DSpace Coleção: Artigo em periódico indexado (CNPGC)

Nutrition management strategies for the adaptation of cull beef heifers to feedlot.

Thu, 01 Jan 2026 00:00:00 GMT

Título: Nutrition management strategies for the adaptation of cull beef heifers to feedlot. Autoria: SILVA, M. G. P. da; ÍTAVO, L. C. V.; GOMES, R. da C.; ÍTAVO, C. C. B. F.; ARCANJO, A. H. M.; SANTANA, J. C. S.; TEIXEIRA, P. D.; GURGEL, A. L. C. Conteúdo: ABSTRACT - Providing diets with high roughage in the first days of confinement is the common way of adapting beef cattle to intensive production. However, it is possible to offer the final finishing diet from the first day of adaptation. Our objective was to compare a traditional adaptation protocol, in which animals received a diet with a higher proportion of roughage, with an experimental protocol, in which animals received the final finishing diet in restricted amounts, on the productive performance of beef heifers in the first 42 days ofconfinement, divided into two periods (0–14 days, 15–42 days). A total of 552 heifers were evaluated and subjected to 2 adaptation strategies: (1) traditional protocol—ad libitum feed with a quantified greater proportion of roughage in the first 14 days, and (2)experimental protocol—gradual increase in the amount of final finishing feed. The nutrient intake and productive performance were evaluated. The intake was greater in the traditional protocol in all periods, 8.2 vs. 7.9 kg/day, 9.6 vs. 9.2 kg/day, and 9.2 vs. 8.8 kg/day,to 0–14, 15−42, and 0–42 days, respectively. However, performance was better in the experimental protocol in the initial period(0–14 days), 0.7 vs. 0.3 kg/day. After adaptation (15–42 days), the traditional protocol performed better, 1.5 vs. 1.3 kg/day. The nutritional protocol of gradual adaptation to total feed is recommended for heifers adapting to confinement.

Management practices for the control of Haematobia irritans, Dermatobia hominis, and Cochliomyia hominivorax in cattle across Latin America: a sustainable, collective approach.

Thu, 01 Jan 2026 00:00:00 GMT

Título: Management practices for the control of Haematobia irritans, Dermatobia hominis, and Cochliomyia hominivorax in cattle across Latin America: a sustainable, collective approach. Autoria: RODRIGUEZ-VIVAS, R. I.; CUTOLO, A. A.; BARROS, A. T. M. de; CUORE, U. D.; MOLENTO, M. B.; LÓPEZ-OSORIO, S.; RODRIGUES, D. S.; SPINA, M.; BORGES, F. A.; LOPES, W. D. Z.; PULIDO-MEDELLIN, M. O.; FIEL, C. A.; COSTA-JUNIOR, L. M.; ANZIANI, O. S.; SAN MARTÍN, L. M.; SABATINI, G. A. Conteúdo: ABSTRACT - Bovines are suitable hosts and can be affected by fly infestations. Flies pose a significant threat to cattle livestock in Latin America (LA), causing substantial economic repercussions to animal production (reduced productivity, veterinary expenses, and decreased animal welfare) and damage to human health. The most important flies affecting cattle in Argentina, Brazil, Colombia, Mexico, and Uruguay are Haematobia irritans, Dermatobia hominis, and Cochliomyia hominivorax. Due to production losses and the consequent economic costs associated with these flies, control measures must be implemented, primarily relying on insecticidal products. However, decision-making for preventing and treating animals with insecticides varies due to differences in environmental conditions across countries and regions, production systems, animal populations, infestation levels, animal welfare, and the prevalence of myiasis, among other factors. Although insecticides remain the most effective option for fly control in cattle, resistant populations have developed, rendering them less effective. To overcome fly resistance to insecticides, non-chemical (mechanical, environmental, biological, and genetic) methods are being integrated into alternative control and eradication strategies. The use of integrated livestock fly control contributes to safeguarding animal, public, and environmental health. This review is designed to support individuals and institutions, both civil and governmental, addressing the ongoing challenge posed by flies affecting livestock.

One or two cyclicity inductions on TAI pregnancy rate and pregnancy loss in precocious Nellore heifers.

