Immune status of PIC Camborough-15 sows, 25% Meishan sows, and their offspring kept indoors and outdoors

Newer genetic lines of pigs are being used in indoor and outdoor production systems. The objectives of Exp. 1 were to describe the effects of the maternal sow line genotype, environment (indoor vs outdoor), and the genotype x environment interactions on blood hemoglobin (Hb), immunoglobulin G (IgG) concentrations, white blood cell (WBC) numbers, lymphocyte transformation/blastogenesis (LTA), natural killer (NK) cell activity, neutrophil chemotaxis, cortisol concentrations, and leukocyte differentials. Studies were performed using two genotypes: PIC Experimental-94 (Exp-94, an experimental line containing 25% Meishan) and PIC Camborough-15 (C-15). The Exp-94 sows had lower LTA at 0.2 microg/mL mitogen than the C-15 sows, whereas Exp-94 sows had higher NK cytotoxicity than the C-15 sows. When indoors, the two genotypes showed similar neutrophil chemotaxis. When outdoors, the C-15 genotype had higher (P < .01) neutrophil chemotaxis than the Exp-94 sows. The other immune measures were statistically similar for the two genotypes for each environment and for the genotype x environment interaction of sows. Experiment 2 sought to determine the effects of genotype on the immune system of nursery-age offspring of the experimental lines. Each sow line was bred to a common PIC 405 boar line. The Exp-94 x 405 pigs had elevated WBC numbers than C-15 x 405 pigs. The social status of the Exp-94 x 405 or the C-15 x 405 pigs showed no effect on any of the immune measures studied. The other immune measures were statistically similar for the two lines of pigs. The Exp-94 line had marginally increased NK activity but reduced lymphocyte blastogenesis and neutrophil chemotaxis compared with the C-15 line.     

The effects of branched-chain amino acids on sow and litter performance

Sows (n = 306; PIC, Line C-19; average parity 2.1) were used to evaluate the interrelationship between valine, isoleucine, and leucine on sow and litter performance. Our objective was to determine whether the increase in litter weaning weight associated with added dietary valine is specific for valine or a result of the total branched-chain amino acid (i.e., isoleucine and[or] leucine) concentration of the diet. Eight dietary treatments (36 to 41 sows/treatment) were arranged as a 2 x 2 x 2 factorial with two levels of valine (.80 and 1.20%), isoleucine (.68 and 1.08%), and leucine (1.57 and 1.97%). This provided total branched-chain amino acid levels of 3.05, 3.45, 3.85, and 4.25%. The lowest level of each branched-chain amino acid was similar to that in a .90% lysine corn-soybean meal diet containing .15% L-lysine HCl. Amino acids other than valine, isoleucine, and leucine met or exceeded their suggested estimates relative to lysine using ratios derived from the National and Agricultural Research Councils. Average number of pigs on d 2 of lactation was 11.2, and average lactation length was 20.9 d. Number of pigs weaned (x = 10.6), sow ADFI (x = 5.85 kg), and sow weight loss (x = 4.25 kg) were not affected by dietary treatment (P > .10). Sow backfat loss (P < .02), litter weaning weight (P < .04), and litter weight gain from d 2 to weaning (P > .05) increased as dietary valine increased. Litter weight at weaning and litter weight gain were not affected by dietary isoleucine (P > .80) or leucine (P > .60). Sixteen or 17 sows per treatment (129 total) were milked manually on d 14 to 16 of lactation. Increasing dietary valine tended to increase milk urea N (P < .07) but did not affect milk DM, CP, fat, lactose, or ash. Increasing dietary isoleucine or leucine had no effects on milk composition. These results confirm the importance of dietary valine for increased litter weaning weight, independent of either additional dietary leucine or isoleucine.     

