Study protocol for a multicenter prospective controlled and randomized trial of transanal total mesorectal excision versus laparoscopic low anterior resection in rectal cancer.

PURPOSE: Compared with the open approach, laparoscopic total mesorectal excision (TME) achieves faster patient recovery, reduces morbidity rates, and shortens hospital stay. However, in laparoscopic low anterior resection (L-LAR), conversion to open surgery is required in almost 20% of cases. Transanal TME (Ta-TME) combined with laparoscopy, also called hybrid natural orifice transluminal endoscopic surgery (NOTES), is a less invasive procedure that can overcome some of the limitations of laparoscopic rectal surgery. In this study, we aim to determine whether Ta-TME has a lower rate of conversion to open surgery than L-LAR, and thus achieves faster patient recovery without altering the pathological, functional, or oncological results. The main objective is to compare the results for conversion to open surgery between Ta-TME and L-LAR. METHODS: Multicenter, prospective randomized controlled study of patients diagnosed with rectal adenocarcinoma who will be randomly allocated to Ta-TME or L-LAR groups after the application of inclusion and exclusion criteria. The main endpoint is conversion to open surgery and the secondary endpoints are general morbidity and mortality and hospital stay. Demographic, surgical, and pathological variables will also be studied, along with quality of life and survival. A sample size of 53 patients per group is calculated. With an estimated loss of 10%, the final sample required will be 116 patients. CONCLUSIONS: Ta-TME achieves a lower conversion rate to open surgery than L-LAR, thus improving patient recovery and reducing overall morbidity. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02550769. Registration no. Ethical and Clinical Research Committee, Parc Taulí University Hospital: ID 2014/064.

Production objectives, trait and breed preferences of farmers keeping N'Dama, Fulani Zebu and crossbred cattle and implications for breeding programs.

Many local livestock breeds in developing countries are being replaced by exotic breeds, leading to a loss of genetic resources. In southern Mali, for the past two decades, a trend towards increasing crossbreeding between the trypanotolerant N'Dama cattle and the trypano-susceptible Fulani Zebu cattle has been taking place. A survey with 160 farmers owning a cattle herd was carried out in southern Mali to investigate their production objectives, as well as trait and breed preferences and correlated socio-economic determinants in order to understand farmers' breeding decisions and to identify comparative advantages of three breed groups (N'Dama, Fulani Zebu and crossbreds) raised in the study area. Data were analyzed using an exploded logit model. The reasons for raising cattle, as well as trait and breed preferences reflected the multiple objectives of the farmers. Draught power and savings were the most important production objectives. Productive traits were ranked highest; farmers reported large body size as the most preferred trait, followed by fertility, draught ability and milk yield. Crossbreds were the favored breed group. Breed preferences were mainly explained by 'resistance to disease' for N'Dama cattle and 'high market price' for Fulani Zebu and crossbred cattle. Production objectives, trait and breed preferences were mainly influenced by farmer group (local farmers and settled transhumants). Local farmers put comparatively more emphasis on livestock functions linked to crop production such as draught power. They had a higher preference for traction ability as a selection trait and preferred N'Dama over Fulani Zebu cattle. Settled transhumants emphasized milk yield as a selection trait and preferred Fulani Zebu over N'Dama. The results indicate that the trend towards more crossbreeding will continue putting the N'Dama breed under high risk of genetic dilution in southern Mali. The N'Dama cattle remain a valuable breed due to their adaptive traits such as disease and drought tolerance and their good traction ability, fulfilling the diverse objectives of local farmers. Crossbreeding was found to be a promising breeding strategy, which might contribute to the maintenance of the local breed, provided that breeding schemes are thoroughly planned and organized.

Community-based livestock breeding programmes: essentials and examples.

