Se presentan los principales parámetros productivos, reproductivos y de manejo de los tres principales tipos de sistemas de producción bovinos lecheros que existen en México. La importancia de mostrar el valor con número de cada parámetro permitirá al lector observar que existen diferencias en la forma de producir leche de bovino en México. Además, cada sistema se adapta a la región agroecológica donde se localiza. La información del presente manuscrito compara los sistemas de producción de leche de bovinos. Las diversas estrategias de manejo alimenticio y reproductivo en estos sistemas permiten producir de manera eficientemente para ser competitivos dentro de una economía mundial globalizada, enfrentando el reto de ser sustentables, por otro lado, mitigar los efectos que la ganadería en el cambio climático.

Different nutritional factors affect the resumption of postpartum ovarian activity in dual-purpose cattle in the tropical region. First, this review establishes the importance of reducing postpartum anestrus in cows to achieve greater reproductive performance. Next sections describe how each nutritional component has affected reproductive parameters. In most of the studies analyzed, comparisons of reproductive parameters were made between a group receiving the treatment and the control group. Then, a series of strategies to improve reproduction in dual-purpose cattle were described. Finally, the conclusions and practical implications were presented. http://dx.doi.org/10.21929/abavet2022.251 e2022-18 https://www.youtube.com/watch?v=2pjtZqmxN78 Son diversos los factores nutricionales que afectan al reinicio de la actividad ovárica posparto en bovinos de doble propósito en la región tropical. En este manuscrito se describe la importancia de reducir el anestro posparto de las hembras con el propósito de lograr una mayor eficiencia reproductiva. Las secciones siguientes describen como cada componente de los alimentos ha afectado los parámetros reproductivos. En la mayoría de los estudios analizados se realizaron comparaciones de los parámetros reproductivos entre un grupo que recibe el tratamiento y el grupo control. Asimismo, se describe una serie de estrategias para mejorar la reproducción en bovinos doble propósito. Finalmente, se presenta las conclusiones e implicaciones prácticas. http://dx.doi.org/10.21929/abavet2022.251 e2022-18 https://www.youtube.com/watch?v=2pjtZqmxN78 http://dx.doi.org/10.21929/abavet2022.251 e2022-18 https://www.youtube.com/watch?v=2pjtZqmxN78

This study aimed to evaluate whether exposure to artificial long-day photoperiods stimulates growth performance in young male goats, either intact or castrated. Forty young male goats (13 wk old), either intact (I) or castrated (C), were assigned to one of two photoperiod treatments: artificial photoperiod (AP; 16h light:8h dark) or natural photoperiod (NP; 12h light:12 dark). Animals were housed individually, and four experimental groups were established: NP-I (n = 10), AP-I (n = 11), NP-C (n = 10), and AP-C (n = 9). Males were weighed weekly; glucose, testosterone, and insulin-like growth factor 1 (IGF-1) concentrations were monitored biweekly; and feed intake was measured every 3 wk from September to February. At 38 wk of age, males were slaughtered to assess carcass yield. Each animal was considered an experimental unit, and the data were analyzed using mixed models and repeated measures of SAS. Goats exposed to AP gained more weight and had greater final body weights than those under NP conditions (P < 0.001). Intact males also gained more weight than castrated males (P < 0.001). Feed intake was greater in AP-treated animals (P < 0.001). Carcass yield was greater in both AP- and I-males compared to NP- and C-males, respectively (P < 0.001). IGF-1 concentration increased in AP- and I-males than in NP- or C-males (P < 0.001), and glucose concentration increased in AP-treated animals compared to those exposed to NP (P < 0.001). Testosterone concentration increased in AP males than in NP males in weeks 15 and 17 (P < 0.01), but not at the other time points (P > 0.05). These findings suggest that exposure to artificial long-day photoperiods increases daily weight gain, feed intake, final body weight, and carcass yield in young male goats, regardless of their reproductive status. These improvements were associated with increased IGF-1 and glucose concentrations, while testosterone concentration remained unaffected.