Impacts of a modified farrowing pen design on sow and litter performances and air quality during two seasons

The impacts of using a modified farrowing pen (MOD) on the performance of sows and their litters and on ambient air quality over a hot and a cool season were evaluated. Primiparous Yorkshire × Landrace sows farrowed either during the months of February and March (thermoneutralily, TN) or June and July (heat-stress, HS). Temperatures within each season were controlled to 21 and 29 °C, respectively, for TN and HS. Animals from each group were assigned to a standard farrowing crate (STD; TN, n = 17; HS, n = 16) or a MOD pen (TN, n = 19; HS, n = 19). The MOD pen consisted of a STD crate with a 1.5 × 1.6-m comfort zone in the back, equipped with rubber floor mats, a feeder and a nipple waterer. Litter size was standardized to 10 or 11. No creep feed was provided and piglets were weighed weekly. Sows were weighed on days 2 and 22. Feed intake of sows was monitored daily, a milk sample was obtained on day 21 for compositional analyses and jugular blood samples were collected on days 2 and 21 to measure prolactin, IGF-I and urea. Sows consumed less feed (3.4 vs. 4.7 ± 0.1 kg/day, P < 0.001) in a hot than in a cool season and, at 29 °C, sows in MOD pens consumed more feed (3.9 vs. 3.0 ± 0.2 kg/day, P < 0.01) than sows in STD pens. Sow lactation weight loss was greater (− 26.4 vs. − 19.1 ± 1.9 kg, P < 0.05) for sows in STD than MOD pens in a hot season. The reduction in prolactin concentrations from days 2 to 22 of lactation tended to be greater (P = 0.08) in a hot season for sows in STD pens. Concentrations of urea and IGF-I increased as lactation advanced (P < 0.01) and IGF-I was lower for HS compared to TN sows on both days (P < 0.01), whereas urea was greater for HS sows on day 2 only (P < 0.01). Milk DM was less in a hot than in a cool season (P < 0.01). Average piglet weight gain was reduced in a hot compared to a cool season during the second week of lactation (P < 0.05) and this reduction was less in MOD than STD pens during the third week of lactation (P < 0.01). During a hot season, even though not significant, average weight gain of piglets from days 2 to 21 of lactation was reduced by 6.0% in MOD pens compared to 9.7% in STD pens.     

发酵饲料对妊娠母猪产仔性能及粪便中微生物区系组成的影响

为了探究饲喂发酵饲料对妊娠母猪的产仔性能、肠道微生物发酵参数及微生物菌群组成的影响,选取经产母猪16头,随机分为2组,对照组饲喂常规饲料,试验组饲喂发酵饲料。试验从母猪妊娠85 d开始,采集妊娠105 d的母猪粪便用于发酵参数测定及高通量测序,记录母猪的产仔数和产活仔数和仔猪初生重。结果:与对照组比较,饲喂发酵饲料显著提高了母猪粪便中乙酸、丁酸、异丁酸、异戊酸和戊酸的含量(P<0.05),但对产仔数、产活仔数及平均初生重无显著影响(P>0.05)。微生物测序结果表明,2组菌群的多样性和结构存在相似性。在门水平上,饲喂发酵饲料显著降低了Fibrobacteres的相对丰度;在属水平,饲喂发酵饲料显著降低了Oscillospira和Fibrobacter属的相对丰度(P<0.05),对Blautia和Bacteroides相对丰度有提高的趋势(P<0.1)。综上所述,饲喂发酵饲料可改变母猪肠道微生物菌群结构,促进后肠发酵,有助于改善母猪的肠道健康,但对母猪的产仔性能无显著影响。     

三元母猪留做繁殖母猪的问题探讨及建议

三元母猪做繁殖母猪是现下一种很无奈又很普遍的现象,但由于母猪没有经过专业的选育及科学的饲喂,往往产仔后问题很多,最常见的问题表现在新生仔猪腹泻,这种腹泻多是因为三元母猪在生长的过程中没有添加脱霉剂,导致霉菌毒素中毒,霉菌毒素破坏了仔猪的肝脏及免疫系统,导致新生仔猪对乳脂利用率差以及自身免疫力低下的双重原因引起腹泻。文章针对仔猪的腹泻情况做详细阐述及针对三元母猪留做繁殖母猪给出一些相应的建议。     

