• Asian-Australasian Journal of Animal Sciences
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• v.14 no.11
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• pp.1610-1615
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• 2001

Three studies were conducted to determine the effect of sex on pre- and post-weaning performance of pigs. These studies were conducted in response to observations that female pigs appear to grow faster than male pigs after weaning. In addition, female pigs have been found to grow faster than male pigs when supplied with supplemental milk before weaning. The aims of the present work were to further characterise the ontogeny of sex differences growth of nursing and growing pigs. In the first study, piglets sucking 32 sows were crossfostered to produce litters of 10 boars (n=9), 10 gilts (n=l 1) or 5 boars and 5 gilts (n=12). Liveweight of the sucking pigs was then measured weekly until weaning at 4 weeks of age. In the second study, 80 boars and 80 gilts were weaned at 26 days of age and growth performance measured until 21 days post-weaning. In the third experiment, 40 boars and 40 gilts were weaned into groups of 5 pigs at either 17 or 25 days of age and pigs were weighed until they were approximately 90 kg liveweight. All-boar litters grew more slowly than the all-gilt and mixed litters such that by 14 days of age the all-boar litters were 10% lighter than the all-gilt or mixed litters (39 vs. 43.8 kg, p=0.050). The proportional difference in litter weight appeared to be maintained at 21 days of age (53.9 vs. 59.4 kg, p=0.063) but was diminished by 28 days of age (66.5 vs. 70.8 kg, p=0.28). In the second study, gilts grew more quickly than boars over the first 7 and 21 days post-weaning and as a consequence were 10% heavier than boars at 21 days after weaning (13.7 vs 12.48 kg, p=0.001). In the third study, gilts grew more quickly than boars in the immediate 7 days post-weaning (40 vs. 5 g/day, p=0.014) whereas from 7 until 35 days post-weaning there was no significant difference in growth rate (381 vs. 360 g/day, p=0.19). Gilts also grew more quickly than boars over the 14 days after being moved into the grower (631 vs. 570 g/day, p=0.013) and finisher (749 vs. 688 g/day, p=0.038) sheds. However, these differences were not maintained over the entire period in each shed. These data support the hypotheses that gilts handle the stresses of weaning and other transitions better than boars.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.7
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• pp.1004-1012
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• 2016

This experiment was conducted to investigate the effects of dietary energy levels on the physiological parameters and reproductive performance of gestating first parity sows. A total of 52 F1 gilts ($Yorkshire{\times}Landrace$) were allocated to 4 dietary treatments using a completely randomized design. Each treatment contained diets with 3,100, 3,200, 3,300, or 3,400 kcal of metabolizable energy (ME)/kg, and the daily energy intake of the gestating gilts in each treatment were 6,200, 6,400, 6,600, and 6,800 kcal of ME, respectively. During gestation, the body weight (p = 0.04) and weight gain (p = 0.01) of gilts linearly increased with increasing dietary energy levels. Backfat thickness was not affected at d110 of gestation by dietary treatments, but increased linearly (p = 0.05) from breeding to d 110 of gestation. There were no significant differences on the litter size or litter birth weight. During lactation, the voluntary feed intake of sows tended to decrease when the dietary energy levels increased (p = 0.08). No difference was observed in backfat thickness of the sows within treatments; increasing energy levels linearly decreased the body weight of sows (p<0.05) at d 21 of lactation and body weight gain during lactation (p<0.01). No significant differences were observed in the chemical compositions of colostrum and milk. Therefore, these results indicated that high-energy diets influenced the bodyweight and backfat thickness of sows during gestation and lactation. NRC (2012) suggested that the energy requirement of the gestation gilt should be between 6,678 and 7,932 kcal of ME/d. Similarly, our results suggested that 3,100 kcal of ME/kg is not enough to maintain the reproductive performance for gilts during gestation with 2 kg feed daily. Gilts in the treatment 3,400 kcal of ME/kg have a higher weaning number of piglets, but bodyweight and backfat loss were higher than other treatments during lactation. But bodyweight and backfat loss were higher than other treatments during lactation. Consequently, an adequate energy requirement of gestating gilts is 6,400 kcal of ME/d.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.6
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• pp.802-810
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• 2000

