Cycle Synchronization and Induction in Zebu Cattle with Chlormadinone Acetate in Differing Dosage Forms: Effects of Season

Contents Two different formulations and dosing regimens of Chlormadinone (CAP) were used for estrous cycle synchronization or for estrous cycle induction in cows with lactational anestrus, in open field trials with purebred Zebu (Brahman) cattle in the tropics (Gulf coast area of Central Mexico). In trial 1, during the dry season (February) animals received a single injection of 50 mg CAP in oily solution i. m., followed 10 days later by 5 daily oral doses of 10 mg CAP in raw sugar. In trial 2, during the rainy season (August) animals received 10 mg CAP/day orally for 15 days in an oily solution as a top dressing on raw sugar. In both trials, animals in heat were inseminated over a 30 day period. Data from 107 (61 lactating and 46 dry) cows were evaluated in trial 1, and from 214 lactating cows in trial 2. Synchronization of estrus within 3 to 8 days occurred in 67.4 % and 52,5 % of the dry and of the lactating cows in trial 1, and in 53,3 % of lactating cows in trial 2. 21.7 % of the dry and 41.0 % of the lactating cows in trial 1 and 37,9 % of the cows in trial 2 had their first heat 17 to 27 days after CAP withdrawal, indicating that they may have shown silent heat during the initial synchronization period. In the spring, conception rates from breeding during days 1 to 8 after CAP were low (33.3 %), but increased for animals bred on days 17 to 27 (54.5 %). In the summer, in congruence with the overall seasonal decline of fertility observed in Zebu cattle, the initially low conception rate from breeding on days 1–7 (27,1%) remained low for animals bred during days 18 to 27 (29.8%). Inhalt Induktion und Synchronisation von Sexualzyklen beim Zeburind mit Chlormadinonazetat in verschiedenen Darreichungsformen: Einfluβ der Jahreszeit. Zur Zyklussynchronisation bzw. Zyklusinduktion bei Zeburindern unter tropischen Haltungsbedingungen (mexikanische Golfküste) wurde Chlormadinonazetat (CAP) in zwei verschiedenen Darreichungsformen und Applikationsarten angewandt. Im 1. Feldversuch, wiihrend der Trockenzeit (Februar), wurden 50 mg CAP in öliger Lösung i. m. injiziert; 10 Tage später wurden 10 mg CAP in Rohrzucker täglich für fünf Tage verabreicht. Im 2. Feldversuch, während der Regenzeit (August) erhielten die Tiere 10 mg CAP in öliger Lösung auf eine Rohrzuckerration zur oralen Aufnahme, für 15 Tage. In beiden Versuchen wurden alle in Brunst kommenden Tiere während der ersten 30 Tage nach Medikation besamt. Im ersten Versuch kamen 107 Tiere zur Auswertung (61 laktierende und 46 trocken stehende Kühe), im 2. Versuch insgesamt 214 laktierende Zebukühe mit dem Kalb bei Fuss. Im 1. Versuch rinderten, synchronisiert zwischen dem 3. und 8. Tag, 67,4 % der trockenstehenden und 52,5 % der laktierenden Kühe; im Versuch 2, 53,5 % der in Laktation stehenden Tiere. Von den trokkenstehenden Tieren in Versuch 1 rinderten jedoch 21,7% und von den laktierenden Tieren 41,0 % erst zwischen dem 17. und 27. Tag nach letzter CAP-Gabe; im 2. Versuch waren es 37,9 %. Es wird angenommen, daβ diese Tiere unmittelbar nach CAP-Anwendung stillbrünstig waren. Ein Vergleich der Konzeptionen aus Besamungen vom Tag 1 bis 8 und vom Tag 17 bis 27 zwischen Versuch 1 und Versuch 2 zeigt einen Anstieg der Konzeptionsrate im Frühjahr von 33,3 % (Tag 1–8) auf 54 % (Tag 17–27), während im Sommer die Rate von 27,1 % (Tag 1–8) nicht weiter ansteigt (29,8 %: Tag 18 bis 27). Dies entspricht der Erfahrung, daβ beim Zeburind die Fertilität mit dem Frühjahr zunimmt, nach Beginn der Regenzeit jedoch bald abzusinken beginnt.     

