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Biomedical subjects

A Kunavongkrit

Publications and source records attributed to A Kunavongkrit.

At least 19 recordsLinked to original sources
PubMed2006

Age, body weight and backfat thickness at first observed oestrus in crossbred Landrace x Yorkshire gilts, seasonal variations and their influence on subsequence reproductive performance.

The objective of the present study was to investigate puberty attainment in crossbred Landrace x Yorkshire (LY) gilts reared under tropical conditions and their subsequent reproductive performance. This study was carried out in a 2400-sow herd over a 1-year period. A total of 696 crossbred LY replacement gilts were included. Faecal samples from 214 gilts were collected to determine the faecal progesterone profiles around the time of first oestrus. Solid-phase 125I-radioimmunoassay was used to determine the progesterone concentrations in the faecal extract. The gilts entered the herd at an average age of 177.5 +/- 12.6 days, 95.7 +/- 10.2 kg body weight (BW) and a backfat thickness (BF) of 12.0 +/- 2.9 mm. On average, the gilts expressed first standing oestrus at 195 days of age, 106 kg of BW and a BF of 13.0 mm. The interval from entry to the gilt pool to the first observed oestrus (EOI) was 24.4 +/- 18.0 days (range 0-88 days). The hormonal profile indicated that the gilts that actually ovulated during the first observed oestrus was 34% (group A), the gilts that had ovulated before the first observed oestrus was 21% (group B) and the gilts that did not ovulate during the first observed oestrus was 45% (group C). During summer the proportion of group A gilts was significantly lower than during the winter and the rainy seasons (P < 0.05). The BW of gilts at entry significantly correlated with the BF at entry (r = 0.31, P < 0.001), the age at entry (r = 0.47, P < 0.001), the BW at first oestrus (r = 0.65, P < 0.001) and the BF at first oestrus (r = 0.33, P < 0.001). An increase of BW at entry of 1 kg resulted in a decrease of EOI of 0.28 days. The age, BW and BF of gilts at the first observed oestrus significantly influenced the total number of piglets born per litter (TB) and the number of piglets born alive per litter (BA) in the first three parities. Gilts expressing their first oestrus between 181 and 200 days had a significantly larger TB than gilts that expressed first oestrus between 150 and 180 days (P = 0.03) and between 201 and 220 days (P = 0.003). Gilts that showed first oestrus between 110.1 and 120.0 kg had a larger TB and BA than gilts that showed first oestrus between 80.0 and 100.0 kg (P < 0.05). Gilts that showed first oestrus with a BF between 13.1 and 15.0 mm had a larger TB and BA than gilts that showed first oestrus with a BF between 11.1 and 13.0 mm (P < 0.05). Group A gilts had a significantly larger TB than group B (10.5 piglets/L versus 9.4 piglets/L, P = 0.02), while farrowing rate (FR) did not differ significantly among groups A, B and C (78.1, 76.9 and 77.6%, respectively). Gilts that farrowed in the summer had a larger TB and BA than gilts that farrowed in the winter (TB, P = 0.03; BA, P = 0.09) and the rainy season (TB, P = 0.006; BA, P = 0.003). In conclusion, LY gilts reared under tropical conditions expressed first standing oestrus at 195 days of age, 106 kg BW and a BF of 13.0 mm. Under field conditions, 21% of the gilts with an observed oestrus had ovulated. The proportion of gilts that showed first oestrus and ovulated normally was lowest during the summer. The age, BW and BF at first observed oestrus influenced subsequent reproductive performance over the first three parities. The mean litter size (TB and BA) in the first three parities were highest in gilts that had a first observed oestrus between 181 and 200 days with 110.1-120.0 kg BW and 13.1-15.0 mm BF.

Adipose Tissue↗
PubMed2005

The effect of post-ovulatory insemination on the subsequent embryonic loss, oestrous cycle length and vaginal discharge in sows.

