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Faced with the challenges posed by the need for fertilizers to maintain agricultural production, a biological process of atmospheric nitrogen fixation occurs naturally, which is carried out by a group of symbiotic bacteria that form a very close association with plants of the legume group, among which is the sweet clover (Melilotus spp.). From an ecological point of view, this plant has an essential function due to its good ability to associate with native nitrogen-fixing bacteria of the genus Sinorhizobium. A fundamental aspect is that this plant species can grow normally in alkaline soils, which doubles its importance since, on the one hand, it fixes nitrogen, and on the other hand, it can be incorporated as green manure. With this, the physicochemical properties of the soil are improved, and the levels of organic matter, which is in extremely poor condition in arid zone areas, are increased. Additionally, this species can withstand low temperatures and grow satisfactorily in winter. This paper presents a synthesis of the genus Melilotus and its symbiont Sinorhizobium meliloti and its importance as a potential natural soil improver. [ABSTRACT FROM AUTHOR]

Tick infestations represent a major difficulty for cattle production in tropical and subtropical countries around the world. The traditional ways to combat this pest are chemicals (acaricides) and integrated management of grasslands. Nevertheless, these methods have not been able to conclusively control the presence of this ectoparasite. This has led to the search for vaccines that allow the control of these parasites. Currently, there are immunogens containing the gut antigen Bm86 of Rhipicephalus microplus, which have proven to be an effective alternative, as they have reduced tick populations and the use of synthetic acaricides. However, the polymorphism of this locus in ticks from different geographical areas represents a limitation in its effectiveness. A significant number of studies have been conducted on the Bm86 gene as a vaccine antigen, so this paper presents an update on studies conducted with this antigen and its potential use as an immunological control to reduce tick infestations in cattle. [ABSTRACT FROM AUTHOR]

The horn fly Haematobia irritans is a cosmopolitan hematophagous ectoparasite of great importance in livestock. In Mexico, H. irritans is distributed across the country, and is found during the whole year. The fluctuation of H. irritans population is related with climate conditions. Despite its wide distribution, the effects on animal health, and its negative impact on meat and milk production, little data exists on its infestation and epidemiology is limited. This paper is a review on the current situation of H. irritans in cattle in Mexico, its economic impact, control methods, perspectives, and research opportunities. [ABSTRACT FROM AUTHOR]

The ultrasound allows to visualize the female reproductive tract and helps to understand some of the most relevant reproductive events such as follicular and corpus luteum development, ovulation, pregnancy diagnosis, uterine infections, embryo and fetal growth, among others. Nowadays, there is a massive amount of information regarding the physiology and ultrasonography of the reproductive events mentioned above. However, the overwhelming number of available papers review technical aspects of ultrasonography, physiology and reproductive management separately. Therefore, the objective of the present review is to merge a physiological description with reproductive management and technical aspects of original ultrasound pictures of the most relevant reproductive events in dairy cattle to promote ultrasound use during dairy cattle reproductive management by practitioners and researchers. [ABSTRACT FROM AUTHOR]

The National Institute of Forestry, Agricultural and Livestock Research in Mexico has been active for decades in researching genetic improvement in beef cattle. This review uses master theses, congress papers and scientific articles published from 1987 to 2020 to summarize much of the relevant research, and addresses research challenges and outlook over the short-, medium- and long-term in this area. Research done over the last 34 yr has evaluated the productive and reproductive performance of Bos indicus and Bos taurus x Bos indicus beef cattle raised under tropical conditions. Multibreed genetic evaluations have been done for Simmental-Simbrah and Charolais-Charbray populations in Mexico. Analyses have quantified the importance of maternal effects on growth traits, and estimated heritability and genetic correlations for growth and reproductive traits in male and female Bos taurus and Bos indicus animals. The genotype-environment interaction has been confirmed to influence expression of weaning weight in Simmental cattle. Age adjustment factors have been developed for maternal age for weights at birth and weaning, and prototypes of national genetic evaluation were developed for stayability and heifer fertility. Genetic diversity has been quantified for Simmental, Charolais and Simbrah populations, and SNPs identified that are associated with growth traits in Simmental and Simbrah populations. Short-term goals include development of selection indices and prediction of the genetic merit of carcass traits. Over the medium-term, emphasis is needed on genomic evaluations for tolerance to heat stress, residual feed intake and health traits, while in the long-term the goal is to make interbreed genomic predictions. [ABSTRACT FROM AUTHOR]