A total of 120 finishing crossbred pigs ($Landrace{\times}Large$ $White{\times}Duroc$) with equal numbers of barrows and gilts weighing 58.5 kg body weight were used in a feeding trial, and 6 pigs (three of each sex) were used in a metabolic trial to investigate the effect of phase feeding. Finishing period was divided into two phases and 4 different diets were fed for those periods. Growth performance was not significantly different among treatments within the same sex. This result showed that 16% crude protein for early finishing period and 14% crude protein diet for late finishing period should be optimum. During the early finishing period, only feed intake was significantly different between sexes (p<0.01), but in late finishing period daily weight gain (p<0.001) and feed intake (p<0.01) of barrows were significantly higher than those of gilts. During the early finishing period, digestibilities of dry matter, protein and phosphorus were significantly higher in gilts than in barrows (p<0.05). However, there was no treatment effect within same sex during the early and late finishing period. During early finishing period, excretion of N of pigs fed 16% CP diet in early and 14% CP diet in late-finishing period was less than that of pigs fed 17% CP diet in early and 15% CP diet in late-finishing period (p<0.05), but the difference was not significant. During the late finishing period, N excretion with two phase feeding was reduced by 8.5% compared with single feeding. In gilts, total cost reduction by two phase feeding compared to single feeding was 9.1%, but in barrows it was just 3.19%. Relative margin increased with two phase feeding by 2.5% in gUts and 0.2% in barrows. There was a tendency that backfat thickness at 10th rib of gilts was thinner than that of barrows (p>0.05). Within the same sexes, there was no treatment effect on back fat thickness (p>0.05). Carcass grade was improved by two phase feeding compared to single feeding. Carcass grade of gilts was significantly better than that of barrows (p<0.001). From this results, it is concluded that finishing pigs could be fed two-phase diets to improve profit and reduce pollution.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.6
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• pp.795-801
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• 2000

A total of 120 growing crossbred pigs ($Landrace{\times}Large$ $White{\times}Duroc$) with equal numbers of barrows and gilts were used in the feeding trial in a $2{\times}3$ factorial arrangement (gender by feeding regimens) to investigate the effect of phase feeding on growth performance during the 25 to 58 kg body weight growth stage, and 6 pigs (three of each sex) were used in a metabolic trial. The growing period was divided into two phases and 4 different CP diets were used to make 3 different feeding regimens (GE18-GL18; 18% CP diets for both early and later growing period, GE18-GL16; 18% CP diet for early and 16% CP diet for later growing period, GE19-GL17; 19% CP diet for early and 17% CP diet for later growing period). There were no significant differences in growth performance among treatments during the entire growing period. However, during the later growing period, feed intake of barrows was significantly higher than that of gilts (p<0.05). Average daily gain of barrows was higher than that of gilts (p>0.05). Based on the result, growth performance differences between barrows and gilts appeared to begin after 40 kg of body weight. There was no significant difference in digestibility among treatments or between sexes. During the early growing period the 18% CP diet showed better digestibility than the 19% CP diet. However, during the later growing period, the 18% and 17% CP diets exhibited similar digestibilities, although 16% CP diet showed slightly lower digestibility than 18% and 17% CP diets. During the early growing period, fecal N and P excretion of pigs fed the 19% CP were higher than that of those fed the 18% CP diet. During later growing period, fecal N and P excretion by those receiving the two phase feeding compared to single phase feeding was reduced by 10.2% and 2.0%, respectively. In the gilts, the cost reduction by two phase feeding (GE18-GL16) compared to single feeding was around 3.81%, but that of barrows was only 0.52%. The results suggested that the same nutrient levels could be applied to barrows and gilts during the growing period. Also, this study suggested the optimum protein and lysine level for early and later growing pigs to be 18% CP, 1.0% lysine and 16% CP, 0.8% lysine, respectively. Feeding two diets to growing pigs, i.e., two-phase feeding, would be more appropriate than feeding a single diet on economic and environmental considerations.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.1080-1088
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• 2010

