Tropical animal health and production最新文献

Rosa roxburghii tratt residue (RRTR) is a regional and uncommon byproduct in Guizhou. Little information is available on whether RRTR can be used as feed for ruminants. In this study, the feasibility of using RRTR as a new feed resource for cattle was investigated by chemical composition analysis, in vitro gas production (Trial 1) and animal feeding experiments (Trial 2). In trial 1, compared to the commonly used fruit residues, RRTR had a proximate nutrient level; the in vitro gas production curve and dynamics fell within the normal range. In trial 2, 16 cattle were allocated to the control and treatment groups, with 8 replicates of 1 cattle each. Cattle in the control group were fed a basal diet without RRTR, while those in the treatment group were fed a diet containing 30% RRTR to replace 30% whole corn silage in basal diet. Feeding RRTR had little effect on the growth performance of the control and treatment cattle (P > 0.05). The feed-to-gain ratio was greater in the treatment group than in the control group throughout the trial period (P < 0.05). The plasma urea levels in the treatment group were lower (P < 0.05) than that in control group, and the levels of other plasma biochemical metabolites were not different between the two groups of cattle (P > 0.05). The in vivo rumen fermentation parameters did not differ between the control and treatment groups (P > 0.05). Our findings indicate that RRTR has a nutritional profile (crude protein, neutral detergent fiber, acid detergent fiber, and crude fiber) similar to that of commonly used fruit residues (such as apple, pineapple, and citrus residue et al.); improves plasma protein utilization efficiency; and has no negative impact on growth performance, albeit with limited effects on feed conversion; blood metabolites, and rumen fermentation parameters in cattle. Accordingly, we conclude, based on the above-mentioned result, that RRTR can serve as a novel feed alternative resource when considering the affordability and as a practical choice for low-cost diets for cattle.

Dietary supplementation of fat can be an important source of energy to compensate for the reduction in dry matter intake in dairy cows during heat stress periods. Studies have reported that supplementing dairy cow diets with linseed oil (LO) can increase milk yield and enhance the levels of beneficial fatty acids, such as omega-3 fatty acids, in the milk. The objective of this research was to evaluate the effect of LO supplementation on milk fatty acids profile, milk yield and composition, and physiological parameters of grazing cows. The study was conducted in two seasons, one in spring and one in summer. A 2 × 2 Latin square design was used in each experiment. Twelve Holstein and crossbred Holstein x Jersey cows were involved in each season. Cows were divided into two groups: control (TC) with no supplementation and treatment (TL) supplemented with 400 g/day of LO. The results showed that LO supplementation altered the milk fatty acid profile: decreased concentrations of short and medium-chain fatty acids (C10:0 - C17:1) except for C13:0 and increased concentrations of long-chain fatty acids (C18, C18:1 (both trans and cis isomers), C18:2 (specific conjugated linoleic acid - CLA isomers), and C18:3 n3 (omega-3)). Additionally, milk yield increased by 1.5 l per day during summer in LO-supplemented cows, while milk fat, protein, and casein content decreased. Milk stability increased by 2.2% in the LO-supplemented group. LO-supplemented cows reduced internal body temperature and heart frequency in the afternoon and increased daily rumination time by 20 min. In conclusion, LO supplementation can be an effective strategy to improve the nutritional profile of milk by altering fatty acid composition towards potentially healthier fats, mitigate the negative effects of heat stress on grazing cows during summer, as evidenced by reduced body temperature and heart frequency and increase milk yield.