Breeding programmes described as community-based (CBBP) typically relate to low-input systems with farmers having a common interest to improve and share their genetic resources. CBBPs are more frequent with keepers of small ruminants, in particular smallholders of local breeds, than with cattle, pigs or chickens with which farmers may have easier access to alternative programmes. Constraints that limit the adoption of conventional breeding technologies in low-input systems cover a range of organizational and technical aspects. The analysis of 8 CBBPs located in countries of Latin-America, Africa and Asia highlights the importance of bottom-up approaches and involvement of local institutions in the planning and implementation stages. The analysis also reveals a high dependence of these programmes on organizational, technical and financial support. Completely self-sustained CBBPs seem to be difficult to realize. There is a need to implement and document formal socio-economic evaluations of CBBPs to provide governments and other development agencies with the information necessary for creating sustainable CBBPs at larger scales.

Ovulation requires the activation on proestrus of M1 muscarinic receptors in the left ovary.

We analyzed the effects of chemically blocking type 1 muscarinic receptors (M1R) on either the left or right ovary on ovulation rate, number of ova shed and steroid hormones levels. M1R were unilaterally blocked in ovary with the M1R selective antagonist pirenzepine (PZP). PZP was delivered into the bursa ovarica of the left or right ovary of adult rats at 13:00 h on proestrus day. PZP treatment in the left but not in the right ovary blocked ovulation. PZP did not modify the number of ova shed, nor progesterone or 17ß-estradiol serum levels. The surge of luteinizing hormone levels was diminished while that of follicle-stimulating hormone did not change in animals treated with PZP in the left ovary. Interestingly, treatment with either synthetic luteinizing hormone-releasing hormone or human chorionic gonadotropin 1 h after PZP administration in the left ovary restored ovulation in both ovaries. The presence of M1R protein in the theca cells of the ovarian follicles as well as in cells of the corpus luteum was detected on proestrus day. These results suggest that M1R activation in the left ovary is required for pre-ovulatory gonadotropin-releasing hormone (GnRH) secretion and ovulation. Furthermore, these results also suggest that M1R in the left ovary might be regulating ovulation asymmetrically through a stimulatory neural signal relayed to the hypothalamus via the vagus nerve to induce the GnRH secretion which then triggers ovulation.

Osteocalcin, under-carboxylated osteocalcin and osteopontin are not associated with gestational diabetes mellitus but are inversely associated with leptin in non-diabetic women.

OBJECTIVE: To measure serum osteocalcin (OC), under-carboxylated osteocalcin (ucOC), osteopontin (OPN), and leptin in pregnant women with gestational diabetes mellitus (GDM) and in healthy pregnant women during pregnancy and after birth and relate these markers to glucose metabolism. METHODS: This was a prospective study including 60 women with GDM and 60 subjects with normal gestation who were evaluated at gestational week 30 and 6 weeks postpartum. Serum OC, ucOC, OPN, leptin, insulin and insulin resistance were evaluated during the study. RESULTS: Bone biomarkers and leptin were similar between GDM and normal pregnancy. After delivery, OC, ucOC and OPN increased in both groups, while leptin decreased only in healthy controls. Bone markers did not correlate with insulin and insulin resistance in the two groups, but leptin was positively correlated with insulin and insulin resistance and negatively correlated with bone biomarkers only in healthy women. Furthermore, the women who developed diabetes postpartum had lower levels of OC than women with normal glucose tolerance. CONCLUSION: GDM is not associated with OC, ucOC, OPN, and leptin and does not correlate with insulin resistance. At postpartum, women who develop diabetes have lower osteocalcin concentrations. Leptin correlates with insulin resistance and bone biomarkers in non-diabetic women.

[Clinical relevance of the K-ras oncogene in colorectal cancer: experience in a Mexican population]. / Relevancia clínica del oncogén K-ras en cáncer de colon, experiencia en una población mexicana.

