Vol. 8 No. 3 (2025): Vietnam Journal of Agricultural Sciences

This study aimed to find the best model to describe the growth of Tien Yen female chickens and predict their live weight, weight gain, and suitable slaughter age. The body weights of 180 female chickens were measured every week from birth to 24 weeks of age. The chickens of the control group were fed a diet lower in protein and fiber. The chickens of the treatment group were fed a diet higher in protein and fiber. The data for growth performance were analyzed in R using six mathematical functions (von Bertalanffy, Janoschek, Gompertz, Logistic, Lopez, and Richards). The best models to describe the growth of Tien Yen females were Janoschek for the control group and Richards for the treatment group. The maximum absolute weekly gains occurred at 10 and 11 weeks of age (at the reflection point of the growth curves) and the maximum average weekly gains were obtained at 13.39 and 14.62 weeks of age for the control group and treatment group, respectively. Under the current local market conditions, the estimated economically optimal slaughter ages were 14.33 weeks (1,392.89g) for the control group and 15.17 weeks (1,565.23g) for the treatment group.

The effects of conventional cage and cage-free systems on the welfare quality of laying hens have been assessed recently, but with conflicting results. This study aimed to identify the welfare issues of laying hens when kept in a battery cage or deep litter system. In the cage system, white hybrid hens were kept in three cage lines, with three hens per cage and two tiers per line. In the deep litter system, hens were equally allocated to three compartments of a barn. A total of 450 hens were randomly chosen from different locations of barn and cages for scoring by one assessor at 5% of laying, peak period, and end of laying with several main health and social behavior parameters according to Welfare Quality (2009). The logistic analysis was applied using a proportional odds model to compare the prevalence of each welfare measure between the two housing systems at 5% significance level using R software. Hens in the conventional cages had worse plumage conditions and keel bone deformations than those in the deep litter system, especially at the end of laying (P < 0.05). In the deep litter system, hens showed a higher prevalence of foot pad dermatitis (46.0% hens scored 1 in the deep litter system compared with 11.33% in cages) and a higher avoidance distance test at the different ages (P <0.05) than those in the battery cages. The deep litter system showed more benefits for hen welfare than the battery cages except for foot pad dermatitis.

This study was aimed to analyze the growth curves and predict the optimum slaughter ages of Na Tau ducks. Six mathematical models, namely von Bertalanffy, Janoschek, Gompertz, Logistic, Lopez, and Richards, were employed. Body weight data were collected weekly from birth to 10 weeks of age. The parameters used to evaluate the growth functions were the coefficient of determination (R2), the AIC (Akaike's information criterion), BIC (Bayesian information criterion), and the standard error of the regression function (SER), as analyzed using R software. Among the models tested, the Janoschek model provided the best fit for both male and female ducks, as it exhibited the lowest AIC, BIC, and SER values, together with the highest R2. The asymptotic body weights of male ducks ranged from 2213.16g (Logistic model) to 2726.58g (Lopez model), whereas for female ducks, they were estimated between 1968.89g (Logistic model) and 2401.25g (Lopez model). The maximum average weekly gains (AWGmax) estimated by the best-fit model were recorded at 6.28 and 5.81 weeks for males and females, respectively. Based on these findings, the optimal slaughter ages were determined to be 6.28 weeks for male Na Tau ducks (with a body weight of 1617.34g) and 5.81 weeks for females (with a body weight of 1410.9g).

This study investigated the potential of replacing soybean meal with lupin (Lupinus angustifolius) at varying inclusion levels in the diets of growing–finishing pigs from 12 to 22 weeks of age. A total of 120 crossbred pigs (Duroc × [Yorkshire × Landrace]) were randomly assigned to one of four dietary treatments: a control diet without lupin (LP0), and diets containing 5% (LP5), 9% (LP9), or 12% (LP12) lupin. Growth performance parameters were recorded over a 70-day feeding period. Pigs fed the LP12 diet exhibited a significantly lower body weight and average daily gain (P <0.05) than those fed the LP0, LP5, and LP9 diets. Feed intake did not differ significantly among the treatments (P >0.05), whereas the feed conversion ratio was significantly higher in the LP9 and LP12 groups than in LP0 and LP5 (P <0.05). Economic analysis indicated that the LP5 diet provided the greatest economic benefit, reducing feed cost per kilogram of gain without impairing performance. These findings suggest that the dietary inclusion of lupin up to 9% does not compromise growth performance, with 5% being the most economically advantageous level for fattening pigs.