Transrectal ultrasonography is a technology used in cattle reproductive management as a means of gestation diagnosis and estrous cycle monitoring. Likewise, it has application in the management, diagnosis and treatment of both reproductive processes and in reproductive biotechnology programs. The objective of the work was to carry out a bibliographic review on the reproductive processes in cows and the use of ultrasonography. A bibliographic review was carried out including publications from 2022 and previous years. Criteria that support the development achieved in the use of ultrasound were considered, based on the logical analysis of the consulted bibliography. The keywords used were ultrasonography, ultrasound, cattle, bovine reproduction, transrectal palpation, estrous cycle, follicular dynamics, ovarian function, Doppler, corpus luteum functionality, early pregnancy diagnosis, embryonic death. Transrectal ultrasonography has increased our knowledge and understanding of bovine reproductive physiology. Technological advances have allowed its use in the reproductive management of cattle to increase. Ultrasonography is a revolutionary advance in research that has influenced the efficiency of cow reproductive management. http://dx.doi.org/10.21929/abavet2023.18 e2022-81 https://www.youtube.com/watch?v=DYXRCAvYA-8 La ultrasonografía transrectal es una tecnología utilizada en el manejo reproductivo de los bovinos como medio del diagnóstico de gestación y de seguimiento del ciclo estral. Asimismo, tiene aplicación en el manejo, diagnóstico y tratamiento tanto de procesos reproductivos como en programas de biotecnología reproductiva. El objetivo del trabajo fue realizar una revisión bibliográfica sobre los procesos reproductivos en vacas y el uso de la ultrasonografía. Se realizó una revisión bibliográfica incluyendo publicaciones del 2022 y años previos. Se consideraron criterios que sustentan el desarrollo alcanzado en el uso de ultrasonido, basados en el análisis lógico de la bibliografía consultada. Las palabras clave utilizadas fueron ultrasonografía, ecografía, bovinos, reproducción bovina, palpación transrectal, ciclo estral, dinámica folicular, función ovárica, Doppler, funcionalidad del cuerpo lúteo, diagnóstico precoz de la preñez, muerte embrionaria. La ultrasonografía transrectal ha aumentado nuestro conocimiento y comprensión de la fisiología de la reproducción del bovino. Los avances tecnológicos han permitido que su empleo en el manejo reproductivo del ganado bovino se incremente. La ultrasonografía es un avance revolucionario en la investigación que ha influenciado la eficiencia en el manejo reproductivo de la vaca. http://dx.doi.org/10.21929/abavet2023.18 e2022-81 https://www.youtube.com/watch?v=DYXRCAvYA-8 A ultrassonografia transretal é uma tecnologia usada no manejo reprodutivo de bovinos como meio de diagnosticar a gestação e monitorar o ciclo estral. Também é usada no manejo, diagnóstico e tratamento de processos reprodutivos e em programas de biotecnologia reprodutiva. O objetivo deste estudo foi realizar uma revisão da literatura sobre os processos reprodutivos em vacas e o uso da ultrassonografia. Foi realizada uma revisão da literatura, incluindo publicações de 2022 e de anos anteriores. Foram considerados critérios para apoiar o desenvolvimento alcançado no uso do ultrassom, com base na análise lógica da literatura consultada. As palavras-chave utilizadas foram ultrassonografia, ultrassonografia, bovinos, reprodução bovina, palpação transretal, ciclo estral, dinâmica folicular, função ovariana, Doppler, funcionalidade do corpo lúteo, diagnóstico precoce de gestação, morte embrionária. A ultrassonografia transretal aumentou nosso conhecimento e compreensão da fisiologia reprodutiva bovina. Os avanços tecnológicos permitiram o aumento de seu uso no manejo reprodutivo de bovinos. A ultrassonografia é um avanço revolucionário na pesquisa que influenciou a eficiência do manejo reprodutivo dos bovinos. http://dx.doi.org/10.21929/abavet2023.18 e2022-81 https://www.youtube.com/watch?v=DYXRCAvYA-8

Objective: Evaluate the adaptation of calves in the transition from intensive to dual-purpose system during extreme drought. Design/methodology/approach: The study was carried out in Tamaulipas, Mexico with calves in transition from an Intensive Production System (IPS) in Ciudad Victoria to a Dual-Purpose System (DPS) located in Altamira. Two groups of Swiss×Gyr×Holstein cross calves were analyzed, control group (CG; n = 8) born in DPS, and the adapted group coming from IPS (GA; n =6), zoometric measurements were recorded: height at the withers, length of the animal, chest circumference, pelvis length, pelvis width, height at the rump, body condition and weight, the blood concentration of betahydroxybutyrates (BHB) and glucose were measured. An ANDEVA was carried out with a factorial design and a correlation analysis. Results: There were differences between GA and GC (P < 0.01), as well as in the date factor (P < 0.01). Blood concentrations of BHB and glucose had no difference between groups (P < 0.05). There was a negative correlation (R = - 0.47; P < 0.05) between BHB and body condition. Limitations on study/implications: Although the dual-purpose system is very versatile, in the study area only 33% of ranchers manage it, due to the accentuation of drought and climate change. Findings/conclusions: The calves showed adequate development with good adaptation in the transition from SPI to SDP, although there was an effect of the factors, the calves responded favorably to management