Comparative reproductive performance of Saanen and Toggenburg bucks raised under tropical environment.

The objective of this study was to evaluate the effect of breed and age on scrotal measurements and semen characteristics of Saanen and Toggenburg bucks raised under extensive system in the tropic. The study was conducted using Toggenburg and Saanen bucks; the bucks were allocated into two different groups based on breed and age in 2 × 2 factorial completely randomized design. The body weight was determined using a hanging weighing scale expressed in kilogrammes (kg). Scrotal circumference and scrotal length were measured using metal measuring tape. Semen characteristics evaluated were volume, consistency, mass activity and progressive motility, live sperm cells, normal morphology and spermatozoa concentration. The current study found that breed of bucks had no influence on body weight, scrotal circumference, scrotal length, volume, mass activity, progressive motility, live sperm cells and sperm morphology. The study also found that Toggenburg bucks had higher semen consistency and spermatozoa concentration as compared with Saanen bucks. Therefore, it can be concluded that Toggenburg bucks can produce high number of total spermatozoa and as a result higher semen doses for artificial insemination purposes. Further studies with more number of animals are recommended.

Lipopolysaccharide binding protein in the acute phase response of experimental murine Trypanosoma brucei brucei infection.

Cellular responses to lipopolysaccharide (LPS) are enhanced by LPS-binding protein (LBP). The present study investigated the acute phase response of LBP during Trypanosoma brucei brucei infection in mice. Mean plasma concentrations of LBP increased two-fold by the seventh day following infection, but decreased to intermediate levels by the 14th day. There were no significant differences in LBP concentrations of infected/antibiotic-treated and infected/untreated mice. At 35 days post-infection, the infected mice were treated with the anti-trypanosomal diminazine aceturate (Berenil). LBP levels of the mice then decreased to pre-infection levels within one-week. This demonstrated that LBP is an acute phase protein during murine trypanosomosis. Furthermore, opportunistic secondary bacterial infection during trypanosomosis did not seem to play an important role in the changes in plasma LBP levels. We speculate that the marked concomitant increases in plasma LBP and endotoxin-like activity following murine trypanosome infection might play an important role in the pathogenesis of trypanosomosis.

Effects of post-ovulatory food deprivation on oviductal sperm concentration, embryo development and hormonal profiles in the pig.

Nutrition is one of the multiple factors that modulate reproduction in animals. The effect of 48 h food deprivation on reproductive and metabolic hormonal changes in relation to cleavage rates was studied. Insemination of 15 sows was performed 20-10 h prior to expected ovulation and ova were recovered at slaughter 65-91 h post ovulation. Blood samples were collected every second hour, beginning from the time of insemination until slaughter, for measurements of progesterone, cortisol, the prostaglandin F2alpha metabolite (15-keto-13,14-dihydro-PGF2alpha) and insulin levels. The embryos from the food-deprived sows (D-group) had fewer accessory spermatozoa in their zona pellucida (ZP) compared with the control sows (C-group). A lower cleavage rate of the embryos in the D-group compared with the C-group was detected. Plasma progesterone, cortisol and prostaglandin F2alpha metabolite levels were significantly higher in the D-group compared with the C-group. Food deprivation is associated with changes in reproductive and metabolic hormones that might lead to changes in the oviductal environment, culminating in a lower cleavage rate of the embryos and presence of fewer viable spermatozoa in the reservoir.

Changes in sperm ultrastructure and localisation in the porcine oviduct around ovulation.

Changes in the morphology and localisation of spermatozoa in the utero-tubal junction (UTJ) and three equal segments of the isthmus (lower, middle and upper isthmus) within +/-8 h of ovulation were studied with scanning and transmission electron microscopy. Spermatozoa were located at specific sites within the UTJ-isthmic environment. Two sperm subpopulations were evident, one with epithelial contact and one without such contact. Most of the sperm population with epithelial contact maintained intact plasma membrane during the pre-ovulatory period and showed acrosome reacted-like membrane changes during the post-ovulatory period. In contrast, plasma membranes in most of the spermatozoa with no epithelial contact were already broken before ovulation. Ovulation was also accompanied by a relocation of spermatozoa from the mucosal crypts/interfolds towards the more central part of the mucosal surface.

Distribution, number and membrane integrity of spermatozoa in the pig oviduct in relation to spontaneous ovulation.

