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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.

Ascorbic acid (vitamin C: VC) is an antioxidant that participates in the regulatory processes involved in the development of ovarian structures and fertility. However, supplementation of VC to dairy cattle to improve fertility has received little attention. However, reduced fertility in dairy cattle associated with high genetic merit for milk production and heat stress, which also diminish blood VC concentrations, suggest a potentially beneficial role for VC supplementation. The objectives of this review are to contribute to the current knowledge regarding the relationship between VC and fertility and to share many experiences that support the relevance of VC supplementation to improve dairy cattle reproductive performance.

Vitamins C and E have been supplemented separately to improve fertility in cattle. The objective of this study was to evaluate the effect of combined injections of increased doses of vitamins C and E on reproductive parameters in dairy cattle. Lactating Holstein cows (n= 44) were randomly assigned to one of three treatments: 1) Control: n= 15, cows were not injected with vitamins; 2) VCE3: n= 15, cows received a single intramuscular injection of 3,000 IU of vitamin E before estrus and multiple subcutaneous injections of vitamin C with a total dose of 3,000 mg before and after estrus; 3) VCE6: n= 14, cows were treated as in VCE3, but doses of vitamins C and E were increased to 6,000 mg and 6,000 IU. The reproductive indicators measured were diameter of the preovulatory follicle, time to estrus, area of the corpus luteum, pregnancy rate 35 and 45 d after AI and plasma concentrations of estradiol and progesterone. There was no effect of treatment on any of the evaluated reproductive parameters (P˃0.05), except that the lowest dose of vitamins sustained similar pregnancy rates among treatments, even though they had lower progesterone concentrations (P≤0.05) (19.4 ± 2.66 vs 10.1 ± 2.55 vs 19.2 ± 0.44 ng mL-1 for Control, VCE3 and VCE6, respectively). In conclusion, the supplementation with the highest amount of vitamin C and E (6,000 mg and 6,000 IU versus 3,000 mg and 3,000 IU) does not significantly increase the reproductive parameters measured.

A new device (Chapingo device) to deposit semen at the base of the uterine horns of cattle was developed at Universidad Autonoma Chapingo, Mexico. Nine Holstein heifers were inseminated by transvaginal laparoscopy, using a laparoscope for cattle and the Chapingo device. A dose of sexed semen (2.1 × 106 spermatozoa) was deposited at the base of the uterine horn ipsilateral to the ovary where the preovulatory follicle was identified. Insemination was achieved in all the heifers, taking on average 13.7 ± 3.1 min per animal. In all cases, it was possible to see both ovaries, the base of the uterine horns and the oviducts. After the procedure, none of the heifers showed any type of complications such as haemorrhage, adhesions or trauma. On days 21 and 22 after insemination, four of the nine heifers (44.4%) returned into oestrus; on day 30 after insemination, one heifer was found to be pregnant by ultrasound. The results show the feasibility of generating pregnancies by transvaginal laparoscopy in heifers inseminated with sexed semen.

