using feed antibiotics. Bacteriophages, which are only harmful to specific bacterial strains, have been suggested as a feed additive replacing antibiotics. β-mannanase, which degrades mannan, is known to promote nutrient digestibility, animal growth, or both, thus improving feed efficiency. The objective of this study was to evaluate the effects of dietary supplementation with bacteriophage and β-mannanase on health and growth performance in calves. We assigned 36 pre-weaning male Holstein calves to one of four treatments with a 2 × 2 factorial arrangement: no supplementation, 0.1% β-mannanase, 0.1% bacteriophage, and both 0.1% bacteriophage and 0.1% β-mannanase supplementation in a starter on a dry matter basis. Compared to unsupplemented, the bacteriophage supplemented group showed a tendency to improve the survival rate without growth promotion. Supplementation of β-mannanase, on the other hand, increased the starter intake and the weekly body weight (BW) gain and tended to increase the final BW. Our study indicated that bacteriophage supplementation has a positive effect on survival rate, while β-mannanase supplementation improves growth performance in calves.The objective of this study was to evaluate the effects of dietary supplementation with bacteriophage and β-mannanase on health and growth performance in calves. Thirty-six pre-weaning male Holstein calves were randomly allocated to one of four dietary treatments with a 2 × 2 factorial arrangement: no supplementation, 0.1% β-mannanase, 0.1% bacteriophage, and both 0.1% bacteriophage and 0.1% β-mannanase supplementation in a starter on a dry matter basis. The experiment lasted from 2 weeks before weaning to 8 weeks after weaning. Twenty-two calves survived to the end of the experiment. No interaction was observed between the two different feed additives. The bacteriophage supplementation tended to increase the odds ratio of survival (p = 0.09). The number of Escherichia coli in feces significantly decreased by bacteriophage supplementation one week after weaning. β-mannanase supplementation increased the concentrate intake (p < 0.01) and tended to increase the final BW (p = 0.08). Analysis of repeated measures indicated β-mannanase supplementation increased weekly body weight gain (p = 0.018). We conclude that bacteriophage supplementation may have a positive effect on calf survival rate, while β-mannanase supplementation may increase the growth rate and starter intake by calves just before and after weaning.

Genetic and environmental analysis of female calf survival in the Israel Holstein cattle population

The objectives were to estimate the effects of various environmental factors on female calf survival of Israeli Holsteins, to estimate the economic value of calf survival under Israeli conditions, to estimate the genetic and environmental variance components for calf and cow survival using the individual animal model, to perform GWAS analyses of survival to first calving and herd life after first calving, to estimate the genetic and environmental trends for calf survival since 1985, to estimate genetic correlations of calf survival with the traits included in the current Israeli breeding index, and to estimate the consequences of inclusion of calf survival in the national selection index. Mean calf survival rate of Israeli Holsteins from 2001 through 2008 was 0.85, and the mean economic value of survival to first calving was $526. Birth month, gestation length, dystocia, and twin birth significantly affected calf survival rate. Dystocia and twin birth each reduced survival rate by 0.034. Survival rate was highest for calves born in October and lowest for calves born in February. The difference between these months was 3.4%. Maximum survival was at a gestation length of 276 d, the mean gestation length for this population. Survival rate was reduced to 0.76 for calves born after a gestation length of 260 d. The individual animal model was applied for all the genetic analyses. Heritability for calf survival to first calving, as estimated by REML, was 0.009, whereas heritability of herd life from first calving was 0.15. The complete data set for genetic analysis of survival to first calving included 1,235,815 calves born between 1985 and 2017. Annual genetic and phenotypic trends for calf survival were 0.019 and 0.015%, respectively. Correlations of transmitting abilities of 226 sires born since 2010 for calf survival with the traits included in the Israeli breeding index were significant only for the maternal effects of dystocia and stillbirth. The GWAS analysis was based on the transmitting abilities of 1,493 bulls with genotypes and reliabilities >0.5 for calf survival and cow herd life. There were 7 single nucleotide polymorphisms with coefficients of determination >0.03 for calf survival and 12 single nucleotide polymorphisms with coefficients of determination >0.05 for cow survival. There was no overlap between the genome-wide significant markers for the GWAS analyses of calf survival and cow herd life. This corresponds to the conclusion from the REML results and the low correlations between the sire evaluations that the genetic control of the 2 traits are not similar. Inclusion of calf survival in the Israeli breeding would result in a 0.5% increase in calf survival over 10 yr but reduce progress for the other traits by 8%.

