Factors affecting the in vitro embryo production in buffalo (Bubalus bubalis): A review.

Under natural and well-managed conditions, the buffalo has good reproductive and productive indices. However, in vitro embryo production (IVEP) has been used commercially to maximise the number of elite animals. In this species, several factors (donor management, in vitro culture medium, semen, in vitro conditions, embryo transfer) still affect the IVEP results. In addition, the cost of this technique is very high for this purpose. Therefore, more studies, as well as adequate plans, are needed to achieve this objective efficiently. In this review, we discussed the current commercial status, influencing factors (in vivo and in vitro), and the progress and future challenges of IVEP in buffalo. A total of 81 references were used from 1979 to 2022. The relevant data or literature were searched using the following databases: Google, ResearchGate, Science Alert, Science Direct and PubMed, using the following keywords: buffalo oocytes/COCs, buffalo embryos, pregnancy and calving or live birth rate after embryo transfer. The best maturation, cleavage and blastocyst rates in the in vitro production of buffalo embryos were 95.8, 75.2 and 33.4%, respectively. The pregnancy and live birth rates ranged from 22.2% to 43.5% and from 15.3% to 36.5%, respectively, after the transfer of fresh embryos produced in vitro to the recipients. This review will help to contextualise IVEP in buffaloes, as well as create an adequate plan for implementing IVEP in buffaloes.

Effect of oestrous resynchronization on the reproductive efficiency of zebu cows.

The aim of this study was to develop a resynchronization strategy before the return of oestrus in cows diagnosed as not pregnant after fixed-time artificial insemination (TAI). A total of 839 cows, approximately 45 days post-partum, were synchronized using TAI. On day 0, intravaginal progesterone-releasing devices were inserted and 2 mg of oestradiol benzoate was administered. Eight days later (D8), the progesterone-releasing devices were removed and oestradiol cypionate (0.5 mg, eCG [300 IU]) and prostaglandin (7.5 mg) were administered. All cows were inseminated between 48 and 56 hr after device removal (D10). Thirty days after TAI, cows that were not diagnosed as pregnant by ultrasound were immediately resynchronized and again inseminated at a fixed time. The hormonal protocol used in the first and second rounds of TAI was the same. The pregnancy rate after the first TAI was 52%, and after the second TAI, it was 49%. The increase in the total pregnancy rate (synchronization + second oestrous synchronization) compared to a single synchronization was 23.5%. In conclusion, resynchronization of oestrus and ovulation in zebu cows that had previously undergone TAI protocols is effective in increasing the reproductive efficiency.

Oocyte competence and gene expression in parthenogenetic produced embryos from repeat breeder and normally fertile buffaloes (Bubalus bubalis) raised in sub-humid tropical climate.

The reproductive management of the buffalo species still faces several unresolved problems, which directly affect the productivity of the herd, one of them being the presence of repeat breeder females. Given this scenario, this study aimed to verify the developmental competence of oocytes obtained from repeat breeder females and submitted to parthenogenetic activation. In addition, embryo gene expression was compared to normally fertile females. Murrah buffaloes were divided into two groups: repeat breeder (RB, n = 8) and normally fertile or control (CR, n = 7). Cumulus-oocyte complexes (COCs) were aspirated by transvaginal ovum pick-up from estrus synchronized females. The COCs were submitted to IVM for 24 h, and subsequently, the oocytes were activated using ionomycin, followed by 6-DMAP. Afterwards, the presumptive parthenotes were cultured for six or seven days in a microenvironment of 5 % CO2, 5 % O2, and 90 % N2 at 38.5 °C. The expression of OCT4, GLUT1, BCL2 and TFAM genes from blastocysts was evaluated. The overall COCs recovery rate was 70.9 % (190/268). The maturation (57.8 vs 71.1), cleavage (45.2 vs 62.2) and blastocyst (30.1 vs 45.9) rates did not differ (P > 0.05) between RB and CR females, respectively. Similarly, no significant difference (P > 0.05) was observed for the expression of studied genes in both RB and CR females. In conclusion, oocytes obtained from RB were as developmentally competent as those collected from CR females, with similar energy metabolism and in vitro development capacity. Thus, the low fertility rate of repeat breeder buffaloes, when compared to normal cyclic females, must be due to subsequent events to the blastocyst stage.

