Physical and mathematical modeling of cleaning fibrous material from coarse-grained litter

The article provides a recommended scheme and principle of operation of the cleaner of fibrous material from large litter. The results of theoretical studies to determine the laws of motion and the recommended parameters of the working bodies of the cleaning machine are presented. The results of comparative production tests of a fibrous material cleaner from large litter are given. Substantiated the receipt of parameters and modes of operation of the working bodies of the cleaner of fibrous material, in particular cotton.

Differences in gene expression and variable splicing events of ovaries between large and small litter size in Chinese Xiang pigs

Background Although lots of quantitative trait loci (QTLs) and genes present roles in litter size of some breeds, the information might not make it clear for the huge diversity of reproductive capability in pig breeds. To elucidate the inherent mechanisms of heterogeneity of reproductive capability in litter size of Xiang pig, we performed transcriptome analysis for the expression profile in ovaries using RNA-seq method. Results We identified 1,419 up-regulated and 1,376 down-regulated genes in Xiang pigs with large litter size. Among them, 1,010 differentially expressed genes (DEGs) were differently spliced between two groups with large or small litter sizes. Based on GO and KEGG analysis, numerous members of genes were gathered in ovarian steroidogenesis, steroid biosynthesis, oocyte maturation and reproduction processes. Conclusions Combined with gene biological function, twelve genes were found out that might be related with the reproductive capability of Xiang pig, of which, eleven genes were recognized as hub genes. These genes may play a role in promoting litter size by elevating steroid and peptide hormones supply through the ovary and facilitating the processes of ovulation and in vivo fertilization.

Theoretical study of the grate-saw-type large-litter cleaner of the mounted type

This paper reports a theoretical study into the saw-type-grate section of a large litter cleaner in mounted cleaners that operate on a cotton harvester, as well as the theoretical and experimental justifications for its parameters. The effect exerted by a mounted cleaner on the process of cleaning raw cotton when processing in a cotton gin has been studied. A theoretical model of the impact of grates on weeds in cleaning processes has been developed. A condition for repelling the litter by grates and removing it from a cotton technological flow has been studied. The use of grates with a flat-shaped front edge allows for a steady reduction in the amount of damage in the raw cotton fiber, which improves the fiber quality and leads to a decrease in the number of defects and debris. The experimental and theoretical studies have produced evidence that enables the efficient operation of mounted-type cleaning machines in the cotton-cleaning industry. The movements of raw cotton as a viscoelastic body at the free impact of litter with the teeth of the saw against a stationary surface of the grate were investigated; the force schemes between the grates and saws were considered. The effect of a saw-type drum on the technological properties of raw cotton was investigated, namely on seed damage and the formation of the free fiber. A model of interaction between weed particles and grates was considered; the trajectories of the litter flight were shown in the function of the slope of the grate and the recovery factor. The issues of the relationship between the physical-mechanical properties of raw cotton, the elastic characteristics of raw cotton, and the impact force of cotton flies against the grate with a flat working face. Solving these issues could make it possible to determine the optimal structure of the raw cotton cleaning mechanisms, which would improve the effectiveness of cleaning raw cotton from weeds. Based on the identified functional links, it has become possible to construct new or improve existing structures of the saw-type grate section of mounted cleaners. Practical experience shows that the use of the designed structure in large litter cleaners of the mounted type produces a significant increase in the cleaning effect of the machine

Two mouse lines selected for large litter size display different lifetime fecundities

We recently described two outbred mouse lines that were selected for large litter size at first delivery. However, lifetime fecundity appears to be economically more important for the husbandry of many polytocous species for which mouse lines might serve as bona fide animal models (e.g., for pigs). In the present study, we compared the lifetime fecundities of two highly fertile mouse lines (FL1 and FL2: >20 offspring/litter at first delivery) with those of an unselected control line (ctrl) and two lines that were selected for high body weight (DU6) and high protein mass (DU6P) without selection pressure on fertility. We tested the hypothesis that selection for large litter size at first parturition would also increase lifetime fecundity in mice, and we observed very large differences between lines. Whereas FL1 and ctrl delivered up to 9 and 10 litters, none of the DU6 and DU6P females gave birth to more than 5 litters. In line with this observation, FL1 delivered the most pups per lifetime (85.7/female). FL2 females produced the largest average litter sizes (20.4 pups/litter) in the first four litters; however, they displayed a reduced number of litters. With the exception of ctrl, litter sizes declined from litter to litter. Repeated delivery of litters with high offspring numbers did not affect the general health of FL females. The presented data demonstrate that two biodiverse, highly fertile mouse lines selected for large litter size at first delivery show different lifetime reproductive fitness levels.

