ISSN / EISSN : 2448-7546 / 2594-0252
Published by: Colegio de Postgraduados (10.32854)
Total articles ≅ 543
Latest articles in this journal
Agro Productividad; doi:10.32854/agrop.v14i6.1850
Objective: To estimate the lactation curve and milk production of Pelibuey ewes andthe relationship with preweaning growth rate of the lambs.Design/methodology/approach: Forty five Pelibuey ewes were milked during 70days in Montecillo, México, in 2018, to estimate daily and total milk production. Thelactation curve was fitted with the incomplete gamma function. In addition, the effectsof type of birth and ewe weight at milking on milk production were analyzed, andcorrelations were calculated between ewe milk production and growth rate of thelambs, per week and for the entire lactation Results: A “typical” lactation curve was found, average ewe milk production for theentire lactation, weighted for the number of lambs suckling, was 131±8 L, with444±24 g d -1 . Ewe weight at milking had an effect (p<0.01) on milk production.Positive correlations were found (p<0.05) between ewe milk production andpreweaning growth rate of the lambs.Limitations on study/implications: There is a strong dependency of the lambs forthe milk production of the Pelibuey ewe, a factor of great relevance so that lambs cangain body weight and survive during lactation.Findings/conclusions: Pelibuey ewes produce less milk than dairy ewes. Therefore,lambs should be weaned at a maximum of 10 weeks of lactation.
Agro Productividad; doi:10.32854/agrop.v14i6.1948
Objective: To measure the effect of zin injection, during an estrus synchronization protocol, on pregnancy rate in sheep from the “Valle de Mexicali”.Design/methodology/approach: The experimental units were 157 ewes, which wereallocated in five farms (UP): UP1 (n=19), UP2 (n=27) UP3 (n=20) UP4 (n=71) and UP5(n=21). In each farm, the ewes were randomly assigned to one of three treatments:control, z-100 and z-200. The ewes from control groups were subcutaneously injectedwith 4 mL of olive oil as placebo. The ewes from groups z-100 and z-200 weresubcutaneously injected with 100 and 200 mg of zinc oxide. The response variableswere the preovulatory diameter of the largest follicle and pregnancy rate.Results: The differences between experimental groups on diameter of the largestpreovulatory follicle and pregnancy rates were not significant different (p>0.05). Limitations of the study/implications: The ewe’s reproductive response to zincinjection might be affected by the animal mineral status, it is recommended to carry onsupplementation with base on mineral blood concentrations.Conclusion: The subcutaneous injection with 100 or 200 mg of zinc oxide did not affectthe size of the largest preovulatory follicle and pregnancy rate in ewes.
Agro Productividad; doi:10.32854/agrop.v14i6.1930
Objective: To assess the testicular and semen characteristics in Criollo LecheroTropical (CLT) bulls in the subhumid Mexican tropics.Design/methodology/approach: Eight bulls were included in the study and distributedin two groups: G1 (n=5): young bulls and G2 (n=3): adult bulls. All bulls were managedunder grazing and were evaluated throughout one year. From each bull the followingmeasurements were taken once a month: live weight, body condition score, scrotalcircumference, and testicular width, length and volume. Semen was obtained every 3months via artificial vagina. Semen variables evaluated in each collection were: aspect,volume, mass and individual motility, and sperm concentration and morphology. Results: Live weight and testicular measurements increased linearly during the study inbulls from both groups. All bulls had scrotal circumference larger than the minimumthreshold value for cattle and semen of high quality.Study limitations/implications: The low availability of CLT bulls prevented theinclusion of a larger number of animals in the study. This low availability of animalsmakes it necessary to establish standard values for testicular measurements and semencharacteristics in the CLT breed in order to select the best individuals as sires andcontribute to its conservation.Findings/conclusions: The CLT bulls had good scrotal circumference and semenquality since a young age and into adulthood. These traits make the CLT bulls animportant alternative for livestock breeding in the tropics.
