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Biomedical subjects

F X Aherne

Publications and source records attributed to F X Aherne.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effect of delayed breeding on the endocrinology and fecundity of sows.

The effect of serving sows at first or second estrus after weaning was determined using 114 Camborough sows (Parities 1 to 8). Eighty sows were paired according to weaning-to-estrus interval and parity. One sow of each pair was bred at first and the other at second estrus after weaning. A further 27 sows were catheterized on d 3 after weaning or d 20 of the first estrous cycle and bred at first or second estrus, respectively. Blood samples were taken every 30 min from 0800 to 1330 on the day after catheterization, every 6 h from catheterization until 1 d after standing estrus, and every 12 h for a further 3 d. Of the 80 sows, litter size increased (P < .002) by breeding Parity 1 and 2 sows at second rather than at first estrus (10.4 vs 12.8 total pigs born). These increases in litter size were achieved in the absence of any significant changes in sow weight or backfat during lactation and between weaning and breeding, and predicted changes in fat and protein during lactation. Similar but nonsignificant results (P = .15) were observed for the 27 catheterized sows. Plasma progesterone concentrations measured 50 h after the preovulatory LH surge were higher in Parity 1 and 2 sows bred at second rather than at first estrus (5.4 +/- .7 vs 3.7 +/- .3 ng/mL, P < .04). Sows of Parity 1 and 2 bred at first rather than at second estrus had higher plasma IGF-I (P < .05) and glycerol (P < .001) concentrations and tended to have lower preprandial insulin concentrations (P = .09).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1994

The effects of lysine:energy ratio on the performance of weanling pigs.

In five trials, 382 weaned pigs with an average BW of 9.1 +/- .07 kg were randomly allotted in groups of four to determine the optimum ratio of lysine:energy and the interrelationship between lysine and DE levels. Twelve dietary treatments, three levels of DE (13.3, 14.0, and 14.7 MJ of DE/kg), and four lysine:energy ratios (Lys:DE) of .7, .8, .9, and 1.0 g of lysine/MJ of DE were used in a 3 x 4 factorial arrangement. All diets were formulated to have similar CP levels (19.5%) and were based on wheat, barley, and soybean meal. There was a linear decrease (P < .05) in feed intake as the energy in the diet increased. Feed intake was not affected by Lys:DE. A positive linear effect (P < .001) of Lys:DE on ADG was observed. Also, ADG increased linearly (P < .05) with an increase in DE level. Increases in DE level and Lys:DE resulted in linear (P < .001) improvements in gain to feed. Plasma urea nitrogen (PUN) concentrations decreased (linear, P < .001; quadratic, P < .007) as Lys:DE increased up to .9 g of lysine/MJ of DE. As the level of DE increased, there was a linear decrease in PUN concentration (P < .001). Backfat thickness of pigs increased linearly (P < .003) with an increase in DE level. Ratio of lysine:DE had a quadratic (P < .002) effect on backfat thickness, with an increase up to .9 g of lysine/MJ of DE and a decrease thereafter. The combination of DE level and Lys:DE, based on response surface analysis, that produced maximization of weight gain (612 g/d) was 14.13 MJ of DE/kg and .95 g of lysine/MJ of DE for pigs from 9.1 to 25.7 kg of BW.

Adipose Tissue↗
PubMed1993

Jejunum is preferable for construction of a Bianchi bowel-lengthening procedure in swine short bowel.