Фактори, що впливають на мертвонародження поросят у свиноматок великої білої породи

This study considers signs of a sow that affect the stillborn piglets number in the nest and the likelihood of stillbirth. The animals that were used for this study were kept on the pig farm of «Tavriys’ki svyni» LLC, located in the Skadovsky district (Kherson region, Ukraine). The experimental materials used for this study consisted of 100 animals from productive parent sows of the Large White pig. The reproductive indicators of each animal included in this study were evaluated. The total number of piglets at birth (both live and dead), i.e. total litter size and and sow farrowing number were monitored for the first eight farrows during the period of eleven years (2007–2017). Stillborn piglets were observed in 63.3 ± 1.7% of litter, and their average proportion in the nest was 11.5 ± 0.4%. The proportion of piglets born dead of the total piglets at birth obtained in this study is within the range of 5 to 15%, which has been previously noted for commercial pig farms in other countries. With an increase in the age of the sow (the number of farrowing’s), there was a gradual decrease in the proportion of the litter in which no stillborn piglet was observed (χ2 = 51.35; P < 0.001), and, conversely, the proportion of nests in which 2–4 stillborn piglets were recorded gradually increased (χ2 = 46.32; P < 0.001). The number of stillborn piglets and the frequency of stillborn piglets in the litter tended to increase in sows that had a large litter size at birth (in both cases: P < 0.001).The binary logistic regression analyses indicated that the probability of a piglet being stillborn was significantly associated with the farrowing number of the sow and the total number of piglets in the litter (χ2 = 155.00; P < 0.001). This model predicted well the presence of at least one stillborn piglet per litter (in 86.6% of cases) and more or less adequately predicted its absence (in 42.9%). Our results indicate that there is a significant interaction between the number of farrowing and the total size of the litter when determining the estimate of the proportion of stillborn piglets in the litter. The same predicted estimates can be obtained for a small litter in an older sow, or, conversely, for a large litter in a first-farrowing sow.

374 Early embryonic loss is an important mechanism for maximizing litter size in the pig

Litter size of commercial dam lines of pigs has seen a significant increase over the last 20 years. Although the current large litter size of gilts and sows can be attributed to improved genetic selection and nutrition, much of the increase in total number born has occurred through the continued increase in ovulation rate over the last four decades. Ovulation rate has increased from 14 in the 80’s to today’s average of 20–25 in commercial dam lines. However, high ovulation rate not only causes increased competition between embryos (uterine crowding), but the number of potential piglets born can out strip the number available teats. In addition, fetal crowding can reduce fetal growth and comprise health and survivability of lighter weight piglets at birth. Since there is usually minimal embryo loss observed up to blastocyst formation and hatching, the majority (20 to 30%) of embryonic loss occurs during Days 10 to 30 of gestation, which encompasses a critical period of conceptus development and differentiation, pregnancy recognition signaling, and onset of implantation. This period of early embryo loss is actually essential for establishing adequate uterine space to support fetal survival for a large litter. The period of rapid conceptus elongation on Day 12 of pregnancy provides a key “selection point” for regulating potential litter size in the pig. Establishing the fundamental roles of conceptus- and uterine-secreted factors is an essential step to develop strategies to increase placental and fetal growth to improve overall health and survivability of piglets before and after birth. During the peri-implantation period of pregnancy, porcine conceptuses produce interleukin-1B2, estrogens, prostaglandins and interferons. CRISPR/Cas9 genomic engineering technology has provided a direct method to evaluate the role of key pig conceptus genes. Loss-of-function studies have increased our understanding of the multiplicity of uterine/conceptus factors that are involved with maintenance of pregnancy.

High laboratory mouse pre-weaning mortality associated with litter overlap, advanced mother age, small and large litters

High and variable pre-weaning mortality is a persistent problem among the main mouse strains used in biomedical research. If a modest 15% mortality rate is assumed across all mouse strains used in the EU, approximately 1 million more pups must be produced yearly to compensate for those which die. A few environmental and social factors have been identified as affecting pup mortality, but optimizing these factors does not cease the problem. This study is the first large study to mine data records from 219,975 pups from two breeding facilities to determine the major risk factors associated with mouse pre-weaning mortality. It was hypothesized that litter overlap (i.e. the presence of older siblings in the cage when new pups are born), a recurrent social configuration in trio-housed mice, is associated with increased newborn mortality, along with high mother age, large litter size, as well as a high number and age of older siblings in the cage. The estimated probability of pup death was two to seven percentage points higher in cages with compared to those without litter overlap. Litter overlap was associated with an increase in percentage of litter losses of 19% and 103%, respectively, in the two breeding facilities. Increased number and age of older siblings, high mother age, small litter size (less than four pups born) and large litter size (over 11 pups born) were associated with increased probability of pup death. Results suggest that common social cage configurations at breeding facilities are dangerous for the survivability of young mouse pups. The underlying mechanisms and strategies to avoid these situations should be further investigated.

Perfection of Designs and Rationale of Parameters of Plastic Koloski Cleaning Cleaners

The article provides effective design schemes and the principle of operation of plastic grates on elastic supports in cotton cleaners for large litter. Based on experimental studies, the nature of the oscillatory movement of plastic grates was determined; the effect of parameters on the grate vibrations was studied. Fully factor experimental studies determined the optimal value of the parameters of the cotton cleaner from large litter

Still birth and mummification in swine-A review

Mummification is often noticed in pigs compared to other species due to large litter size. The agents responsible for the reproductive failure in sows may lead to a wide range of sequelae, including abortions, stillbirth, mummification, embryonic death. High prolificacy is associated with increased incidence of stillbirths and mummified fetuses. Plethoras of other foetal and maternal factors have been associated with incidence of still birth and mummification. Identification of those risk factors have been associated with stillbirth and mummified fetuses can helps in optimal herd reproductive efficiency