Commercial Genetic Lines Research Articles

256 Body Condition Association with Production Records and Feed Management Decisions

Abstract Body condition prior to and after farrowing has been shown to be associated with sow productivity. The objective for this study was to evaluate body condition impacts at a snapshot in time and determine its association with sow production measures. Data were collected from Midwestern commercial breed-to-wean farms (n = 3). These farms represented typical commercial genetic maternal lines and management systems. Two separate sow groups were measured at each farm representing sows entering farrowing (pre-farrow, n = 717, d 90 – 113 gestation) and sows that had been most recently weaned (post-farrow, n =756, d 2 – 30 post-weaning). A BCS sow caliper was used to objectively assess body condition. Using the caliper measurements, condition was broken into 3 categories: “thin” (< 12), “ideal” (13-15), and “fat” (>16). Production records were obtained for number born live, stillborn, mummified, and weaned piglets as well as the wean-to-estrus interval. Data were evaluated using the mixed model methods (PROC MIXED, SAS Institute, Cary, NC). Pre-farrow caliper measurements indicated sows categorized as “fat” had fewer pigs born live compared with “thin” sows (P < 0.15). Sows classified as “fat” prior to farrowing had the least number of pigs weaned compared with sows in “ideal” or “thin” condition (P < 0.05). Retrospective post-farrow results revealed there was tendency for “thin” sows to have had more pigs born live than “fat” sows (P < 0.15). “Thin” sows had weaned the most pigs when compared with sows in either the “ideal” or “fat” category (P < 0.05). This suggests that gestational feed management and preventing sows from putting on excessive body fat prior to farrowing has positive effects on the number of pigs born alive at the subsequent farrowing and pigs weaned following lactation. This leads to feed savings and economic benefits.

Investigating the Features of PDO Green Hams during Salting: Insights for New Markers and Genomic Regions in Commercial Hybrid Pigs.

Simple SummaryIn recent years, the meat industry is looking with increased interest at the implementation of non-invasive new tools for predicting the final quality of dry-cured hams and monitoring ham aging. The selection of raw meat and the control of the salting procedure to predict the quality of dry-cured hams are of primary importance for meat processors. The identification of genetic markers associated with ham traits and related to different aptitudes of the thighs towards salting phases and weight losses is a primary goal for the Italian pig production chain. This paper addresses the need for investigating the associations between genomic markers and ham traits obtained through the application of non-invasive technologies for monitoring hams before and during the salting process. To our knowledge, this is the first study investigating the markers and genes associated with ham traits obtained through the use of Ham InspectorTM apparatus.Protected Designation of Origin (PDO) dry-cured hams production is greatly dependent on raw meat quality. This study was performed to identify genetic markers associated with the quality of dry-cured ham. Carcass traits of 229 heavy pigs belonging to three commercial genetic lines were registered (weight, EUROP classification). Phenotypic traits (Semimembranosus muscle ultimate pH, ham weight and lean meat content, adsorbed salt) of the corresponding thighs, undergone PDO ham process in three different plants, were measured, using a fast and non-invasive technology. Green ham weight and lean meat percentage influenced the estimated salt content and the weight loss during salting, even if the processing plant greatly affected the variability of the measured ham traits. The genomic data were obtained with the GeneSeek Genomic Profiler (GGP) 70k HD Porcine Array, using the slaughter day and the sex of the animals in the statistical analyses. The phenotypic traits were associated with the genotypes through GenAbel software. The results showed that 18 SNPs located on nine porcine chromosomes were found to be associated with nine phenotypic traits, mainly related to ham weight loss during salting. New associations were found between markers in the genes Neural Precursor Cell Expressed Developmentally Down-Regulated 9 (NEDD9, SSC7), T-Cell Lymphoma Invasion and Metastasis 2 (TIAM2, SSC1), and the ham quality traits. After validation, these SNPs may be useful to improve the quality of thighs for the production of PDO dry-cured hams.