BACKGROUND: Colorectal cancer is frequent in the developed countries, with a cancer-specific mortality rate of 33%. Different biomarkers are associated with overall survival and the prediction of monoclonal treatment effectiveness. The presence of mutations in the K-ras oncogene alters the response to target therapy with cetuximab and could be an independent prognostic factor. AIMS: To analyze the difference in survival between patients with mutated K-ras and those with K-ras wild-type status. METHODS: Thirty-one clinical records were retrospectively analyzed of patients presenting with colorectal cancer that underwent K-ras sequencing through real-time polymerase chain reaction within the time frame of 2009 to 2012 at the Hospital de Alta Especialidad de Veracruz of the Instituto para la Salud y Seguridad Social de los Trabajadores del Estado (HAEV-ISSSTE). Survival analysis for patients with and without K-ras mutation was performed using the Kaplan Meier method. Contrast of covariates was performed using logarithmic transformations. RESULTS: No statistically significant difference was found in relation to survival in the patients with mutated K-ras vs. those with K-ras wild-type (P=.416), nor were significant differences found when analyzing the covariants and survival in the patients with mutated K-ras: ECOG scale (P=.221); age (less than, equal to or greater than 65years, P=.441); clinical stage according to the AJCC (P=.057), and primary lesion site (P=.614). CONCLUSIONS: No relation was found between the K-ras oncogene mutation and reduced survival, in contrast to what has been established in the international medical literature. Further studies that include both a larger number of patients and those receiving monoclonal treatment, need to be conducted. There were only 5 patients in the present study that received cetuximab, resulting in a misleading analysis.

Breeding programmes for smallholder sheep farming systems: II. Optimization of cooperative village breeding schemes.

A simulation study was conducted to optimize a cooperative village-based sheep breeding scheme for Menz sheep of Ethiopia. Genetic gains and profits were estimated under nine levels of farmers' participation and three scenarios of controlled breeding achieved in the breeding programme, as well as under three cooperative flock sizes, ewe to ram mating ratios and durations of ram use for breeding. Under fully controlled breeding, that is, when there is no gene flow between participating (P) and non-participating (NP) flocks, profits ranged from Birr 36.9 at 90% of participation to Birr 21.3 at 10% of participation. However, genetic progress was not affected adversely. When there was gene flow from the NP to P flocks, profits declined from Birr 28.6 to Birr -3.7 as participation declined from 90 to 10%. Under the two-way gene flow model (i.e. when P and NP flocks are herded mixed in communal grazing areas), NP flocks benefited from the genetic gain achieved in the P flocks, but the benefits declined sharply when participation declined beyond 60%. Our results indicate that a cooperative breeding group can be established with as low as 600 breeding ewes mated at a ratio of 45 ewes to one ram, and the rams being used for breeding for a period of two years. This study showed that farmer cooperation is crucial to effect genetic improvement under smallholder low-input sheep farming systems.

Breeding programs for smallholder sheep farming systems: I. Evaluation of alternative designs of breeding schemes.

Village- and central nucleus-based schemes were simulated and evaluated for their relative bio-economic efficiencies, using Ethiopia's Menz sheep as example. The schemes were: village-based 2-tier (Scheme-1) and 1-tier (Scheme-2) cooperative village breeding schemes, dispersed village-based nuclei scheme (Scheme-3), conventional 2-tier central nucleus-based scheme (Scheme-4), and schemes linking a central nucleus and village multiplier nuclei with selection in central nucleus (Scheme-5) or in both central and village nuclei (Scheme-6). Among village-based schemes, Scheme-1 gave the highest genetic progress, while Scheme-2 was economically the most efficient with genetic gain in the breeding objective of Birr 5.6 and a profit of Birr 37.2/ewe/year. The central nucleus schemes were more efficient than the village schemes. Scheme-4 was the most efficient with genetic gain in the breeding objective of Birr 13.5 and a profit of Birr 71.2, but is operationally more difficult as it requires a very large central nucleus. The choice between village and central nucleus-based schemes would depend on local conditions (availability of infrastructure, logistics and technical knowhow and support). Linking central nucleus with village-based nuclei (Scheme-6) would be a feasible option to overcome the operational difficulties of the conventional central nucleus scheme. If a village-based breeding program is envisaged as should be the 1st step in most low-input systems, then Scheme-2 is the most efficient. To scale out to an entire Menz breed level, Scheme-3 would be recommended.