Summary Background: recombinant bovine somatotropin (rbST) is used in bovine embryo donors to improve superovulatory response and embryo quality. Objectiv e: this study evaluated the effect of applying one versus two injections of 500 mg of rbST to donor Holstein heifers on estrus incidence (IE), diameter of the largest preovulatory follicle (dLPF), superovulation response (SR), embryo yield, and pregnancy rate in recipient Holstein cows (PRR). Methods: two superstimulation programs were conducted. Heifers were assigned to one of two treatments: 1) rbST-I, n = 5: heifers received one injection of rbST on day 0 (day of CIDR (controlled internal drug release) removal); 2) rbST-II, n = 5: heifers received the first rbST injection on day -8 and the second one on day 0. Thirty-eight cows were used as recipients and were assigned to receive one embryo from one of the two treatments. Results : there was no effect of treatment (p > 0.05) on PRR, dLPF, IE, and SR. The number of oocytes increased (p 0.05) of degenerated (1.0 ± 0.5 vs 4.5 ± 3.0) or transferable (1.0 ± 0.5 vs 1.4 ± 0.7) embryos between heifers in the rbST-I and rbST-II treatments, respectively. Moreover, no oocytes or embryos were recovered from 36.8% of donor heifers in either treatment. Conclusion : the application of 500 mg of rbST on days -8 and 0 of the follicular wave synchronization program did not increase the superovulatory response but significantly reduced the number of oocytes recovered from superovulated Holstein heifers. Keywords: conception rate, donor heifers, incidence of estrus, preovulatory follicle. Resumen Antecedentes : la somatotropina bovina recombinante (rbST) ha sido aplicada en vacas donadoras de embriones con el objetivo de mejorar la respuesta superovulatoria y la calidad embrionaria. Objetivo : este trabajo de investigacion evaluo el efecto de aplicar una versus dos inyecciones de 500 mg de rbST a novillas Holstein donadoras de embriones sobre la incidencia de celo (IE), diametro del foliculo preovulatorio de mayor tamano (dLFP), respuesta superovulatoria (SR), produccion de embriones y tasa de concepcion en vacas Holstein receptoras de embriones (PRR). Metodos : se llevaron a cabo dos programas de superestimulacion. En cada programa las novillas fueron asignadas a uno de dos tratamientos: 1) rbST-I, n = 5: las novillas recibieron una inyeccion de rbST el dia cero (dia de remocion del CIDR (dispositivo intravaginal liberador de progesterona); 2) rbST-II, n = 5: las novillas recibieron la primera inyeccion de rbST el dia -8 y la segunda el dia cero. Treinta y ocho vacas fueron utilizadas como receptoras. Cada receptora recibio un embrion proveniente de una donadora de uno de los dos tratamientos. Resultados : la aplicacion de una o dos inyecciones de rbST no afecto (p > 0,05) la PRR, dLFP, IE ni la SR. El numero de ovocitos fue mayor (p 0,05) entre las vaquillas del tratamiento rbST-I y rbST-II. Ademas, del 36,8% de donadoras de ambos tratamientos no se colecto ningun ovocito o embrion. Conclusion : la aplicacion de 500 mg de rbST los dias -8 y cero del protocolo de sincronizacion de la onda folicular no incremento la respuesta superovulatoria pero redujo significativamente el numero de ovocitos recolectados de vaquillas Holstein superovuladas. Palabras clave: foliculo preovulatorio, incidencia de celo, novillas donadoras, tasa de concepcion. Resumo Antecedentes : a somatotropina bovina recombinante (rbST) tem sido aplicada em vacas doadoras de embrioes com o objetivo de melhorar a resposta superovulatoria e a qualidade embrionaria. Objetivo : o presente trabalho avaliou o efeito da aplicacao de uma contra duas injecoes de 500 mg de rbST em novilhas de raca Holandesa doadoras de embrioes na incidencia do cio (IE), diâmetro do maior foliculo pre-ovulatorio (dLFP), resposta superovulatoria (SR), producao de embrioes e taxa de gestacao em vacas receptoras de raca Holandesa (PRR). Metodos : foram feitos dois programas de superestimulacao, em cada superstimulacao as novilhas foram distribuidas em um de dois tratamentos: 1) rbST-I, n = 5: as novilhas receberam uma injecao de rbST no dia zero (dia de remocao do CIDR -dispositivo intravaginal de liberacao controlada de progesterona). 2) rbST-II, n = 5: as novilhas receberam a primeira injecao de rbST no dia -8 e a segunda injecao no dia zero. Trinta e oito vacas foram utilizadas como receptoras e receberam um embriao proveniente de uma doadora de um dos dois tratamentos. Resultados : a aplicacao de uma ou duas injecoes de rbST nao afetou (p > 0,05) a PRR, dLFP, IE nem a SR. O numero de oocitos foi maior (p 0,05) entre as novilhas do tratamento rbST-I e rbST-II. Alem disso, do 36.8% das doadoras de ambos os tratamentos nao foi possivel coletar nenhum oocito ou embriao. Conclusoe s: A aplicacao de 500 mg de rbST o dia -8 e zero do protocolo de sincronizacao da onda folicular nao aumentou a resposta superovulatoria, mas diminuiu significativamente o numero de oocitos coletados de novilhas de raca Holandesa superovuladas. Palavras chave: foliculo pre-ovulatorio, incidencia do cio, novilhas doadoras, taxa de gestacao.

World trade challenges food safety and quality. This chapter is focused on a deep insight into the performance of potential hazards on food safety and biosecurity associated with foodstuffs. This detailed framework provides definitions, potential risks, prevention, antimicrobial resistance, epidemiology, and the surveillance of each potential hazard associated with agro-chemical and veterinary drug residues, genetically modified organisms, heavy metals, microbial pathogens, naturally occurring toxicants, parasitic organisms, persistent organic pollutants, physical contaminants and adulterants, prions, and zoonotic diseases. Biosecurity aspects are discussed and policy and regulatory frameworks for analyzing and managing relevant health risks, and those associated with the environment. It covers safety and risk management in the food supply chain, traceability and recalls, on-farm biosecurity management and animal hygiene as well as joint risk management tool release of living modified organisms and their products. Furthermore, inherent elements according to a range of economic factors are included on both topics as well. It also provides future challenges on food control and biosecurity.