Plasma concentration of progesterone and 17beta-estradiol of black-rumped agouti (Dasyprocta prymnolopha) during the estrous cycle.

Plasma concentration of progesterone and 17beta-estradiol of black-rumped agouti (Dasyprocta prymnolopha) during the estrous cycle. The agouti is a game animal that have been raised in captivity for conservation and sustainability purposes. However, the management of wild animals in an intensive breeding system requires an assertive knowledge of its reproductive parameters, one of the most important features for production improvement. Besides, little information is available regarding changes in reproductive hormone profiles in agouti. The objective of this study was to evaluate the hormonal profile of progesterone and 17beta-estradiol during the estrous cycle of the agouti (Dasyprocta prymnolopha). The hormones were analyzed by radioimmunoassay. Blood samples were collected without sedation twice a week. The concentrations of progesterone were as follows: proestrus 0.78 +/- 0.39 ng/ml, estrus 2.83 +/- 2.34 ng/ml, metestrus 1.49 +/- 1.24 ng/ml, diestrus 3.71 +/- 1.48 ng/ml. In the estrous phase, an increase in the progesterone level was observed during a period of 24h. The average 17 beta-estradiol levels were as follows: proestrus 2 030.98 +/- 961.00 pg/ml, estrus 1 910.56 +/- 650.54 pg/ml, metestrus 1 724.83 +/- 767.28 pg/ml, diestrus 1 939.94 +/- 725.29 pg/ml. The current results suggest that the progesterone plasma concentration during the estrous cycle in the agouti has a similar increasing, stabilizing and decreasing pattern, as in domestic mammals. Agoutis have two phases of follicular development, as two periods of 17beta-estradiol peaks were observed, the first one in the metestrus and the second during the proestrus. Spontaneous ovulation seems to occur after the progesterone peak, possibly indicating that this hormone is associated with the ovulatory process. A more detailed investigation is needed for better understanding of how progesterone influences ovulation. Studies on the involvement of progesterone in follicular rupture can be carried out, using steroid biosynthesis inhibitors and observing the effect of this hormone on ovarian activity of proteolytic enzymes in the follicular wall.

Eficiência produtiva de búfalos no estado do pará em diferentes condições de suplementação mineral / Productive efficiency of buffalos in the state of pará in different conditions of mineral supplementation

O monitoramento do consumo de diferentes misturas minerais foi avaliado em 84 búfalos mestiços distribuídos em duas fazendas (1 e 2) localizadas na Meso-região do Nordeste Paraense para a avaliação do custo benefício de cada produto. As fazendas apresentavam pastagens do tipo Brachiaria brizantha, cv. Marandú onde os animais foram mantidos durante 14 meses. Os animais foram divididos em dois lotes. O lote 1 de cada fazenda recebeu um produto comercial de suplementação mineral recomendado para bubalinos (Topbúfalo Matsuda®) e o lote 2, o produto comercial de suplementação mineral convencional da propriedade, no qual era indicado para a espécie bovina. Na fazenda 1, o consumo da mistura mineral a ser testada foi inferior ao consumo da mistura mineral convencional e na fazenda 2, o consumo de ambos os lotes foi semelhante. O produto comercial recomendado para búfalos em regime de pastagem, em ambos os sistemas, promoveu um melhor desempenho no ganho de peso dos búfalos quando comparado a produtos comerciais recomendados para a espécie bovina. O peso médio da carcaça quente dos animais que consumiram a mistura mineral a ser testada foi superior a dos animais que receberam a mistura mineral convencional. O gasto com a suplementação mineral foi superior com os produtos convencionais em ambas as fazendas, com rendimentos líquidos menores do que a suplementação a ser testada. Conclui-se que a eficiência produtiva dos animais utilizando uma suplementação recomendada para bubalinos em regime de pastagem supera a eficiência produtiva de búfalos quando se utiliza uma suplementação recomendada para bovinos.