African Swine Fever Virus infections have significantly impacted swine production in many parts of the world. Rodents are considered vectors of several swine disease agents but their role in ASFV transmission has not been determined. This work sought to determine whether rats could be experimentally infected with ASFV. In a pilot project prior to the experimental trial, 27 rats, mice, and shrews were trapped from 3 farms (range 7-10 per farm) with current ASFV outbreaks. These animals were euthanized, sampled, and tested for ASFV with polymerase chain reaction (PCR). None of the samples (n = 81) were PCR-positive for ASFV. The experimental trial utilized 45 commercially obtained rats (Rattus norvegicus domestica): 9 were orally inoculated with ASFV, 9 were intraperitoneally inoculated with ASFV, 18 were non-inoculated contacts, and 9 were negative controls. On each of days 7, 14, and 21 post-inoculation, 3 orally inoculated, 3 intraperitoneally inoculated, 6 non-inoculated contacts, and 3 negative control rats were euthanized, sampled, and tested for ASFV with PCR. Clinical signs did not develop in any of the rats. Body temperatures increased during week 2, but there was no difference between the inoculated and non-inoculated groups. None of the samples (blood, spleen, liver, lung, ileum) were PCR positive for ASFV. Serum tested with ELISA for ASFV antibodies was negative. Despite direct ASFV challenge, inoculated rats did not develop clinical disease symptoms or transmit ASFV to contacts. Further work is necessary to demonstrate the competence of rodents as biological vectors for ASFV transmission in swine herds.

This study investigated the effects of binder type (molasses and cassava flour) and inclusion level (5% and 10%) on the physical and nutritional characteristics of ruminant pellet feeds formulated with pineapple and passion fruit peels. Four treatments were evaluated: 5% molasses, 10% molasses, 5% cassava flour, and 10% cassava flour, each replicated three times in a completely randomized design. The results showed that pellets with 10% molasses had the greatest durability (95.67%), a high density (475.72 mg mL-1), and elevated sugar (18.44%) and saponin (9.47%) contents, alongside improved concentrations of key amino acids such as lysine (1.29%) and glutamic acid (3.12%). By contrast, the 10% cassava flour treatment produced the lowest pellet durability (92.11%), density (468.06 mg mL-1), and amino acid levels, particularly lysine (0.47%) and aspartic acid (1.01%). Overall, molasses, especially at a 10% inclusion, proved more effective than cassava flour in enhancing both the physical quality and nutritional value of fruit by-product pellets. These results highlight the potential of utilizing fruit processing residues with natural binders to produce sustainable, cost-effective pellet feeds for ruminant production systems.

Tannins, found in many plants, have traditionally been used to treat diarrhea in pigs, but few in vivo studies have evaluated their effects in piglets. The objective of this study was to evaluate the effects of tannin supplementation on post-weaning diarrhea and the growth performance of weaned piglets. Eighty-one Duroc x (Landrace x Yorkshire) piglets were randomly allocated to treatment based on age and sex-balanced groups: 27 piglets for the control group with basal feed (CON) and 54 piglets for the treatment group with a supplementation of a 0.25-g tannin blend for every 1.0kg of the basal feed (TAN). At weaning, each piglet was individually identified by ear tag and had their diarrhea status evaluated for 30 days. Body weights were recorded at weaning (IBW) and at the end of the nursery period (FBW) to calculate the average daily gain (ADG). Diarrhea was evaluated by scoring fecal consistency twice per day. From this trial, the odds-ratio for the treatment and for IBW were 3.014 and 0.841, respectively, showing positive effects that the TAN treatment and increased IBW had on the diarrhea rate. Increasing the IBW by one kilogram led to a decrease in the diarrhea rate by 0.841 times. FBW and ADG in TAN were higher (P = 0.0089 and P = 0.0044, respectively) than those in CON. It was concluded that tannin supplementation at 0.25g per 1.0kg of feed reduces post-weaning diarrhea and improves ADG in weaned piglets. Higher body weight at weaning also lowers the incidence of diarrhea.

This study investigated the effects of dietary guanidinoacetic acid (GAA) supplementation on the growth performance, carcass characteristics, and meat quality in Ross 308 broilers. A total of 270 one-day-old chickens were randomly assigned to three dietary groups: treatment 1 (0.6 g GAA kg-1 feed), treatment 2 (1.2 g GAA kg-1 feed), and a control group (no GAA). GAA supplementation had no significant effect on the survival rate or feed intake (P >0.05). However, it tended to improve the cumulative body weight gain, average daily gain, and feed conversion ratio (FCR) in treatments 1 and 2 during the finishing phase (P <0.05), with the 1.2 g GAA kg-1 feed achieving the lowest overall FCR (1.33). Furthermore, GAA supplementation increased the carcass yield, breast meat yield, and thigh meat yield, and reduced breast meat toughness; however, most of these differences were not statistically significant (P >0.05). These results indicate that dietary GAA supplementation may have the potential to enhance the growth performance and meat quality in Ross 308 broiler chickens.

H'Mong cattle are considered to have several advantages over other local cattle in Vietnam, serving as a valuable livestock genetic resource. This breed is not only a primary livelihood but also a source of pride deeply tied to the cultural identity of the H'Mong people. Several research and development projects have been undertaken to utilize this cattle breed. This paper reviews available research findings to provide an overview of the breed’s origins, actual strengths and weaknesses, and proposes sustainable solutions for its utilization.