scispace - formally typeset
Search or ask a question

Showing papers by "University of Veterinary Science published in 1990"


Journal Article
TL;DR: Sodium n-butyrate can be recommended for use in pig feeding as a growth promoter because of its favourable biological and economic effect and because it is not alien to the body.
Abstract: Pigs weighing 7 to 102 kg were fed a diet containing 0.17% sodium n-butyrate. The diet increased the average daily body mass gain of pigs by 23.5%. Due to its dietetic effect, feed consumption increased by 8.9%. However, owing to the higher feed conversion, specific feed utilization was reduced by 11.8%. The experimental diet markedly reduced the percentile proportion of coliform bacteria in the ileum as compared to Lactobacillus ssp.: it decreased the coliform count and increased the counts of Lactobacillus spp. The diet increased the length of ileal microvilli and the depth of caecal crypts. It raised the concentration of immunoreactive insulin in the blood plasma. The feed supplemented with sodium butyrate did not alter adversely the clinical indices tested. It reduced feed costs by 9% and increased the returns from sales by 13%. As the additive is normally produced by microbial fermentation in the large intestine, it is not alien to the body. Sodium butyrate exerted its favourable effect in 3.6- to 24.2-fold lower concentrations than the organic acids (citric acid, fumaric acid, propionic acid) used earlier. With respect to its favourable biological and economic effect, sodium n-butyrate can be recommended for use in pig feeding as a growth promoter.

171 citations


Journal ArticleDOI
TL;DR: Three methods for diagnosing early pregnancy in cattle are compared: 1) a trans-rectal ultrasound scan of the uterus, 2) a cow-side enzymeimmunoassay (EIA) milk progesterone test, and 3) a radioimmunosorbent test, which focuses on the effects of early embryonic death and the accumulation of intrauterine fluids.

115 citations


Journal ArticleDOI
TL;DR: An antibacterial effect inhibiting salmonella multiplication was demonstrable in vitro in colon contents from pigs of herd L and no such effect was found to exist in samples taken from pig of herd H, likely due to the non-dissociated volatile fatty acid molecules present in the colon content.
Abstract: Factors affecting colonization of the intestinal tract by salmonellas were studied in two pig herds. In herd H 18% of the faecal samples taken from live pigs and 30% of the colon content samples collected at slaughter contained salmonellas. In contrast, the 50 faecal samples taken from pigs of herd L were negative and only 2% of the colon contents collected at the yielded salmonellas. An antibacterial effect inhibiting salmonella multiplication was demonstrable in vitro in colon contents from pigs of herd L. No such effect was found to exist in samples taken from pigs of herd H. The antibacterial effect is due to the non-dissociated volatile fatty acid (VFA) molecules present in the colon content. As the degree of VFA dissociation depends on the pH of the environment, at lower pH values (pH 6.1 +/- 0.2) of the colon contents from herd L the ratio of non-dissociated VFA molecules is higher and the resulting antibacterial effect is stronger than in samples from herd H (pH 7.1 +/- 0.3).