This study compared the efficacy of a Bianchi bowel-lengthening procedure performed in residual ileum and jejunum of a 75% short bowel model. Eighteen female piglets underwent a 75% mid small bowel resection. After a 6-week period, animal weights were similar and pigs were randomly assigned to one of three treatment groups: (1) a control group receiving no further therapy; (2) a group receiving a Bianchi procedure in the residual jejunal segment; and (3) a group receiving a Bianchi procedure in the residual ileal segment. All were followed for a further 12 weeks. Jejunal Bianchi-treated short bowel animals demonstrated a greater final weight gain (78.8 +/- 4.9 kg) compared with nontreated short bowel (63.0 +/- 6.6 kg) and ileal Bianchi-treated short bowel groups (69.3 +/- 6.9 kg) in addition to a larger jejunal diameter. The increased weight gain in the jejunal Bianchi-treated group was not a consequence of initial bowel length, food intake, changes in bowel length, digestibility of nitrogen or fat, or nutritional status. Furthermore, kinetic constants for D-glucose absorption following 18 weeks of short-bowel syndrome demonstrated a lowered glucose maximal transport rate (Vmax) in animals with nontreated short bowel compared with sham-operated controls. Additionally, jejunal and ileal glucose Vmax was further lowered in the presence of a Bianchi procedure. We conclude that: (1) during short-bowel syndrome, body weight gain was significantly higher in animals when the Bianchi procedure was performed in jejunum; (2) the short-bowel syndrome decreased intestinal glucose absorption; and (3) the Bianchi procedure itself further impaired glucose transport.

Animals↗
PubMed1993

Performance of young pigs: relationships with periparturient progesterone, prolactin, and insulin of sows.

Blood collected from 54 sows over 2 to 8 d of the periparturient period was assayed for progesterone, insulin, and prolactin to determine whether the sows' hormonal state was correlated with perinatal pig mortality and weight gain. Sows with larger litters had higher concentrations of progesterone and prolactin and a lower concentration of preprandial insulin during the 48 h preceding parturition. Pig mortality was higher in larger litters and involved pigs of lower birth weight. Most pigs that died lost weight during the 24 to 48 h that preceded their deaths. Litters with lower weight gain during the first 24 h postpartum tended to have higher mortality during the next 48 h. For some sows, progesterone remained elevated during the 48 h postpartum and litters of these sows had lower than average 3-d weight gains. Low milk intake by pigs is a major cause of death and poor growth, and we suggest that poor milk production by the sow is one contributing factor. Elevated postpartum progesterone may inhibit lactogenesis and contribute to poor pig performance.

Animals↗
PubMed1993

Innate variability in sexual development irrespective of body fatness in gilts.

To separate the effects of fatness from those of lean tissue growth on reproductive development, 52 gilts (33.2 kg, 75 d) had ad libitum access to a high-energy diet (HE; n = 31) or were fed restrictively a low-energy diet (approximately 80% of ad libitum; LE; n = 31) until 160 d of age. All HE and 15 LE gilts were then slaughtered; the 16 LE gilts that remained were then allowed ad libitum access to the low-energy diet until slaughter at 175 d (LER). Twelve littermate trios allocated across treatments were cannulated and bled during both unfed and fed states before slaughter. Gilts in the HE group were 8 kg heavier, 3.5 mm fatter (backfat), and consumed 14.9 MJ of DE more per day than gilts in the LE group at 160 d (hereafter P < .05); LER gilts were 7 kg heavier, 2.2 mm fatter, and consumed 21 MJ of DE more per day at 175 d than LE gilts at 160 d. Carcass fat was lower in LE gilts than in HE or LER gilts, but carcass lean was similar among groups. Treatment did not affect basal or episodic LH or growth hormone secretion, reproductive tract weight, follicular volume, or plasma or follicular fluid estradiol-17 beta. Postprandial plasma insulin was greater in LER than in HE or LE gilts, but plasma insulin-like growth factor I and urea nitrogen were similar among groups. Plasma nonesterified fatty acids and creatinine were greater in HE than in LE or LER gilts. These results suggest that when protein accretion rate is maximal, differences in fatness do not influence reproductive development in the prepubertal gilt. Irrespective of treatment, the only measured factor showing an association with ovarian development was the innate variability in episodic and basal LH secretion.

Adipose Tissue↗
PubMed1992

Nutrition for optimizing breeding herd performance.