The aim of present study was to study the effect of post-ovulatory insemination on the subsequent embryonic loss, oestrous cycle length and vaginal discharge in sows. Ten Large White multiparous sows were divided into two groups. Group A sows were inseminated once at 15 h after ovulation. Thereafter, they were ovariohysterectomized on day 11 (n = 5, first day of standing oestrus = day 1) and flushed for recovery of embryos. Group B sows were also inseminated once at 15 h after ovulation. They were further observed for return to oestrus and vaginal discharge (n = 5) after insemination. The endometrium tissues were biopsied from sows with vaginal discharge, embedded with paraffin, stained with haematoxylin and eosin and examined under light microscope. Only two embryos were observed in one of four sows from group A. All embryos had a spherical shape but differed in size (range 1-2 mm). In group B, only one sow had a regular return to oestrus (i.e. on day 23) and another sow had an irregular return to oestrus (i.e. on day 27). The other two sows in this group had shown vaginal discharge on days 20 and 38 after standing oestrus. For the number of leucocytes in the endometrium of sows with vaginal discharge, a large number of lymphocytes and plasma cells were observed in the connective tissue of the subepithelial layer. In conclusion, post-ovulatory insemination resulted in early embryonic loss, a subsequent prolonged oestrus interval and also vaginal discharge (i.e. endometritis) in sows.

Animals↗
PubMed2001

Body weight loss during lactation and its influence on weaning-to-service interval and ovulation rate in Landrace and Yorkshire sows in the tropical environment of Thailand.

The aim of this study was to investigate the ovulation rate and the weaning-to-service interval (WSI) of sows in relation to their body weight loss during lactation in tropical climatic conditions. Effect of lactation length (LL), number of total born piglets, number of live born piglets, litter birth weight, average piglet birth weight, number of pigs weaned, litter weaning weight and average pig weaned weight on sow weight loss during lactation were also studied. This study was conducted in two commercial purebred sow herds (A, B) in the central part of Thailand from August to December 1997. The herds had both Landrace (L) and Yorkshire (Y) sows. The 123 sows (55 L and 68 Y) in herd A and 153 sows (95 L and 58 Y) in herd B, parity 1-4, were weighed within 4 days after farrowing and at weaning. Lactation length, litter size at birth and at weaning, litter weight at birth and at weaning, and WSI were recorded for each of these sows. In herd A, 52 sows (20 L and 32 Y) were examined once by laparoscopy between days 8 and 14 after AI-service. These sows had farrowed at least seven piglets in the previous parturition. The numbers of corpora lutea (CL) in both ovaries were counted, and were assumed to equal the ovulation rate. L-sows had significantly (P < 0.05) higher relative weight loss during lactation (RWL) than Y-sows. The RWL increased by 0.7% for each extra pig weaned. When LL increased by 1 day, within the interval of 17-34 days, RWL decreased by 0.6%. Sows with a high weight loss had significantly (P < 0.05) longer WSI than sows with medium or low weight loss. Weight loss had a significant (P < 0.05) effect on WSI in parity 1 and 2 sows. Y-sows had more CL than L-sows (15.7 versus 14.0) (P < 0.05). RWL, parity and regression on lactation length had no significant effect on number of CL. In conclusion, sows with higher number of pigs weaned lose more weight. Under the restricted feeding regime applied, high weight loss during lactation prolongs WSI in parity 1 and 2 sows, but has no influence on the ovulation rate at first oestrus after weaning. The ovulation rate is higher in Yorkshire than in Landrace sows. The ovulation rate is independent of parity.

Animals↗
PubMed2000

Effects of lactation length and weaning-to-service interval on subsequent farrowing rate and litter size in Landrace and Yorkshire sows in Thailand.

