Undecorticated cottonseed meal as a substitute for soya bean meal in diets for weaner and growing-finishing pigs

Fifty-six weaner and growing-finishing Large White × Landrace pigs were used in two growth studies and a digestibility study to determine the value of undecorticated cottonseed meal (UCSM) as a protein supplement replacing soya bean meal (SBM). In a 35-day feeding experiment with pigs averaging 18.8 kg, four lots of six pigs were individually fed on isonitrogenous diets containing 0, 10, 20 and 30% UCSM. Daily feed intake (FI) did not differ significantly between treatments. Daily gain and feed/gain did not differ significantly between the control and the 10% UCSM diets but the control group gained significantly more than the 20 or 30% UCSM diets (P < 0.05).

In a second growth experiment lasting 35 days, 24 cross-bred pigs averaging 53.1 kg were fed on diets containing 0, 20, 30 and 41.1% UCSM (without SBM) in a randomized design involving six individually fed pigs per treatment. There were no differences in FI across the treatments. Weight gain was significantly depressed with only 20% UCSM and both gain and feed/gain declined linearly with increasing proportion of UCSM. The growth studies showed that 10% was the optimum level of inclusion of UCSM in the diets. These were supported by the results of the metabolic studies.     

Einfluß der Futterration und des Entnahmezeitpunktes von Pansensaft auf seine Zusammensetzung in Untersuchungen an Kühen

Different starch components were added to rations with maize silage measuring the influence of the supplements on the digestibility and energy content of maize silage in cattle (n = 36) and sheep (n = 36). The starch‐rich components maize, wheat, barley, oat, cassava meal and potatoe starch were added to the total rations on average of 33%. All supplements were ground (sieve of 2.5 mm), additionally, wheat was added in extruded or crushed form. All rations including the control ration without starch components were supplemented with soybean meal to an average crude protein content of 12.4% DM. The mean starch content of the total rations was 42% DM.

The supplementation of maize silage with the different starch components increased the digestibility of the organic matter of all rations on average only slightly from 77% to 78% in cattle, while the mean digestibility in sheep rised from 74% to 79% more pronounced. However, the influence of the different starch components on the digestibility was similiar for both ruminants. The supplementation with the ground, crushed or extruded wheat, with barley and with oats impaired the digestibility of the crude fibre of the total ration and of the maize silage, respectively. Therefore, the digestibility of the organic matter of maize silage was reduced and the energy content decreased by about 6% in comparison to the control ration without starch supplementation. However, the supplementation with maize, cassava meal or pota‐toe starch had no negative effects on the digestiblity and energy content of maize silage.     

Biological control of the cassava mealybug Phenacoccus manihoti (Hom., Pseudococcidae) by Epidinocarsis lopezi (Hym., Encyrtidae) in Malawi

From 1985 to 1989 five large scale surveys were made to document the spread of the cassava mealybug (CM) Phenacoccus manihoti Matile‐Ferrero (Hom., Pseudococcidae) and the releases and successful establishment of its exotic parasitoid Epidinocarsis lopezi (De Santis) (Hym., Encyrtidae) through most cassava‐growing areas of Malawi. In a multiple regression analysis involving 29 meteorological, agronomic and plant variables from 476 fields, the duration of E. lopezi's presence was the major factor influencing CM population densities. In the first year the CM was recorded in a particular place, 25% of all tips had more than 100 CM. Wherever E. lopezi had been present for two years or more, CM populations were reduced on average seven times and tips infested with more than 100 CM became rare (1%). In parallel, damage on cassava tips stabilized at a low level. Similarly, along Lake Malawi, 84.9% of all tips had more than 10 CM in 1986; this value stabilized at 3.3%‐4.0% in 1988–1989. Indigenous coccinellids were often abundant in the first year of the CM infestation, but their populations collapsed later, while the frequency of fields with E. lopezi increased. In 1987, farmers abandoned 28.4% of all fields where E. lopezi was just introduced as compared with 2.7% where the parasitoid had been present for two years or more. Overall, satisfactory control was achieved by E. lopezi in all but a few fields concentrated on extremely poor soils characterized by sand dune vegetation. The socioeconomic implications of this ongoing and apparently successful biological control program are discussed.     