Modern sows are younger and leaner at time of mating and probably have poorer appetites than sows of 10 to 15 years ago. Therefore, feeding strategies should aim to minimize weight loss and maintain a sow's body condition throughout her reproductive life. The efficiency with which gilts are introduced into the breeding herd is as important in economic terms as is the efficiency with which the sow returns to estrus after weaning. Gilts should be selected at 50 to 60 kg, and fed a 16% protein diet ad libitum until mated at their second estrus, when they weigh 115 to 120 kg and have 17 to 20 mm backfat. Flushing gilts before the onset of second or third estrus increases ovulation rate of restricted gilts to the levels achieved by gilts fed ad libitum. During gestation, maintenance represents 75 to 85% of total energy requirements. The aim should be to achieve 20 to 25 mm backfat at farrowing. Increased feed intake from day 2 to 3 after mating will not increase embryo mortality. Feeding an extra 1 kg feed/sow/day for the last 10 days of gestation increases piglet birth weight slightly and prevents a loss of 1.5 to 2.0 mm of sow backfat. Wherever possible, sows should be fed ad libitum from the day after farrowing until weaning. Reduced feed intake by lactating sows, for whatever reason, results in excessive weight and condition loss. Excessive weight loss in lactation causes extended remating intervals, a lower percentage of sows returning to estrus within 10 days of weaning, reduced pregnancy rate, and reduced embryo survival. Ovulation rate is not affected by level of feed intake in lactation. It has been suggested that sows will have minimum weaning-to-service intervals when they weigh 150 kg or more at weaning. It is likely that the sow must be anabolic for about 10 days before she will exhibit postweaning estrus. The decision when to rebreed is made some time prior to weaning and is mediated by a host of substrates, hormones, and neurotransmitters. Sows with a delayed return to estrus also have a lower pregnancy rate and smaller subsequent litters. If sows lose considerable weight or condition during lactation, a high level of feeding in the postweaning period will improve embryo survival.

Animal Nutritional Physiological Phenomena↗
PubMed1992

A study of repair cartilage from osteochondrotic humeral condyles of swine: preliminary report.

A total of 16 animals, including 12 lame and four normal boars, were used. All lame boars had severe osteochondrotic humeral condyles in which repair cartilage tissues originating from subchondral bone were observed. Quantitative chemical studies of repair cartilage and normal cartilage were carried out using humeral condyles from four selected animals (two lame and two normal boars, respectively). The repair cartilage contained a higher concentration of collagen and lower concentration of proteoglycan than did the normal cartilage, consistent with the light microscopic observation of fibrous and fibrocartilaginous tissues in the repair cartilage. The proportion of proteoglycan extractable with 4M-guanidine hydrochloride was less in the repair cartilage than the normal cartilage. The proportion of proteoglycan that can interact with hyaluronic acid was also less than normal in the repair cartilage.

Animals↗
PubMed1992

Tolerance of growing pigs for dietary vitamin A, with special reference to bone integrity.

Weanling crossbred pigs (144) of 8 kg initial weight were fed to 90 kg on diets containing graded levels of vitamin A representing 0, 1, 5, 10, 50 and 100 times the NRC (1988) estimated requirement. No clinical signs of deficiency or toxicity were recorded although plasma and liver retinol levels were affected by treatment. Histopathological examination indicated a high incidence of lesions in the cartilage of the distal femur and ulna, but they were not related to treatment. There was some evidence that excessive vitamin A levels in the diet significantly reduced the uronic acid concentration in joint cartilage, indicating a reduced concentration of proteoglycans. However no relationship was established between dietary vitamin A level and the incidence of clinical osteochondrosis. The results suggest that the allowable range of vitamin A set out in the Canadian feeds regulations is appropriate for practical pig production.

Animals↗
PubMed1992

Morphology and water and lipid contents of stifle menisci of growing swine.