Differential physiological response of slow- and fast-growing broiler lines to hypoxic conditions during chorioallantoic membrane development

Ambient conditions during chicken embryogenesis, such as insufficient oxygen or changes in temperature, are expected to cause permanent phenotypic changes and affect their posthatch performance. Decades of genetic selection for high growth rate resulted with various physiological and morphological changes that can affect the broiler fitness under environmental stress. To evaluate the selection effect on responses to environmental challenge during embryonic development, and the long-term implications, we have used a unique genetic line, that was not selected for over 30 yr (since 1986), as control for the modern commercial genetic line. At embryonic day 5 (E5), broiler embryos from these 2 genetic lines were divided into 2 treatments: 1) control; 2) 15% O2 concentration for 12 h/day from E5 through E12 the embryonic period of chorioallantoic membrane formation. Embryos and hatched chicks were characterized for physiological and morphological parameters. Significant differences in relative embryo weight and yolk consumption were found between the 2 lines. The modern line was characterized by a higher metabolic rate and rapid growth, supported by higher hemoglobin levels and hematocrit concentrations, whereas the 1986 line had slower metabolism, lower levels of hematocrit and hemoglobin, higher oxygen volume per 1 g of embryonic tissue indicating higher oxygen availability. Both lines exhibited changes in heart rate, and blood parameters corresponding to cardiovascular system adaptation after hypoxic exposure, seemingly implemented to increase oxygen-carrying capacity to the embryo tissues. Our finding stand in agreement that the genetic selection for high growth rate that led to higher metabolism without a fit of the cardiovascular system, increased the imbalance between oxygen supply and demand.

Genetic variation of keel and long bone skeletal properties for 5 lines of laying hens

Fractures to the keel bone is one of the greatest problems facing the laying hen industry. With most severe effects observed in non-cage housing, frequencies are expected to dramatically increase as the industry continues transitioning away from battery cages. Incidences within commercial systems are well documented, where the main cause is believed to be high egg production and the associated need for calcium drawing on endogenous reserves (i.e., bone) leaving bone weakened and prone to fracture. The current work sought to characterize various bone mineral and biomechanical properties of 5 distinct purebred or crossbred laying hen lines (3 commercial: Bovans Brown, Dekalb White, and Institut de Sélection Animale Dual Brown; 2 non-commercial: Experimental Brown and Experimental White), following previous work that demonstrated differences in susceptibility to keel fracture using an ex vivo impact testing apparatus. The keel was then removed to undergo analysis by computer tomography; the humerus and tibia were also removed for biomechanical testing. The keel bone mineral density and moment of area correlated moderately with hen weight and susceptibility to fracture. The biomechanical properties of the tibia, but not the humerus, showed a strong relationship with hen weight. One commercial genetic line (Dekalb White) with a high susceptibility to fracture exhibited a mean tibia strength below the value expected from its mean weight. Our results suggest that for the purebred or crossbred lines other than Dekalb White, rather than properties of bone, lower mean weight may imply higher levels of activity, higher risk of collisions, and lower soft tissue protection that reflect greater susceptibility to keel fracture.

Bump feed for gestating sows is really necessary?

The objective of this study was to evaluate the effect of bump feeding for the final third of gestation on the performance of sows and their litters and on colostrum nutritional quality. Seventy hyperprolific sows of a commercial genetic line were selected according to their reproductive history. Sows were assigned to two treatments, no increase of feed (control, 2.4 kg/d of 3.25 Mcal/kg diet) or with increased feed (Bump feeding, 3.0 kg/d) from 81 days of gestation to farrowing with 35 replicates per treatment. No differences were observed for treatments on sow weight, weight gain, piglet birth weight, litter birth weight, coefficient of variation, number of total births, stillbirths, live births, and placental efficiency. The treatments also did not influence the calcium, phosphorus, ash, lactose, crude protein, zinc, ether extract, and crude energy content of the colostrum. Based on the results of the present study, the use of bump feeding in the final phase of gestation of sows becomes questionable, due the lack of effect on sow and litter performance.