The pattern of distribution, number and membrane integrity of spermatozoa in the utero-tubal junction (UTJ) and isthmus during three oestrous stages were related to spontaneous ovulation in flushed and fixed oviducts of multiparous sows. Three unrelated boars were each used once to mate or artificially inseminate (neat ejaculate) six out of 18 sows, 18 h prior to expected ovulation. The sows were slaughtered 6-8 h before, during or 6-8 h after ovulation. The ad-uterine oviductal region (UTJ and isthmus) was divided into UTJ, lower isthmus, middle isthmus and upper isthmus segments. A higher fraction of middle and upper isthmus segments contained spermatozoa during the peri- and post-ovulatory periods than during the pre-ovulatory period. The distribution, numbers and membrane integrity of spermatozoa in the UTJ-isthmus region were influenced by the ovulation event. Numbers and distribution of spermatozoa varied depending on the boar used. The flushing technique allowed a better assessment of the distribution, number and membrane integrity of tubal spermatozoa than in situ observation with a scanning electron microscope (SEM).

Ovulation as determined by transrectal ultrasonography in multiparous sows: relationships with oestrous symptoms and hormonal profiles.

Twenty-four cross-bred multiparous sows in their second and fourth parities were studied during two consecutive oestruses after weaning. Careful oestrous control was done on the animals and ovulation was monitored by transrectal ultrasonography. Blood for analysis of LH and E2 contents was collected through an indwelling catheter. The sows were mated/inseminated once approximately 18 h before expected ovulation in their second oestrus. The interval between weaning and ovulation varied from 86 h-204 h (153 +/- 26). Onset of standing oestrus to ovulation was found to be longer in sows with long oestruses and ovulation occurred within a mean of 68% of the oestrous period. Duration of the first pro-oestrus was significantly shorter than the second pro-oestrus (40 h and 71 h, respectively). There was no significant difference within sows for the intervals from onset of oestrus to ovulation during the first and second oestrus after weaning (37 h and 39 h, respectively). The diameter of the largest follicles at onset of oestrus and at ovulation had very small variation between animals. The mean intervals from E2 peak to onset of oestrus and to ovulation were 1 h (range -10-(+)22 h) and 44 h (range 34-54 h) respectively, and from LH peak to onset of oestrus and to ovulation 12 h range -10-(+)32 h) and 35 h (range 27-48 h), respectively. The present study indicates that repeated ultrasonographic examination of ovaries during one oestrus can be used to predict the time of ovulation during the subsequent oestrus.(ABSTRACT TRUNCATED AT 250 WORDS)

Thyroid hormones and metabolic rate during induction of Vitamin B12 deficiency in goats.

Vitamin B12 deficiency was induced in 15 small East African goats by feeding cobalt deficient Chloris gayana hay (containing 0.02 mg of Co/kg dry matter) over a 25 week experimental period. Cobalt was supplemented as an oral drench to supply 0.3 g of Co/goat/week to 15 treated goats. At intervals of 3-4 weeks, serum concentrations of Vitamin B12 , total thyroxine (TT4), free tetra-iodothyronine (FT4) and free tri-iodothyronine (FT3) were determined by radioimmunoassay, while the rate of resting metabolism was determined by measuring the goats' rate of oxygen consumption. Serum Vitamin B12 concentration was significantly higher (p<0.01) in cobalt-treated (289.6 +/- 40.76 pg/ml) than in control (142.8 +/- 28.27 pg/ml) goats. The mean serum TT4 concentration was significantly (p<0.01) higher in control (59.0 +/- 1.70 nmol/l) than in cobalt-treated (51.6 +/- 2.45 nmol/l) goats. However, the levels of FT4, FT3 and the rate of resting metabolism were unaffected by the goats' cobalt status. Furthermore, the goats did not lose weight or become anaemic.

Changes in serum levels of vitamin B12, feed intake, liveweight and hematological parameters in cobalt deficient small east African goats.

Thirty short-horned East African goats were divided into two groups (treatments 1 and 2) consisting of fifteen goats each. All the goats were fed on a cobalt deficient diet containing 0.02 mg Co/kg of dry matter for a period of twenty three weeks. Goats in treatment 1 were supplemented with an oral cobalt chloride drench. Cobalt deficiency developed in goats in treatment 2 after ten weeks when their serum vitamin B12 concentration fell below 200-250 pg/ml. Between the third and the twenty-third weeks of the experiment, the mean serum concentration of vitamin B12 was significantly (P < 0.01) higher in cobalt supplemented (289.6 +/- 40.76 pg/ml) than deficient (142.8 +/- 28.27 pg/ml) goats. Total dry matter intake, intake per metabolic body weight and liveweight changes were not significantly (P > 0.05) different between goats in the two treatments. Although packed cell volume, hemoglobin concentration, and erythrocyte count were significantly (P < 0.05) higher in cobalt adequate than deficient goats, these blood parameters were within the normal range for goats. It is suggested that although serum vitamin B12 standard for sheep is applied for goats, the latter species is likely to be more resistant to low dietary cobalt intake than sheep.