西部地区主要猪种H-FABP基因多态性,IMF含量及不同基因型脂肪细胞脂滴量的关系

H-FABP是FABP家族成员之一,在长链脂肪酸的吸收和代谢平衡中发挥关键作用,但它对猪IMF含量的影响还知之甚少,对中国西部地区的猪种更是如此.文章利用PCR-RFLP（HinfⅠ、HaeⅢ和Msp Ⅰ 3种限制性内切酶）分子标记技术,检测了杜洛克猪、长白猪、大白猪、内江猪、荣昌猪、汉江黑猪、汉中白猪、八眉猪和野猪共计265头猪H-FABP基因5＇-上游区和第二内含子区的遗传变异,利用最小二乘模型分析了H-FABP基因对猪肌内脂肪含量的遗传效应,并运用猪脂肪细胞培养,油红O染色和TG测定等技术检测了H-FABP基因不同基因型脂肪细胞内脂滴的形态和沉积的量.结果表明：（1）在HinfⅠ-RFLP位点上,上述品种和野猪均存在多态性,其中大白猪、八眉猪、汉江黑猪、汉中白猪和野猪表现为低度多态,杜洛克、长白猪、内江猪和荣昌猪为中度多态;除汉江黑猪（P＜0.05）和野猪（P＜0.01）外,其他猪种基因频率和基因型频率都处于Hardy-Weinderg平衡状态（P＞0.05）;而在HaeⅢ-RFLP和Msp Ⅰ-RFLP位点上,仅内江猪、荣昌猪、汉江黑猪和八眉猪为单态;（2）9种基因型对肌内脂肪（IMF）含量的影响,HH＞Hh＞hh,DD＜Dd＜dd,AA＜Aa＜aa,遗传效应值分别为：3.89,3.42,3.17,2.27,2.49,2.91,2.28,2.70,2.95,H-FABP基因可显著地提高IMF含量（P＜0.05）;（3）aaddHH型的脂肪细胞脂滴的形态,密度和含量与其他基因型细胞差异显著（P＜0.05）.结果提示：可通过提高＂aaddHH＂基因型的频率来增加IMF含量,达到改善猪肉质的目的.     

Sustained biological control of the cassava mealybugPhenacoccus manihoti [Hom.: Pseudococcidae] byEpidinocarsis lopezi [Hym.: Encyrtidae] in Nigeria

Following the successful introduction ofEpidinocarsis lopezi (De Santis) for biological control of the cassava mealybug (CM)Phenacoccus manihoti Mat.-Ferr. in southwestern Nigeria in 1981 and 1982, 11 groups of cassava fields were sampled every 2 weeks up to 1988 for impact assessment. After 1984, CM populations remained mostly below 10 per tip despite the presence of native hyperparasitoids, demonstrating the long-term success of biological control byE. lopezi in the region. Indigenous polyphagous coccinellids were found only during peak host densities, whereas the specificE. lopezi was common throughout the year. During some periods, percentage parasitism indicated delayed density dependence. Since 89% of all sampled cassava tips had no CM at all and the parasitisme is very mobile, parasitization rates were also calculated for individual infested tips (N=4,878). Parasitism increased slightly with host density on tips having between 1 and 10 CM of the 3^rd and 4^th instars, indicating positive density dependence. Such tips comprised 64% of all infested tips. At higher host densities, parasitism rates fell rapidly. The results are discussed in view of different theories on population regulation by biological control agents.      

Formulating rations with cassava meal to promote high live weight gain in crossbred Limousin bulls

Formulating rations with high energy and protein feeds such as cassava and locally sourced protein meals is an important strategy to increase live weight gain (LWG) of crossbred bulls in Indonesia. Current systems of production for Indonesian smallholders fatten bulls using cut and carry. Formulating a diet for an optimal combination of available feeds will increase production and potential profitability for smallholders. An experiment was conducted to evaluate the effect of using cassava meal in the diet at levels of 70C, 60C, 50C, 40C and 30C% (with most of the remainder being the protein meals) on the LWG of Limousin × Ongole bulls so as to determine the optimum combination of cassava meal and protein meals for LWG. Thirty bulls were allocated in a completely randomized block design with 6 blocks based on initial live weight (LW) and 5 treatments based on level of cassava meal. The combination of cassava meal (with 2% urea) and protein meals significantly affected LWG with the highest (1.35 kg/day) recorded at 40C (40% cassava meal, 40% protein meals and 20% maize stover). The LWG and nutrient intake increased curvilinearly with decreasing cassava meal and increasing protein meals (P < 0.05). Measured cassava meal inclusion in the final ration as a consequence of the changes in intake was 60, 56, 47, 37 and 28% for the designated 70C, 60C, 50C, 40C and 30C treatments, respectively. Dry matter intake reached 96 g/kg^0.75 per day or equal to 2.24% LW at this 40% level of inclusion. At the 70C treatment with 60% cassava meal and 9% protein meals, DM digestibility (69.1%) was lowest and that value increased as the proportion of cassava meal decreased and was highest at the 40C treatment (75.8%). Feed treatments significantly affected rumen pH, ammonia N (NH₃N) and volatile fatty acid concentrations (P < 0.05). There was no significant effect on protozoal population (P > 0.05). Rumen pH ranged from 6.3 to 6.9. It was concluded that a combination of 40% dried cassava meal and 40% protein meals with roughage (20%) maximized intake and LWG and beyond that level of cassava meal inclusion, LWG and intake decreased markedly.     

