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1.
An experiment was conducted to examine the effect of progesterone prior to a GnRH‐PGF2α treatment on oestrus and pregnancy in seasonally anoestrous Awassi ewes. Twenty‐four ewes were randomly assigned to three groups to be pre‐treated with 60 mg medroxyprogesterone acetate sponges (group A), 600 mg progesterone sponges (group B) or blank sponges (group C) for 4 days. All ewes were injected with 100 μg of GnRH 24 h after sponge removal followed, 5 days later, by 20 mg PGF2α injection. Ewes were exposed to three fertile rams at the time of PGF2α injection (day 0, 0 h) and were checked for breeding marks at 6‐h intervals for 5 days. Blood samples were collected from all ewes 1 day (day ?10) prior to sponge insertion, at the time of sponge removal (day ?6), 1 day following sponge removal (day ?5, at the time of GnRH injection) and at the time of PGF2α injection (day 0) for analysis of progesterone. Progesterone concentrations on days ?10 and ?5 were basal and averaged 0.2 ± 0.04 and 0.2 ± 0.2 ng/ml, respectively. Progesterone concentrations on day ?6 were elevated only in group B ewes and were higher (p < 0.0001) than those of groups A and C. Progesterone concentrations on day 0 were higher (p = 0.002) in groups A and B than group C. Oestrous responses occurred only in ewes of groups A and B (p > 0.05). Induced oestrus conception rate was greater (p < 0.01) in group A than groups B and C. Ewes returned to oestrus 17–20 days following day 0 were two of eight, six of eight and three of eight of groups A, B and C, respectively, all of which eventually lambed. The overall lambing rate was 82% in progesterone‐primed ewes compared with only 38% non‐progesterone‐primed ewes (p < 0.05). Progesterone priming apparently sensitizes GnRH‐PGF2α‐treated seasonally anoestrous ewes and increases their response in oestrus and pregnancy rates.  相似文献   
2.
In this study, we evaluated the effects of including cassava wastewater in the diet on the feeding behavior of feedlot lambs in 35 male uncastrated Santa Inês × Dorper crossbred lambs at an approximate age of 3 months, with an average live weight of 20.0?±?3.4 kg. Diets were formulated with hay of cassava shoots (roughage) and a concentrate based on corn and soybean, with a roughage:concentrate ratio of 50:50, plus inclusion of cassava wastewater at the levels of 0, 12, 24, 36, or 48 g/kg of the total diet. Feeding behavior was evaluated between the 46th and 52nd days of the experiment. Increasing cassava wastewater levels in the diet reduced (P?<?0.05) the intakes (kg/day) of dry matter and neutral detergent fiber as well as the efficiency of rumination (g/cud and g/h) of dry matter and neutral detergent fiber. The other behavioral parameters were not affected by wastewater inclusion in the diet. Therefore, the inclusion of up to 48 g/kg of cassava wastewater on fresh matter of diets is not recommended for feedlot lambs.  相似文献   
3.
通过近几年的实践,笔者对我国兽医生物制品生产中传统的细胞培养工艺进行了一些改进,包括用洗洁精代替其他洗液,用自行研制的营养液代替常规营养液用于细胞培养,改变培养时的转速,改变细胞消化液,改进细胞的保存方法.这些方法均成功应用于生产,取得了良好的效果.  相似文献   
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5.
An experiment was conducted to examine the effect of progesterone (P(4)) and oestradiol benzoate (ODB) on fertility of repeat-breeder lactating dairy cows during summer. One hundred repeat-breeder lactating dairy cows were randomly allocated to four groups (Tr1, Tr2, Tr3 and C) in a study conducted at a private dairy farm. All cows were injected with 2 mg ODB (day 0), which were at random stages of their oestrous cycles. Cows in Tr1, Tr2 and Tr3 were administered with intravaginal progesterone-releasing devices (controlled internal drug-releasing, CIDR) at the time of ODB injection for 7 days and those in group C were untreated and served as controls. Following CIDR removal, all cows were given an intramuscular injection of 25 mg Prostaglandin (PGF(2 alpha)). Twenty-four hours after the PGF(2 alpha) injection, cows in Tr1, Tr2 and C groups were injected with 1 mg ODB. Cows in Tr3 group were injected with 10 microg gonadotropin-releasing hormone (GnRH) agonist 48 h after CIDR removal. Artificial insemination was performed between 24 and 30 h following the second ODB injection for cows in Tr1 group and at the time of GnRH injection for cows in Tr3 group. Cows in Tr2 and C groups were inseminated at detected oestrus. Plasma P(4) and oestradiol 17beta (E(2)) concentrations were determined for all cows daily from day 0 to day 9. Plasma concentrations of P(4) and E(2) among cows of groups Tr1, Tr2 and Tr3 were increased and reached maximum values within 48 h following administration and were greater (p < 0.001) than those of group C cows. The proportion of cows detected in oestrus based on P4 concentration on day 9 was 88%, 72%, 88% and 60% in groups Tr1, Tr2, Tr3 and C, respectively. Oestrous detection rate differed (p < 0.01) significantly between time-inseminated groups (Tr1 and Tr3) and those inseminated at observed oestrous (Tr2 and C) groups. Pregnancy rates based on ultrasonography performed on day 28 were 52%, 56%, 60% and 40%, and those based on rectal palpation on day 45 were 32%, 44%, 36% and 28% for Tr1, Tr2, Tr3 and C cows (p > 0.1), respectively. Whereas pregnancy rates for cows with four or more previous services in all groups (54.55%) were higher (p < 0.03) than those for cows with three previous services (29.49%). In pregnant cows, mean days from calving to the day of insemination were higher (p < 0.01) among cows with four or more previous services (204 +/- 8.0 days) than those with three previous services (157 +/- 6.0 days). Results indicate that treatment with a combination of ODB and CIDR in repeat-breeder dairy cows causes elevation in plasma concentrations of E(2) and P(4). Oestrous detection rate was better in cows that were primed with P(4) than those without P(4) priming. Cows with four or more previous services had significantly higher pregnancy rates than those with three previous services.  相似文献   
6.