Body weight in different mammalian species influences reproductive potential. The aim of the present study was to determine the relationship of body weight at the time of semen collection with libido, seminal characteristics and number of semen doses for artificial insemination (AI) in New Zealand White mature fertile male rabbits. Data came from 728 semen collections of 14 rabbits, 15-months of age that were sexually experienced with proven semen quality and fertility. Semen collection was performed twice a week with two ejaculates at each collection time and lasted 14 weeks. A second ejaculation was collected at 1-2h after the first. Data from each male from first and second ejaculates from 1 day of semen collection throughout the trial were averaged (n=324) and partial correlation coefficients and regression equations were estimated to describe the relationship of male body weight to ejaculation reaction time and 12 semen and sperm characteristics. As body weight increased there was a linear (P0.05) increase in reaction time, abnormal sperm with an intact membrane and abnormal sperm with a damaged membrane and a linear (P0.05) decrease in semen volume, sperm concentration per ejaculate, normal sperm with an intact membrane, number of normal motile sperm with an intact membrane and suitable semen doses for AI. Body weight of the mature male rabbit at semen collection had some influence on libido, semen and sperm characteristics, with a general trend toward a lesser reproduction potential as body weight increases.

International trade scrutinises food safety practices and procedures, and food businesses have to review their safety procedures more rigorously. HACCP is increasingly relied on to ensure food safety in both meat-producing and meat-processing enterprises. The objective of this study was to compare incentives, costs, difficulties and benefits of Chinese and Mexican meat-exporting enterprises related to food safety management systems implementation. A questionnaire was applied to identify the main factors involved in HACCP implementation. Data were collected among 32 Chinese and 42 Mexican companies, and analysed using the SAS package. The implementation of the HACCP system was filled out in all exporting meat industries. The results indicated that the major incentives were related to improving product quality for both countries, whilst improving control of the process was the first motivation in the Chinese industry and access to new foreign markets was the first motivation in the Mexican one. In addition, both countries’ industries reported that staff training was the most important implementing cost, while product testing was the major operating cost. The difficulties found during HACCP implementation and operation activities were associated with availability of personnel for other tasks for China and costs of certification for Mexico. The reported benefits were relevant for the two countries, due to the ability to reduce microbial counts and increased access to foreign and domestic markets. A better understanding of the costs and benefits associated with HACCP systems could be helpful and is necessary in every segment of the food chain in every sector of domestic and international markets in order to assure food quality and safety.

This study evaluated the effect of injecting trace minerals on reproductive performance in over-conditioned Holstein cows before synchronized estrus. Multiparous non-lactating, over-conditioned repeat breeder cows (n=20) were assigned randomly to one of two treatments: 1) control (n=10), and 2) supplementation with an injectable trace mineral complex 25days before expected synchronized estrus (n=10). Follicular waves were synchronized by intravaginal insertion of a CIDR for eight days and an intramuscular (i.m.) injection of a GnRH analogue. Estrus was induced at CIDR removal by an i.m. injection of PGF2α. Blood samples were collected before and after synchronized estrus. The response variables were follicle population (FP), diameter of the preovulatory follicle at CIDR removal (DFP0) and at estrus detection (DFP1), time of estrus after CIDR removal (TE), area of corpus luteum (ACL), pregnancy rate and copper and zinc serum concentrations. The statistical analysis of the variables was carried out with SAS. The FP, DFP0, DFP1, TE, ACL and serum concentrations of copper and zinc were not affected by the trace mineral injection (P>0.05). Even though pregnancy rate at 40 (77.78±13.46 vs 44.44±16.56%) and 60days after AI (66.67±15.71 vs 33.33±15.71%) was numerically higher for cows injected with trace minerals than for the control group, the differences were not significant (P>0.05). In conclusion, while follicular and corpus luteum development were not affected by trace mineral injection, it may be a feasible way to increase the pregnancy rate in over-conditioned cows.

This study evaluated the effect of injecting vitamin C (VC) and E (VE) on size of the preovulatory follicle, volume of the corpus luteum, and pregnancy rates in Holstein cows under heat stress conditions (temperature humidity index > 74). Sixty-two cows were randomly assigned to one of four treatments: 1, control, n = 15: cows were not supplemented with vitamins; 2, VCG, n = 15: cows were simultaneously injected i.v. with 500 and s.c. with 2500 mg of VC before and after estrus; 3, VEG, n = 15: cows received an i.m. injection of 3000 IU of VE before estrus; 4, VCEG, n = 17: cows were injected with VC and VE in the same way and doses as in treatments 2 and 3. Treatment did not significantly affect any of the measured variables, despite a numerical increase in pregnancy rates in cows injected with vitamins (7.5 ± 7.3%, 9.6 ± 9.4%, 15.1 ± 10.0%, and 18.34 ± 9.9% for control, VCG, VEG, and VCEG, respectively). In conclusion, injections of vitamin C and E did not affect either the development of the preovulatory follicle and the corpus luteum or pregnancy rates in Holstein dairy cattle under heat stress conditions.