Agro Productividad; doi:10.32854/agrop.v14i6.1982
Objective: To estimate the population of wild turkey (Meleagris gallopavo, mexicana) and its density in ecosystems of its distribution.Design / methodology / approach: A method based on random sampling with a population density estimator was designed. The design was based on the observation of wild turkeys that go to attraction sites (feedlots) of 2,500 m 2 (50 X 50 m) counted in 12 h a day, three consecutive days. For the total of random sites, the criterion of one site for every 300 ha of surface under study was used. The study was carried out on March 1, 2 and 3, 2019 in 3,000 ha of pine-oak forest, in Monte Escobedo, Zacatecas, Mexico. Observations were made from a fixed point 25 m from each site, from 6:00 a.m. to 6:00 p.m. The attraction sites were located at a random distance within 10 systematically fixed transects in the study area.Results: The results showed a population of 66 turkeys in 3,000 ha, with a density of 0.022 turkeys ha -1 . Limitations / implications: The application of the method was useful for the monitoring of wild turkey in the pine-oak forest, showing that it is a method that does not affect the population, which does not require long sampling times, is reliable, low-cost, and easy to carry out. The method is not reliable in ecosystemsthat do not allow the location of high visibility sites.Findings / conclusions: Considering the distribution of wild turkey in Mexico, the method is a new alternative applicable to population studies of wild turkey.
Agro Productividad; doi:10.32854/agrop.v14i6.1974
Objective: To estimate the hematological and biochemical reference values inMAteles geoffroyi individuals in captivity. Methodology: Eleven males and 23 females were captured. We collected blood,from the coccygian vein; conventional techniques were used to analyze thesamples.Results: mean corpuscular volume (MCV; P < 0.03), platelets (PLT; P < 0.04) were significantly higher in females than in males. In relation to biochemical blood values wasn’t significantly in male and female groups.Limitations/Implications: hematological and biochemical reference values of A. geoffroyi are within normal health parameters, are between the ranges reported for other species of neotropical primates and can be used as a reference in for the management of the health of this species in captivity.Conclusions: hematological and biochemical parameters of captive specimens of A. geoffroyi are described, which provide reference indicators for the management of the health of the species.
Agro Productividad; doi:10.32854/agrop.v14i6.2020
Objective: To characterize the realized niche of the Mexican spotted owl (Strix occidentalis lucida) and compare the environmental values it uses within the Mexican physiographic provinces.Design/methodology/approach: The environmental temperature variables (n =7), precipitation (n = 7) and elevation (n = 1) were extracted from 79 unique occurrences sites of S. o. lucida. These values were grouped by physiographic provinces: Sierra Madre Occidental (n = 59), Sierra Madre Oriental (n = 13) and Transversal Neovolcanic Belt (n = 6). The climate and elevation of these sites were described and compared via non-parametric Kruskal-Wallis and Bonferroni-Dunn tests (P ? 0.05).Results: The presences of the spotted owls were both, dispersed and focallydistributed, over the geographic space in Mexico. The temperature and elevation variables have similar characteristics in the assessed physiographic provinces. To be noted, the precipitation variables showed significant differences among sites.Limitations on study/implications: This study describes the environmental characteristics of the realized niche of the Mexican spotted owl; however, it isnecessary to investigate other habitat variables at a smaller scale. Findings/conclusions: The temperature and elevation environmentalcharacteristics of the ecological niche of the Mexican spotted owl was similar between physiographic provinces.
Agro Productividad; doi:10.32854/agrop.v14i6.2043
Objective: To determine the diet of the desert bighorn sheep and to identify differencesin its composition between sexes during the reproductive and sexual segregation periods.Design/methodology/approach: The study was carried in the UMA Rancho NocheBuena, Hermosillo, Sonora. The microhistological technique and a cell catalog of plantsfrom the study area were used to identify plant species present in fecal samples ofbighorn sheep. The relative frequency, the Shannon-Weaver diversity index and theKulczynski similarity index were determined by sex and period (reproductive andsegregation)Results: The diet of bighorn sheep included 40 species, being herbaceous (36.1 ±4.4%) and grasses (26.8 ±8.9 %) the most common. The diet of males during thesegregation period was mainly composed of grasses (36.2%) and female diet byherbaceous (30%) and grasses (29.8%). No differences were found in the diversity ofthe diet of males and females in the segregation period (H '= 1.0) and in general, their diets were very similar (80%).Limitations/implications: To collect a greater number of fecal samples by sex andperiod (reproductive and segregation) and to analyze the nutritional content of plantsconsumed by bighorn sheep.Findings/conclusions: In this study, the sexual segregation exhibited by the bighornsheep in the Wildlife Management and Conservation Unit Rancho Noche Buena was notdue to food preferences.
