Relationship of ruminal temperature with parturition and estrus of beef cows

Spring-calving Angus cows (n = 30) were used to evaluate changes in ruminal temperature (RuT) related to parturition and estrus. Cows were synchronized and artificially inseminated with semen from a single sire. Temperature boluses were placed in the rumen at 7.0 ± 0.2 mo of gestation. Boluses were programmed to transmit RuT every 15 min. Cows (BW = 623 ± 44 kg, BCS = 4.9 ± 0.4) calved during 3 wk, and estrus was synchronized at 77 ± 7 d after calving with PGF(2α). Cows were observed every 12 h to detect estrus. Daily average ambient temperatures ranged from 2 to 22 °C during parturition (February to March) and 17 to 25 °C during estrus (May to June). Ruminal temperature from 7 d before to 3 d after parturition and 2 d before to 2 d after visual detection of estrus was analyzed using the MIXED procedure. Ruminal temperatures <37.72 °C were attributed to water consumption and excluded from analyses. Day did not influence (P = 0.36) RuT from d -2 to -7 before parturition (38.94 ± 0.05 °C). Ruminal temperature decreased (P < 0.001) from d -2 to d -1 before parturition (38.88 ± 0.05 to 38.55 ± 0.05 °C, respectively). Ruminal temperature was not influenced (P = 0.23) by day from 1 d before to 3 d after parturition (38.49 ± 0.05 °C). Ruminal temperature at 0 to 8 h after detection of estrus (38.98 ± 0.09 °C) was greater (P < 0.001) compared with RuT at the same daily hour of the day before (38.37 ± 0.11 °C) or the day after estrus (38.30 ± 0.09 °C). Ambient temperature did not influence (P > 0.30) RuT at parturition or estrus. Ruminal temperature decreased the day before parturition and increased at estrus in spring-calving beef cows and has potential use as a predictor of parturition and estrus.     

Immunoadjuvant activities of a recombinant chicken IL-12 in chickens vaccinated with Newcastle disease virus recombinant HN protein

Recombinant fowlpox virus (rFPV/HN) expressing Newcastle disease virus (NDV) HN gene and rFPV/HN/chIL-12 co-expressing chicken IL-12 (chIL-12) and HN (rHN/chIL-12) genes have been characterized. rHN/chIL-12 or rchIL-12, expressed by our previous construct rFPV/chIL-12, co-administered with rHN was assessed for adjuvant activities of chIL-12. Chickens were vaccinated with various amounts of rHN/chIL-12 mixed with mineral oil (MO), intramuscularly. Levels of hemagglutination-inhibition (HI) antibody production depended on the concentration of the injected rHN or rHN/chIL-12. The lower HI antibody titers were obtained in chicken groups rHN/chIL-12/7-rHN/chIL-12/9, receiving 60ng rHN/8ng chIL-12 with MO, 30ng rHN/4ng chIL-12 with MO or 15ng rHN/2ng chIL-12 with MO, respectively, compared to those in chicken groups rHN/7-rHN/9, receiving rHN with MO alone. However, chickens in group rHN/chIL-12/7 or rHN/chIL-12/8 and rHN with MO alone showed the same effective protection. Chicken group rHN/chIL-12/9 was even more protective than that in group rHN/9. When rchIL-12 was co-injected with 15ng rHN plus MO, chickens produced low levels of HI antibody titers; while higher levels of IFN-γ production and an effective protection rate (83%) were obtained. On the other hand, low levels of IFN-γ production and low protection response (50%) were obtained in chickens injected with rHN with MO alone. Taken together, when the concentration of rHN decreased to certain levels, rchIL-12 reduced HI antibody production. The increase in the induction of IFN-γ production might suggest the enhancement of the cell-mediated immunity which conferred the protection from the NDV challenge.     