DNA microsatellite analysis for parentage control in Austrian pigs.

We present an efficient parentage control for pigs based on ten polymorphic microsatellite markers analyzed in a single PCR reaction. Assuming one known parent ("paternity control"), combined exclusion probabilities (CEPs) ranged from 99.18% (Landrace), 99.74% (Piétrain) to 99.76% (Large White) for the most important Austrian breeds. Assuming a known parent-pair ("parentage control", e.g. a substituted offspring), the CEP of the 10-plex PCR increased to 99.97% (Landrace) and 99.99% (Piétrain and Large White). We developed an additional standby battery of 5 markers, which might be applied in those cases, where the CEP of the 10-plex PCR is not sufficient. Therefore an automated, cost and time reduced genotype analysis for pigs is available.     

A comparison of the radiation response of the epidermis in two strains of pig

The response of the epidermis was compared in two strains of pig, the English Large White and the G?ttinger Miniature, after irradiation with 90Sr beta rays. The effects of two types of anesthesia were also tested in pigs of each strain, a volatile gas mixture of approximately 70% oxygen, approximately 30% nitrous oxide, and 2% halothane, and an intravenously administered narcotic azaperon/etimodat with the animals breathing air. Strain- and anesthetic-related changes were compared on the basis of dose-effect curves for the incidence of moist desquamation from which ED50 values (+/- SE) were determined, i.e., the dose required to produce this effect in 50% of the fields irradiated. For English Large White pigs anesthetized with the volatile gas mixture, an ED50 of 27.32 +/- 0.52 Gy was obtained for moist desquamation. Irradiation with the azaperon/etomidat anesthesia in this strain of pig produced a significantly higher ED50 of 33.36 +/- 0.76 Gy (P less than 0.001). This appeared to be related to the fact that the animals were breathing air, i.e., a lower oxygen concentration (approximately 21%), at the time of irradiation. For the G?ttinger Miniature pig the ED50 values for moist desquamation were 38.93 +/- 3.12 Gy and 43.36 +/- 1.34 Gy while using the gaseous anesthetic mixture and the azaperon/etomidat anesthesia with the animals breathing air, respectively. These ED50 values are 10-11 Gy higher than those obtained for the English Large White pig under identical conditions of anesthesia, which resulted in a strain difference ratio of approximately 1.35. Radiation under the volatile gas mixture anesthesia resulted in a uniform irradiation response over the skin of the flank in both strains of pig. Radiation under azaperon/etomidat anesthesia resulted in a nonuniform skin response over the flank. The ED50 for moist desquamation was significantly higher in dorsal sites on the flank compared with the ventral area of English Large White pigs; a similar trend was seen in G?ttinger Miniature pigs. This difference in the radiosensitivity over the flank skin while the animals are under azaperon/etomidat anesthesia at the time of irradiation was associated with the animals breathing air and is in agreement with findings published previously for animals under halothane anesthesia and breathing air.     

SLA-11 mutations are associated with litter size traits in Large White and Chinese DIV pigs

Litter size is an important economic traits in pigs. SLA-11 gene is a member of SLA (swine leukocyte antigen) complex. In our previous study, the SLA-11 gene was differentially expressed in PMSG-hCG stimulated preovulatory ovarian follicles of Chinese Taihu and Large White sows. Here, we identified two mutations (c.754-132 T?>?C and c.1421?+?38 T?>?C) in SLA-11 gene and analyzed the associations of two SNPs with litter size traits in Large White (n?=?263) and DIV (n?=?117) sows. The results showed that in Large White pigs, SLA-11 c.754-132?CC sows produced 0.74 and 0.87 more pigs per litter for TNB and NBA of all parities than did TT sows (p?<?.05); In DIV pigs, SLA-11 c.754-132?CC sows produced 1.17 more pigs per litter for TNB of all parities than did TC sows (p?<?.05). In Large White pigs, SLA-11 c.1421?+?38?CC sows produced 0.9 more pigs per litter for TNB of all parities than did TT sows (p?<?.05), while in DIV pigs SLA-11 c.1421?+?38?CC sows produced 0.84 and 0.7 less pigs per litter for TNB and NBA of all parities than did TT sows (p?<?.05). Our research indicated that SLA-11 mutations were potential molecular markers for improving the litter size traits in pigs.     