Effects of housing system (outdoor vs cages) and age of laying hens on egg characteristics

1. Effects of two housing systems (cages vs outdoor) on external and internal egg characteristics were investigated. 2. In total 785 eggs from three different lines in cages and 268 eggs from outdoor-housed layers were examined for egg weight, albumen, yolk and shell content, albumen height and pH, and albumen and yolk dry matter content. 3. Interactions between layer age and housing systems were found for egg weight, eggshell content, albumen height, albumen pH, and dry matter content of the albumen and yolk. This was mainly due to the greater variation with age in the outdoor layers, compared to the caged layers. 4. Irrespective of age eggs from outdoor layers were relatively broader than eggs from the caged layers. Yolk colour was considerably darker in the outdoor group (11.0 vs 9.3). 5. We concluded that it is more difficult to maintain constant external and internal egg quality in an outdoor housing system than in a battery cage system. Factors that determine the greater fluctuations in internal egg quality need to be investigated.     

Effects of stocking rate and crude protein intake during gestation on ground cover,soil-nitrate concentration,and sow and litter performance in an outdoor swine production system

Pregnant gilts (n = 126) were assigned randomly to 12 0.4-ha old world-spar bluestem (Bothriochloa ischaemum) pastures in an outdoor swine (Sus scrofa) production system to examine effects of stocking rates (17.5 or 35 gilts/ha; 7 or 14 gilts per pasture) and dietary N on percentage of ground cover, soil nitrate (NO3-) concentration, and reproductive performance. Treatments were arranged factorially with two stocking rates and two diets equivalent in dietary lysine but different in CP (control = 14.7% CP vs experimental = 12.6% CP) with three pastures per treatment. The experiment was repeated during a second parity with the same animals on the same treatments. Each triangular gestation pasture was subdivided into three regions: 1) near the point or radial center; 2) the middle region that contained a hut and a wallow area; and 3) the outer section where gilts were fed each day. Soil samples (15 cm deep) were taken at the beginning and end of the 306-d study, and soil nitrate-N concentrations were determined. Percentage of ground cover was visually estimated initially and every 30 d thereafter through d 306. Before farrowing, gilts were moved to identical pastures for farrowing and were fed a common 16% CP sorghum (Sorghum bicolor)-based lactation diet beginning at the time of movement to the farrowing pasture. Pregnant gilts were weighed at the time of assignment to treatments in the gestation pastures, when they were moved to farrowing pastures, and at weaning. Production data included total number of pigs born per sow, number of pigs born alive or dead, average birth weight, number of pigs weaned, average weaning weight, and mortality. No differences (P > 0.05) were observed between treatments in soil NO3- concentrations. Percentage of ground cover was decreased (P < 0.01) by the higher stocking rate when grazing was initiated in March/April but recovered rapidly after removal of pigs. More (P < 0.01) pigs were weaned per sow (8.4 vs 7.1+/-0.34) from higher gestation-stocking rate groups. Pig mortality in farrowing was greater (P < 0.05) for lower gestation-stocking rates (25.7% vs. 18.1+/-1.9%). A stocking rate of 35 sows/ha might have increased production potential but was associated with a rapid loss of ground cover during spring.     

非离子型表面活性剂(NIS)对反刍动物瘤胃生态和生产性能的影响

作者综述了3种非离子型表面活性剂（吐温60、吐温80和SOLFA-850）在反刍动物营养方面的研究进展。添加0．05％和0．10％的吐温80．显著提高了体外混合瘤胃微生物培养物中羧甲基纤维素酶、木聚糖酶、淀粉酶和大麦葡聚糖酶等胞外酶的总产量（P〈0．05），胞外和胞内果胶酶的总产量不受影响。吐温60也能促进蛋白酶和纤维素酶的活性．不过需要较高的浓度水平。SOLFA-850能极显著提高羧甲基纤维素酶和木聚糖酶活性（P〈0．01）。添加吐温80显著促进瘤胃内非纤维素分解菌的生长速度，而对纤维分解菌的生长影响不大。添加SOLFA-850能增加总可计数菌的数量，但不影响纤维分解菌的数量。吐温80也能显著增加瘤胃内真菌和原虫的数量。瘤胃灌注吐温80或SOLFA-850能增加瘤胃pH、氨氮和总挥发性脂肪酸浓度，提高干物质降解率和奶牛产奶量。非离子型表面活性剂的作用机理至少可归结为：①增加酶的释放量和／或增强酶的活性；②促进酶和底物之间的相互作用。因此非离子型表面活性剂今后可能成为一种新型反刍动物饲料添加剂。     