The monitoration of the consumption of different minerals mixtures was evaluated in 84 crossbred buffaloes distributed in two farms (1 and 2) located in Meso-area of Paraense's Northeast for the evaluation of the cost benefit of each product. The farms presented pastures of the type Brachiaria brizantha, cv. Marandú where the animals were maintained for 14 months. The animals were divided in two lots. The lot 1 of each farm received a commercial product of mineral supplementation recommended for buffalos (Topbúfalo Matsuda®) and the lot 2, the commercial product of conventional mineral supplementation of the property, in which was indicated for the bovine species. In Finance 1, the consumption of the mineral mixture to be tested was inferior to the consumption of the conventional mineral mixture and in Finance 2, the consumption of both lots was similar. The commercial product recommended for buffalos in pasture regime, in both systems, it promoted a better acting in the earnings of weight of the buffalos when compared to commercial products recommended for the bovine species. The medium weight of the hot carcass of the animals that consumed the mineral mixture to be tested was superior the one of the animals that received the conventional mineral mixture. The expense with the mineral supplementation was superior with the conventional products in both farms, with smaller net yields than the supplementation to be tested. Was ended that the productive efficiency of the animals using a recommended supplementation for buffalos in pasture regime overcomes the productive efficiency of buffalos when a supplementation is used recommended for bovine.

Ocorrência da leucose enzoótica dos bovinos no Estado do Pará, Brasil / Occurrence of enzootic bovine leukosis in the State of Pará, Brazil

The occurrence of the infection with Bovine Leukosis Virus (BLV) was examined in agar-gel immunodiffusion (AGID) test and with indirect enzyme-linked immunosorbent assay (ELISA), in the State of Pará, Brazil. The blood sera were collected from different breeds including Nelore, Piemontes, Simental, Holstein Frisian, Indubrasil, Girolanda, Simbrasil and their cross-breedings. The majority of the animals were adults. The overall occurrence of infections was 49.8% (359/721) and 26.0% (174/668) for ELISA and AGID test, respectively. All animal groups examined showed infection in ELISA, however in the AGID test two groups were sera negative.(AU)

A ocorrência da infecção pelo Vírus da Leucose Enzoótica dos Bovinos (BLV) no Estado do Pará, foi estudada através do método de imunodifusão em ágar-gel (AGID) e por um ensaio imunoenzimatico (ELISA) indireto, paralelamente. Os exames foram realizados com amostras de soros sanguíneos oriundos de bovinos de diferentes raças sendo a maioria deles adultos. A prevalência observada foi de 49,8% (359/721) no ELISA e 26,0% (174/668) no AGID. Todos os 14 grupos dos animais estudados pelo ELISA indireto, mostraram a existência da infeção, enquanto que pelo método da AGID, dois grupos de animais foram negativos.(AU)

Estudo morfológico do sistema genital feminino de cutia (Dasyprocta prymnolopha, Rodentia: Cavidae) / Morphologic study oh the female genital system of agouti (Dasyprocta prymnolopha, Rodentia: Cavidae)

A morfologia do sistema reprodutor feminino foi estudada em oito cutias (Dasyprocta prymnolopha), sendo que dois animais eram sacrificados em cada fase do ciclo estral. Além disso, outras nove fêmeas foram utilizadas nos dados biométricos. A regeneraçao da membrana vaginal e as trompas com circonvoluçoes foram as principais observaçoes anatômicas referentes a esta espécie. Em ambos os ovários constatou-se, na fase estrogênica, a presença de um ou dois folículos pré-ovulatórios, havendo na fase progesterônica a formaçao de um a três corpos lúteos funcionais. As modificaçoes histológicas verificadas no epitélio vaginal e no endométrio foram evidentes nas diferentes fases do ciclo estral.