The sprouted wheat (SW) contains the 6-methoxy-2-benzoxazolinone (6-MBOA), a phenol compound that stimulates reproduction in certain small wild herbivorous mammals. The objective of the present study was to evaluate the effect of short-term supplemental dietary SW on libido, semen and sperm characteristics of rabbit bucks. Five-month old New Zealand White pubertal rabbits (n=18) were randomly allocated to one of two treatments: supplementation or not (control) supplemented with SW. The experimental design was completely random with nine replications, experimental unit was one buck. Semen collection for each male was conducted once a week with two ejaculations during 20 weeks. The SW was given during four consecutive days prior to each semen collection. Analysis of variance was under a mixed model: treatment, ejaculate number and season were fixed and rabbit random effects. There was no effect of treatment (P>0.05) on reaction time, gel presence, volume, pH, sperm motility, sperm number per ml and sperm number per ejaculate. The percentage of normal alive spermatozoa was 13.5% greater in SW-supplemented bucks than in the control and the percentage of abnormal alive spermatozoa was 44.1% greater in the control than in the SW-supplemented bucks. The morphology of dead spermatozoa, integrity of acrosome, number of normal alive motile sperm and semen doses per ejaculate were not influenced (P>0.05) by SW supplementation. The proportion of presence of gel and semen volume in the first ejaculate was greater than the second ejaculate (+140% and +56.4%). However, the semen quality in the latter was greater (P=0.0001) than the former in terms of an increase in motility (+29.7%). Reproductive traits were more desirable (P

Female exposure of males could be a low-cost biostimulation option that benefits AI in commercial rabbit operations by improving buck rabbits reproductive performance. The objective of the study was to evaluate exposure of buck rabbits to females as a biostimulation option to improve reproductive potential. Treatments were: exposure (biostimulated) or not (control) of bucks to does. Bucks were New Zealand White, 15-month-old, sexually experienced and fertile. Experimental design was completely random with nine replications, experimental unit was one buck. Doe exposure was permanent using replacement pubertal does housed in an adjacent wire-mesh cage and changed for new ones every other week. Semen collection lasted 14 weeks (late winter and early spring) twice a week with two ejaculates at each collection. Analyses of variance were under a mixed model: treatments, ejaculate number and season were fixed and rabbit random effects and buck weight at each collection as covariable. Biostimulated bucks showed greater (P0.05) reproductive potential due to: 7% lesser reaction time (greater libido); and increased semen volume (40%), sperm motility (29%), sperm per ejaculate (31%), normal alive motile sperm (65%) and number of semen doses (64%). Semen characteristics differed by season in control bucks but not in doe exposed bucks (treatment × ejaculate number, P0.05). Reproductive potential in spring was greater (P0.05) than in winter in both treatments. Doe exposure is a biostimulation method that improves sexual drive and sperm production and quality of buck rabbits.

"Los objetivos fueron evaluar el efecto de la aplicación de gonadotropina coriónica humana (hCG) el día (d) 7 después de la inseminación en la formación de un cuerpo lúteo accesorio (CLA), la concentración de progesterona (P4) en plasma y la fertilidad. Se usaron 204 vacas Holstein lactantes, asignadas aleatoriamente a dos tratamientos: En el T1 (n=102), las vacas recibieron 1.000 UI de hCG y en el T2 (n=102), las vacas recibieron 2 mL de solución salina. Los d 7 y 14 después del servicio se tomaron muestras de sangre de la vena yugular para determinar la concentración de P4 en plasma y el d 14 se revisaron los ovarios por ultrasonido para evaluar la incidencia de un CLA, su diámetro, perímetro y área. La P4 se determinó mediante radioinmunoanálisis. El diagnóstico de gestación se realizó por ultrasonido 35 y 60 d después del servicio, en vacas que no retornaron a estro. La incidencia de CLA y el porcentaje de gestación fueron analizados mediante regresión logística, y el diámetro, perímetro, área y concentración de P4 con modelos mixtos. La concentración de P4 en los d 7 y 14 después de la inseminación fue similar (P>0,05) entre tratamientos. La incidencia de CLA fue mayor (P0,05) en el diámetro vertical, perímetro y área del CLA entre T1 y T2 (17,1 ± 0.3 vs 17,4 ± 0,8 mm; 65,9 ± 1.3 vs 66,2 ± 3,4 mm; y 299,9 ± 10,9 vs 293,9 ± 29,7 mm2, respectivamente) ni en el porcentaje de gestación entre tratamientos el d 35 (53,9 vs 43,1%) y 60 (43,1 vs 35,3%), respectivamente. En conclusión, la aplicación de hCG el d 7 después de la inseminación induce la formación de CLA, sin afectar sus características morfológicas, la concentración de P4 ni la fertilidad de vacas Holstein."