Effects of prenatal stress and genetics on embryonic survival and offspring growth of laying hens

Early-life exposure to stressors can shape the phenotype of the offspring resulting in changes that may affect their prehatch and posthatch development. This can be modeled indirectly through maternal exposure to stressors (natural model) or by offspring exposure to stress hormones (pharmacological model). In this study, both models were used to investigate the effects of genetic line on hatchability, late embryonic mortality, sex ratio, and body weight until 17 wk of age. To form the parent stock, fertilized eggs of 4 commercial genetic lines — two brown (brown 1 and 2), two white (white 1 and 2), and a pure line White Leghorn — were incubated, hatched, and housed identically in 4 flocks of 27 birds (24 females and 3 males) per strain. Each strain was equally separated into 2 groups: “maternal stress,” where hens were subjected to a series of acute psychological stressors (e.g., physical restraint, transportation) for 8 D before egg collection, and “control,” where hens received routine husbandry. At 3 maternal ages, fertile eggs from both treatments were collected, and additional eggs from the control group were injected with corticosterone (10 ng/mL egg content) (“CORT”). A “vehicle” treatment was included to account for effects of egg manipulation. Each maternal age comprised a replicate over time. Eggs were incubated and hatched, and the offspring (N = 1,919) were brooded until 17 wk under identical conditions. The results show that prenatal stress interacted with strain to decrease embryonic survival and growth. Among all strains, brown 2 was consistently the most affected line in both prehatch and posthatch development. Our study shows that embryonic survival and offspring growth are mostly affected by the pharmacological model and that strain differences may increase susceptibility to prenatal stress. Moreover, it suggests that the natural stressor model may be useful for quantifying the response of the mother to stressors, whereas the pharmacological model may be useful for quantifying the response of the embryo to increased levels of corticosterone.

Contamination of eggs by Salmonella Enteritidis in experimentally infected laying hens of four commercial genetic lines in conventional cages and enriched colony housing

Human illness caused by the consumption of eggs contaminated with Salmonella Enteritidis is a continuing international public health concern. This pathogen is deposited inside the edible contents of eggs as a consequence of its ability to colonize reproductive tissues in infected hens. Conditions in the housing environment can influence the persistence and transmission of avian Salmonella infections, but the food safety ramifications of different poultry management systems are not entirely clear. The present study assessed the deposition of S. Enteritidis inside eggs laid by groups of experimentally infected laying hens of 4 commercial genetic lines (designated as white egg lines W1 and W2 and brown egg lines B1 and B2). Groups of hens from each line were housed at 555 cm2 of floor space per bird in both conventional cages and colony units enriched with access to perches and nesting areas. All hens were orally inoculated with 5.75 × 107 cfu of a 2-strain S. Enteritidis mixture, and the internal contents of eggs laid 5 to 24 D post-inoculation were cultured to detect the pathogen. No significant differences in egg contamination frequencies were found between the 2 housing systems for any of the hen lines. Contaminated eggs were laid between 7 and 21 D post-inoculation at an overall frequency of 2.47%, ranging from 0.25 to 4.38% for the 4 hen lines. The frequency of S. Enteritidis recovery from egg samples was significantly (P < 0.05) lower for line B2 than for any of the other lines, and the egg contamination frequency for line W1 was significantly greater than for line W2. The overall incidence of contamination among white eggs (3.38%) was significantly higher than among brown eggs (1.56%). These results demonstrate that S. Enteritidis deposition inside eggs can vary between genetic lines of infected laying hens, but housing these hens in 2 different systems did not affect the production of contaminated eggs.