Fender design and insulation of farrowing huts: effects on performance of outdoor sows and piglets

Two studies assessed sow and litter performance when design features of farrowing huts varied. A fender is a structure that extends out the front of the hut to create a veranda that prevents young piglets from leaving. In Exp. 1, 206 lactating sows and their litters were used to assess litter performance and the time required to process litters for two fender designs (short wooden [WS] vs. tall metal with a board front [MT-b]) and insulation status (insulated [IN] vs. uninsulated [UN]) farrowing huts. A significant fender x insulation interaction was observed for total litter weaning weight. Lighter litters weaned (P = 0.013) from WS fenders with UN huts compared with the other treatments. Fender design did not (P > 0.05) influence the time required to process a litter with one stockperson. Less total time (P = 0.001) was required to process a litter when two people were present (10.60 +/- 0.74 min) compared with one stockperson (14.52 +/- 0.74 min). There were no (P > 0.05) differences between IN and UN huts for temperature and relative humidity measurements. In Exp. 2, 331 lactating sows and their litters were used to determine sow and litter performance when using one of two fender front designs (boards [MT-b] vs. roller [MT-r]). The front design of the fender did not influence (P > 0.05) most litter performance measures. We conclude that fender design, fender fronts, and insulation effects did not have large influences on sow and litter performance in a West Texas environment.     

Effects of 25% propylene glycol hydrogel (Solugel) on second intention wound healing in horses

OBJECTIVE: To evaluate the effect of a commercially available 25% propylene glycol hydrogel preparation (Solugel; Johnson and Johnson Medical, North Ryde, Australia) on healing of full-thickness skin wounds on the distal aspect of the limb in horses. STUDY DESIGN: Experimental. ANIMALS: Eight Standardbred horses. METHODS: Standardized (2.5 x 2.5 cm) full-thickness skin wounds were created over the mid-dorsomedial aspect of both metacarpi in 8 horses. One wound in each horse was dressed with saline solution (0.9% NaCl) soaked gauze, and one was treated with Solugel under dry regular gauze; wounds were then bandaged with gauze-coated cotton wool and elastic adhesive bandages. Wounds were videorecorded and rebandaged twice weekly until healed. Wound healing variables were measured from the videorecordings using a computer software package and analyzed as a randomized complete block design with repeated measures. Where necessary variables were made positive for analysis; significance was set at P <.05. RESULTS: The area of the wound at the first bandage change did not vary between treated and untreated wounds. Treatment had no effect on the total rate of healing, rate of healing during the retraction phase of healing, rate of healing after the retraction phase was complete, or the amount the wounds retracted. CONCLUSIONS: Using this model of wound healing, Solugel had no effect on second intention healing of distal limb wounds in horses. CLINICAL RELEVANCE: Solugel does not appear to have any beneficial effect on healing of small full-thickness skin wounds to the distal limb of horses.     