The aim of the present study was to investigate the influence of lactation length (LL) on weaning-to-service interval (WSI), and the effect of LL and WSI on the subsequent farrowing rate and litter size among purebred Landrace and Yorkshire sows under tropical conditions. The variation in litter weight at weaning (LWW) was also studied. Data were analyzed from three purebred sow herds located in the central part of Thailand, including sows weaned during the period from January 1993 to December 1996. Data were analyzed with analysis of variance using SAS software. The procedure MIXED was used for analysis of the continuous outcome variables (namely LL, LWW, WSI, number of total born and number of live born piglets). The GLIMMIX macro was used for analysis of the categorical outcome variable, farrowing rate (FR). In the statistical analyses, WSI was grouped into 7 groups, when it was an independent variable, as follows: 1 to 4, 5, 6, 7, 8, 9, to 10, and 11 to 21 days. Lactation length was grouped into 4 groups as follows: 17 to 24, 25 to 27, 28 to 30 and 31 to 35 days. Parities were grouped into 4 groups as follows: 1, 2, 3 + 4, and 5 to 8. Landrace sows had significantly higher LWW (P < 0.001) compared with Yorkshire sows (56.1 vs. 53.6 kg). The LL was significantly (P < 0.05) shorter during the cool season than during the other seasons while no difference was found in LWW between the hot and the cool season. The LL had no effect on WSI, FR and litter sizes. The FR was significantly lower when the WSI was 7 to 10 days than when the WSI was 1 to 6 days. An increase in WSI between Days 9 to 10 and Day 21 resulted in a significant increase in FR. Subsequent litter size decreased by about 0.5 piglets when the WSI increased from 1 to 5 days to 6 to 7 days. Thereafter, litter size increased as the WSI increased from 9 to 10 days to 21 days.

Animals↗
PubMed2000

Pig reproduction in South East Asia.

Asia with over half the population in the world has a thriving agriculture, a large part of which is devoted to pig production. The efficiency of production varies from country to country and is largely the legacy of whether the country relies on backyard farms using native breeds or intensive commercial farms using genetically improved breeds from Europe and North America. Reproductive efficiency is not as advanced as in Europe and this is the result of climatic conditions, which are hot and humid, the presence of most pig diseases, substandard management, the difficulty of obtaining quality feeds and appropriate delivery systems and the reliance on native breeds which are far less prolific than European ones. Improvements can only occur if investments are made in housing, cooling systems, disease control, management, quality feeds and better genetics.

Animal Nutritional Physiological Phenomena↗
PubMed2000

Reproductive performance of purebred landrace and Yorkshire sows in Thailand with special reference to seasonal influence and parity number.

The purpose of this study was to analyze reproductive performance in purebred Landrace and Yorkshire sows with special reference to seasonal influence and parity number, under tropical conditions where day length is almost constant throughout the year. Data from three purebred sow herds in Thailand during the period from 1993 to 1996 were analyzed. The two breeds were present in all three herds. The analysis comprised records of 3848 Landrace sow litters and 2033 Yorkshire sow litters. The statistical models included the fixed effects of month, year, parity, breed of the sow, herd, and two-way interactions of breed-parity, breed-herd, breed-month, breed-year, parity-month, month-herd, year-herd and month-year. The random effect of sow within breed was included in all models. Analysis of covariance was performed to analyze the effect of temperature, humidity and heat index on number of total born per litter (NTB), weaning to first service interval (WSI) and farrowing rate (FR). Landrace sows had significantly higher NTB (0.6 piglets), number of live born per litter (0.5 piglets), and average birth weight (0.13 kg) than Yorkshire sows (P<0.001). Farrowing rate was 3.9% higher in Landrace sows than in Yorkshire sows (P<0.01). However, Yorkshire sows had significantly shorter WSI (P<0.001) and significantly higher proportion of sows served within 7 days after weaning (P<0.01) than Landrace sows. No breed differences were found in number of stillborn per litter and weaning to conception interval. Parity had significant effect on all reproductive parameters analyzed. Number of total born and live born per litter was significantly lower for sows farrowing during the rainy season than in other seasons. Farrowing rate was low for sows mated during the hot and rainy season. Weaning to service interval and WSI7 were prolonged for sows weaned during the hot and rainy season. Reproductive performance was significantly unfavorably influenced by elevated temperature and heat index after mating (NTB and FR) or during lactation (WSI).