Efficiency of selection for body weight in a cooperative village breeding program of Menz sheep under smallholder farming system.

We evaluated the efficiency of selection for body weight in a cooperative village breeding program for Menz sheep of Ethiopia under smallholder farming system. The design of the program involved organizing villagers in a cooperative breeding group to implement selective breeding of their sheep. The program was jump-started through a one-time provision of elite rams from a central nucleus flock, but subsequent replacement rams were selected from within the village flocks. We also evaluated body weight trends in a village where cooperative breeding was not implemented and individual farmers managed their flocks under traditional breeding practices. Under traditional breeding practices, genetic progress over 8 years either stagnated or declined in all the weights recorded. In the cooperative villages, selection differentials of 2.44 and 2.45 kg were achieved in 2010 and 2011 selection seasons, respectively. Birth weight, 3-month weight and 6-month weight increased, respectively, by 0.49, 2.29 and 2.46 kg in the third-generation lambs over the base generation. Improved rams supplied from the central nucleus flock gave an initial genetic lift of 14.4% in the 6-month weight. This was higher than the gain achieved from selection in the village flocks, which was 5.2%. Our results showed that village-based genetic improvement in body weights under smallholder conditions could be feasible if appropriate designs are adopted and that commencing with elite central nucleus rams help jump-start village-based programs.

Risk genes in head and neck cancer: a systematic review and meta-analysis of last 5 years.

The aim of this work was to identify risk genes related to the development and progression of squamous cell carcinoma head and neck (SCCHN) and do a meta-analysis of available estimates. Eligible gene/polymorphism studies were identified by electronic searches. Individual participant data of 8540 patients with HNC and 9844 controls from 19 genetic studies were analyzed, yielding adjusted (tobacco, gender, age and alcohol) odds ratios (OR) and 95% confidence intervals (CIs) comparing cases with controls. A meta-analysis was done on the studies that applied fixed and random models. People have an increase of polymorphism expression related to inflammation (NFKB1-294-ATTG, TNFα308-A2A2/A2A1, and TNFß252- B2B2/B2B1) or carcinogenic metabolism (GSTM1 null, and CYP1A1 m1/m1), representative of malignancy development. Furthermore, the increased expression of genes associated with the stabilization and repair of the cellular (OGG1-Asp267Asn, Ser279Gly Ile253Phe, 1578A>T, 1582C>T Ala399Glu (1542C>A) 1582insG 1543_1544delCT), and genes associated with the regulation of proliferation, apoptosis or tumor survival (miRNA499-CT/CC, CRYABC802G-CG/GG) are considered as risk factors. In this scheme, only the polymorphisms of ADH7A92G-GG and DEC1606-T/C genes are protective against malignancy transformation. The TP53, GSTM1 and CYPA1genes have been evaluated in more than one study and analyzed for homogeneity in each genotype. The meta-analysis showed no significant association between different allelic variants of Arg72Pro rs1042522 and SCCHN risk. In a model of tumorigenesis, an increased risk of SCCHN is associated with DNA repair and DNA stabilization genes. In addition, the polymorphisms involved in inflammation and carcinogenic metabolism processes represent an increased risk of SCCHN.

Increasing crude and adjusted mortality rates for colorectal cancer in a developing South American country.