Altitude effects on technology and productivity of small bovine farms (milk meat) in Veracruz (Gulf of Mexico)

The dual-purpose bovine system represents 98.4% of the bovine livestock of Veracruz, the main cattle-producing state of Mexico. This system supplies calves to meat companies, a sector in which Veracruz has been the national leader in the last decade. The objective of the present study was to analyze the effect of the altitudinal zonation of farms on livestock technology and productivity in a microbasin of the Gulf of Mexico where small farms predominate. Structured interviews were applied to producers located in three altitudinal zones (at average altitudes of 50, 140, and 450 m, respectively, for lower, middle, and upper zones). Sample size was 135 farms having similar land surface (within a range of 15–22 ha). The results indicated multiple differences among farms located in the three zones. Farms in the middle and lower zones presented higher productive indicators than those in the upper zone. Differences in herd structure and management resulted in important differences in productivity, income, and profits in milk and calf production. We concluded from this study that altitudinal zonation in Veracruz had a clear effect on the differentiation of small farms, which are representative of dual-purpose cattle. The upper zone performs cattle activity under conditions with greater disadvantages in the analyzed region.     

An investigation into uterine capacity based on litter and placental characteristics in two sow lines with different prolificacy (Danish Landrace x Danish Yorkshire versus German Saddleback)

Litter size in modern so called hyperprolific pig (Sus scrofa Linnaeus) breeds such as of crossbred Danish Landrace x Danish Yorkshire (LY/YL) sows increased remarkably over recent years, however, commonly associated with reduced piglet birth weight and higher within litter birth weight variability likely due to a limited uterine capacity. Since investigation into this issue is patchy, the aim of this study was to investigate uterine capacity based on litter and placental characteristics in two sow lines with different prolificacy, that is crossbred Danish genetic (Danish Landrace x Danish Yorkshire; DG; n = 14) and purebred German Saddleback (GS) sows (n = 12). Parameters recorded were litter size, piglet birth weight and vitality, placental weight and surface area as well as placental vascularization. Litters of DG were on average larger than of GS (p < .001). Piglets of DG weighed on average less than GS (p < .001) and were less vital (p < .001–.142). Increasing litter size was associated with reduced piglet birth weight and increased within litter birth weight variability in GS, but not in DG. DG had on average a lower placental weight (p < .001) and smaller placentae (p < .001) than GS, but the placenta was on average more efficient than of GS (based on the quotient of piglet and corresponding placental weight; p < .001). Vascularization of placentae was on average not or only slightly different between breeds (p < .05 – .982). Remarkably, however, vascularization of the lateral and apical chorionic epithelium of the chorionic ridges as the immediate foetal/maternal interface was on average slightly higher in DG than GS (p < .05–.111). Results thus demonstrate that uterine capacity based on litter and placental characteristics is higher in DG than GS sows.     

Survey of chicken rearing conditions in Italy: effects of litter quality and stocking density on productivity, foot dermatitis and carcase injuries

1. A survey was carried out to assess some welfare indicators in broilers reared by the largest poultry companies in Italy, to determine whether they accord with European proposal COM (2005) 221 final. 2. Productive traits, carcase injuries and foot dermatitis were recorded from 279,640 broiler chickens reared in winter and in summer in 5 farms representative of the Italian production system. 3. The densities currently used in Italy are in accordance with the European proposal, which recommends that broilers are kept at a density lower than 30 to 32 kg live weight/m(2) and not exceeding 38 to 40 kg live weight/m(2). 4. Season markedly influenced broiler welfare status, with the worst score collected in winter cycles, when the recommended limit of 50 points for foot pad dermatitis was exceeded. 5. Stocking density is not a straightforward indicator for bird welfare; there was no relationship between stocking density and lesion incidence or mortality rate. 6. The control of environmental conditions, particularly litter quality, appears to be a key issue for broiler welfare.     

Intensive indoor versus outdoor swine production systems: genotype and supplemental iron effects on blood hemoglobin and selected immune measures in young pigs.