Survie et aptitudes des veaux issus de croisements entre Brunes des Alpes et Zébus Peuls dans la région des Cascades au Burkina Faso

L’amélioration du potentiel génétique des bovins au Burkina Faso s’appuie sur des programmes de croisements avec des races exotiques par la promotion de l’insémination artificielle (IA) depuis un quart de siècle. Néanmoins, l’adaptation des veaux métis obtenus est controversée aussi bien en élevage périurbain que traditionnel. L’objectif de cette étude a été de déterminer le taux de survie et les aptitudes de métis F1 issus de croisements entre des bovins de races Brune des Alpes et Zébu Peul dans des élevages de la région des Cascades au Burkina Faso. L’étude a été menée sur 142 veaux répartis dans 60 élevages extensifs et semi-intensifs entre octobre 2013 et août 2017. Les animaux ont fait l’objet d’un suivi sanitaire rigoureux et d’une alimentation améliorée grâce à la production locale de fourrages. Le taux de survie des veaux à 42 mois a été estimé à 88 % avec une différence significative (p &lt; 0,05) entre saisons avant sevrage, et entre systèmes d’élevage après sevrage. Au total, 26,76 % des métis F1 ont été atteints de cowdriose, dermatophilose, fièvre aphteuse ou trypanosomoses avant et après le sevrage. Rustiques (82,4 %) avec un rythme cardiaque normal (85,6 %), les croisés ont été dociles et affectueux (64,8 %). Les mâles et les femelles F1 ont été respectivement de potentiels reproducteurs et de véritables conductrices de troupeaux. Les femelles sont d’emblée utilisées pour améliorer la production laitière mais l’utilisation des mâles dans les croisements doit éviter la consanguinité dans les élevages. La survie des métis nécessite un suivi sanitaire permanent et une bonne conduite d’élevage. Cependant, considérant le taux de survie élevé, la bonne adaptation et la docilité des métis, l’IA est en mesure d’améliorer les productions animales bovines au Burkina Faso.

Economic weights of current and new breeding objective traits in Aberdeen Angus

Breeding values estimated for growth, calving performance, and exterior traits are currently combined into simple selection indices for bulls, cows, and heifers of the Aberdeen Angus breed. To establish a comprehensive economic index for this breed, the absolute and relative economic weights (EW) for a complex of 16 production, functional, carcass, and feed efficiency traits were calculated. The absolute EW of a trait expressed the difference in the present values of profit that will be obtained from the descendants of a bull with the average breeding value for this trait, and descendants of a bull with the breeding value one unit higher than the average one. The relative EW of a trait was defined as the standardised EW of a trait (i.e. EW per genetic standard deviation) expressed as percentage of the sum of standardised EWs of all evaluated traits. Sensitivity analysis was conducted to explore the EW of traits under variable production and economic conditions. Variability in the marketing strategy, in product prices and costs, and in trait means was considered in this analysis. Relative EW of the feed efficiency of breeding heifers and of cows reached 4%. The highest relative EW was obtained in three growth traits: weight gains of calves from birth to 120, from 120 to 210, and from 210 to 365 days of age (66% combined). The survival rate of calves until weaning and cow productive lifetime reached 11% and 8% of the total economic importance of traits, respectively. These growth and functional traits accounted for 84% (in marketing strategy involving selling breeding animals) to 90% (in populations with high growth intensity) of the total economic weight of all 16 evaluated traits. Therefore, these traits should be considered as new selection criteria when constructing a comprehensive selection index for the Czech Aberdeen Angus population in future.