49 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used passive haemagglutination test using alkaline antigen extraction for the examination of heat-stable antigens of both C. fetus subsp. and C. jejuni.
Abstract: Summary Of 38 aborted ovine fetuses from 23 sheep flocks 29 C. fetus subsp. fetus and 22 C. jejuni were isolated and examined biochemically and serologically for heat-stable antigens. Serologic examinations were carried out by passive haemagglutination test. In case of C. fetus subsp. fetus strains alkaline antigen extraction was used. Antisera to two serogroups of C. fetus and to Penner serotype reference strains 1 to 60 were produced in rabbits. Abortion was caused in 18 (78.3%) flocks by C. fetus subsp. fetus and in 5 (21.7%) flocks by C. jejuni. Six C. fetus subsp. fetus strains grew well at both 43 and 25 °C. With one exception all C. fetus subsp. fetus were resistant, wheras all 29 C. fetus subsp. venerealis strains were sensitive to 30 μg/ml cefoxitin and cefamandole. These two cephalosporins can be used to differentiate the two subspecies of C. fetus. Passive haemagglutination test using alkaline antigen extraction is a proper method for the examination of heat-stable antigens of both C. fetus subspecies. Out of 24 C. fetus subsp. fetus strains 13 belonged to serogroup A(01), and 11 to serogroup B(02). C. jejuni strains examined belonged to Penner serogroup 1 (6 strains), to serogroup 5 (4 strains) and to serogroup 8 (4 strains). Zusammenfassung Aus 38 abortierten Schaffeten von 23 Schafherden wurden 29 C. fetus subsp. fetus und 22 C. jejuni isoliert und biochemisch sowie serologisch auf hitzestabile Antigene untersucht. Serologische Untersuchungen wurden mit Hilfe der passiven Haemagglutination durchgefuhrt. Bei C. fetus subsp. fetus wurde die alkalische Antigenextraktion angewendet. Antiseren gegen die beiden Serogruppen von C. fetus und gegen die „Penner”-Serotyp-Referenzstamme 1 bis 60 wurden in Kaninchen hergestellt. In 18 Herden (78,3 %) wurden die Aborte durch C. fetus subsp. fetus und in 5 Herden (21,7%) durch C. jejuni verursacht. Sechs Stamme von C. fetus subsp. fetus wuchsen gut bei Temperaturen von 43 °C und 25 °C. Mit einer Ausnahme waren alle C. fetus subsp. fetus-Stamme resistent, wogegen alle 29 C. fetus subsp. venerealis-Stamme empfindlich gegen 30 μg/ml Cefoxitin und Cefamandole waren. Diese beiden Cephalosporine konnen zur Differenzierung der beiden Subspezies von C. fetus herangezogen werden. Der passive Hamagglutinationstest, ausgefuhrt mit alkalischem Antigenextrakt, ist eine geeignete Methode fur die Untersuchung von hitzestabilen Antigenen der beiden C. fetus-Subspezies. Von den 24 C. fetus subsp. fetus-Stammen gehorten 13 zur Serogruppe A(01) und 11 zur Serogruppe B(02). Die untersuchten C. jejuni-Stamme gehorten zur „Penner”-Serogruppe 1 (6 Stamme), zur Serogruppe 5 (4 Stamme) und zur Serogruppe 8 (4 Stamme).

27 citations


Journal Article
TL;DR: The results indicate that bovine venous blood samples stored up to 24 hours on ice are of diagnostic utility, and differences between cattle of differing ages, rectal temperatures, and acid-base status were too small to be of clinical significance.
Abstract: The stability of blood gas and acid-base values in bovine venous blood samples (n = 22) stored on ice for 3, 6, 9, or 24 hours was studied. Values studied include pH, PO2 and PCO2 tensions, base excess, standard base excess, bicarbonate concentration, standard bicarbonate concentration, total carbon dioxide content, oxygen saturation, and hemoglobin. The results indicate that, except for PCO2, changes in blood gas and acid-base values during 24 hours of storage and differences between cattle of differing ages, rectal temperatures, and acid-base status were too small to be of clinical significance. Therefore, bovine venous blood samples stored up to 24 hours on ice are of diagnostic utility.

25 citations


Journal ArticleDOI
TL;DR: A total of 186 campylobacter strains from aborted calf and sheep fetuses, from scouring dogs, rabbits and man, and from retailed poultry were isolated and examined biochemically and serologically for heat stable antigens.
Abstract: A total of 186 campylobacter strains from aborted calf and sheep fetuses, from scouring dogs, rabbits and man, and from retailed poultry were isolated and examined biochemically and serologically for heat stable antigens. Immune sera were produced in rabbits against Penner reference strains from 1 to 60, and against two field isolates. Out of 186 biochemically tested strains 179 (96.2%) proved C. jejuni and only 6 (3.2%) C. coli. One strain has been identified as C. laridis. In cattle and sheep 3.2 and 21.7% respectively of all campylobacter abortions were due to C. jejuni infection. The same agent caused 12.7% of diarrhoea of dogs. The campylobacter infection rate of freshly slaughtered and dressed chicken varied between 25 and 64.3%. Out of the serologically examined 140 C. jejuni strains 118 (84.3%) could be assigned to 16 Penner serogroups and 13 (9.3%) to 2 further serogroups. Serogroups 8 (31.4%), 1 (19.3%) and 2 (12.1%) occurred most frequently. The human isolates represented the widest serotype distribution, as 32 tested strains belonged to 12 serogroups. All those serogroups which caused abortion or diarrhoea in animals or were isolated from poultry carcases were isolated also from man with diarrhoea, but some serogroups were found only in man.

18 citations


Journal ArticleDOI
TL;DR: Primary infection of 3-month-old lambs with AA, AB or BB haemoglobin genotypes induced partial immunity which could prevent the establishment of a part of the secondary infection, irrespective of the presence or absence of the primary worm population.