Anaplasma marginale in tick cell culture

Anaplasma marginale was propagated in a tick cell line derived from Dermacentor variabilis embryos. The rickettsial organism was identified and monitored in culture by transmission electron microscopy and the indirect immunofluorescence technique, using specific monoclonal antibodies. Inoculation of the embryonic tick cell line with midguts of infected adult ticks (culture 1), nymphal ticks (culture 2) and adult ticks that were infected as nymphs and dissected as adults (culture 3) resulted in 3 continuous cultures of A marginale. Culture 1 had been maintained through 22 passages over a 11-month period; cultures 2 and 3 had been maintained for 18 passages over a 9-month period. Growth of A marginale in the cell line began in the area of the nuclear membrane at approximately 4 days after inoculation or transfer. Thereafter, the organisms were observed in inclusions scattered throughout the cytoplasm of the host cells. Maximal growth of the organism occurred at 7 to 14 days, after which numbers of inclusions rapidly decreased to minimal or undetectable levels. The organism began new cycles of growth with each 1:5 to 1:10 split and transfer of the host cells. Electron microscopy of recently infected cells revealed a morphology of the organism that closely resembled that observed in marginal bodies of infected erythrocytes. After several passages, A marginale organisms had a varied morphology and resembled the organism described in midgut cells of naturally infected ticks.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of the enzyme-linked immunosorbent assay for detecting Brucella abortus antibodies.

The specificity of enzyme-linked immunosorbent assays (ELISA) corresponds to conventional methods for detecting brucella antibodies in bovine serum. The ELISA test detected brucella antibodies early in only 12.5% of the cattle sera tested. Also, the sensitivity of ELISA was comparable to complement-fixation and Rivanol methods, but less sensitive than the standard tube agglutination method.     

SOIL MICROBIAL BIOMASS AND NITROGEN MINERALIZATION RATES ALONG AN ALTITUDINAL GRADIENT ON THE COFRE DE PEROTE VOLCANO (MEXICO): THE IMPORTANCE OF LANDSCAPE POSITION AND LAND USE

A study was conducted to examine the responses of microbial activity and nitrogen (N) transformations along an altitudinal gradient. The gradient was divided into three parts. Three areas were sampled: upper part (UP): coniferous forest, corn field, and abandoned corn field; middle part (MP): tropical cloud forest, grassland, and corn field (COL); and lower part (LP): tropical deciduous forest and sugarcane. The results showed that soil microbial biomass carbon (C) and basal respiration were significantly higher in MP and UP than in LP, whereas the microbial quotient (C_mic/C_org) was higher in LP and MP than in UP. The metabolic quotient (qCO₂) was similar among gradient parts evaluated. Net N mineralization, ammonification, and nitrification rates were higher in UP than MP and LP. We found that in UP, the forest conversion to cropland resulted in no significant differences in microbial activity and N transformation rates between land uses. In MP, microbial biomass C, ammonification, and net N mineralization rates decreased significantly with conversion to cropland, but C_mic/C_org and nitrification were higher in COL. Basal respiration and qCO₂ were significantly lower in COL when compared with other land uses. In LP, lower microbial biomass C, C_mic/C_org, and nitrification rates but higher ammonification and net N mineralization rates were observed in tropical deciduous forest than in sugarcane. No significant differences in basal respiration and qCO₂ were found between uses of LP. Clearly, then, soil organic C is not equally accessible to the microbial community along the gradient studied. Copyright © 2012 John Wiley & Sons, Ltd.     

Carotenoid composition and heterotic effect in selected Italian maize germplasm

Maize (Zea mays L.) is a promising crop for improving the nutritional quality of foods, because of the presence of broad natural variability for the content of carotenoids. One hundred Italian and nine public lines were screened by PCR to identify the alleles of Hydroxylase3 (HYD3) and Lycopene epsilon cyclase (LCYE) genes, codifying for key enzymes of the carotenoid pathway and associated with high or low β-carotene contents. Nineteen selected genotypes carrying different alleles were grown in 2011 and/or 2012, and used to obtain F1 seeds. HPLC analysis highlighted the richness in zeaxanthin and β-cryptoxanthin of Italian germplasm (mean values 12.63 and 2.88 mg/kg d.m., respectively). The percentage of positive and significant mid parent heterosis (MPH) and best parent heterosis (BPH) values (51% and 29%) indicated the presence of a high heterotic response for carotenoids. The compounds on the same branch of the pathway were found to be positively correlated; on the contrary, no consistent correlation was observed between the different HYD3 alleles and β-carotene content. Finally, total antioxidant capacity (TAC) was also measured. These lines resulted therefore as interesting raw materials for the market of maize-based foods.     