A study was conducted to evaluate the effect of short-term relocation and male exposure on receptivity rate, kindling rate and total born per litter in lactating does under an artificial insemination (AI) programme. Thirty-two, 2-month-old New Zealand White rabbits were randomly allocated to one of four treatments: (1) relocation and male exposure; (2) relocation without male exposure; (3) no relocation with male exposure; (4) no relocation without male exposure (control). Relocation and male exposure were done 8-10 h before the time of service. First insemination was when does reached 3200 g body weight and does were bred 4-13 days after parturition across parities during a 6 month reproduction period. Of all breeding records, 125 inseminations and 91 kindlings were from nursing does. The mean interval from parturition to insemination for nursing does was 10.3 days. Relocation of lactating does resulted in greater (P0.01) receptivity rate at service (74.8%) as compared with no relocation (55%). Receptivity rate was not influenced by male exposure. However, the interaction of relocationxmale exposure tended to be significant (P=0.07). Receptivity rate in relocated does exposed to males was 62.8 and 86.7% without exposure while in non-relocated does male exposure showed no effect. Kindling rate was not influenced by relocation or male exposure. The mean total born per litter in relocated and non-relocated does was 8.05 +/- 0.33 and 7.39 +/- 0.36, respectively, but no significant difference was observed. There was no effect of male exposure on total born per litter (7.85 +/- 0.34 versus 7.59 +/- 0.34 without male exposure). However, interaction of relocationxmale exposure on this variable was significant (P=0.009). Male exposure in relocated does decreased the size of the litter (7.52 +/- 0.46 versus 8.58 +/- 0.47 without male exposure) whereas mean values in non-relocated does increased when they were exposed to males (8.18 +/- 0.52 versus 6.60 +/- 0.49). Short-term relocation improved receptivity rate and reproduction in lactating does under an artificial insemination programme. Preliminary results indicated that male exposure in non-relocated does improves the total born per litter at a similar level than relocated does without male exposure. Relocation combined with male exposure decreased receptivity rate and total born per litter as compared with relocated does without male exposure, but the reproductive performance in the former was greater as compared with those does where no relocation occurred without male exposure.

El objetivo fue determinar la dinámica folicular, la incidencia de celos, fertilidad y prolificidad de ovejas criollas mexicanas. Se utilizaron 57 ovejas distribuidas al azar a uno de tres tratamientos:T1) Aplicación i.m. de 25 mg de P4 48 horas (h), antes de la remoción de esponja intravaginal (n=19); T2) Aplicación i.m. de 25mg de P4, 24 h, antes de remover la esponja (n =20) y T3) Sin aplicación de P4 o grupo testigo (n=18). Las esponjas contenían20 mg de acetato de fluorogestona (FGA) y permanecieron en las ovejas por 12 días (d). El diseño experimental fue completamente al azar y la unidad experimental fue la oveja. Se determinó con ultrasonido el número de folículos 2 mm de diámetro a la hora cero (considerada el día en que se aplicó P4 en los tratamientos, y en el grupo testigo 48 h, antes de remover la esponja),y a las 24 y 48 h después. La inseminación fue por la paroscopía y la gestación diagnosticada con ultrasonografía. Hubo aumento (P0,05) del número de folículos en los tratamientos, excepto en el testigo de la hora cero a las 24 h. El diámetro del folículo más grande se redujo (P0,05) a las 24 h después de la hora celo sólo cuando la P4 se aplicó 48 h solo en el tratamiento P4 48 h alas 24 h después de la hora cero. El inicio del celo fue más tardío en el tratamiento P4 24 h (P0,05; 167,1 ± 11,0) comparado con los demás tratamientos. El porcentaje de gestación en el tratamiento P4 24 h fue superior (P0,05) al del testigo (70,0 vs 33,3).La aparición del celo se retrasó cuando se aplicó P4, 24 h, antes de la remoción de la esponja y mejoró la fertilidad de ovejas criollas mexicanas.

El objetivo del presente trabajo fue evaluar la eficiencia del lí- quido folicular equino (LFE) adicionado en un protocolo de sin- cronización de estros en ovejas Criollas. Se sincronizaron 79 ovejas multíparas con un peso vivo promedio de 37±7,1 kg usando esponjas intravaginales conteniendo 20 mg de Acetato de Fluorogestona (FGA); diez días (d) después de la inserción se inyectaron vía intramuscular, 0,075 mg de prostaglandinas (D-cloprostenol). El d 11, los animales recibieron 0 (T1; n=20), 2 (T2; n=20), 3 (T3; n=20) ó 4 (T4; n=19) mL de LFE por vía in- tramuscular. El LFE se obtuvo aspirando folículos mayores de 20 mm de diámetro, centrifugado a 952 g por 15 minutos (min) y fue almacenado a -5°C hasta su utilización. Las espon- jas se retiraron el d 12 y 24 horas (h) después se inició la de- tección de estros. Las ovejas fueron inseminadas con semen fresco por laparoscopía 20 h después del inicio del estro, utili- zando 100 x 10 estros (IE, %), tiempo de inicio al estro (TIE, h), número de fo- lículos preovulatorios (NFP), diámetro del folículo preovulatorio (DFP, mm), tasa ovulatoria (TO), diámetro del cuerpo lúteo (DCL), tasa de gestación (TG) y prolificidad (P). Los datos se analizaron con pruebas de Ji-cuadrado y ANOVA. Se encon- traron diferencias (P0,05) en TIE entre T1 y T3 (55,95 ± 2,18 vs. 64,60 ± 2,18), en TO entre T1, T3 y T4 (1,25 ± 0,15 vs. 1,85 ± 0,15 vs. 2,44 ± 0,16 cuerpos lúteos) y en TG entre T1 y T2 vs. T3 y T4. No hubo diferencias (P0,05) entre tratamien- tos en IE, NFP, DFP y DCL. En conclusión, la aplicación de 3 y 4 mL de LFE afectó TIE, TO y TG.