The objectives of Exp. 1 were to determine the effects of production system and genotype on pig performance and health. Sows were bred, gestated, farrowed, and lactated in either an intensive indoor or an intensive outdoor production system. The three dam genotypes of pigs used in each environment were PIC Camborough-15 (C-15), PIC Camborough Blue (CB), and Yorkshire x Landrace (YL). All pigs received 100 mg of iron dextran at d 3 of age. Pigs raised in the outdoor unit had higher blood hemoglobin (Hb) concentrations on d 28 of age than pigs raised indoors (11.5 +/- .22 vs 8.16 +/- .26 g/dL, P < .0001). Outdoor-reared pigs had more white blood cells (WBC) on d 3 than indoor-reared pigs (9.7 +/- .38 vs 8.04 +/- .38 cells/microL x 10(3), P < .05), but outdoor pigs had fewer WBC on d 28 of age than indoor-reared pigs (9.8 +/- .5 vs 11.1 +/- .45 cells/microL x 10(3), P < .05). Genetic lines did not differ in plasma immunoglobulin G (IgG) concentrations at 3 or 28 d of age. Environment and age influenced pig Hb levels and WBC numbers. The objectives for Exp. 2 were to determine whether C-15-405 pigs reared outdoors or indoors needed supplemental iron or whether they would receive enough environmental iron, and how the lack of supplemental iron may impact pig Hb and immunity. Indoor and outdoor pigs received either no supplemental iron, 100 mg, or 400 mg of iron dextran on d 3 of age. Blood percentage neutrophils and neutrophil: lymphocyte ratio were lower (P < .05) indoors, and natural killer cell (NK) activity was greater (P < .05) among indoor- than outdoor-reared pigs (NK % cytotoxicity: 15.6 +/- 2.3 vs 9.7 +/- 2.3). Outdoor-reared pigs that received no injected iron had similar Hb at d 28 of age as indoor-reared pigs that received 100 mg of iron dextran (11.1 +/- .36 vs 10.7 +/- .4 g/dL, P = .59). Supplemental iron may not be necessary in an outdoor production system. Outdoor-reared pigs had lower values for some immune measures, but they had similar survival rates as indoor-reared litters.     

Mutations in BMPR-IB and BMP-15 genes are associated with litter size in Small Tailed Han sheep (Ovis aries)

The Small Tailed Han is a prolific local sheep breed in China. The bone morphogenetic protein receptor IB (BMPR-IB) gene, which affects the fecundity of Booroola Merino sheep, and the bone morphogenetic protein 15 (BMP-15) gene, which affects the fecundity of Inverdale, Hanna, Belclare, Cambridge, and Lacaune sheep, were studied as candidate genes associated with the prolificacy of Small Tailed Han sheep. Single nucleotide polymorphisms of BMPR-IB and BMP-15 genes were detected in Small Tailed Han ewes (n = 188) by PCR-RFLP. The combined effect of the 2 genes on the prolificacy of Small Tailed Han sheep was studied. The results indicated that the same FecB mutation (Q249R) occurred in the BMPR-IB gene in Small Tailed Han ewes as found in Booroola Merino ewes. The Small Tailed Han ewes with genotypes FecB(B)/FecB(B) and FecB(B)/FecB(+) had 1.40 (P < 0.01) and 1.11 (P < 0.01) more lambs, respectively, than those with genotype FecB(+)/FecB(+). The same FecX(G) mutation (Q239Ter) of the BMP-15 gene was found in Small Tailed Han ewes as in Belclare and Cambridge ewes. The Small Tailed Han ewes with the heterozygous mutant FecX(G)/FecX(+) had 0.55 (P < 0.01) more lambs than those with the wild-type FecX(+)/FecX(+). The Small Tailed Han ewes carrying mutations in both BMPR-IB and BMP-15 genes had greater litter size than those with either mutation alone. In view of our results, marker-assisted selection using both BMPR-IB and BMP-15 genes is warranted to increase litter size in sheep and will be of considerable economic value to sheep producers.     