Agro Productividad; doi:10.32854/agrop.v14i6.1916
Objective: Evaluate the growth performance and carcass characteristics as well as the individual and maternal heterosis effects of New Zealand White (NZB), California (CA) rabbits and their crosses.Design/methodology/approach: 450 offspring rabbits, from 48 females mated to 6 stud rabbits, were evaluated, recording the weight (PNC) and litter size at birth (TCN) and at weaning (TCD), as well as, and weight (PMS), weight gain (GMD), consumption (CMS), and feed conversion (CONV) for during 8 weeks post-weaning. The carcass live weight at slaughter, warm carcass weight with head, carcass yield, and carcass parts of the carcass were evaluated.Results: Showed differences (p <0.05) in TCN and TCD with values of 10.47 and 9.03 kits, respectively. When NZB was used as the paternal breed, obtaining an individual heterosis of 5.91% for litter size and 12.44% for weaning weight. In the productive performance and carcass characteristics, the superiority of the California breed as a paternal breed was evidenced, with average values of 36.05 g in GMD and 2.95 kg in CONV. The averageindividual weight at the end of the fattening, at 70 days of age, was 2.09 kg and the weight of the carcass 1.16 kg. Post-weaning heterosis for the characteristics evaluated during fattening was were positive and moderate.Limitations on study/implications: It is necessary to carry out genetic improvement studies, with different crossing systems and to evaluate results based on the productive and reproductive behavior.Findings/conclusions: in reproductive characteristics, when using NZB as apaternal breed, the offspring are superior to those obtained from CA; while inthe productive variables, the offspring from CA show superior results.
Agro Productividad; doi:10.32854/agrop.v14i6.2061
Objective: The objective was to infer the effect of the variables phenology (migration-non-migration), seasonal (rainfall-dry season), sex and forest condition on the abundances of birds (resident-migratory) in a semi-preserved and disturbed oak pine forest. Design/methodology/approach: It was carried out in Monte Tlaloc, State of Mexico, under two conditions of apparent disturbance, semi-preserved oak pine forest and disturbed oak pine forest. Ten bird samplings were carried out with "count on point" with a fixed radius of 25 m, covering the 4 seasons of the year and migratory periods. With the previous data, the Relative Abundance Index (RAI) was estimated. To infer the effect of the variables phenology, seasonality, sex and forest condition on the abundances of birds, generalized linear models were elaborated. Results: The IAR of the birds registered in the semi-considered pine forest indicates that the species with the lowest presence was Aphelocoma ultramarina (0.002) and with the highest frequency Empidonax sp. (0.13), unlike to that found in the disturbed pine forest where the lowest IAR corresponded to Colaptes auratus (0.003) and with the highest appearance was Ptiliogonys cinereus (0.23). The Generalized Linear Model suggested that forest condition and phenology are significantly related to the frequency of species. Limitations on study/implications: In this study it was found that the abundance of birds was affected by the condition of the forest and that the phenology (migration-non-migration), seasonal (rain-dry season), sex and condition of the forest were related to the abundance of birds. Four species classified as under Special Protection and two Threatened according to NOM-059 were registered as well as the presence of four endemic species which highlights the importance of conserving these ecosystems. Findings/conclusions: The fauna communities present in Monte Tláloc highlight the importance of conserving the pine-oak forests since this site is part of the Eje Neovolcanico Transversal.
Agro Productividad; doi:10.32854/agrop.v14i6.2030
Objective: To determine the production cost and profitability of different feedingstrategies during the tropical gar larvicultureDesign/methodology/approach: Growth and survival obtained from the evaluationof an experimental diet with maize starch, comparing against the conventionalstrategy (commercial diet for rainbow trout and co-feeding with Artemia naupliii). Theexperimental diet was evaluated with co-feeding with Artemia and with no Artemia.The productions cost was estimated for each strategy and was calculated the unitcost by juvenile as well as the sale cost. We also determined the cost-benefit relationand the breakeven point for the economic analysis. Results: The direct feeding with no Artemia strategy during the larviculture is notprofitable. According to the relation cost-benefit, comparing the strategy with theexperimental diet in co-feeding with the conventional strategy, the profitability of thefirst was greater. The breakeven point between the profitable strategies was similar,but the greater survival with the experimental diet suggest a higher impact on theoptimization of the product system.Limitations on study/implications: the lack of economic analysis on the tropical garlarviculture affect indirectly the product system tropical gar as there is no accurate information on production costs.Findings/conclusions: From a financial point of view, the feeding strategy usingexperimental diet with co-feeding is the most profitable process of larviculture.