El consumidor es uno de los eslabones de la cadena de alimentos, responsable de mantener la inocuidad de los alimentos y evitar enfermedades por contaminación de los mismos. El objetivo del estudio fue determinar el nivel de conocimiento, actitud y comportamiento respecto a la inocuidad de los alimentos entre estudiantes universitarios, mediante la aplicación de un cuestionario a 97 estudiantes en el último tercio de la carrera profesional. La información se analizó mediante Ji-cuadrado. La inocuidad de los alimentos fue un tema de mediano interés entre otros temas de la vida diaria; sin embargo, la inocuidad fue la característica calificada como más importante de los alimentos y señalando mayoritariamente a los productos pecuarios como los de mayor riesgo de ocasionar enfermedades. La educación formal universitaria, internet y libros especializados fueron las fuentes principales de información sobre el tema de inocuidad. Se concluyó que para la industria pecuaria, la difusión hacia los consumidores de buenas prácticas sanitarias en el manejo de los alimentos es de interés para fomentar y disminuir la caída en el consumo de sus productos

" El estudio se realizó en el Parque Nacional Izta-Popo y Zoquiapan. Se estimaron los aportes nutriciona¬les, biomasa vegetal, capacidad nutricional de carga del hábitat y hábitos alimenticios del Romerolagus diazi. Para ello, las excretas y muestras vegetales se recolectaron y fueron analizadas microhistológi¬camente. Se determinaron la materia seca, proteína cruda y fibra detergente neutro de las plantas. A su vez, se realizó un ensayo de digestibilidad con conejos domésticos proporcionándoles dos tratamientos: Muhlenbergia macrura o Festuca tolucensis adicionadas con heno de alfalfa (80 % gramínea + 20 % de heno de alfalfa). En la mitad de los sitios predominó M. macroura y en la otra mitad F. tolucensis. El análisis microhistológico mostró la presencia predominante de los mismos forrajes. Hubo diferencias en biomasa y capacidad de carga entre sitios (P < 0.05). La inclusión de F. tolucensis incrementó (P < 0.05) la digestibilidad en comparación con M. macroura."

"Se evaluó una cepa bacteriana de Clostridium sordellii y otra de Peptostreptococcus tetradius (aisladas en un trabajo previo, a partir del ciego de conejos en engorda) como complementos, suministrados mediante aspersión en alimento comercial para conejos Nueva Zelanda, blancos, recién destetados y en etapa de engorda. El trabajo se llevó a cabo en un centro de engorda cunícola en el cual se presentaba morbilidad de 60% y mortalidad de 50% a causa de diarreas inespecífi cas. Se crearon tres grupos experimentales: al primero se le proporcionó alimento comercial sin inocular, al segundo se le proporcionó alimento comercial adicionado con C. sordellii y al tercero, adicionado con P. tetradius. Se evaluó ganancia diaria de peso, consumo de alimento y efi ciencia alimenticia durante cinco semanas, además se realizaron tres ensayos de digestibilidad aparente. Asimismo, se cuantifi có la mortalidad y la morbilidad causada por diarreas inespecífi cas durante el periodo señalado. Después del sacrifi cio de los conejos, se midió la concentración de bacterias totales y celulolíticas, pH y amonio en muestras del apéndice cecal, treceava asa cecal y colon. Los resultados no mostraron diferencia signifi cativa (P > 0.05) entre los tratamientos para ninguna de las variables productivas medidas. Se encontraron diferencias estadísticas (P < 0.05) en el pH y la concentración de amonio a nivel del apénentedice cecal entre el grupo al que se le suministró C. sordellii y los dos grupos restantes, mientras que a nivel de la treceava asa cecal se encontraron diferencias (P < 0.05) en la concentración de amonio entre el grupo que recibió P. tetradius y los otros dos grupos. En lo referente a bacterias totales se encontraron diferencias (P < 0.05) a nivel de apéndice cecal entre el grupo testigo y el que recibió P. tetradius, y a nivel de colón distal entre el grupo que recibió C. sordellii y P. tetradius. La administración de C. sordelli estuvo asociada a una morbilidad diarreica más baja (35%) que la observada en el caso delgrupo testigo (80%) y del grupo que recibió complemento de P. tetradius (80%) (P < 0.05)."