This study aimed to assess the combined effects of density of adults of Branchiura sowerbyi and the source of organic matter on the production of eggs and young species. The experimental units used were 250‐mL beakers with 100 mL of fine sand (0.074–0.210 mm) and 150 mL of chlorine‐free water with constant aeration at the temperature 25 C. The experiment was conducted based on a two‐factor model with six treatments and three repetitions, applied in a completely random design. The densities 5 individuals/38.5cm2 (D5; 1298/m2) and 8 individuals/38.5cm2 (D8; 2078/m2) were assessed with commercial fish feed (FF), commercial poultry feed (PF), and turkey manure (TM) as sources of organic matter. A total of 1223 cocoons and 2138 eggs were produced, with average hatching of 40.0 ± 15.1%. The highest number of cocoons and eggs was found with the use of PF, D8 having produced the highest number of cocoons and eggs. The hatching rate was not influenced by the source of organic matter or density and no influence was registered from the density of adults on the survival. The PF provided the highest growth of adults, and generally the use of TM provided the worst performance.  相似文献   
7.
New Forests - The forestry sector has been able to sustainably satisfy the increasing global demand for forest products, thereby positively impacting the economy, while mitigating climate change....  相似文献   
8.
The current increase in the organic agriculture segment has created a new market for fertilisers permitted for use in organic farming. Off-farm N sources for organic farming are scarce, considering the restriction on the use of chemical fertilisers. Thus, when some products are permitted in organic agriculture, commercial opportunities become available. In this study we compare the performances of Vegethumus (Veg) and Phenix (Phe), two manures that are permitted in organic farming, with several other manures, ammonium nitrate (AN) and control treatments. A 3-year field trial and a pot experiment were carried out in order to estimate dry matter yield, N uptake, and N nutritional status of the crops, as well as soil N availability, the latter was assessed by using anion exchange membranes inserted into the soil. Apparent N recovery (ANR) values in the field trial were 6.3% and 58.2% in Veg and AN plots, respectively, after the application of 380 kg N/ha in the previous five growing seasons. In the pot experiment, the ANR of Veg and Phe, the organic amendments permitted in organic farming, were 5.0% and 13.6%, while Beiraadubo (Bei) and Nutrisoil (Nut) had ANR of 27.2% and 42.0%. The poor results of the amendments permitted in organic farming, in light of their high prices suggest that their use must be carefully considered by farmer in their fertilization strategies.  相似文献   
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10.
The in vitro hemolytic activity of Tritrichomonas foetus was investigated. The parasite was tested against human erythrocytes of groups A, B, AB, and O, and against erythrocytes of nine adult animals of different species (the rabbit, rat, chicken, cat, dog, swine, horse, bovine, and sheep). The results showed that T. foetus strains (ATCC KV1, K, PAL, 5022, RJ, 90) did not present any hemolytic activity against any human erythrocyte group nor against rabbit, rat, chicken, cat, dog and swine erythrocytes. T. foetus strains, however, lysed horse, bovine, and sheep erythrocytes. No hemolysin released by the parasites could be identified. Hemolysis did not occur with trichomonad culture supernatants, with sonicated extracts of T. foetus, nor with killed organisms. Scanning electron microscopy (SEM) showed that human erythrocytes did not adhere to the trophozoites, in contrast horse erythrocytes adhered to the surface of the parasites and were phagocytosed for up to 90 min. The parasites are able to exert their cytopathic effects through: (a) physical contact established between the two cell surfaces, (b) toxins released from parasites into the interaction media, or (c) the association of both mechanisms. Further studies are necessary to clarify the importance of the hemolytic activity in the biology of T. foetus.  相似文献   
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