Wed, 01 Jan 2025 00:00:00 GMT

Título: One or two cyclicity inductions on TAI pregnancy rate and pregnancy loss in precocious Nellore heifers. Autoria: TAVEIRA, A. A. R.; SILVA, L. G. da; SILVA, L. G. da; MASCHARELLO, J.; FERREIRA, L. C. L.; NOGUEIRA, E. Conteúdo: ABSTRACT - The objective was to evaluate the pregnancy rate and pregnancy loss of precocious Nellore heifers submitted to one or two previous cyclicity inductions to TAI (timed artificial insemination). A total of 572 Nellore nulliparous aged 12 to 14 months-old were used, divided into two treatments: on D-50, T1- one cyclicity induction (n = 313): 1 ml of 0.9% NaCl and T2- two cyclicity induction (n = 259): 1 ml of injectable progesterone. From that date, the two groups received the same management as follows: On D-26, oral supply of 2.28 g/head/ day (MGA® PREMIX) for twelve days and on D-12, IM application 0.6 mg of estradiol cypionate (E.C.P.®) in all. Subsequently carried out the TAI protocol and pregnancy diagnosis was performed on D41 and pregnancy confirmed on D101. The uterus and ovary were evaluated in D-50, D-26, and D0. There was no difference in pregnancy rate and pregnancy loss (P > 0.05), besides in T2, better grades of uterine and ovarian scores were observed between the beginning of cyclicity induction and D0 (P < 0.05). The two-induction group had better uterus and ovary scores, which did not interfere with pregnancy and pregnancy loss rates. RESUMO - O objetivo foi avaliar a taxa de prenhez e perda de prenhez de novilhas Nelore precoces submetidas a uma ou duas induções prévias à IATF (inseminação artificial em tempo fixo). Foram utilizadas 572 nulíparas nelore com idade entre 12 e 14 meses de idade, divididas em dois tratamentos: no D-50, T1- uma indução (n = 313): 1 ml de NaCl 0,9% e T2- duas induções (n = 259): 1 ml de progesterona injetável. A partir dessa data, os dois grupos receberam o mesmo manejo: no D-26, administração oral de 2,28 g/cabeça/dia (MGA® PREMIX) por doze dias e no D-12, aplicação IM de 0,6 mg de cipionato de estradiol (E.C.P.®) em todos. Posteriormente foi realizado o protocolo de IATF e o diagnóstico de gestação foi realizado no D41 e a gestação confirmada no D101. O útero e o ovário foram avaliados em D-50, D-26 e D0. Não houve diferença na taxa de prenhez e perda gestacional (P > 0,05), apesar de observadas melhores notas dos escores uterino e ovariano entre o início da indução e o D0 no tratamento T2 (P < 0,05). O grupo das duas induções teve melhor desenvolvimento de útero e ovário, não interferindo na taxa de prenhez e perda gestacional.

Transcriptomic analysis of heifers according to antral follicle count.

Wed, 01 Jan 2025 00:00:00 GMT

Título: Transcriptomic analysis of heifers according to antral follicle count. Autoria: GHELLER, J. M.; SILVA, W. A. L. da; SOUZA-CÁCERES, M. B.; SILVA, A. F. da; FERREIRA, M. G. C. R.; SANTANA, T. dos S.; SANTOS, A. C. dos; PEREIRA-JUNIOR, S. A.; NOGUEIRA, E.; ALENCAR, S. A. de; MACEDO, G. G.; SENEDA, M. M.; CHIARATTI, M. R.; MELO-STERZA, F. de A. Conteúdo: ABSTRACT - While antral follicle count (AFC) has been associated with higher pregnancy rates, at present, our understanding of it as a reproductive parameter remains incomplete. This study aimed to characterize gene expression profile of oocytes from crossbred Bos taurus x Bos indicus heifers with high and low AFCs. Crossbred Nelore-Angus heifers (n = 50) with a mean (SD) age of 9.6 ± 0.55 months, a weight of 295.4 ± 32.6 kg, and a BCS of 3.44 ± 0.41 were studied in a feedlot system. The heifers received a hormonal protocol based on injectable progesterone and estradiol cypionate administered 12 days apart, and ovarian ultrasonography (US) was performed 12 days after to assess the AFC. Based on AFC, heifers were divided into low (≤14 follicles) and high (≥31 follicles) AFC, groups.Forty-five days after US, 14 heifers were slaughtered, and their ovaries were collected for morphological analysis and follicle aspiration. Cumulus-oocyte complexes (COCs) from the high and low AFC groups were graded according to their quality. Only best-quality COCs were stored for RNA-seq analysis. No differences were found in the presence or diameter of the dominant follicle and corpus luteum in the US, nor in the volume of the dominant follicle postmortem. The quantity of COCs recovered from high-AFC heifers was higher than that from low-AFC heifers (P < 0.05), and a tendency (P = 0.07) toward a higher amount of grade II COCs was observed. Thirty-two genes were differentially expressed between the groups, of which 30 were up-regulated and two down-regulated in the low AFC group. Among these, 22 % (7/32) were associated with fertility (CAB39, SLC2A6, CITED2, FDX1, HSD11B2, CD81, and PLA2G12B). Moreover, 9 and 2 exclusive genes were identified in the high and low AFC groups, respectively. Enrichment analyses showed that genes exclusive to oocytes from low-AFC heifers were associated with fundamental cellular processes, such as biosynthesis/biogenesis of ribosomes, peptides, amides, and nucleotides, and also with autophagy, mitophagy and mTOR signalling pathways.On the other hand, only one pathway was enriched in the high AFC group, but this cannot be related to the events studied No differences were observed in the ovarian structures after pre-synchronization of the estrus cycle of young Crossbred Nelore-Angus heifers. However, a tendency of a higher amount of grade II COCs was observed in heifers with high AFC than in those with low AFC. RNA sequencing results indicated that the main differences between high and low AFC heifers were not reflected in the genes directly related to fertility.