PSIII-7 Production trait differences between show pig and commerical genetic lines

Abstract The objective was to compare growth and body composition of pigs sired by boars from the show pig industry to those sired by modern commercial genetic lines. Data included one group of 174 male pigs from 16 sires and 50 dams. Pigs were sired by Large White (LW) show pig sires (SHOW) or one of two maternal LW commercial genetic lines (W or P). Dams of all pigs evaluated were from line P. Pigs were weaned at 27 d of age and placed into a mechanically ventilated nursery (0.23 m2 per pig). After 35 d in the nursery, pigs moved to a naturally ventilated finisher (0.74 m2 per pig) with fully slatted floors. Weight, 10th rib backfat, and loin eye area (LEA) were collected at 156 d of age (backfat and LEA adjusted to 114 kg). Data was analyzed using PROC GLM with a fixed effect of genetic line and covariates of weaning age and birth weight. A one day increase in weaning age increased (P &lt; 0.01) 156 d weight by 658 g. Nursery average daily gain (ADG) was greater (P &lt; 0.01) for pigs sired by SHOW and W when compared to P (414 and 397 vs. 351 g, respectively) yet finishing ADG did not differ (P &gt; 0.05) (821 and 817 vs. 797 g, respectively). Backfat was thicker (P &lt; 0.01) for SHOW when compared to W or P (16.7 vs. 14.7 and 14.7 mm, respectively) and LEA was larger (P &lt; 0.05) for SHOW when compared to W or P (47.3 vs. 44.8 and 44.0 cm2, respectively). Finishing lean gain per day was greater (P &lt; 0.05) for SHOW and W when compared to P (323 and 322 vs. 309 g per d, respectively). Results suggest pigs sired by LW SHOW are fatter, heavier muscled, and have comparable lean growth to those sired by commercial LW genetic lines.

67 Structural conformation differences between show pigs and commercial genetic lines

Abstract Structural conformation differences between show pig and commercial genetic linesD.R. Obermier, Z.C. Peppmeier, M.T. Knauer North Carolina State University, Raleigh.The objective was to compare the structural conformation of pigs sired by boars from the show pig industry to those sired by modern commercial genetic lines. Data included 174 male pigs from 16 sires and 50 dams. Pigs were sired by Large White (LW) show pig sires (SHOW) or one of two maternal LW commercial genetic lines (W or P). Dams of all pigs evaluated were from line P. Pigs were reared in barns (0.74 m2 per pig) with natural ventilation and totally slatted concrete flooring. Two technicians visually evaluated pigs at five months of age for front leg side view (FSIDEVIEW), rear pastern angle (RPASTERN), rib width (RIB) and locomotion (LOCO). The traits FSIDEVIEW and RPASTERN were scored on a seven point scale where one was soft pasterns, four was normal and seven was buck-kneed and straight pasterns, respectively. Rib width was scored on a five point scale with five being wide ribbed. Locomotion was scored on a seven point scale where one was ideal. Correlations between technicians for FSIDEVIEW, RPASTERN, RIB and LOCO were 0.54, 0.66, 0.77 and 0.72, respectively. Males sired by SHOW had lower (P &lt; 0.01) FSIDEVIEW scores than those sired by W or P (2.2 vs. 3.3 and 3.6, respectively) and softer (P &lt; 0.05) RPASTERN (3.4 vs. 3.8 and 4.2, respectively). Rib width was wider (P &lt; 0.01) for SHOW when compared to W or P (3.7 vs. 2.6 and 2.4, respectively) Locomotion was superior (P &lt; 0.01) for SHOW when compared to W or P (2.6 vs. 3.4 and 3.6, respectively). Line W had lower (P &lt; 0.05) FSIDEVIEW and RPASTERN than P. Yet RIB and LOCO did not differ (P &gt; 0.05) between W and P. Results suggest pigs sired by SHOW had softer pasterns, greater rib width and superior locomotion when compared to those sired by commercial genetic lines.