Influence of Gonadotrophin‐Induced First Oestrus on Gilt Fertility

The aim of this study was to determine the association between the oestrous response of pre‐pubertal gilts to gonadotrophin injection or boar exposure and their subsequent farrowing rate and litter size. At 154 days of age, randomly selected pre‐pubertal gilts received an intramuscular injection of 400 IU equine chorionic gonadotrophin plus 200 IU human chorionic gonadotrophin (PG600^®; Merck Animal Health; n = 181). From the remaining pool of animals not treated with hormones, the first gilts showing signs of oestrus were selected to act as controls (n = 201). Boar exposure began at 155 days of age for both groups, and gilts were bred at a weight of approximately 130 kg. Comparisons were made between PG600^®‐treated gilts exhibiting oestrus or not within 7 days post‐injection (early and late responders, respectively) and control gilts exhibiting oestrus or not within 30 days after beginning of boar exposure (select and non‐select control gilts, respectively). By 162 days, oestrus was detected in 67.5% of PG600^®‐treated gilts compared with 5.7% of control gilts (p < 0.0001). The proportion of animals observed in oestrus at least three times before breeding was greater for select control gilts compared with early and late responder PG600^®‐treated gilts (p ≤ 0.001). There were no significant differences in farrowing rate and litter size between the four treatment groups. These data indicate that PG600^® is an effective tool to induce an earlier oestrus in gilts, that subsequent farrowing rate and born alive litter size compare favourably to that of select gilts and that gilts failing to respond promptly to hormonal stimulation do not exhibit compromised fertility.     

Effect of tocopherols in the antioxidative activity of oxidized lipid-amine reaction products

Phosphatidylethanolamine (PE), phosphatidylcholine (PC), lysine (Lys), and mixtures of them were tested for antioxidative activity in a tocopherol-stripped olive oil (TSO) and the same oil after addition of 250 microg of alpha-tocopherol g of oil/(tocopherol-added olive oil, TAO) to evaluate the role of tocopherol in the antioxidant activity of oxidized lipid-amine products. Neither PE nor PC nor Lys protected TSO when tested alone, but both PE and Lys increased the induction period (IP) of TAO. On the contrary, PE/Lys and PC/Lys mixtures, but not PC/PE mixtures, protected both TSO and TAO. These results were a consequence of both the formation of oxidized lipid-amine products, which were determined by gas chromatography-mass spectrometry after their conversion into volatile derivatives, and a synergism between alpha-tocopherol and the produced compounds. These results were confirmed by analyzing the antioxidative activity of two of the produced carbonyl-amine products: 6-amino-2-(1H-pyrrol-1-yl)hexanoic acid (1) and 2,3-dipalmitoylpropyl 2-(1H-pyrrol-1-yl)ethyl phosphate (2). The hydrophilic compound 1 was more antioxidant than the analogous lipophilic compound 2, and this antioxidative activity was observed in TAO and not in TSO. All these results suggested that antioxidative activity of carbonyl-amine products may be greatly increased with the addition of tocopherols, and those products derived from Lys are more antioxidant in bulk oils than those derived from PE.     

Conversion of phenylalanine into styrene by 2,4-decadienal in model systems

2,4-Decadienal was heated under an inert atmosphere and in the presence of phenylalanine to investigate whether this secondary lipid oxidation product is a final product of lipid oxidation or it reacts with the amino acid. The results obtained showed that, in the presence of the alkadienal, the amino acid was degraded to styrene. This reaction was favored in dry systems at pH approximately 6 and in the absence of oxygen. If oxygen was present, the alkadienal was oxidized and the Strecker degradation of the amino acid was produced. The activation energy for the formation of styrene from phenylalanine was 150.4 kJ/mol. The reaction mechanism is suggested to be produced either by an electronic rearrangement of the imine produced between the aldehyde and the amino acid with the formation of styrene, 2-pentylpyridine, carbon dioxide, and hydrogen, or by Michael addition of the amino compound to the alkadienal followed by beta-elimination to produce the same compounds. Both reaction schemes were supported on the results obtained by studying both the degradation of phenylethylamine and phenylalanine methyl ester produced by 2,4-decadienal, and the formation of ethylbenzene in decadienal/phenylalanine reaction mixtures heated in the presence of platinum oxide. All these results suggest that, analogously to carbohydrates, certain lipid oxidation products may degrade appropriate amino acids to their corresponding vinylogous derivatives.