Coxiella burnetii, a bacterium that causes Q fever. It can infect mammals and has a global geographical distribution, but data on its occurrence in Egyptian dromedaries and the associated ticks are limited. Therefore, this study aims to detect C. burnetii in the blood of infested camels and associated ticks collected from Egypt by using molecular techniques and to examine the possibility of coinfections with C. burnetii. A total of 133 blood samples and 1260 hard ticks infesting these camels were collected from Egyptian slaughterhouses. Nested PCR and sequencing were used based on the IS1111 gene for molecular detection of C. burnetii. The identification of tick species at the molecular level was performed using the COX1 gene. C. burnetii was detected in Hyalomma (H) dromedarii, H. anatolicum, H. marginatum, Amblyomma (Am) lipidium, and Am. cohaerens with an overall prevalence rate of 1.3% (16/1260), while in the camel blood samples, it was 15.8% (21/133). Out of C. burnetii-positive ticks, there were double infections by Borrelia species and C. burnetii in H. dromedarii and Am. lipidium and triple infections at one Am. cohaerens tick (C. burnetii, Borrelia spp., and Babesia microti). In addition, two positive camel blood samples were found to carry C. burnetii with Borrelia spp. Our research findings indicate the presence of Coxiella burnetii among camels and their associated ticks in Egypt and emphasize the potential of having coinfection. To prevent the transmission of this infection to other animal species or humans, appropriate control measures should be implemented.

Colombian Creole pigs have adapted to tropical conditions for over 500 years. They have been modified by natural and artificial selection in different regions. At present, the diversity and current introgression status are unknown. The objective was to estimate the genomic diversity, linkage disequilibrium, population structure, and admixture of four Colombian pig breeds and their relationship with other breeds worldwide. Three Colombian pig breeds (SPE-San Pedreño, 11 samples; ZUN-Zungo, 11 samples; CM-Casco de Mula, ten samples) from the conservation nucleus and one biotype not recognized as a breed (CCH-Criollo Chocoano, seven samples) were genotyped using the Illumina GGP-Porcine80K chip. Open-access data from seven international breeds were also included. Colombian Creole pigs showed moderate genetic differentiation (F_ST 0.14) globally, but several groups of animals separated, suggesting local clustering due to geographical isolation or different founding effects. Colombian Creole pigs showed breed imprinting and specific grouping in all analyses except for CCH, which, like the Ecuadorian Creole, was a cluster of admixtures. The Colombian Creole pigs revealed a significant relationship with the Iberian pig and some other breeds to varying degrees. However, good maintenance of the conservation nucleus was evidenced. Potential adaptive genes, mainly related to immunological functions, were found, according to F_ST and pcadapt analyses. This study provides a foundation and scientific data for policy decisions on zoogenetic resources.

60-days trial was performed to study the effect of inland saline water (ISW) at 10ppt salinity on lipid requirement of Genetically Improved Farmed Tilapia (GIFT) juveniles. Six purified iso-nitrogenous (37% crude protein) and hetero-caloric (380-430 Kcal DE/100 g) diets having graded levels of dietary lipid viz., 4, 6, 8, 10, 12 and 14% were prepared. Two hundred and seventy acclimated GIFT juveniles (1.90 ± 0.1 g) were randomly distributed (15 fish per 300 L tank) into six different treatments viz., T4, T6, T8, T10, T12 and T14 in triplicates. The increase in dietary lipid resulted in an increase in body lipid and a diminution in moisture levels in fish. There was a significant (p < 0.05) increase in weight gain (g), percent weight gain (WG%), protein efficiency ratio (PER) and feed efficiency ratio (FER) with increasing dietary lipid level up to 8% and decreased thereafter, but an opposite trend was noted in the feed conversion ratio (FCR). The serum glucose level linearly elevated with the rise in dietary lipid level, but higher lipid (beyond 8%) fed groups showed significantly (p < 0.05) more total protein in serum. Though there was a significant (p < 0.05) difference in cholesterol levels, no clear trend was observed; while other parameters viz., body indices (VSI and HSI), serum albumin, globulin and A-G ratio was not showed any significant (p > 0.05) variation with varying dietary lipid level. Based on regression models, it was observed that the optimum lipid level required for GIFT in ISW (10ppt) is in the range of 8.35-9.05%.