Colonization of internal organs by Salmonella Enteritidis in experimentally infected laying hens of four commercial genetic lines in conventional cages and enriched colony housing

The prevalence of Salmonella Enteritidis in commercial egg-laying flocks is a prominent public health concern because contaminated eggs cause human illness. Deposition of this pathogen inside eggs results from bacterial colonization of reproductive tissues in infected hens. Environmental conditions can influence avian Salmonella infections, but the food safety consequences of different poultry housing systems remain uncertain. The present study assessed the invasion of internal organs by Salmonella Enteritidis in groups of experimentally infected laying hens of four commercial genetic lines (designated as white egg lines W1 and W2 and brown egg lines B1 and B2). Groups of hens from each line were housed at 555 cm2 of floor space per bird in both conventional cages and colony units enriched with access to perches and nesting areas. All hens were orally inoculated with 5.75 × 107 colony-forming units of a two-strain Salmonella Enteritidis mixture. At 6 to 7 d post-inoculation, hens were euthanized, and samples of liver, spleen, ovary, oviduct, and intestinal tract were removed for bacteriologic culturing. The frequency of Salmonella Enteritidis recovery from intestinal samples was significantly (P < 0.05) greater for the two white egg lines combined than for the two brown egg lines combined in both conventional cage (72.2% vs. 50.0%) and enriched colony housing systems (66.7% vs. 37.5%). The frequency of intestinal Salmonella Enteritidis isolation from line B1 was significantly higher from hens in conventional cages (47.2%) than in enriched colonies (22.2%), but no differences were observed for other hen lines. Line W1 yielded more positive intestinal samples than either brown egg line in conventional cages, and line B2 had fewer positive intestinal samples than all other lines in enriched colonies. There were no significant differences between hen lines or housing systems in Salmonella Enteritidis isolation from other internal organs. These results demonstrate that Salmonella Enteritidis colonization of the intestinal tract can vary between genetic lines of egg-laying hens and that some lines are subject to housing system influences on Salmonella susceptibility.

Productive and economic parameters of pigs supplemented from weaning to finishing with prebiotic and probiotic feed additives.

Practical evidence suggests possible beneficial effects with the combined use of prebiotics and probiotics which can improve production parameters. The objective of the study was to investigate the addition of Saccharomyces cerevisiae (SC) as prebiotic and the combination of Lactobacillus spp. (L), Bacillus spp. (B) as probiotics on productive parameters and economic feasibility. Four hundred male pigs, hybrids of commercial genetic lines (Pietrain), were used: T1 = control group, T2 = 4 kg/tonne SC, T3 = 0.8 kg/tonne feed L and B, T4 = 4 kg/tonne SC + 0.8 kg/tonne L and B. Productive parameters were recorded in the treatment groups for four periods. Then, the viscera of five pigs per treatment were collected after slaughter to evaluate the histological changes and cytokine concentrations in the ileum. The weight gains of groups at 70–100, 100–125 and 125–150 days in the T4 group showed statistically increases (p < .05). Feed intake had a significant difference (p < .05) in T3 versus T1. The feed‐conversion ratio improved for all periods in the T4 group (p < .05). The eosinophil, mononuclear infiltration and cytokines (tumor necrosis factor‐α and interleukin‐6) in the mucosa were lower for treatments with probiotics. In conclusion, there was an economic benefit when using both prebiotics and probiotics in the diet of pigs from weaning to finishing.