猪ACTA2基因的克隆、表达分析及其与生产性状的关联

为鉴定对猪生产性状有重要影响的新分子标记,文章采用电子克隆结合PCR方法获得了猪肌动蛋白α2(Actin alpha 2, ACTA2)基因编码区序列和部分基因组序列,建立了第2内含子C1554T替换的PCR-HinfⅠ- RFLP基因分型方法,在所检测的7个不同猪群中除大白和梅大群体外,其他群体中均是C等位基因频率高于T等位基因的频率。标记与性状关联分析发现ACTA2基因型与肩部背膘厚、臀部背膘厚、肥肉率、瘦肉率、股二头肌pH和肌内脂肪显著或极显著相关,TT基因型与CC基因型相比具有更高的瘦肉率以及更低的肥肉率和背膘厚。通过Real-time RT-PCR分析发现ACTA2在大白和梅山两个品种猪骨骼肌中的表达量都随着日龄的增加而降低,在各个阶段,梅山猪中的表达量都比大白猪中的表达量高。     

Developmental patterns of serum leptin levels, leptin gene expression in adipose tissue and Ob-Rb gene expression in hypothalamus of Erhualian and Large White pigs

~~Developmental patterns of serum leptin levels, leptin gene expression in adipose tissue and Ob-Rb gene expression in hypothalamus of Erhualian and Large White pigs~~     

Mapping Full-Length Porcine Endogenous Retroviruses in a Large White Pig

Xenotransplantation may bridge the widening gap between the shortage of donor organs and the increasing number of patients waiting for transplantation. However, a major safety issue is the potential cross-species transmission of porcine endogenous retroviruses (PERV). This problem could be resolved if it is possible to produce pigs that do not contain replication-competent copies of this virus. In order to determine the feasibility of this, we have determined the number of potentially replication-competent full-length PERV proviruses and obtained data on their integration sites within the porcine genome. We have screened genomic DNA libraries from a Large White pig for potentially intact proviruses. We identified six unique PERV B proviruses that were apparently intact in all three genes, while the majority of isolated proviruses were defective in one or more genes. No intact PERV A proviruses were found in this pig, despite the identification of multiple defective A proviruses. Genotyping of 30 unrelated pigs for these unique proviruses showed a heterogeneous distribution. Two proviruses were uncommon, present in 7 of 30 and 3 of 30 pigs, while three were each present in 24 of 30 pigs, and one was present in 30 of 30 animals examined. Our data indicate that few PERV proviruses in Large White pigs are capable of productive infection and suggest that many could be removed by selective breeding. Further studies are required to determine if all potentially functional proviruses could be removed by breeding or whether gene knockout techniques will be required to remove the residuum.     

Effects of pig genotype (Iberian v. Landrace × Large White) on nutrient digestibility, relative organ weight and small intestine structure at two stages of growth

Although the effects of pig genotype on total-tract apparent digestibility (TTAD) have been widely reported in the literature, there is controversial information on the digestive capacity of indigenous breeds compared with lean-type pigs. The strategy of this study was to test the effects of pig genotype and crude protein (CP) supply on performance, digestive utilization of nutrients, relative organ weight and morphometric analysis of the small intestine. Thirty-eight Iberian (IB) and Landrace × Large White (LD) pigs were used. Three pigs per genotype were slaughtered at approximately 15 kg BW. The remaining pigs were fed one of two diets differing in CP content (13% or 17% as fed) using a pair-fed procedure. Feeding level was restricted at 0.8 × ad libitum of IB pigs. Nutrient digestibility and nitrogen (N) balance trials were performed at 30 and 80 kg BW. Four pigs per dietary treatment and genotype were slaughtered at approximately 50 and 115 kg BW. The gastrointestinal tract and the rest of the visceral organs were weighed and samples of the small intestine were taken to carry out histological and histometrical studies. Daily gain and gain-to-feed ratio were higher in LD than in IB pigs during the fattening and growing-fattening periods (P < 0.01). N TTAD was significantly higher for LD pigs at 30 kg BW (P < 0.05), whereas at 80 kg BW we observed greater values for digestibility of organic matter and energy in IB pigs (averaging 1.5%, P < 0.01). Both N retention (NR) and efficiency of NR were increased in LD pigs at 30 and 80 kg BW (30% as mean value). The proportional weight of the small intestine was greater in LD than in IB pigs at 50 and 115 kg BW. Histometry showed that IB presented a lower muscle layer thickness than LD pigs in ileum, irrespective of the BW (P < 0.05). In contrast, LD pigs showed approximately 10% higher ileal villi length and villi-to-crypt ratio than IB pigs at 115 kg BW. CP supply affected to a larger extent the small intestinal micro-anatomical structure of LD pigs at 50 kg BW. In conclusion, our results suggests that although the higher growth rate, NR and efficiency of NR observed in LD pigs might be associated with presumably more efficient structural aspects of the small intestine, the main differences between the two genotypes should be attributed to a larger extent to protein and energy utilization in tissues with consequences for the overall efficiency of energy use.     