The aim of this study was to estimate the genetic parameters of the reproductive performance of the Azawak zebu, bred on station during the period 1981 to 2007, in order to contribute to the implementation of an effective selection programme for improving the zootechnical performance of cattle herds. The data contained records of 2453 calvings from 650 Azawak cows, daughters of 55 bulls, all bred at the Toukounous experimental centre (Niger). Non-genetic factors were evaluated using linear mixed models and genetic parameters were estimated using REML procedures with a multi-trait animal model. The effects of year and calving rank were significant (P < 0.001) for the three reproductive traits studied. Heritability was low for age at first calving (h² = 0.09 ± 0.03) and calf birth weight (h² = 0.07 ± 0.03). It was moderate for calving interval (h² = 0.30 ± 0.04) indicating the possibility of genetic improvement of this trait by selection. Repeatability estimates for calf birth weight and calving interval were 0.10 ± 0.02 and 0.42 ± 0.03 respectively. Calving interval had very strong and significant genetic correlations with age at first calving (0.84 ± 0.08) and calf birth weight (-0.40 ± 0.20). There was also a significantly favourable genetic correlation between calf weight at birth and age at first calving (-0.32 ± 0.25), implying a simultaneous improvement in all three reproductive traits through selection. An increase in heritability of calf birth weight was observed after the active phase of the program, reflecting an overly open selection scheme. These genetic parameter estimates suggest that the three reproductive traits could be used in selection index with the aim to improve the three reproductive traits of Azawak cattle.

The aims of this study were to estimate the genetic and phenotypic parameters for growth traits and evaluate genetic trends on 585 indigenous Tswana goats. The population was maintained under low input production system at the Department of Agricultural Research in Lesego ranch, Botswana, from 2005 to 2008. Data included birth weight (BW), weaning weight (WW), weight at 8 months (PW), yearling weight (YW), pre-weaning average daily gain (ADG) and two post weaning average daily gains (ADG2 and ADGYW). Data was analysed using general linear model of SAS to determine non-genetic effects. Estimation of genetic and phenotypic parameters were estimated using ASREML fitting an animal model that accounted for fixed effect of parity, sex, type of birth and year of birth. Least squares means for BW, WW, PW and YW were 2.88 ± 0.03, 12.15 ± 0.17, 16.52 ± 0.28 and 21.04 ± 0.32Kg, respectively, while those for ADG, ADG2 and ADGYW were 74.52 ± 1.41, 28.78 ± 1.55 and 33.66 ± 2.28 g/day, respectively. Estimates of heritability for BW, WW, PW and YW were 0.79 ± 0.11, 0.63 ± 0.14, 0.32 ± 0.13 and 0.48 ± 0.16, respectively. The genetic correlations for all the traits studied were positive and moderate to high (0.48 to 0.82) whilst phenotypic correlations ranged from 0.21 to 0.72. Positive average genetic trends of 12.32% (WW), 13.39% (PW) and 7.38% (YW) were attained. The results have demonstrated the potential of this breed to be improved through selection.

This study investigated the effects of in ovo betaine and thermal manipulation during incubation on growth performance, and some immune parameters of broilers under cyclic heat stress (CHS). Eggs were divided into 5 groups and incubated at 1) 37.8 °C and 60% relative humidity (Control incubation and not-injected, CI); 2) eggs were incubated at CI and in ovo betaine injected into yolk sac on d 11 (E11) (CI + In ovo); 3) eggs were exposed to 38.8 °C for 8 h between 10 and 18d of incubation (heat acclimation, HA); 4) eggs were incubated at HA and in ovo betaine applied (HA + In ovo); 5) positive control: eggs were incubated at CI and injected with saline. Hatched chicks were raised under standard management conditions until 21 d, between 21 and 42 d half of the chickens in each incubation treatment were kept either at optimum (OPT) or at CHS. In ovo and HA did not affect hatching performance. In ovo increased thymus and spleen weights of chicks. Serum IgG was higher in HA + In ovo chicks. From d 7 to 21, in ovo chicks were heavier body weights, consumed more feed, and better feed conversion than those from CI. The body weights of HA chickens were similar in OPT and CHS on d 28 and 35. CHS reduced the body weight of CI chickens which was compatible with their feed consumption. Moreover, feed intake of HA + In ovo chickens exposed to CHS was higher than those not injected indicating that HA + In ovo enhanced thermoregulation of chickens under CHS.