17 citations


Journal ArticleDOI
TL;DR: An increasing number of VIP cells appeared in the neo- and allocortex, developing by postnatal day 12 all the features of the mature cortical bipolar fusiform neurons.
Abstract: Numerous cells were observed to show intense vasoactive intestinal polypeptide (VIP) immunoreactivity from birth to postnatal day 8 in the subventricular zone of the rat occipital hemisphere This cell population was markedly reduced by postnatal day 8, but isolated clusters of VIP cells persisted into adulthood In addition, long, L-shaped VIP fibers were seen in the hemispheric wall up to postnatal day 16, but not in the adult Parallel to the reduction in number of the subventricular VIP cells an increasing number of VIP cells appeared in the neo- and allocortex, developing by postnatal day 12 all the features of the mature cortical bipolar fusiform neurons As possible alternatives, the migration of subventricular VIP cells into the cortex, the transient character of the subventricular VIP population or the expression of VIP by radial glia are discussed

12 citations


Journal ArticleDOI
TL;DR: Two strains of Streptococcus bovis and one strain of Escherichia coli isolated from the surface of bovine ruminal mucous epithelium were examined for adherence to isolated and cultured ruminal epithelial cells and it was postulated that the bacterial glycocalyx of the S.bovis organisms acted as ligand.
Abstract: Two strains of Streptococcus bovis (A1 and A5) and one strain of Escherichia coli (0141: H28) isolated from the surface of bovine ruminal mucous epithelium were examined for adherence to isolated and cultured ruminal epithelial cells. The E. coli adhered to the target cell by means of fimbriae, which had several common properties with type 1 common fimbriae and caused mannose-sensitive haemagglutination. The A1 strain of S. bovis was devoid of fimbriae and its adherence to the epithelial surface was not inhibited by treatment with sugars or phenol-treated bacterial membrane from the same organism. It was therefore postulated that the bacterial glycocalyx of the S. bovis organisms acted as ligand. The extent of bacterial adherence depended on the state of differentiation of the target cell in both the isolated and the cultured ruminal cell systems. The receptors for both adherent bacterial species were in all probability associated with the glycocalyx of the target cells.

11 citations


Journal Article
TL;DR: Both the animal fat and the vegetable oil surplus modified the fatty acid composition of blood lipids and the proportion of polyunsaturated fatty acids increased.
Abstract: The effect of mixed animal fat and sunflower oil supplementation (5%) of a feed of medium (1202 MJ DE/kg) and low (854 MJ DE/kg) energy concentration upon the digestibility of nutrients and on some blood parameters was investigated The ether-extractable content of feed and faecal samples was determined by diethyl ether extraction (after Soxhlet) and the total (true) fat level was measured by the method of Stoldt (1952), viz petroleum ether extraction of samples pretreated with 4 N HCl In the majority of cases the voluntary feed intake decreased after the addition of animal fat or vegetable oil Mixed animal fat supplementation significantly (by 5 and 11 units) improved the digestibility of the ether extract if added to either of the basal diets The digestibility of crude fibre and N-free extract increased only in the case of the basal diet of low energy concentration (by 4 and 7 units, respectively) Sunflower oil addition produced changes of the same tendency (9, 9, 28 and 5 units) The digestibility of the crude protein was practically not altered by either supplementation The total fat content of feed and faecal samples proved to be higher than that of the ether extract, on an average by 27 and 100%, respectively Consequently, the digestibility coefficients of the total fat are by 10 units lower than those of the ether extract The DE concentrations, calculated by means of the digestible ether extract or the total fat content, differed significantly only between the basal diets The addition of mixed animal fat to either of the basal diets increased the blood concentration of total lipids (by 18 and 32%, respectively), while that of sunflower oil did not cause such an alteration Neither fat nor oil supplementation had an effect on the cholesterol level of the blood plasma Both the animal fat and the vegetable oil surplus modified the fatty acid composition of blood lipids It was characteristic of each treatment that the proportion of polyunsaturated fatty acids increased