This experiment was conducted to investigate the effects of dietary energy levels of gestating gilts on physiological parameters and reproductive performance for primiparous sows. A total of 40 F1 gilts (Large White${\times}$Landrace) were allocated to 4 treatments using a completely randomized design (CRD). Four different experimental diets contained 3,165, 3,265 3,365 and 3,465 kcal of ME/kg and each diet was provided to gilts at 2.0 kg/d during gestation. Consequently, energy intake of each treatment of gestating gilts was 6,330, 6,530, 6,730 and 6,930 kcal ME/kg, respectively. During the whole gestation period, body weight, fat mass gain and backfat thickness of gilts were increased in proportion to dietary energy levels (p<0.01). However, estimated protein mass gain of gilts was not affected by dietary energy level (p>0.10). At farrowing, the total number of pigs born per litter did not show any significant difference among treatments. However, the number of pigs born alive per litter in treatment 6,730 kcal ME/d was significantly higher than that of other treatments (p<0.05). Moreover, litter weight at birth was improved as dietary energy level was increased (p<0.05). Feed intake of sows during lactation tended to decrease as dietary energy level of gestation was increased, but litter weight gain was not affected by dietary treatment during the gestation period. Fat content in colostrum was higher as dietary energy level was increased during gestation. The concentration of blood estradiol-$17{\beta}$ was increased and was higher at the first trimester of gestation in 6,730 kcal ME/d treatment compared to other treatments. These results suggested that increased dietary energy level during gestation resulted in higher body weight and backfat thickness of sows. In addition, reproductive performance of the sow, such as litter weight at farrowing and the number of pigs born alive, was improved when 6,730 kcal of ME/d treatment diet was provided. Consequently, the NRC (1998) recommendation of energy for gestating gilts (6,015 to 6,150 kcal of ME/d) should be reevaluated to maximize reproductive performance because recent high-producing sows require much more energy to produce a large litter size and heavier piglets from the first parity.

• Journal of Animal Science and Technology
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• v.47 no.1
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• pp.57-72
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• 2005

The present study was undertaken to investigate the effects of nutrient density diets and sex on carcass and pork quality characteristics in finishing pigs. A total of 96 pigs(58.04 $\pm$ 6.85 kg) were divided into 2 groups(gilts and barrows), each sex group was assigned to 3 nutrient density(high : 18.5%, middle : 16.0% and low: 14.0% CP, respectively) and raised up to 1l0kg live weight. Each treatment had four replicates with three or five pigs per replicate. The treatments comprised the feeding regimes of 1) the low density diet for 60 days, 2) the middle nutrient density diet for the 30 days followed by a low nutrient density diet for the remaining 30 days and 3) the high nutrient density diet for the 30 days followed by a middle nutrient density diet for the remaining 30 days. Pigs were conventionally slaughtered, and then chilled overnight. Carcass characteristics and grades were determined on those carcasses, and pork loin muscle was removed from each left side at 5th to 13th rib for quality evaluation were evaluated. There were no differences in the carcass weight between sex and nutrient density. Dressing percent of L-L(gilts) treatment was significantly higher than that of other treatments(P< 0.05). Barrows showed a thicker back fat thickness than gilts. There were no difference in intramuscular fat, subcutaneous fat and springiness between sex and nutrient density. Intermuscular fat of barrows groups was significantly higher than the gilts groups(P < 0.05). In the meat quality characteristics, there were no difference in general composition, meat and fat color between sex and nutrient density. pH of L-L(gilts) treatment was significantly higher than that of other treatments(P < 0.05). Cooking loss and shear force value of H-M(barrows) treatment were significantly higher than those of other treatments(P< 0.05). Purge loss of barrows groups was significantly higher than the gilts groups(P < 0.05). Myoglobin content of H-M treatment was significantly lower than L-L and M-L treatments(P< 0.05). Texture of H-M treatment was higher than L-L and M-L treatments. The content of myristic, palmitic, palmitoleic and oleic acid were significantly higher in the barrows groups(P< 0.05). However, stearic, linoleic and arachidonic acid were significantly higher in the gilts(P < 0.05). Amino acid content of L-L treatment was significantly higher than M-L and H-M treatments(P < 0.05). In conclusion, carcass and pork quality characteristics were affected by sex and nutrient density.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.5
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• pp.677-681
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• 1999

Estimates were made of genetic parameters for average daily gain (ADG) and average backfat thickness (ABF), and of the effect of sex on estimates of variance-covariance components for average daily gain of boars (DGM) and gilts (DGF) and average bacfat thickness of boars (BFM) and gilts (BFF) by residual maximum likelihood (REML) under a bivariate animal model. Data included a total of 2233 records (757 for boars and 1476 for gilts) of the Large White breed born between 1981 and 1986 in Miyazaki and Iwate prefectures in Japan. Heritability estimates for ADG and ABF were 0.43 and 0.69, respectively, with a genetic correlation of -0.08. Heritability estimates for DGM and DGF were 0.54 and 0.46, respectively, with a genetic correlation of 0.79, including that the two traits are influenced by similar but not identical genes. Respective estimates for BFM and BFF were 0.71 and 0.72 with a genetic correlation of 0.95, indicating that identical genes influence backfat thickness in boars and gilts.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.211-218
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• 1993