Animals↗
PubMed1992

Comparison of virus isolation, immunofluorescence and DNA probe hybridization for detection of pseudorabies virus in experimentally infected pigs.

Virus isolation, immunofluorescent staining and DNA probe hybridization, three techniques for the detection of pseudorabies virus (PRV) have been compared in pigs experimentally infected with the Thailand CB-1 strain PRV. The virus isolation and DNA hybridization detection demonstrated a good correlation in detecting infection in live animals by nasal swabbing. In white blood cells an earlier detection was seen with the DNA-hybridization techniques. Consistent results with all the three techniques tested were found in organ materials as nasal mucosa and tonsils as well as in the olfactory bulb.

Animals↗
PubMed1987

Increase of insulin and decrease of glucagon levels in response to total and fractionated weaning in sows.

The effect of weaning on plasma levels of insulin and glucagon as well as on plasma glucose levels was studied in sows after final weaning (all the piglets removed in week 5 of lactation) and fractionated weaning (7 out of 12 piglets removed in week 3 of lactation). Insulin levels rose from 24 +/- 6 to 106 +/- 22 microU ml-1 4 days after final weaning and from 11 +/- 1 to 128 +/- 20 microU ml-1 7 days after fractionated weaning. Glucagon levels fell from 60 +/- 20 and 42 +/- 8 to 35 +/- 10 and 24 +/- 5 pm in the two groups, respectively. Plasma glucose levels increased from 4.5 +/- 0.5 to 7.2 +/- 1.2 mM after fractionated weaning and remained unchanged after final weaning. One possible mechanism that can explain this pronounced insulin increase and decrease of glucagon is the elevation of plasma glucose, since milk is no longer emptied from the mammary gland and since insulin resistance occurs after weaning in rats. Another possible explanation could be a decreased number of insulin receptors in the mammary gland, since prolactin which is known to increase insulin receptors is decreased in weaned rats.

Animals↗
PubMed1986

Investigation into the use of prostaglandin F2 alpha (PGF2 alpha) and oxytocin for the induction of farrowing.

This experiment was conducted in order to compare the effects of injecting PGF2 alpha alone, PGF2 alpha with oxytocin and placebo on the induction of farrowing in swine and to compare the relative effects of 3 different dosages of oxytocin (10, 20 and 30 iu per animal) when combined with PGF2 alpha (10 mg). The findings revealed that animals treated with 30 iu oxytocin farrowed within 10.6 h which was similar to those receiving PGF2 alpha only (9.4 h), but shorter than control animals (53.6 h). Animals receiving 20 and 10 iu of oxytocin farrowed within 1.4 and 1.7 h, respectively. Difficult farrowings requiring manual assistance occurred in 30%, 30%, 50% and 10% of sows given 30 iu, 20 iu and 10 iu of oxytocin and in the control group, respectively. Thirteen of 73 sows treated with PGF2 alpha farrowed within 12.6 +/- 5.3 h. Stillbirths were highest (10.2%) in the control animals whilst in the others it was under 7%. Oxytocin at dosages of 20 and 10 iu, seemed most promising in terms of synchronising farrowing following PGF2 alpha treatment in swine. However, farrowing complications were more common in these groups.

Animals↗
PubMed1985

Plasma levels of oxytocin increase in response to suckling and feeding in dogs and sows.

The objective of the present study was to investigate whether oxytocin is released in response to feeding in analogy to the response induced by suckling. Therefore, repeated plasma samples were drawn from dogs and pigs during feeding and suckling and oxytocin levels were determined by radioimmunoassay. As expected suckling gave rise to immediate and short-lasting increases of oxytocin levels in both species. More surprisingly, feeding in female and male dogs as well as in lactating sows was accompanied by a similar-sized rise of oxytocin levels. The oxytocin peak sometimes occurred before the actual period of suckling or feeding, suggesting that the output of oxytocin had been conditioned to visual, olfactory or auditory stimuli associated with both types of situations. It is well known that oxytocin is released in lactating animals in response to touching of the teats. It is possible that also the presence of food in the gastro-intestinal tract activates neurogenic mechanisms which stimulates the release of oxytocin. Since oxytocin causes a release of insulin and VIP (vasoactive intestinal polypeptide), peptides which appear in the circulation following both suckling and feeding, it is suggested that oxytocin may be involved in the control of the suckling- and feeding-related output of these peptides.