Subclinical mastitis treatment for non-milking cows

The article deals with the clinical research of cows during the interlactation period, through reviewing their medical histories and the clinical examination of the animals and their milk glands, trial milking and organoleptic evaluation of the secretion. The secretion was evaluated according to its color, texture, smell and the presence of foreign substances. The best therapeutic dosage of Vetom-3, a medicine based on Bacillus amyloliquefaciens, was determined through the examination of 30 non-milking cows suffering from subclinical mastitis. The probiotic and difumast were injected into the milk glands of the cows diagnosed with subclinical mastitis two weeks prior to the expected calving and in accordance with the examination results received on the 4th day of lactation. After the treatment, the milk was fed to the calves. The evaluation of the change rates of the microflora composition was carried out using calf feces samples. The bacteriological tests of the microflora were carried out using the standard procedures for determining the morphological properties of germ cultures. We ascertained that the use of Vetom-3, a medicine based on Bacillus amyloliquefaciens RNCIM V-10642 (DSM 24614), for the treatment of subclinical mastitis in non-milking cows allows to increase the efficiency of the treatment, as well as receive the milk of high sanitary quality, increase the survival rate of the newborn calves, and prevent dysbacteriosis and dyspepsy incidence in newborn calves.

Survival Rate of Calves and Assessment Reproductive Performance of Heifers and Cows in Dida Tuyura Ranch, Borana Zone, Southern Ethiopia

Survival Rate of Calves and Assessment Reproductive Performance of Heifers and Cows in Dida Tuyura Ranch, Borana Zone, Southern Ethiopia

Position at Birth and Possible Effects on Calf Survival in Finless Porpoises (Neophocaena asiaeorientalis)

Odontocetes are usually reported giving birth to calves in breech position (fluke-first). Cephalic position (head-first) is less frequently observed and, therefore, is considered to be abnormal for the parturition. However, the influence of the calf position at birth on the parturition process and calf survival has not been thoroughly studied. More information is needed to improve the captive breeding success of odontocetes-especially for endangered species such as finless porpoises (Neophocaena asiaeorientalis). In this study, we observed the labor of eight captive finless porpoises (N. asiaeorientalis asiaeorientalis and N. a. sunameri). The duration of parturition and the time of particular events in the parturition process were recorded for both breech and cephalic births. Cephalic births were shorter than breech births, and the calf position at birth did not seem to have a negative effect on its survival. The results presented herein could be used as recommendations to improve the management of future parturitions of captive finless porpoises by ensuring the safety of both cows and calves, potentially increasing the survival rate of calves. Better management of the parturition process could facilitate the improvement of the captive breeding success of these endangered species.

Selection of Calf Bedding Sites by Female Elk in the Central Appalachian Mountains

AbstractAcross eastern North America, Rocky Mountain elk Cervus canadensis nelsoni have been reintroduced to 11 states and provinces that were previously occupied by the extinct eastern elk C. canadensis canadensis. Outside of Kentucky, these elk reintroductions have resulted in small populations, typically numbering fewer than 1,000 elk per state. Limited information is available about the demographics and habitat selection within these small eastern populations. The availability of high-quality habitat during the first weeks of life is important for promoting annual recruitment and the identification of these characteristics should aid in management efforts. We characterized habitat at two spatial scales surrounding the bedding sites of 83 elk calves (≤ 7 d old) in the Pennsylvania Elk Management Area during the annual calving seasons of 2005–2008. A concurrent study found that calves in this area experienced high survival (92%) during the first 4 mo of life, despite occupying an area with high predator densities. At a local scale, bedding sites used by calves were closer to ecotones, had less leaf litter, and had greater density of vegetation below 1 m compared to random sites (n = 82). At a landscape scale, calf habitat surrounding bedding sites had greater density of edges between forest and open vegetation and less coniferous forest compared to random areas. The selected habitats appear to balance the high energetic needs of lactating females at the landscape scale and the need for cover to conceal calves and reduce predation risk at a local scale. Conclusions drawn from our models suggest future habitat management include enhancements of transitional vegetation along ecotones between forest and herbaceous openings that address the needs of both lactating females and recently born calves. We recommend that managers periodically evaluate the availability of calf habitat and calf survival rates. These monitoring activities will provide insight necessary to adaptively manage elk and the habitats driving their population growth to maintain their viability in the central Appalachian Mountains.