AIM: Colorectal cancer (CRC) is a major cause of cancer death worldwide. We examined temporal trends in death rates from colorectal cancer in Chile from 1983 to 2008. METHOD: We analysed the mortality database in Chile from 1983 to 2008. Cases were selected using ICD-9/10 codes. We calculated mortality rates per 100,000 inhabitants according to sex, age group and type of cancer - colon (CC) or rectal (RC). The rates were adjusted by a direct method using the WHO-2000 standard population. Time trends were assessed with Prais-Winsten regression models. RESULTS: There were 26,250 deaths from CRC (75.7% for CC). There was a higher frequency of deaths from CC (57.6%) in women than in men, who had a higher frequency of deaths from RC (51.3%). The crude CC mortality rate increased by 116% (from 3.6 to 7.8), while the overall RC rate increased by 71% (from 1.4 to 2.4). After adjusting for age, a significant increase in mortality rate was found for CC (coefficient 0.09, 95% CI 0.08-0.11, P < 0.001) and RC (coefficient 0.02, 95% CI 0.009-0.04, P = 0.002) in men. In women, this increase was significant for CC (coefficient 0.03, 95% CI 0.005-0.05; P = 0.02), but not for RC (coefficient -0.007, 95% CI -0.02 to 0.005, P = 0.23). CONCLUSION: The crude mortality rate from CRC has doubled in Chile in this period. After adjustment of mortality rates, it appears that much of this increase is due to the aging population. However, part of this increase could be explained by other factors.

New treatment for faecal incontinence using zinc-aluminium ointment: a double-blind randomized trial.

AIM: In a randomized double-blind study the therapeutic effect of a novel zinc-aluminium ointment was compared with placebo in patients with faecal incontinence. METHOD: A randomized double-blind trial was performed. Patients who met the inclusion criteria were randomized to receive the ointment or a placebo. All were evaluated prior to and 3 weeks after ointment application, using the Wexner incontinence score and the Fecal Incontinence Quality of Life (FIQL) score. RESULTS: Fifty patients were randomized and six were lost to follow-up, leaving 24 in the treatment and 20 in the placebo group. The average ages were 61.3 and 60.7 years. The respective Wexner scores prior to intervention were 16.6 and 16.7. They decreased significantly after treatment to 8.5 and 13.1 (P<0.001 and P=0.002 respectively). There was a significant difference in the final scores, favouring the treatment group (P=0.001). The FIQL scores for the treatment group were also significantly better in all parameters compared with those of the placebo group. CONCLUSION: The study shows that the zinc-aluminium based ointment decreases faecal incontinence significantly compared with placebo.

Genetic and economic evaluation of a basic breeding programme for Kenya Boran cattle.

The objective of this study is to describe the present organisational structure of Boran cattle breeding and develop a model breeding programme using a deterministic approach under the current structure of the Boran Cattle Breeders Society. A breeding unit of 13,000 cows supplying bulls to a commercial population of 39,000 cows was assumed. Selection criteria used were growth and reproduction traits while breeding objective traits targeted were growth, carcass, reproduction, survival, milk yield and feed intake traits. Higher selection intensity was possible for breeding sires resulting in higher genetic gains compared to dams even though selection accuracies were generally low. Annual genetic gains were positive except for dressing percentage, cow survival rate, and age at first calving. However, a reduction of age at first calving by 9.5 days obtained a return of Ksh 49.76. The overall monetary genetic gain obtained was Ksh 84.89 with a profit per cow per year of Ksh 377.98. The basic breeding programme could be expanded to accommodate a larger population of Boran cattle. The implications of the results are also discussed.

Prevalence of mastitis and brucellosis in cattle in Awassa and the peri-urban areas of two smaller towns.