The study analyzed, in two years, the effects of breed [Brahman (BHM; n= 65); Braunvieh (BR; n= 56 )], supplementation with Zilpaterol® (ZIL; treated or control), season of birth (spring or autumn) and their interactions on body surface (BS), age (APB), body weight (WPB), body condition (BC), long dorsal muscle (DM) depth, dorsal fat (DF) thickness and serum leptin concentration (LEP) at puberty (PB) of 121 heifers. At PB, BMHs were heavier and older than BRs (376.8 ± 7.4 vs 302.0 ± 6.6 kg; 588.1 ± 14.7 vs 445.5 ± 12.5 days). ZIL increased APB, WPB, BC and DM, but did not affect DF and LEP. BHMs had 18 % more BS than BRs. However, the difference in WPB/BS was only 6.4 %. When metabolic weight (MW) was used as a proportion of BS (MW/BS) instead of WPB, the difference between BHM and BR disappeared ( P >0.05). The DF was 63.7 % higher in BHM than in BR. Those born in spring started PB with 24.4 % less DF than those born in autumn. Most of the BHM heifers (73.8 %) started PB in the months when light hours were increasing ( P <0.05), while in BRs, the beginning of PB was uniformly distributed throughout the year, regardless of the length of light hours; this effect was present in the two years of study. It is concluded that the establishment of puberty is a multifactorial phenomenon; seasonality affects BHM and BR differently and, apparently, BS is an important fac tor, probably associated with efficiency in energy use. This paper reiterates the importance of dorsal fat and documents, for the first time, MW/BS and its association with the establishment of puberty. [ABSTRACT FROM AUTHOR]

Adequate design of diets to animal health and productivity is essential in livestock industry. For the above, commonly are use bulky ingredients (fibrous sources) combined with a concentrates ingredients as cereals (energy sources), legumes (protein sources) and mineral concentrates. Mucuna spp. is a tropical legume in which its nutrients characteristics have been underutilized by livestock industry. Mucuna seed have an important nutritional characteristics as feedstuff: 1) Crude protein and energy concentration (dry matter basis) of 20 to 30 % and 15.7 to 24.7 MJ kg-1, respectively; 2) Presence of unsaturated fatty acids; 3) Similar concentration of anti-nutrient factors than other legumes, within which L-3,4 dihidroxiphenilalanine (L-DOPA,) can be easy reduced until no adverse effects on animal growth are noted. In addition, mucuna seed is a feedstuff economically advantageous, since is commonly considered as agriculture waste. The aim of this paper is to present a review of available information about the presence and concentration of nutritional compounds in the seed of Mucuna spp. with high potential for livestock industry. [ABSTRACT FROM AUTHOR]

This paper analyzes the relationship between the quality and value of a well-Protected Geographical Indications (PGI) with respect to its price, taking the experience of 20 yr of beef producers of the Sierra de Guadarrama. Through a qualitative research through the focus group technique and the use of the software Atlas.ti, it was found that the meat of the Sierra de Guadarrama has several factors that strengthen consumer confidence in the Autonomous Community of Madrid to the good and specialty, such as: cultural identity; the attachment to be a local product; good practices of animal health and meat safety. Despite the social prestige of the specialty, there are limitations to achieve better prices paid to farmers due to a market failure based on the lack of complete information to the consumer (importance of livestock to the preservation of the heritage landscape assessment), as well as a window of opportunity to improve the organization of the association, greater collective action of producers which helps to improve the form of governance, in particular their capacity to negotiate with other actors in the marketing phase and this may be a better balance between the quality, value and price to the farmer of the PGI. [ABSTRACT FROM AUTHOR]

This paper identifies the socio-economic and farm variables and cognitive and social factors influencing the use of cultivated pastures by small-scale dairy farmers. A field survey was conducted. The sample was divided in two groups defined as: users (Group 1, n= 55) and non-users of the innovation (Group 2, n= 51). Data were analysed through the Mann Whitney test and the Theory of Planned Behaviour (TPB). Socioeconomic and farm variables influenced the use of cultivated grassland, as observed in Group 1. This group showed a bigger proportion of farmers (60%) who indicated a positive intention to use cultivated grasslands, in comparison with 36% of farmers from Group 2. Farmers from both groups perceived similarly the utility and importance of the use of cultivated grassland; however, farmers' intention of Group 1 showed a significant correlation (P<0.05) with utility and importance. Other factors influencing the use of cultivated grasslands were the positive beliefs, social referents and difficulties perceived of the innovation. It concludes that different factors influenced the use of cultivated grassland in each group. [ABSTRACT FROM AUTHOR]