Morphology and distribution of water and lipid were examined in menisci of growing swine. The broadness of menisci and the size of protruded tissue in the inner anterior portion of menisci varied among animals. Small tears of tissues were frequently observed. Both the thickness and tissue weight were greater in the lateral than in the medial meniscus. Water content and intensity of glycosaminoglycan staining with safranin-O were found to be greatest in the inner one-third of the meniscus, and greater in the middle than in the outer one-third of the meniscus. Lipid content was greater in the outer one-third than in the inner two-thirds of the meniscus.

Animals↗
PubMed1991

Effects of pre- and postpubertal feeding on production traits at first and second estrus in gilts.

The effects of feeding level on body weight (BW), lifetime growth rate, backfat thickness (BF), fatness (BF/BW) and ovulation rate at first (puberty) and second estrus were examined in 145 gilts. From 47.2 kg until puberty, gilts were fed 2.0 kg/d (L) or had ad libitum access to feed (H). From puberty to second estrus, the feed allowance of one-half of the L gilts was increased to 2.8 kg/d. Flush-feeding only normalized ovulation rate (OR) to that observed in gilts with ad libitum access to feed. At puberty, a quadratic negative relationship between lifetime growth rate and age indicated that age at puberty was minimum at a growth rate of less than or equal to .60 kg/d. Thereafter, age at puberty became independent of, or possibly positively related to, lifetime growth rate. Gilts with higher lifetime growth rate also were heavier and fatter at puberty. It was concluded that puberty may have been attained when a certain BF or fatness was achieved, because growth rate of restricted-fed gilts and quickly growing gilts with ad libitum access to feed may have been associated with reduced fat deposition. Hence, maximizing growth rate in replacement gilts does not hasten the attainment of puberty. Growth rate may be manipulated by feed restriction, in order to attain a target BW at boar stimulation (approximately 90 kg), which would coincide with a minimum age (approximately 155 d) and BW at puberty (approximately 97 kg). Nutritional flushing during the first estrous cycle then could be used to normalize OR at mating at second estrus of gilts that were restricted-fed when prepubertal.

Adipose Tissue↗
PubMed1988

Involvement of trauma in the pathogenesis of osteochondritis dissecans in swine.

Limb joint soundness was examined in 40 pigs loaded into a wooden box cart and 40 control pigs not subjected to loading. On postmortem examination, eight loaded pigs showed osteochondritis dissecans in their medial humeral condyles, suggesting that porcine joints are vulnerable to osteochondral lesions when mechanically overloaded. Prevention of trauma by careful handling of pigs during penning and transportation should help to control joint lesions and lameness.

Animals↗
PubMed1987

Effects of glycosaminoglycan polysulfate treatment on soundness, hyaluronic acid content of synovial fluid and proteoglycan aggregate in articular cartilage of lame boars.

Eighteen lame boars were equally assigned to two treatment groups based on initial bodyweight and leg soundness. The boars were injected intramuscularly with an aqueous solution of glycosaminoglycan polysulfate or saline on day 0, 5, 10, 15, 20 and 25 and killed on day 27. The glycosaminoglycan polysulfate treatment significantly (P less than 0.05) improved leg soundness score, and resulted in an increase (P less than 0.06) in the hyaluronic acid concentration of the cubitus joint synovial fluid, and an increase (P less than 0.05) in the proportion of aggregated proteoglycans in the articular cartilage of the medial femoral condyle. Feed intake, growth rate and articular cartilage soundness score for the cubitus and stifle joints were not significantly (P greater than 0.10) affected by the treatment.

Animals↗
PubMed1986

Blood flow distribution in hind limb bones and joint cartilage from young growing pigs.

Blood flow distribution was studied in hind limb bones and joint cartilage from four ten week old and four 20 week old pigs using 141Ce-microspheres. In general, blood flow rate was greater in the epiphyseal and metaphyseal cancellous bone than in the cortical bone and joint cartilage. In the epiphyseal cancellous bone, blood flow rate was three to tenfold greater (P less than 0.01) in the surface 2 mm layer than in the remaining deeper bone in all femoral and tibial samples examined. In the joint cartilage, blood flow rate in the femoral condyle was greater (P less than 0.05) than in the proximal femur, patella, central tarsus and metatarsus in ten week old pigs, and was greater (P less than 0.05) in the femoral condyle than in the patella and metatarsus in 20 week old pigs. A significant (P less than 0.05) age-associated decrease in the rate of blood flow was observed in the femoral, patellar and metatarsal cartilage. Within the femoral condyle, no differences in blood flow were found between areas associated with relatively high versus relatively low incidences of osteochondrosis.