The prevalence of mastitis and brucellosis in urban and peri-urban settings was studied in Awassa and two smaller nearby towns in southern Ethiopia, because milk-born diseases are causing a risk for human health, besides direct impacts on animal production. Mastitis was investigated by examining 80 cows (320 udder quarters) using California mastitis test (CMT) and somatic cell count (SCC). The prevalence of brucellosis was assessed by sampling 177 cattle in Awassa and its peri-urban areas using serological methods. Logistic regression was used to analyse risk factors associated with mastitis. Prevalence of clinical mastitis on quarter level was 0.9%, and 1.9% of quarters were non-functional or blocked. Prevalence of sub-clinical mastitis at quarter level in urban and peri-urban areas was significantly different (P < 0.05). Cows in large herds and at advanced lactation number were associated with higher risk of infection. The percentage of quarters positive on CMT (42.5%) was close to the percentage-positive detected by SCC (41.2%). Prevalence of brucellosis was 3.9% in the peri-urban area, while no brucellosis cases were detected in Awassa. More frequent use of artificial insemination in the urban than in peri-urban area might have contributed to the absence of brucellosis in the urban location. The extent of mastitis is, however, a threat to the dairy enterprise in and around Awassa. Pasteurization of milk and milk products is indicated in some parts of the area because of the danger of brucellosis.

Traditional llama husbandry and breeding management in the Ayopaya region, Bolivia.

The llama claims the largest population of the domestic South American camelids, most of which are raised in Bolivia. More than 53,000 rural families are dedicated to llama husbandry as part of their livelihood strategy. Contemporary Andean societies deliberately select animals for specific traits and employ substantial livestock management to secure subsistence. This study presents traditional llama husbandry and breeding management activities in the Ayopaya region, Bolivia. Traditional selection traits for male and female llamas are documented and assessed by a ranking and a ratio-scaled evaluation. Husbandry and management parameters are in concordance with other studies conducted in the region, but show a high variation. Average llama herd sizes are rather small (mu = 45.6). In some herds, breeding males are utilized for a long time and mix with other herds, causing concerns about inbreeding. Preferred trait groups for llama males according to farmers' responses were body conformation, fibre, testicle conformation, fleece colour and height at withers. Traditional selection criteria generally relate to the phenotype, but also include the commercially interesting fibre trait. The presented results should be considered in breeding and management programmes for the respective llama population to ensure sustainable use of this genetically and culturally valuable resource.

Are topical oestrogens useful in faecal incontinence? Double-blind randomized trial.

BACKGROUND: Histopathological studies have shown the presence of oestrogenic receptors in the anal sphincter, which presumes a role in muscular trophism for circulating oestrogens. This could explain the increase in faecal incontinence (FI) in postmenopausal women. OBJECTIVE: To evaluate the effect of topical oestrogens (TE) in controlling symptoms of FI in postmenopausal women. Hypothesis The application of TE in postmenopausal women with FI improves continence. METHOD: We performed a prospective double-blind randomized trial applying TE to the anal mucosa in postmenopausal women with FI. STUDY PERIOD: 2005-2006. The patients were randomized into two groups: I--topical estriol, II--placebo. In both groups, the ointment was applied three times daily for a period of 6 weeks. We compared Wexner's FI score and the FI quality of life scale, before commencing and after 6 weeks of application. RESULTS: In this period we evaluated 36 patients. Average age: 67 years (48-84). Group I: 18 patients and group II: 18 patients, one patient was excluded. Wexner's FI score in group I was 11 (5-18) and 7 (0-19) with pre- and postapplication respectively (P = 0.002). Wexner's FI score in group II was 12 and 9 with pre- and postapplication respectively (P = 0.013). When we compared the results between both groups, this was not statistically significant (P = 0.521). CONCLUSION: There is improvement of continence in both groups that had the ointment applied; nonetheless this study could not show that TE improves FI more than a placebo does.

Effects of the genetically reduced feather coverage in naked neck and featherless broilers on their performance under hot conditions.