Evaluation of the Protection against Infectious Bursal Disease (IBD) Challenge in Progeny Born to Parents Having Received a Vaccination Program Using a Herpesvirus of Turkey-Infectious Bursal Disease (HVT-IBD) Vector Vaccine

Broiler breeder vaccination against IBD is usually based on the injection of at least one inactivated vaccine in oil adjuvant, typically included in a combined vaccine. Priming using one or several IBD vaccine (s) has been the most common way to immunize the breeders so far. In summary, protection against vvIBD challenge in chicks of one commercial genetic line vaccinated in ovo with the HVT-IBD vector vaccine was demonstrated. The parents’ IBD vaccination program, using the HVT-IBD vector vaccine alone, the HVT-IBD vector vaccine plus IBD inactivated vaccine, and inactivated IBD vaccine alone, did not impair their progeny’s in ovo HVT-IBD vector vaccine take and subsequent protection against vvIBD virus challenge. An advantage in terms of immunization of the progeny against vvIBD was shown in the chicks born to breeders vaccinated with the HVT-IBD vaccine as a primer, as compared to breeders vaccinated with the inactivated vaccine alone. High level of IBD maternally-derived antibodies transmitted to the progeny by their parents induces together with an early onset of immunity by in ovo injection of a HVT-IBD vector vaccine clinical protection, as monitored on bursas, after vvIBD virus challenge.

Análise do desempenho reprodutivo e do uso de energia elétrica em instalações climatizadas de cachaços

Objetivou-se, com este estudo, avaliar e comparar dois sistemas de climatização do ambiente com dezoito machos da linhagem genética comercial AG337, provenientes da empresa AGROCERES–PIC. Os animais do grupo A foram submetidos à climatização por meio de ventilação artificial e nebulização com acionamento automatizado enquanto os do grupo B foram submetidos apenas a ventilação, sendo o acionamento dos equipamentos feito de forma manual e de acordo com o manejo já praticado. Foram considerados aspectos de desempenho reprodutivo e conforto térmico dos animais, além das variáveis climáticas mensuradas no ambiente externo ao galpão e o uso de energia elétrica pelos equipamentos de climatização. Os principais resultados demonstraram que os animais do grupo A permaneceram em condição ambiental mais segura, porém não houve melhora nos índices de qualidade seminal dos animais deste grupo. Ressalta-se que o incremento de custo relativo ao aumento no consumo de energia elétrica, ocasionado pelo uso dos equipamentos de climatização e automação, não acarretará acréscimo significativo na conta de energia pois se trata de equipamentos de baixa demanda de energia elétrica.

Natural Infection and Transmission of a Retrovirus Closely Related to Myeloblastosis-Associated Virus Type 1 in Egg-Type Chickens

Myeloblastosis-associated virus type 1 (MAV-1) is an exogenous avian retrovirus with oncogenic potential. MAV-1 was detected in young chicks hatching from eggs produced by an experimental genetic line of egg-type chickens. Transmissibility of MAV-1 had not been documented previously. This investigation was intended to partially characterize the virus involved and to study its transmissibility and oncogenicity in naturally and contact-infected chickens. Commercially produced white and brown layer pullets free of exogenous avian leukosis viruses were commingled at hatch with naturally MAV-1-infected chickens. The original MAV-1-infected chickens were discarded after approximately 8 wk, and the contact-exposed chickens were maintained in isolation for 36 wk. Young specific-pathogen-free (SPF) single comb white leghorn chickens were added to the group to study possible horizontal transmission of MAV-1 in young chickens. Upon weekly virus isolation attempts, MAV-1 was readily isolated from the contact-exposed white layers but not from the brown layers between 36 and 53 wk of age (18 wk in total). Three-week-old SPF chickens were readily infected with MAV-1 by contact as early as 1 wk postexposure. Throughout 22 hatches derived from the white and brown MAV-1-contact-exposed layers (between 36 and 53 wk of age), MAV-1 was frequently detected in the white layer progeny, whereas the virus was seldom isolated from the progeny produced by the brown layers during the same 18-wk period. MAV-1 induced a persistent infection in some of the SPF chickens that were exposed by contact at 3 wk of age. Gross tumors were not detected in any of the originally infected experimental chickens at 8 wk of age, in the contact-exposed brown or white layers at the termination of the study at 53 wks of age, or in the contact-exposed SPF chickens at the end of the study at 12 wk of age. Exogenous avian leukosis-related viruses may still be detected in egg-type chickens, emphasizing the importance of thorough screening before incorporation of experimental genetic material into commercial genetic lines of egg-type chickens.