Age Factors↗
PubMed1986

Distribution of glycosaminoglycans and the nonreducible collagen crosslink, pyridinoline in porcine menisci.

Glycosaminoglycans and the nonreducible collagen crosslink, pyridinoline were determined in stifle joint menisci from adolescent pigs. Medial and lateral menisci were dissected into two portions, the inner third (zone 1) and the remaining two thirds (zone 2) at three different regions; anterior, central and posterior regions. Both glycosaminoglycan and pyridinoline concentrations were greater (P less than 0.05) in zone 1 than in zone 2 in both the medial and lateral menisci. In zone 1, the anterior region had a greater (P less than 0.05) glycosaminoglycan concentration than did the central and posterior regions. Light microscopic observations indicated zonal variations in collagen fiber arrangement.

Amino Acids↗
PubMed1985

Energy intake, body composition and reproductive performance of the gilt.

The relationship between age, live weight, body composition and energy status on the onset and maintenance of reproductive activity in females is reviewed. When possible, swine studies have been employed, although, of necessity, much data are drawn from other species. The relationship between age, weight and puberty is controversial. However, from the available data we conclude that neither age nor weight are reliable indices of reproductive development, but that minimum threshold values for these characteristics must be achieved before puberty can occur. Human data provides a strong indication that a minimum adipose to lean tissue ratio is a prerequisite for puberty onset. Limited data from swine support this contention and indeed it may be a superior measure of reproductive development than either age or weight. However, the value of this ratio remains to be defined in pigs, and again it is minimum threshold level, the attainment of which is necessary, but not in itself sufficient, for puberty onset. A positive energy balance seems to be necessary for puberty onset and the maintenance of estrous cycles in some species, but this has not been investigated in swine. The mechanisms whereby adiposity and energy status influences reproduction are discussed. Human studies demonstrate a negative correlation between energy status, body fatness and plasma gonadotrophin levels. Also, adipose tissue has the ability to metabolize sex steroids, aromatizing androgens to estrogens and changing the direction of estrogen metabolism to produce more or less biologically potent estrogens.

Adipose Tissue↗
PubMed1985

Nutrition and sow prolificacy.

Prolificacy has been defined as the number of viable piglets produced per year or per breeding lifetime. Prolificacy is influenced by age at first successful mating, ovulation rate and embryo survival at each mating, number of live born, viable pigs and the sow's ability to be successfully remated at regular intervals. It is concluded that under normal conditions of feeding and management nutrition will have a minimal influence on gilt prolificacy. However, to gain the advantages of a slightly younger age at puberty, maximal ovulation rate and an adequate fat cover (if only to ensure against subsequent poor management), gilts should be fed ad libitum up to the time of mating. Long-term performance is best served by minimizing fluctuations in live weight and fat reserves, so avoiding extremes of body condition and subsequent poor performance. This is achieved by small controlled increases in sow body weight during pregnancy and feeding to appetite for restricted periods each day during lactation. Assuming the sow has not achieved a very poor condition during lactation, feeding level during pregnancy will have little effect on numbers of piglets born, and only a limited influence on piglet birthweights. The conclusion that piglet birth weights will be influenced more by total pregnancy feed intake than pattern of feed distribution is unchallenged. Lactation feed intake is shown to have marked effects on the post-weaning performance, low-level feeding leading to an extension of the remating interval and possibly increasing embryo mortality. No benefit of high-level feeding after weaning is demonstrable, except possibly in primiparous sows or sows having suffered an extreme loss of liveweight and body condition during the previous lactation.

Age Factors↗