Under hot conditions, contemporary commercial broilers do not reach their full genetic potential for growth rate, body weight (BW), or breast meat yield because dissipation of their excessively produced internal (metabolic) heat is hindered by the feathers. Therefore, it was hypothesized that heat stress can be alleviated by using the naked-neck gene (Na) or the featherless gene (sc). The study consisted of 4 experimental genetic groups (fully feathered, heterozygous naked neck, homozygous naked neck, featherless), progeny of the same double-heterozygous parents (Na/na +/sc), and commercial broilers. Birds from all 5 groups were brooded together until d 21 when one-half of the birds from each group were moved to hot conditions (constant 35 degrees C), and the others remained under comfortable conditions (constant 25 degrees C). Individual BW was recorded from hatch to slaughter at d 45 and 52 at 25 and 35 degrees C, respectively, when breast meat, rear part, heart, and spleen weights were recorded. Body temperature was recorded weekly from d 14 to 42. Feather coverage significantly affected the thermoregulatory capacity of the broilers under hot conditions. With reduced feather coverage (naked-neck), and more so without any feathers (featherless), the birds at 35 degrees C were able to minimize the elevation in body temperature. Consequently, only the featherless birds exhibited similar growth and BW under the 2 temperature treatments. The naked-neck birds at 35 degrees C showed only a marginal advantage over their fully feathered counterparts, indicating that 20 to 40% reduction in feather coverage provided only limited tolerance to the heat stress imposed by hot conditions. Breast meat yield of the featherless birds was much greater (3.5% of BW, approximately 25% advantage) than that of their partly feathered and fully feathered counterparts and the commercial birds under hot conditions. The high breast meat yield (at both 25 and 35 degrees C) of the featherless broilers suggests that the saved feather-building nutrients and greater oxygen-carrying capacity contribute to their greater breast meat yield. Because of these results, further research on genetically heat-tolerant broilers should focus on the featherless phenotype.

Design of a village breeding programme for a llama population in the High Andes of Bolivia.

No national breeding programme for llamas is in place in Bolivia. Initiatives for genetic improvement are rarely found and are usually carried out by NGOs working in rural development or improvement of livestock production or research stations. Farmers in the Province of Ayopaya in the District of Cochabamba have formed a breeders' organization with the aim of improving fibre production. In this study, a detailed outline of a breeding programme with a focus on organizational and technical details is described. Facing constraints like illiteracy of farmers, bad infrastructure and lack of finances, a simple breeding programme is set up. The breeding goal is a higher fleece weight while keeping the fleece quality at the current high level. Greasy fleece weight and fibre diameter are identified as main selection criteria. Mass selection of males is carried out. Selected males are either exchanged between farmers and used in the herds or are kept during the mating season in a central mating station owned by the breeders' organization. Model calculations were carried out with the program zplan, which is based on a deterministic approach. zplan evaluates the genetic and economic efficiency of breeding strategies considering one cycle of selection. Scenarios with only intra-herd use, using only the central mating station or combinations of those were compared in terms of expected genetic gain and expected increase of inbreeding. Fastest genetic progress is achieved when the males are kept in a central mating station as the selection intensity is on a high level. Rates of inbreeding vary between 0.08 and 0.32% per generation.

Evaluation of biological and economic efficiency of smallholder pig production systems in North Vietnam.

This study evaluates smallholder pig production systems in North Vietnam, comparing a semi-intensive system near a town with good market access, where a Vietnamese improved breed has replaced the indigenous pig breed, and an extensive system away from town, where the indigenous breed still prevails. Fieldwork was conducted in 64 households in four villages. Repeated farm visits yielded 234 structured interviews. Data were analysed by linear models and non-parametric tests. Production inputs and outputs were quantified, and feed use efficiency and economic efficiency were assessed. The gross margin was higher for semi-intensive production with the improved breed, while the benefit-cost ratio was higher under extensive conditions with the indigenous breed. The net benefit did not differ between systems. Twenty-four per cent of farmers yielded a negative net benefit. In one village under extensive conditions, live weight output from indigenous sows with crossbred offspring compared positively with the output from semi-intensive production with improved genotypes, but was associated with high inputs, making production inefficient. Results indicate that improved genotypes might not be an efficient production alternative for saving-oriented production with limited resource supply. Suitability of evaluation parameters, farmers' production aims, and factors impacting the production success in different systems are discussed.