Effects of particle size and drying methods of corn on growth performance,digestibility and haematological and immunological characteristics of weaned piglets

The objective of this study was to evaluate the effects of particle size and drying methods of corn on growth performance of weaned piglets. Crossbreed weaned piglets (n = 192; Duroc × Landrace × Large White) were assigned to one of four treatments (2 × 2 factorial arrangement). All piglets were fed corn–soybean meal diets and treatments were (1) hot air-dried and coarsely ground corn, (2) hot air-dried and finely ground corn, (3) sun-dried and coarsely ground corn and (4) sun-dried and finely ground corn. The results showed that finely ground corn (FGC) improved the performance of piglets. Additionally, the apparent total tract digestibility (ATTD) of gross energy (GE) and ether extract (EE) were increased by FGC, but the drying methods did not affect the performance of piglets or ATTD. Furthermore, smaller particle size significantly decreased the intestinal permeability, which was also not influenced by drying methods. FGC increased the total number of white blood cells, but not other blood parameters. Finally, the level of serum interleukin-1 was decreased by fine grinding and that of serum tumour necrosis factor α was decreased by sun drying. Conversely, these characteristics of weaned piglets can hardly have been affected either by the corn drying method or its interaction with grinding methods.     

Copy number variants in Italian Large White pigs detected using high‐density single nucleotide polymorphisms and their association with back fat thickness

The aim of this study was to identify copy number variants (CNVs) in Italian Large White pigs and test them for association with back fat thickness (BFT). Within a population of 12 000 performance‐tested pigs, two groups of animals with extreme and divergent BFT estimated breeding values (EBVs; 147 with negative and 150 with positive EBVs) were genotyped with the Illumina Porcine SNP60 BeadChip. CNVs were detected with penncnv software. We identified a total of 4146 CNV events in 170 copy number variation regions (CNVRs) located on 15 porcine autosomes. Validation of detected CNVRs was carried out (i) by comparing CNVRs already detected by other studies and (ii) by semiquantitative fluorescent multiplex (SQFM) PCR of a few CNVRs. Most of CNVRs detected in Italian Large White pigs (71.2%) were already reported in other pig breeds/populations, and 82.1% of the CNV events detected by penncnv were confirmed by SQFM PCR. For each CNVR, we compared the occurrence of CNV events between the pigs of the high and low BFT EBV tails. Sixteen regions showed significance at P < 0.10, and seven were significant at P < 0.05 but were not significant after Bonferroni correction (Fisher's exact test). These results indicated that CNVs could explain a limited fraction of the genetic variability of fat deposition in Italian Large White pigs. However, it was interesting to note that one of these CNVRs encompassed the ZPLD1 gene. In humans, a rare CNV event including this gene is associated with obesity. Studies identifying CNVs in pigs could assist in elucidating the genetic mechanisms underlying human obesity.     

Developmental patterns of serum leptin levels, <Emphasis Type="Italic">leptin</Emphasis> gene expression in adipose tissue and <Emphasis Type="Italic">Ob-Rb</Emphasis> gene expression in hypothalamus of Erhualian and Large White pigs