11 citations


Journal Article
TL;DR: Lung and serum samples from pigs that died or were emergency-slaughtered in a pooled, conventional fattening herd were examined to survey Actinobacillus pleuro-pneumoniae infection and to compare the sensitivity of different testing methods.
Abstract: Lung and serum samples from pigs that died or were emergency-slaughtered in a pooled, conventional fattening herd were examined to survey Actinobacillus pleuro-pneumoniae infection and to compare the sensitivity of different testing methods. A total of 110 lungs were used for cultural isolation of the agent and direct immunofluorescence (IF) of impression smears. Boiled lung suspensions were tested by coagglutination (Co-A) and agar gel precipitation (AGP). Eighty-seven sera were tested along with lung samples from the same pigs. The lungs yielded a varied bacterial flora most often containing Pasteurella multocida and less frequently Actinomyces (Corynebacterium) pyogenes, E. coli and Salmonella. A. pleuropneumoniae was isolated from 30 lungs: from 22 lungs it grew out in pure culture, from 7 as mixed culture with P. multocida and from 1 as mixed culture with A. pyogenes. The number of positive samples obtained by the different methods was as follows: coagglutination test (with boiled lung suspensions): 63 (57.3%); immunofluorescence: 43 (39.2%); AGP test (with serum): 31 (35.6%); AFP test (with boiled lung suspension): 25 (22.7%). A total of 23 samples (20.7%) were negative by all serological tests and by cultural isolation. Most samples gave positive results by two or more tests while 26 samples only by one test (most often, on 13 occasions, by the Co-A test). The Co-A test detected antigenic components of serotypes that have not been isolated in Hungary so far. This indicates that it is not enough to test one strain from a given lung sample: several colonies must be cultured and serotyped.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal Article
TL;DR: The effect of tannin treatment and subsequent urea supplementation on the digestibility of sunflower meal (SFM) protein was studied by means of a three-phase laboratory method simulating the ruminant's digestion, and the quantity of dissolved protein decreased and that of oligopeptides increased.
Abstract: The effect of tannin treatment (TSFM) and subsequent urea supplementation (TSFM + U) on the digestibility of sunflower meal (SFM) protein was studied by means of a three-phase laboratory method simulating the ruminant's digestion. Under the influence of the ruminal fluid 67% of SFM protein, 62% of TSFM protein and 58% of TSFM + U protein was degraded. The pepsin and pancreatin digestibilities of rumen undegraded protein (UDP) were as follow: 58.2% (SFM), 56.6% (TSFM), 43.3% (TSFM + U), and 22.0% (SFM), 28.8% (TSFM), 17.5% (TSFM + U), respectively. The four fractions (dissolved protein, oligopeptides, amino acids, and ammonia) of rumen degradable protein (DP) were also determined: 85 to 92% of rumen degradable protein was recovered in these four fractions. Owing to tannic acid treatment the quantity of dissolved protein decreased and that of oligopeptides increased.

Journal ArticleDOI
TL;DR: Serum CK, ALD activities and TRIG and TRP concentrations may serve as useful complementary values to the specific diagnosis of paratuberculosis, particularly in the advanced stage of the disease.
Abstract: Summary Ten bull-calves were infected with 108 viable cells of Mycobacterium paratuberculosis per os. During the 400-day period of observation faecal and blood samples were taken from animals at 30-day intervals. Faecal samples were examined microscopically, blood samples by the CFT, AGID and LST tests. Intradermal allergic tests were carried out at PI (post infection) days 92, 217, 336, using mammalian, avian and johnin PPD. In the period of study, these efficiency indices showed fluctuations characteristic of the given tests. In the period between PI day 160 and 400 fifteen biochemical parameters were measured monthly, TRP, ALP, TRIG and CHOL were reduced by day 400, pointing to disorders of digestion and absorption. Increased activities of CK, ALD, LDH, α-HBDH and ALT indicated skeletal muscle and/or liver damage in the first place. Serum CK, ALD activities and TRIG and TRP concentrations may serve as useful complementary values to the specific diagnosis of paratuberculosis, particularly in the advanced stage of the disease.

Journal Article
TL;DR: The liquid synthetic medium was compared with the nitrofurantoin broth and the solid one with cetrimide agar by parallel inoculation of 60 raw milk samples and 20 P. aeruginosa pure cultures to show high selectivity, high sensitivity and rapidity.
Abstract: Selective and differentiating media consisting of simple chemical components have been developed, both in solid and in liquid form, for culturing Pseudomonas aeruginosa from foodstuffs. These media work on the basic principle that Gram-negative bacteria can utilize ammonia as inorganic nitrogen source. This principle has already been utilized for developing a culture medium for coliform bacteria (Szita and Biro, 1986; Szita et al., 1988). P. aeruginosa can produce the ammonia needed for its growth by decomposing acetamide. The liquid synthetic medium was compared with the nitrofurantoin broth and the solid one with cetrimide agar by parallel inoculation of 60 raw milk samples and 20 P. aeruginosa pure cultures. The main advantages of the synthetic media are their high selectivity, high sensitivity and rapidity. Owing to their advantageous properties, the new media can be recommended for replacing cetrimide agar and nitrofurantoin broth.