Effect of Supplementing Alfalfa Powder to Diet on Growth Performance and Meat Quality of Goose

The experiment was aimed to investigate the effects of dietary alfalfa powder on the growth performance,body size,slaughter performance,organ index and meat quality of Siji geese.A total of 256 15-day-old geese (half male and half female) with similar body weight were randomly divided into four groups with 4 replicates of 16 geese each.The geese in control group were fed with corn-soybean meal-based diet (control diet),and geese in the experimental groups were fed the basal diet replaced with 10%,20% and 30% alfalfa powder,respectively.The results showed that,compared with the control group,dietary alfalfa powder supplementation had no significant effect on the average daily intake,average daily gain,feed conversion ratio,body oblique length,keel length,shin circumference,semi diving length,chest width and shin length (P>0.05),and also had no effect on the carcass ratio,half-eviscerated carcass ratio and pectoral muscle ratio (P>0.05).However,dietary 20% and 30% alfalfa powder supplementation significantly increased the chest depth (P<0.05),dietary 30% alfalfa powder significantly decreased the full-eviscerated carcass ratio (P<0.05),and dietary 10% alfalfa powder significantly increased the leg muscle ratio (P<0.05) of geese.In addition,dietary alfalfa powder significantly decreased the abdominal fat ratio (P<0.05),raised the growth index of liver,jejunum,ileum,and cecum (P<0.05),and increased the water loss rate of pectoral muscle and leg muscle (P<0.05) compared with the control group.Dietary 10% and 30% alfalfa powder significantly increased duodenal growth index (P<0.05) of geese.In conclusion,dietary alfalfa powder supplementation might improve the slaughter performance (increase chest depth and leg muscle ratio,reduce abdominal fat rate) and organ growth index (increase the growth index of liver,duodenum,jejunum,ileum and cecum).However,dietary alfalfa powder increased water loss rates in pectoral muscle and leg muscle,and 30% alfalfa powder reduced the full-eviscerated carcass ratio of geese.The appropriate supplementation level of alfalfa powder was recommended at 10% in the present study.     

Safety of an attenuated West Nile virus vaccine, live Flavivirus chimera in horses

REASON FOR PERFORMING STUDY: West Nile virus (WNV) infection is endemic and able to cause disease in naive hosts. It is necessary therefore to evaluate the safety of new vaccines. OBJECTIVES: To establish: 1) the safety of a modified live Flavivirus/West Nile virus (WN-FV) chimera by administration of an overdose and testing for shed of vaccine virus and spread to uninoculated sentinel horses; 2) that this vaccine did not become pathogenic once passaged in horses; and 3) vaccine safety under field conditions. METHODS: There were 3 protocols: 1) In the overdose/shed and spread study, horses were vaccinated with a 100x immunogenicity overdose of WN-FV chimera vaccine and housed with sentinel horses. 2) A reversion to virulence study, where horses were vaccinated with a 20x immunogenicity overdose of WN-FV chimera vaccine. Horses in both studies were evaluated for abnormal health conditions and samples obtained to detect virus, seroconversion and dissemination into tissues. 3) In a field safety test 919 healthy horses of various ages, breeds and sex were used. RESULTS: Vaccination did not result in site or systemic reactions in either experimental or field-injected horses. There was no shed of vaccine virus, no detection of vaccine virus into tissue and no reversion to virulence with passage. CONCLUSIONS: WN-FV chimera vaccine is safe to use in horses with no evidence of ill effects from very high doses of vaccine. There was no evidence of reversion to virulence. In addition, administration of this vaccine to several hundred horses that may have been previously exposed to WNV or WNV vaccine resulted in no untoward reactions. POTENTIAL RELEVANCE: These studies establish that this live attenuated Flavivirus chimera is safe to use for immunoprophylaxis against WNV disease in horses.     

A comprehensive framework of forest stand property–density relationships: perspectives for plant population ecology and forest management

? Context

There are many stand property–density relationships in ecology which represent emergent properties of plant populations. Examples include self-thinning, competition–density effect, constant final yield, and age-related decline in stand growth. We suggest that these relationships are different aspects of a general framework of stand property–density relationships.

? Aims

We aim to illustrate the generalities and ecological implications of stand property–density relationships, and organize them in a comprehensive framework.