The sprouted wheat contains great amounts of 6-methoxybenzoxazolinone (6-MBOA) a phenol compound that stimulates reproduction in certain small wild herbivorous mammals. The objective of the present study was to evaluate the effect of dietary sprouted wheat as supplement on reproduction in artificially inseminated doe rabbits. Two-month-old New Zealand White doe rabbits (n = 48) were randomly allocated to one of two treatments: (1) pelleted diet plus sprouted wheat for 6 consecutive days prior to service, (2) pelleted diet only (control). First insemination occurred when does reach 3200g body weight and bred 6 days after parturition across 6 months period during summer and autumn. Records from 41 does completing the experiment accounted for 192 inseminations and 142 kindlings equivalent to 4.6 +/- 0.15 and 3.5 +/- 0.15 litters per doe, respectively. Mean daily intake of sprouted wheat on wet and dry matter bases were 196.1 +/- 7.5 and 75.4 +/- 2.9g, respectively. The number of young born produced per doe during the trail was significantly (P = 0.02) greater in does fed sprouted wheat (28.1 +/- 1.2 versus 23.6 +/ -1.3 control). Does fed sprouted wheat had 0.65 +/- 0.06 receptivity rate at AI over 28 per cent greater (P = 0.001) than does in the control treatment. Sexual receptivity was not influenced by physiological status of does and season (P0.05). Diet and season had no effect (P0.05) on kindling rate. However, physiological status had an effect (P = 0.002) on this variable. Kindling rates for nulliparous, lactating and non-lactating does were 0.95 +/- 0.08, 0.63 +/- 0.04 and 0.78 +/ -0.11, respectively. Sexually receptive does had a greater (P = 0.0001) kindling rate (0.95 +/- 0.05) than non-receptive females (0.63 +/-0.05). Does fed sprouted wheat produced larger (P = 0.02) litters than those in the control group: 7.7 +/- 0.30 and 6.8 +/- 0.32, respectively. There was an effect of season (P = 0.04) on the size of the litter at birth. Largest litters were born during autumn (7.9 +/- 0.37) than during summer (6.6 +/- 0.41). Receptive does had more (P = 0.002) young in the litter (7.9 +/- 0.28) than non-receptive (6.6 +/- 0.35). Feeding sprouted wheat as a source of biological 6-MBOA enhanced sexual receptivity and prolificacy in artificially inseminated doe rabbits bred in summer and autumn.

Se utilizaron 139 registros de 43 conejas nulíparas Nueva Zelanda Blanco (NZB) y 46 hembras Californianas (CAL) para determinar la relación del nivel de alimentación (alto vs bajo), cambio de jaula (sí vs no), ayuno (sí vs no) y raza (NZB vs CAL) en el comportamiento reproductivo. Se estudiaron el color de la vulva, receptividad, tasa de gestación y tamaño de camada al nacimiento (TCN). Los datos se analizaron con un arreglo factorial 24 mediante la metodología de modelos mixtos. En el nivel alto de alimentación se observó (p #8804;0.01) 57% de vulvas rosas y 16% de rojas. El no ayuno influyó (p #8804;0.05) en el color de la vulva, prevaleciendo las vulvas rosas, 47%, y rojas, 19%. Al cambio de jaula, las conejas CAL presentaron mejor receptividad (74±8%; p #8804;0.03) que las NZB (55±9%). En el nivel alto de alimentación y el no ayuno la receptividad fue diferente entre genotipos (p #8804;0.01) al primer intento de cubrición, con 79±11% en las NZB y 61±11% en las CAL. El nivel alto de alimentación y ayuno mejoró (p #8804;0.05) la tasa de gestación (83±8%), con respecto al nivel bajo de alimentación y ayuno (48±3%). Para el nivel bajo de alimentación y ayuno el TCN fue 8.5±1 para NZB y 6.4±2 para CAL (p #8804;0.05). Se concluye que un nivel alto o bajo de alimentación puede influir en el color de la vulva y receptividad de conejas nulíparas. A su vez, el cambio de jaula 24 h antes de la cubrición puede favorecer su receptividad. El nivel alto de alimentación favoreció la tasa de gestación, pero no cambió el tamaño de camada al nacimiento.