Animals↗
PubMed1984

Receptors for estrogens and progesterone in the porcine cervix.

In vitro binding and exchange methods were used to determine the levels of estradiol and progesterone receptors in cytosolic and nuclear fractions of cells obtained from the porcine cervix at different stages of the estrous cycle. The concentration of estradiol cytosolic receptors was about 4500 sites/cell during the luteal phase and increased to a maximum of approximately 7600 sites/cell on day 1 of the cycle, decreasing to a level of 2700 sites/cell on days 3-4. The estradiol nuclear receptor level increased between the end of the luteal phase and the onset of heat from 300 to 1200 sites/cell. No reduction in the number of nuclear sites was seen between day 1 and 3-4. The level of the progesterone cytosolic receptor and its cycle profile was very similar to that of the estradiol receptor. The nuclear receptor, however, reached its lowest level of 760 sites/cell on day 1 of the cycle, increased to a value of 4700 sites on days 3-4 and showed a steady level of about 1000 sites/cell during the luteal phase. The data obtained agree with present theories on the endocrine mechanisms regulating receptor levels in the uterus. Furthermore, these data support a concept in which the constriction of the cervix occurring in response to increased concentrations of circulating estradiol is mediated via steroid receptors.

Journal Article↗
PubMed1984

Influence of suckling and feeding on insulin, gastrin, somatostatin and VIP levels in peripheral venous blood of lactating sows.

Blood samples were collected in peripheral venous blood of seven lactating sows, when their piglets were suckling. In four of the experiments samples were also taken when the sows were fed a meal. Gastrin, insulin, somatostatin and VIP levels were measured by radioimmunoassay. Insulin levels increased by approximately 100% for about 10 min in response to suckling, in some experiments even before the suckling occurred, i.e. when the sows saw, heard and smelled their piglets. In four of the sows suckling caused a biphasic twofold increase in gastrin levels - one immediate peak which lasted for a few min and a second peak of longer duration (about 30-60 min), whereas gastrin levels remained unchanged in three animals. Somatostatin levels usually reflected gastrin levels in a reciprocal way. Thus, a biphasic decrease of somatostatin levels occurred in the high gastrin responders. In contrast, somatostatin levels increased in the experiments, in which gastrin levels did not change. Immediate and short-lasting (a few minutes long) increases of VIP levels were also induced by suckling. Large litters and long suckling periods appeared to be related to greater changes of the levels of all the peptides measured. Feeding influenced insulin, gastrin and somatostatin levels in the same way as did suckling from both a qualitative and a quantitative point of view. In contrast, VIP levels were not increased by feeding. The possible functional effects of the suckling-induced release of gastrointestinal hormones and possible mechanisms of their release are discussed.

Animals↗
PubMed1984

Laparoscopy in post partum sows with special emphasis on the effects of uterine manipulation on the release of prostaglandin F2 alpha.

One hundred laparoscopies were performed on 30 primiparous post partum sows and complications during and after examinations recorded. Nineteen of these animals were separated into two groups and subjected to different treatments: group 1 (10 sows), with conventional laparoscopy; group 2 (nine sows) with two minutes extra manipulation of the uterus after laparoscopy. Blood was sampled before and after the operations. The plasma was analysed for its content of 15-keto-13,14-dihydroprostaglandin F2 alpha by radioimmunoassay. The results indicate that laparoscopies were successful and can be used in post partum sows during lactation and after weaning without any severe complications. In some sows laparoscopy alone or laparoscopy followed by manipulation of the uterus for two minutes caused a peak of the prostaglandin metabolite. However the height and duration of this peak were not sufficient to influence reproductive performance in pigs.

Animals↗