Journal Article
TL;DR: The findings suggest that healthy salmonella carrier pigs carried the infection from the farm to the abattoir and, thereafter, that of the pork and pork products.
Abstract: A total of 35 Salmonella derby strains, isolated from 6 types of samples of porcine origin from 9 different places in Hungary were examined for their characteristics. Thirty-two strains (91%) were of phage type 25, 2 (6%) of phage type 15 and 1 (3%) of phage type 58. Colicin production was observed in 3 (9%) strains. Five strains (14%) were found to be resistant to tetracycline (Tc). The strains harboured plasmids of 2.2, 2.4, 3.4, 4.2 and 72 Md. The 72 Md plasmid appears to be characteristic of S. derby and possibly encodes Tc resistance. The 72 Md plasmid belonged partly to incompatibility (Inc) group I1, while the other plasmid of the same size belonged to Inc. group B. The findings suggest that healthy salmonella carrier pigs carried the infection from the farm to the abattoir. Slaughtering of infected pigs may have led to contamination of the carcasses and, thereafter, that of the pork and pork products.

Journal Article
TL;DR: The protein quality of mixtures of blood meal, feather meal and bone meal showed an optimum if blood meal constituted 60% of the protein content of the mixtures; however, poor feed intake and growth data were obtained.
Abstract: The protein quality of two- or three-component mixtures of blood meal, feather meal and bone meal was characterized by amino acid scores and rat net protein utilization (NPU) values. A graphic method designed to find optimum levels of the limiting essential amino acids in the mixtures was suitable for predicting the optimum of NPU values determined by feeding rats with diets having 10% crude protein. The protein quality of mixtures of blood meal, feather meal and bone meal showed an optimum if blood meal constituted 60% of the protein content of the mixtures; however, poor feed intake and growth data were obtained.


Journal Article
TL;DR: It is concluded that the possible relationship of thyroid hormone levels and blood pH is a complex one and the underlying mechanism requires further study.
Abstract: Thyroid hormone levels in the plasma and blood pH were compared in 38 newborn calves and their dams immediately at parturition, then 24 and 72 h thereafter. Both thyroid hormone levels and pH exhibit much higher variation in calves than in cows. Applying a linear model at different sampling times, a weak (r = -0.112 to -0.397) but significant (P less than 0.05) negative correlation was found between thyroid hormone levels and blood pH in calves 24 and 72 h postpartum. At birth, when no correlation was found with linear approach, a polynomial regression model showed curvilinear relationship between thyroid hormone levels and blood pH in calves. Since these correlations could not be substantiated by comparing data of different sampling times, one can conclude that the possible relationship of thyroid hormone levels and blood pH is a complex one. Revealing the underlying mechanism of the above observations requires further study.



Journal ArticleDOI
TL;DR: Colonisation of type D Pasteurella multocida was studied in five groups of seven SPF piglets each and both single and repeated inoculation failed in piglets of Group 4.

Journal Article
TL;DR: SCA concentration showed a characteristic change on the days immediately after calving: on calving day it was close to the mean SCA concentration found for dry cows, then it underwent a striking abrupt rise and reached the value typical of post- parturient cows by post-partum (PP) day 4-5.
Abstract: Serum cholic acid (SCA) and serum chenodeoxycholic acid (SCDCA) concentrations were determined in healthy dairy cows by radioimmunoassay (RIA). The levels of these two primary bile acids were correlated with the cows' reproductive status. The lowest concentrations were measured in dry cows (SCA: 7.8 +/- 3.3 mumol/l, SCDCA.: 1.5 +/- 1.0 mumol/l). In freshly calved cows SCA and SCDCA was 17.8 +/- 6.9 mumol/l and 2.3 +/- 1.0 mumol/l, respectively, while in milking cows SCA and SCDCA was 15.8 +/- 5.7 and 2.3 +/- 0.8 mumol/l, respectively. SCA concentration showed a characteristic change on the days immediately after calving: on calving day it was close to the mean SCA concentration found for dry cows, then it underwent a striking abrupt rise and reached the value typical of post-parturient cows by post-partum (PP) day 4-5. Cholic acid was found to be the major primary bile acid in the blood of dairy cows. In dry cows the SCA:SCDCA ratio is 5:1. If the serum bile acid concentration rises, the SCA:SCDCA ratio will increase further.