Herbal extracts and symbiotic mixture replacing antibiotics in piglets at the initial phase

The objective of this work was to evaluate the use of vegetable extract based addictives associated or not to symbiotics as an alternative for antibiotic as growth promoters for piglets at initial phase. It was used 125 pigs of commercial genetic line with initial weight of 7.4 ± 1.1 kg, weaned at 20 days of age, during 50 days. The experimental design used was randomized blocks (initial weight), with five treatments and five replicates with five animals per experimental unit. The experimental diets were a basal diet, without additive, and other four diets, one diet containing antibiotic (colistin + zinc oxide); diet with 0.3% of a symbiotic mixture; diet with 0.3% of a symbiotic mixture plus 0.05% of herbal mix (plant extracts and microencapsulated essential oils); and another diet with 0.3% of symbiotic mixture plus 0.1% of herbal mixture. It was observed that the use of the symbiotic mixture associated to 0.05% of herbal mixture showed positive results, similar to the ones obtained with diets containing antibiotics for the final weight, average weight gain, average daily feed intake and pH of stomach and diarrhea incidence. The use of symbiotics promoted smaller vilous:depth crypt ratio, except when associated to 0.1% of herbal mixture, which was similar to the diet without addictives. There was no differences in the feed conversion, coliform and lactobacillus count in the jejune and in the cecum and in the pH of cecum. The use of herbal mixture associated to symbiotic is a viable alternative for replacing the use of antibiotics as growth promoters for piglets in the initial phase. However, the concentration of the herbal mixture is an important factor to be considered.

Alimentação de porcas lactantes com dietas contendo silagem de grãos úmidos de milho e ácido fumárico

Estudou-se o efeito de dietas elaboradas com silagem de grãos úmidos de milho e ácido fumárico sobre os desempenhos de porcas lactantes e suas leitegadas. Foram utilizadas 20 porcas de genética comercial em um delineamento de blocos ao acaso com quatro tratamentos - dieta basal (DB), elaborada a cada 24h; DB + 0,3% de ácido fumárico - (AF); DB + 0,6% AF; e DB + 0,9% de AF, e cinco repetições. As dietas contendo ácido fumárico foram elaboradas a cada 48 horas. O consumo médio diário da dieta das porcas lactantes foi de 7,42kg de matéria natural e não houve diferença (P&gt;0,05) entre os tratamentos. A adição de 0,9% de ácido fumárico às dietas reduziu (P&lt;0,01) em 6% o pH do leite em relação à dieta-basal. A média de ganho diário e a média de peso dos leitões não diferiram (P&gt;0,05) entre os tratamentos. A adição de ácido fumárico às dietas não alterou os desempenhos de porcas lactantes e de suas leitegadas. A adição de ácido fumárico às dietas de lactação elaboradas com silagem de grãos úmidos de milho reduziu o pH do leite e aumentou a frequência de fezes normais dos leitões lactentes.

Epididymal lithiasis in Gallus gallus domesticus

A study on the occurrence of epididymal lithiasis (EL) in Gallus gallus domesticus of different breeds and from different geographical regions of Brazil was carried out. Forty breeding roosters were collected in the states Santa Catarina, São Paulo, Minas Gerais, Espírito Santo and Goiás, representing two specific pathogen free Leghorn lines (SPF), one commercial Leghorn layer breeder (Hy-Line) line, two commercial broiler breeder lines (Ross and Cobb), and two backyard chicken flocks. In commercial poultry breeders, EL was observed mainly after 55 weeks of age, and lithus resulted in lower fertility caused by inadequate maturation of spermatozoa and testicular atrophy, which evolved to more severe testicular dysfunction at 100 weeks of age. One hundred percent of the sampled roosters of the evaluated SPF lines presented epididymal lithiasis, which was also observed in all commercial genetic lines. The analysis of EL occurrence revealed no differences among regions and breeds: all regions and genetic lines presented epididymal calculi and the occurrence seemed higher in the more intensively-reared chickens. As for the backyard roosters, 50% presented calculi. Considering the occurrence of EL in the SPF flocks, its primary association with infectious bronchitis virus (IBV) infection was discarded, despite its contribution to fertility loss.