The present study was aimed to investigate the developmental patterns of leptin mRNA expression in dorsal subcutaneous adipose tissue and Ob-Rb mRNA expression in hypothalamus in pigs of different breeds and sexes. Erhualian gilts and boars and Large White boars were sampled at birth, 3, 20, 30, 45, 90, 120 and 180 days of age, respectively. Serum concentration of leptin was measured with RIA and single tube semi-quantitative RT-PCR was applied to determine the relative abundances of mRNA expression using 18S rRNAas an internal standard. The results showed that leptin mRNA expression in adipose tissue increased with age and displayed both sex and breed differences. In Erhualian pigs, females expressed higher leptin mRNA compared with males, and Erhualian boars showed higher abundance of leptin mRNA than Large White boars (P < 0.01). Serum leptin levels were in good agreement with adipose leptin mRNA, displaying similar sex and line differences. In contrast, expression of Ob-Rb mRNA in hypothalamus exhibited a distinctive pattern, decreased gradually after birth, and then increased till weaning. After weaning, Ob-Rb gene expression decreased gradually with age but rose gradually again from 120 to 180 days of age in Erhualian pigs. The expression of Ob-Rb mRNA was higher in Large White pigs than that in Erhualian pigs (P< 0.01). The results suggest that the serum leptin level and leptin gene expression in adipose tissue highly correlate with adiposity.     

猪ATF4基因多态性与生产性状的关联及基因表达分析

为进一步了解和认识ATF4基因的功能,揭示ATF4对猪脂肪代谢的影响,寻找与肉质性状相关联的分子标记,文章采用PCR方法扩增了ATF4基因部分序列,通过序列比对发现在翻译起始密码子ATG下游159 bp处存在A159G转换,通过PCR-AluⅠ-RFLP对大白猪、长白猪、梅山猪和通城猪进行酶切分型,发现在大白猪和长白猪中均为AA基因型,在梅山猪和通城猪中均为GG基因型。进一步对大白猪×梅山F2群体资源家系进行了酶切分型,并分析该位点的多态性与生产性状的关系。结果表明,ATF4的多态性与臀部平均膘厚存在极显著相关(P<0.01),与胸腰椎间膘厚、平均膘厚、眼肌高、眼肌面积存在显著相关(P<0.05)。采用Real-time PCR分析了ATF4基因在大白猪与梅山猪背最长肌不同发育阶段的表达模式。结果表明,ATF4基因在大白猪和梅山猪胚胎期65 d和出生后3 d中的表达水平相对都比较低,且在两品种间无明显差异;而在出生后60 d和120 d,ATF4基因在大白猪中与梅山猪均出现了上调表达,并且在梅山猪中的相对表达水平要显著高于大白猪。研究结果为进一步深入研究猪ATF4基因在脂肪代谢中的分子机理奠定了基础。     

Age-related changes in plasma porcine growth hormone (GH) profiles and insulin-like growth factor-I (IGF-I) concentrations in Large White and Meishan pigs

Plasma GH profiles and IGF-I concentrations were determined in Large White intact male (LW-M), female (LW-F) and castrated male (LW-C) and in Meishan intact male (MS-M) pigs between 10 and 140 d of age. Mean GH levels slightly increased between 10 and 45 d of age in LW pigs, in connection with an alteration in the temporal distribution of GH peaks, whereas neither interpulse GH level nor maximum GH level were affected. Mean GH levels decreased after 45 d of age, in connection with a decline in maximum and interpulse GH levels. IGF-I concentrations were low between 10 and 45 d of age and increased thereafter. GH secretory profiles did not differ significantly between LW-M and LW-F at either age. Castration had no effect at 45 d of age whereas LW-C exhibited lower mean, maximum and interpulse GH levels and smaller sum of GH pulse areas and widths than LW-M or LW-F at 140 d of age. IGF-I was lower in LW-C or LW-F than in LW-M at 140 d of age. The pattern of age-related changes in GH and IGF-I was similar in MS and LW pigs. However, interpulse GH level was higher and sum of GH pulse widths was smaller in MS-M than in LW-M, whatever the age. The results indicate that: i), GH and IGF-I secretions were similar in Meishan, and Large White pigs; ii), in both breeds, GH secretion declined after 45 d of age, due to decreased maximum and interpulse GH levels; iii), sex and/or castration effects on GH and IGF-I secretion were observed after 45 d of age only.     

The effect of duration of sprinkling on total moisture losses from pigs

Total moisture losses (TML) from 2 Large White X Landrace pigs sprinkled (800 ml/min) for 0, 30, 60, 90 or 120 seconds at 35C ambient temperature were measured in a hygrometric tent. TML increased to peak values of 5–6 g/min after sprinkling for 60–120 seconds. Irrespective of duration, TML declined to control levels within 60–70 minutes. To obtain most benefit in terms of feed intake and growth in a hot climate it is suggested that pigs should be sprinkled with approximately 800 ml water every 30 minutes.