Beekeeping is practiced in Mexico since pre-Columbian times, nowadays it has presence in several agricultural regions of the country and more than half of the production of honey is exported. The importance of this activity is given by its generation of foreign currency earnings, income and employment, so that changes in foreign markets affect the income of rural families and the economy of the livestock subsector. For this reason, this paper analyze the level and competitive position of Mexican honey considering the external supply of the main producing countries; therefore its relation with their main variable. Four indicators were estimated ex post, taking into consideration the procedure proposed by the Interamerican Institute for Cooperation on Agriculture. The volume of former supply and the yield per hive, place Mexico in the sixth position worldwide, while as an exporter is located as third. It was found that honey obtained in the country has a high level of competitiveness in the domestic and international markets, exceeded only by China and Argentina. Production and exports evolution of honey are related to the primary phase of the supply chain, marketing processes and the physical and natural environment that determine the productivity, as well as the exportable surpluses and the economic value. [ABSTRACT FROM AUTHOR]

Genetic variation in three populations of pigs in Cordoba, Colombia was evaluated by 20 microsatellite. All loci studied were polymorphic, with an observed heterozygosis ranging from 0.2 to 84.2% (mean 68.6%) and expected heterozygosis ranged from 5.6 to 83.8% (mean 70.2%). The polymorphic information content (PIC) value for all markers analyzed ranged from 0.17 (least informative) and 0.83 (the most informative). The level of genetic differentiation FST between pairs of populations varied in the range from 0.07 to 0.11, being statistically significant in all analyzed pairs. In conclusion, the levels of expected heterozygosis found in the present paper show that the domestic pig in Cordoba, exhibits a high degree of genetic variability. Similarly, the genetic identity of Nei and statistical FST indicate genetic closeness between populations Momil and Cereté, which binds Tierralta, indicating migration between these three populations but keeping each its genetic identity. [ABSTRACT FROM AUTHOR]

This paper reviews the effect of plant lipids added to dairy ruminant diets on milk fat fatty acid profile. Changes in milk fatty acid profile when oils and oilseeds are added to the diet are broadly similar in cows, ewes and goats. Some of the observed effects are common to all oils and oilseeds whatever the quantitatively main fatty acid (i.e. oleic or linoleic or α-linolenic acids) they supply to the diet: butyric acid content does not usually change, medium chain saturated fatty acid content is lowered and unsaturated fatty acid content increases. Oils and oilseeds rich in linoleic acid raise the content of vaccenic, rumenic and trans10-18:1 and increase the n-6 to n-3 ratio in milk fat. Adding linseed oil or linseeds to the diet also increases vaccenic and rumenic acid contents, but does not affect that of trans10-18:1 in milk fat and lower its n-6 to n-3 ratio. As a conclusion, including oils and oilseeds into dairy ruminant diets widely modifies milk fat fatty acid profile. Best results from human health point of view are obtained adding linseed oil or linseeds to the diet. [ABSTRACT FROM AUTHOR]

An estimate of animal prevalence or the detection of infectious agents is of vital importance to a country or state to protect food safety and to safeguard local and foreign trade. However, significant human and material resources are required to perform these two tasks. This article presents an overview of the estimate and detection processes with the statistical technique known as group testing. In animal science, group testing can help save substantial resources in the estimate and detection of infectious diseases when the prevalence is less than or equal to 10%. Group testing is a sound statistical technique proposed by Dorfman (1943). It consists of mixing the material of k individuals. Instead of a diagnostic test for each individual, only one test is performed with the resulting mixture of the material. This allows significant savings. Furthermore, this paper presents some methods to classify individuals, it describes the process of point and interval estimation of animal prevalence, and it illustrates the calculation of sample size according to this model. The intention is to help researchers in animal science to use this technique and save significant resources. [ABSTRACT FROM AUTHOR]

Development of historic vegetation growth curves for both grasslands and shrublands in Mexico becomes a real challenge due to lack of statistics. Remote sensing technology using satellites, allows obtaining a first approximation through vegetation indices (VI). The present study discusses an indirect parametric modeling of the biomass growth curve in individual pixels of both Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS), thus allowing their characterization using pre and post process algorithms. Results obtained through application of the algorithms discussed in the present paper, allow obtaining annual growth curves at 100 ha (AHVRR) and 6.25 ha (MODIS) scales that can be used in studies on climate change and on grassland/shrubland management in Mexico. [ABSTRACT FROM AUTHOR]

An analysis of innovation in value strategies followed by Mexican beef market leaders for competitive positioning is offered in the present paper. Using the methodology suggested by W.C. Kim and R. Mauborgne (2005), known as the Blue Ocean Strategy, nine different categories with their respective variables were laid down in favor of building strategic maps of the ten selected enterprises. Areas in which the Mexican beef industry most invests are shown in those maps: animal production items which directly affect beef quality (breed, age, weight, finishing); product presentation and market diversification. However, what really sets these firms apart is how they integrate their production chain, the range of products offered, food safety programs and certification used or obtained customer services and marketing strategies. [ABSTRACT FROM AUTHOR]