Growth and body nutrient deposition of two broiler commercial genetic lines

The objective of this work was to study growth and body nutrient deposition profiles of male and female Cobb and Ross broilers using Gompertz equations. A total number of 1,920 one- to 56-day-old broilers were used. A randomized experimental design in a factorial arrangement (2 strains x 2 sex), with 4 replicates of 120 birds each, was applied. Diets were formulated to supply the nutrient requirements recommended by the genetic companies. A sample of birds was weekly weighed and sacrificed after 24 hours fasting. Carcasses were defeathered and weighed again. The parameters of the Gompertz equation for body weight and its components (water, ashes, protein, and fat) were estimated. An interaction (p<0.05) between sex and breed was observed for mature weight (Wm) (kg), growth rate (b) (daily) and time at maximum growth rate (t*) (day) of body weight, and body water and ash. Cobb was presented earlier growth and body protein and ash deposition. Ross strain was superior in body water deposition.

National Pork Producers Council Maternal Line National Genetic Evaluation Program: A comparison of sow longevity and trait associations with sow longevity1

Data from the National Pork Producers Council Maternal Line National Genetic Evaluation Program were used to compare longevity of sows from 6 commercial genetic lines and to estimate the phenotypic associations of sow longevity with gilt backfat thickness, ADG, age at first farrowing, litter size at first farrowing, litter weight at first farrowing, average feed intake during lactation, and average backfat loss during lactation. The lines evaluated were American Diamond Genetics, Danbred North America, Dekalb-Monsanto DK44, Dekalb-Monsanto GPK347, Newsham Hybrids, and National Swine Registry. The data set contained information from 3,251 gilts, of which 17% had censored longevity records (sows lived longer than 6 parities). The line comparison was carried out by analyzing all lines simultaneously. Because the survival distribution functions differed among genetic lines, later analyses were carried out separately for each genetic line. All analyses were based on the non-parametric proportional hazard (Cox model). Dekalb-Monsanto GPK347 sows had a lower risk of being culled than sows from the other lines. Moreover, the shape of the survival distribution function of the Delkab-Monsanto GPK347 line was different from the other 5 lines. The Dekalb-Monsanto 347 line had lower culling rates because they had lower gilt reproductive failure before the first parity than gilts from the other lines. Within line, sows with lower feed intake and greater backfat loss during lactation had a shorter productive lifetime. Thus, producers should implement management practices having positive effects on sow lactation feed intake. Additionally, the swine genetics industry is challenged to simultaneously improve efficiency of gain of their terminal market pigs and to obtain high feed intake during lactation of their maternal lines for future improvement of sow longevity. Recording sow feed intake and backfat loss during lactation in nucleus and multiplication breeding herds should be considered. Between-line differences in this study indicate that it is possible to select for sow longevity, but more research is needed to determine the most efficient selection methods to improve sow longevity.

Mathematical Model to Compare Egg Production C

A segmented polynomial model was used on several egg production curves in an attempt to analyze the differences between the curves in a more descriptive manner. Production curves from different commercial and experimental genetic lines of layers were used. The parameters of the model include the age and level of peak production, rate of decrease in production after the peak and time between start and peak of production. These and other derived variables were compared between the curves using contrasts. The methodology used allowed an easier interpretation of the curves, and the detection of differences in sexual maturity, uniformity and peak of production. This work validates the segmented polynomial model for use in future research dealing with analysis of egg production curves.