? Methods

We illustrate relationships between stand property and density (1) at one point in time, (2) over time, and (3) independent of time. We review the consequences of considering different variables to characterize stand property (mean tree size, mean tree growth, stand growth, stand yield, stand leaf area).

? Results

We provide a framework that integrates the broad categories of stand property–density relationships and individual expressions of these relationships. For example, we conclude that constant final yield is a special case of the growth–growing stock relationship for life forms were yield is a reasonable approximation of growth (non-woody plants).

? Conclusion

There is support in the literature for leaf area being broadly integrative with respect to various expressions of stand property–density relationships. We show how this is and suggest implications for plant population ecology and forest management.     

沙颍河周口段水质生物学检测及评价

对沙颍河周口段水质进行检测,包括微生物学检测、叶绿素a测定等,结合理化检测对其水质做出初步评价.结果表明大闸上游段水质为β-中污带,贫营养型;胜利桥段水质为α-中污带,中营养型;地区医院段水质为多污带,属富营养型.     

Lactation persistency: insights from mammary cell proliferation studies

A persistent lactation is dependent on maintaining the number and activity of milk secreting cells with advancing lactation. When dairy cows are milked twice daily, the increase in milk yield from parturition to peak lactation is due to increased secretory activity per cell rather than to accretion of additional epithelial cells. After peak lactation, declining milk yield is due to loss of mammary epithelial cells by apoptosis. During lactation, only 0.3% of mammary cells proliferate in a 24-h period. Yet this proliferative rate is sufficient to replace most mammary epithelial cells by the end of lactation. Management practices can influence lactation persistency. Administration of bovine somatotropin may enhance persistency by increasing cell proliferation and turnover, or by reducing the rate of apoptosis. Increased photoperiod may also increase persistency of lactation by mechanisms that are as yet undefined. Increased milking frequency during the first weeks of lactation increases milk yield, even after return to less frequent milking, with increases of approximately 8% over the entire lactation. A mammary cell proliferation response to frequent milking during early lactation appears to be involved. Conversely, advanced pregnancy, infrequent milking, and mastitis increase death of epithelial cells by apoptosis. Regulation of mammary cell renewal provides a key to increasing persistency. Investigations to characterize epithelial cells that serve as the proliferative population in the bovine mammary gland have been initiated. Epithelial cells that stain lightly in histological sections are evident through all phases of mammary development and secretion and account for nearly all proliferation in the prepubertal gland. Characterization of these cells may provide a means to regulate mammary cell proliferation and thus to enhance persistency, reduce the effects of mastitis, and decrease the necessity for a dry period.     

Genetic parameters for various random regression models to describe total sperm cells per ejaculate over the reproductive lifetime of boars

The objective of this study was to model the variances and covariances of total sperm cells per ejaculate (TSC) over the reproductive lifetime of AI boars. Data from boars (n = 834) selected for AI were provided by Smithfield Premium Genetics. The total numbers of records and animals were 19,629 and 1,736, respectively. Parameters were estimated for TSC by age of boar classification with a random regression model using the Simplex method and DxMRR procedures. The model included breed, collector, and year-season as fixed effects. Random effects were additive genetic, permanent environmental effect of boar, and residual. Observations were removed when the number of data at a given age of boar classification was < 10 records. Preliminary evaluations showed the best fit with fifth-order polynomials, indicating that the best model would have fifth-order fixed regression and fifth-order random regressions for animal and permanent environmental effects. Random regression models were fitted to evaluate all combinations of first- through seventh-order polynomial covariance functions. Goodness of fit for the models was tested using Akaike's Information Criterion and the Schwarz Criterion. The maximum log likelihood value was observed for sixth-, fifth-, and seventh-order polynomials for fixed, additive genetic, and permanent environmental effects, respectively. However, the best fit as determined by Akaike's Information Criterion and the Schwarz Criterion was by fitting sixth-, fourth-, and seventh-order polynomials; and fourth-, second-, and seventh-order polynomials for fixed, additive genetic, and permanent environmental effects, respectively. Heritability estimates for TSC ranged from 0.27 to 0.48 across age of boar classifications. In addition, heritability for TSC tended to increase with age of boar classification.