Journal Article
TL;DR: Changes in the electric resistance of the vaginal mucus were monitored in a large pig herd at 4-h intervals with a heat detector in multiparous sows that showed a positive standing test and conceived and lower resistance values were obtained, though the difference was not statistically significant.
Abstract: Changes in the electric resistance of the vaginal mucus were monitored in a large pig herd at 4-h intervals with a heat detector (Hauptner, Federal Republic of Germany) in multiparous sows (n = 16; litter size = 11.4 +/- 2.9) that showed a positive standing test and conceived. The initial value of resistance was 74.4 +/- 7.4 ohms. In 36 h this value gradually increased to 93.6 +/- 7.6 ohms. One to 2 h after the artificial inseminations (AI) lower resistance values were obtained, though the difference was not statistically significant. In the second part of the experiment 73.9% and 82.7% of the gilts (n = 92) and multiparous sows (n = 98) conceived, respectively, with an average litter size of 9.6 +/- 2.2 and 11.0 +/- 2.7, respectively. The conception rate of animals that immediately before AI had vaginal mucus resistance values between 75 and 90 ohms was about 20% higher. The only exception were 8 multiparous sows which had an average vaginal mucus resistance of 70 +/- 4.6 ohms after the first insemination. Litter size was also the biggest in sows with vaginal mucus resistance between 75 and 90 ohms. This difference was statistically significant for the multiparous sows. The heat detector is considered to be a useful complement to conventional methods of oestrus detection.

Journal ArticleDOI
TL;DR: The authors have revealed the main value characteristics of pork production by testing in five different types of pig the volume of contractile and collagen proteins, that of proteoglycans, the constituents of blood and the enzymes of the blood plasma.
Abstract: The authors have revealed the main value characteristics of pork production by testing in five different types of pig the volume of contractile and collagen proteins, that of proteoglycans, the constituents of blood and the enzymes of the blood plasma. The contractile proteins of the muscle tissues basically determine the quality of pork. The same applies to the water retention capacity, colloidal characteristics and glycogen content of meat. The amount of contractile proteins has decreased in the best meat producing types of pig. Parallel with the decrease of white meat, and with the increase in the volume of ham, chop and chuck the contractile protein content of muscles decreased. The scientific fact according to which there is a certain correlation among the changes in the volume of contractile proteins, blood sugar level, blood serum CPK and the intensity of activity of the LDH enzymes promotes the qualifying of live animals and the work of the geneticists aiming at the increasing of the contractile protein content of the muscle tissues of pigs by selection. According to tests carried out by us the primary cause of PSE changes is a decreased volume of contractile proteins. Increased stress sensitivity and all the other factors have but a secondary importance and are all consequential. The decrease in the quantity of contractile proteins or--it is better to put it this way--the lack of the proper amount of such proteins characterizing a fully developed pig's organism is caused by the nowadays usual breeding technologies and can be well explained by those selection activities which aim at a one-sided kind of pork production.

Journal Article
TL;DR: The chemical mechanisms and nutritional consequences of heat processing of feeds for sterilization and to destroy antinutritive substances, and complex reactions between proteins and carbohydrates, are reviewed.
Abstract: The consequences of heat processing of feeds for sterilization and to destroy antinutritive substances can be beneficial as well as detrimental. Damages to feed proteins may be primarily explained by complex reactions between proteins and carbohydrates, by interactions between protein molecules and by oxidation. The chemical mechanisms and nutritional consequences of these reactions are reviewed.


Journal Article
TL;DR: It is suggested that an important reason for anoestrus in mares is the absence of a functional corpus luteum that can be substituted for by exogenous gestagen administration, and the timing of ovulation should still be improved.
Abstract: Anoestrous mares were treated with prostaglandin (n = 43) and those that did not respond to prostaglandin (n = 29) with a synthetic progestagen, allyloestrenol, at a dose of 0.05 mg/kg body mass for 12 days. After the cessation of the long-term per os gestagen blockade the animals were checked for heat and, if a preovulatory follicle could be palpated, 2000 IU hCG was administered to induce ovulation. In some animals the plasma 17 beta-oestradiol (E2) and progesterone (P4) levels were also followed up throughout the gestagen treatment and for 10-14 days thereafter. As the favourable oestrus rate (86.2%) and pregnancy rate (65.5%) indicate, the 12-day allyloestrenol treatment seems to be a reliable tool for induction of cycling in mares anoestrous early in the season. These results, supported by the E2 and P4 profiles, suggest that an important reason for anoestrus in mares is the absence of a functional corpus luteum that can be substituted for by exogenous gestagen administration. The timing of ovulation, however, should still be improved.