In vitro effects of dexamethasone on bovine CD25(+)CD4(+) and CD25(-)CD4(+) cells

This paper investigates the in vitro effect of dexamethasone on bovine CD25(high)CD4(+), CD25(low)CD4(+) and CD25(-)CD4(+) T cells. Only a small percentage of bovine CD25(high)CD4(+) (2-4%) and CD25(low)CD4(+) (1-2%) cells expressed Foxp3. Dexamethasone caused considerable loss of CD25(-)CD4(+) cells, but it increased the relative and absolute numbers of CD25(high)CD4(+) and CD25(low)CD4(+) lymphocytes, while at the same time reducing the percentage of Foxp3(+) cells within the latter subpopulations. Considering all these, as well as the intrinsically poor Foxp3 expression in bovine CD25(+)CD4(+), it can be concluded that the drug most probably increased the number of activated non-regulatory CD4(+) lymphocytes. It has been found that changes in cell number were at least partly caused by proapoptotic effect of the drug on CD25(-)CD4(+) cells and antiapoptotic effect on CD25(high)CD4(+) and CD25(low)CD4(+) cells. The results obtained from this study indicate that the involvement of CD4(+) lymphocytes in producing the anti-inflammatory and immunosuppressive effect of dexamethasone in cattle results from the fact that the drug had a depressive effect on the production of IFN-γ by CD25(-)CD4(+) cells. Secretion of TGF-β and IL-10 by CD4(+) lymphocytes was not involved in producing these pharmacological effects, because the drug did not affect production of TGF-β and, paradoxically, it reduced the percentage of IL-10(+)CD4(+) cells.     

Efficacy of Fipronil (9.8% w/w) + (S)-Methoprene (8.8% w/w) and Imidacloprid (8.8% w/w) + Permethrin (44% w/w) against Dermacentor variabilis (American Dog Tick) on Dogs.

This study evaluated overall efficacy, percentage of dogs free of live ticks, retention of ticks, and efficacy against retained ticks of fipronil (9.8% w/w) + (S)-methoprene (8.8% w/w) and imidacloprid (8.8% w/w) + permethrin (44% w/w) spot-on topical solutions against Dermacentor variabilis infesting dogs. Fipronil + (S)-methoprene provided significantly (P less than .05) greater tick control compared with the control dogs for the entire 30-day study period. Conversely, the combination product of imidacloprid + permethrin demonstrated activity significantly (P less than .05) different from control dogs only up to day 23. Significantly (P less than .05) more dogs treated with fipronil + (S)-methoprene were free of live ticks compared with controls on days 3, 9, and 16. There was never a significant difference (P greater than .05) between control and imidacloprid + permethrin-treated dogs in numbers of dogs free of live ticks. After the initial 10-minute tick exposure, lower numbers of ticks were retained on the imidacloprid + permethrin-treated dogs than on the fipronil + (S)-methoprene-treated dogs. However, when evaluating the effectiveness of the acaricides on "retained ticks," it appears that while some of the ticks were rapidly knocked down on the imidacloprid + permethrin-treated dogs, efficacy against ticks still retained at 10 minutes was never greater than 50%.     

Detection of novel single-nucleotide polymorphisms (SNPs) in the CYP21 gene and association analysis of two SNPs for CYP21 and ESR2 with litter size in a commercial sow population

Altogether 129 F₁ sows from a commercial sow farm with at least four litters were genotyped for the oestrogen receptor 2 gene (ESR2) and cytochrome P450 hydroxylase 21 gene (CYP21) and investigated for associations on the litter‐size parameters: total number born and number born alive. Five novel polymorphisms were found in the 3′‐untranslated region for the CYP21 gene. Genotype and allele frequencies for the CYP21 (position 3462G > A) single‐nucleotide polymorphism (SNP) were 0.434 (GG), 0.504 (AG), 0.062 (AA) and 0.69 (G):0.31 (A), respectively. No association was found between this polymorphism and litter‐size parameters. For the ESR2 gene, the SNP in exon 5 associated with an amino acid substitution MET (allele A) > VAL (allele G) was investigated. Only two genotypes were found leading to allele frequencies of 0.34 (A):0.66 (G). Only number born alive piglets were significantly increased for the AG genotype (p = 0.034) with 11.64 piglets per sow and litter in comparison with the GG genotype, leading to only 10.96 piglets per sow and litter. From these data, it can be concluded that the investigated SNP of the ESR2 gene is associated with the number of liveborn piglets in the commercial population considered, and hence could be useful in selection for litter size. Therefore, this gene should be investigated in additional populations.