[EN] A total of 713 inseminations and 431 kindling records were used for statistical analysis to determine the fixed effects of season, sexual receptivity and physiological status on kindling rates (KR) and total born per litter (TB). Rabbits were reared in México under a moderate climate located at 2240 m above sea leve! with an average yearly temperature of 15ºC. Eighty four New Zealand White rabbits two months of age were reared in a 64-cage replacement system and bred throughout a one-year reproduction cycle. Does kept in 32 cages were inseminated regularly 4-8 days after parturition while does maintained in the other 32 cages were under a 9-13 days reproductive rhythm. Season had no influence on reproductive performance (P>0.05). Kindling rates for spring, summer, autumn and winter were 0.67, 0.67, 0.66, and 0.65 respectively, with TB values of 8.35 ± 0.26, 8.06 ± 0.25, 8.03 ± 0.27 and 7.86 ± 0.40 respectively. Does that were sexually receptive at insemination had significantly (P, [FR] Une analyse statistique, portan! sur les données enregistrées de 713 inséminations et 431 mises bas, a été effectuée pour déterminer l'effet fixe de la saison, de la réceptivité sexuelle et du stade physiologique sur le taux de mise bas (KR) et le nombre total de lapereaux par portée (TB). Ces lapins ont été élevés au Mexique, sous un clima! modéré a 2240m d'altitude avec une température moyenne annuelle de 15ºC. Quatre-vingtquatre lapines NZW sélectionnées a l'age de 2 mois ont été élevés pendan! un cycle de reproduction d'un an dans un ensemble de 64 cages avec remplacement des sujets morts ou réformés. Les lapines, logées dans 32 des cages, ont été réguliérement inséminées 4-8 jours aprés la mise bas, tandis que celles des 32 autres cages l'ont été 9-13 jours aprés la mise bas. La saison n'a pas eu d'influence sur les performances de reproduction (P>0.05). Le taux de mise bas au printemps, en été, a l'automne et en hiver a été de 0,67 ; 0,67 ; 0,66 et 0,65 respectivement avec des nombres de lapereaux nés de (TB) 8,35 ± 0,26 ; 8,06 ± 0,25 ; 8,08 ± 0,27 et 7,86 ± 0,40 respectivement. Les femelles sexuellement réceptives a l'insémination ont eu un taux de mise bas significativement (P

Stress is the result of an imbalance between free radicals and antioxidants. Under normal physiological conditions, free radicals are involved in reproductive events such as cell cycle activation, ovulation and luteolysis. However, when an overproduction of free radicals surpasses antioxidant capacity, oxidative damage, reproductive anomalies and diminished fertility occur. Supplementation with antioxidants prevents oxidative damage and can be incorporated into reproductive management to improve fertility in females. Selection of the preovulatory follicle, ovulation, fertilization, embryo development and formation of the corpus luteum occur during the periconceptional period. This is a dynamic period and the events are susceptible to oxidative stress damage. Therefore, the objective of this review is to discuss the effect of oxidative stress on reproductive events during the periconceptional period, as well as to address antioxidant supplementation during this period. Key words: embryo, fertility, free radicals, oocytes, ovulation, oxidative stress. Resumen El estres oxidativo es generado por un desbalance entre radicales libres y antioxidantes. Bajo condiciones fisiologicas normales, los radicales libres participan en eventos reproductivos tales como activacion del ciclo celular, ovulacion y luteolisis. Sin embargo, cuando estos son producidos en cantidades que sobrepasan la capacidad antioxidante del organismo producen dano oxidativo y trastornos reproductivos que disminuyen la fertilidad de la hembra. La suplementacion con antioxidantes previene el dano oxidativo y su incorporacion a programas de manejo reproductivo puede ser una opcion para mejorar la fertilidad de la hembra. La seleccion del foliculo preovulatorio, ovulacion, fecundacion, desarrollo embrionario y formacion del cuerpo luteo ocurren durante el periodo periconcepcional. Este es un periodo dinamico y los eventos que ocurren en el son susceptibles a dano por estres oxidativo. Por tanto, el objetivo de esta revision es discutir el efecto del estres oxidativo en los eventos reproductivos durante el periodo periconcepcional, asi como la suplementacion de antioxidantes en rumiantes durante este periodo. Palabras clave: embrion, estres oxidativo, fertilidad, ovocito, ovulacion, radicales libres. Resumo O stress oxidativo e gerado por um desequilibrio entre radicais livres e antioxidantes. Sob condicoes fisiologicas normais, os radicais livres participam de eventos reprodutivos, como ativacao do ciclo estral, ovulacao e luteolise. No entanto, quando e produzido em quantidades que excedem a capacidade antioxidante do organismo, produzem danos oxidativos e disturbios reprodutivos que diminuem a fertilidade da femea. A suplementacao com antioxidantes previne o dano oxidativo e sua incorporacao em programas de gerenciamento reprodutivo pode ser uma opcao para melhorar a fertilidade da femea. A selecao do foliculo pre-ovulatorio, ovulacao, fecundacao, desenvolvimento embrionario e formacao do corpo luteo ocorrem durante o periodo periconcepcional. Este e um periodo dinâmico e os eventos que ocorrem sao suscetiveis ao dano por estresse oxidativo. Portanto, o objetivo dessa revisao e fornecer ao leitor conhecimento sobre o efeito do estresse oxidativo em eventos reprodutivos durante o periodo periconcepcional, e tambem discutir a suplementacao com antioxidantes em ruminantes durante este periodo. Palavras-chave: embriao, estresse oxidativo, fertilidade, ovocito, ovulacao, radicais livres.