The effect of active immunization against porcine somatostatin (SRIF-14) on somatostation and somatotropin secretion profile in 18 gilts was investigated. Gilts were assigned to the following treatments: control (sham injection, n = 6); bovine serum albumin (BSA) (injection of BSA with bacterial protein adjuvant, n = 6); SRIF (injection of BSA-SRIF-14 conjugate with bacterial protein adjuvant n = 6). Serum SRIF and pST were assayed from the blood samples taken on day 7 after the last immunization injection. Anti-SRIF antibody titres were assayed in weekly samples two weeks after the initial immunization to one week after the last immunization. Results revealed that the immunization protocol used in the present investigation failed to produce antibodies capable of neutralizing endogenous somatostatin. In addition, the porcine somatotropin assay revealed no significant differences in baseline pST concentration, mean peak amplitude and number of peaks during a 24 h secretory period among SRIF, BSA and control treatment. There were also no differences in SRIF baseline concentration, peak amplitude, and number of peaks during a 24 h secretory period among any of the three treatments. Circulating concentrations of pST and pSRIF were highly correlated (r = -0.09). Furthermore, anti-SRIF antibody titre was not detected in the serum of the gilts actively immunized against SRIF. These data, collectively, suggest that the protocol employed in the present investigation for active immunization against SRIF is not an effective method for changing SRIF and pST secretion profiles of the gilt and thus to enhance performance.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1181-1187
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• 2016

The objective of the study was to evaluate fattening performance, carcass value and meat quality in pigs of Prestice Black-Pied breed in relation to slaughter weight (SW) and gender (barrows and gilts, resp.). Pigs were divided into weight categories: SW1 (75 to 99.9 kg), SW2 (100 to 109.9 kg) and SW3 (110 to 130 kg) and all individual traits were analyzed by the general linear model procedure (SAS 9.3). Average SW of each weight group was as follows: SW1 94.2 kg, SW2 105.8 kg, and SW3 115.2 kg. Differences among average backfat thickness of 36.07 mm in SW1, 40.16 mm in SW2, and 43.21 mm in SW3 were significant (p<0.01). Lean meat content was 48.94% (SW1), 48.78% (SW2), and 48.76% (SW3). Pigs were slaughtered at average weight of 105.7 kg for barrows and 104.4 kg for gilts. Average backfat thickness for barrows was 40.90 mm and 38.72 mm for gilts (significant difference p<0.05). Lean meat content was 48.75% in barrows and 48.91% in gilts. The values of pH45, characterizing the meat of very good quality. The loin in SW3 was darker than the muscles of SW1 and SW2. Drip loss was the lowest in SW1 (1.96%), compared to the highest drip loss in SW3 (2.59%). Content of intramuscular fat was 2.68% in SW3, 2.79% in SW2, and SW1 had the lowest content 2.47%. The values of pH45, colour lightness and drip loss were similar in both genders. However barrows had higher intramuscular fat content by 0.31% than gilts (p<0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1157-1163
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• 2001

First-litter gilts were used to determine how different dietary treatments during gestation affect the reproductive performance of gilts and immunity development of their piglets. Twenty-two crossbred $Landrace{\times}Yorkshire$ gilts were randomly assigned to three dietary treatments, Following conception, the gilts were fed experimental diets until farrowing occurred. The diet for treatment I was low protein diet (8% CP), treatment 2 had an additional supplement of 0.14% threonine that was added to the low protein diet, and treatment 3 was a control diet containing 12% CP. During gestation, net body weight gain of sows in treatment group 2 was higher than in treatment group 1 (p=0,075), However, during lactation there was no difference between all treatments groups on body weight loss and their live piglets at birth. Although milk IgG between treatments did not differ, treatment groups 2 and 3 were slightly higher than treatment group I was, Plasma IgG concentrations in piglets were however equal within all treatment groups at birth and at 7 days of age, at 21 days of age, it was higher in treatment group I than it was in the other two groups (p<0.01), Threonine supplementation to a low protein diet during gestation slightly increases milk IgG of sows, It is beneficial for piglets to acquire more passive immunity, but a suppressive effect was also noted on the endogenous IgG synthesis in piglets. A gestation diet of 8% CP for gilts can stimulate immuno-system of her piglets.