Corriedale Lambs Research Articles

Confinamento e semiconfinamento de cordeiras em um sistema integrado de produção: impactos na produção, infecção por nematódeos gastrointestinais e em variáveis sanguíneas

ABSTRACT: This trial evaluated the production performance, gastrointestinal nematode infection (GIN), and selected blood analytes, in Corriedale lambs during the finishing phase in an integrated crop-livestock system (ICLS) with 2 stocking rates. Fifty-two Corriedale lambs were divided into 4 groups: a semi confinement system with a low stocking rate (T1) for 70 days; a semi confinement system with a high stocking rate (T2) for 70 days; confinement for 28 days, followed by semi confinement with a low stocking rate (T3) for 42 days; and confinement for 28 days, followed by semi confinement with a high stocking rate (T4) for 42 days. Body weight, dry matter intake, blood collection, and faecal analysis of nematode eggs were performed for each animal. The stocking rates did not influence body weight gain for the semiconfined lambs (T1 and T2) or for the confined/semiconfined lambs (T3 and T4). All treatments had lower EPG counts at the end of the experimental period. The nematode genera identified during the experiment trial were Haemonchus and Trichostrongylus. There were no significant differences (P > 0.05) for packed cell volume, total plasma protein, and eosinophil means between treatments. These results suggested that the confinement followed by semi confinement in an ICLS, was an option for lamb production during the finishing phase which could be useful in reducing GIN without affecting the production performance.

Eficiência produtiva e econômica na terminação de borregas de descarte reprodutivo com dietas de alto concentrado

ABSTRACT This study aimed to evaluate the performance of reproductive culled lambs kept in confinement, through weight gain, carcass yield, and the state of non-carcass components using two high concentrate diets (90%). One diet was formulated on the property compared to commercially available concentrate. The cost-benefits of each diet were analyzed and compared. We used 24 Corriedale lambs, aged 180 days weighing an average of 28 ± 4 kg. The animals were randomly separated into two groups: the commercial concentrate group (CC) which received 0.4% and 4% of their live weight in Tifton hay and commercial concentrate, respectively, and the property concentrate group (CP) received hay and a high-concentrate diet produced on the property (using whole grain corn as a base), in the same proportions. The study was conducted, for a period of 55 days, along with ten days of adaptation, until they reached 40 ± 2 kg body weight (BW). Animals in the property concentrate group achieved a higher average daily gain (0.232 kg/day), but there was no significant difference in carcass yield between the groups The weights of non-carcass components such as the liver, spleen, and kidneys with fat were higher in the concentrate group. The property concentrate group presented a net income of R$ 0.40, while the animals that received the commercial concentrate presented a negative income of R$ - 0.45, per day. Therefore, the use of a high-grain diet produced on the property under the conditions of this study allowed for better weight gain, and a better cost-benefit ratio.

Assessment of lamb meat quality in two cooking methods: Water bath versus oven cooking

This study investigated the influence of the cooking methods on lamb meat quality traits. Water bath (WB) vs. oven cooking (OC) was compared using commercial cuts known as T-bone and Leg steak (n = 20/treatment), sampled from feedlot-finished Corriedale lambs. All meat samples were analyzed for muscle area (MA) or cut size, final pH, color (L*, a*, b*), water-holding capacity (WHC), shear force (SF), cooking losses (evaporation (EL) and dripping (DL)), intramuscular lipid content (ILC), and myofibrillar fragmentation index (MFI). The associations between meat quality variables and cooking methods were studied by correlations, principal components (PCs), as well as factor analysis. There was no interaction between the cooking methods and the cuts (p > 0.05). Variables MFI and WHC were similar (p > 0.05); however, MA, L* , a* , pH, and SF were higher in Leg steak, whereas b* and ILC were higher in the T-bone cut (p < 0.05). Cooking loss variables (EL and DL) differed (p < 0.01) according to the cooking method. The multivariate approach showed that the first two PCs (PC1 and PC2) explained about 44% of the variability in lamb meat. Variables related to cut size (MA), tenderness (SF and MFI), and chemical composition (ILC) defined PC1 (24%), while variables EL and DL contributed to define PC2 (20%). The sum of EL and DL (total cooking losses – CL) was lower in the WB method for both cuts studied. Besides, EL was greater in OC, while DL was greater in WB, which may affect water loss and juiciness of lamb meat. Leg steak had higher MA, but lower ILC, and showed higher SF regardless of the cooking method used.

Therapeutic advantages of the combined use of closantel and moxidectin in lambs parasitized with resistant gastrointestinal nematodes

The serious widespread development of nematode resistance has motivated the use of combined anthelmintic formulations. However, the advantages/disadvantages of the combined use of anthelmintics require further scientific characterization. The goals of the current trial were a) to characterize the pharmacokinetics of closantel (CLO) and moxidectin (MXD) administered both subcutaneously (sc) and orally either separately or co-administered (CLO + MXD) to lambs; b) to compare the nematodicidal activity of both molecules given individually or co-administered to lambs infected with resistant nematodes. Seventy (70) Corriedale lambs naturally infected with multiple resistant gastrointestinal nematodes were involved in the pharmacokinetic and efficacy trials. The animals were allocated into six groups (n = 10) and treated with either CLO, MXD, or with the CLO + MXD combined formulation by both the oral and sc routes. Additionally, an untreated control group (n = 10) was included for the efficacy trial. The efficacy was estimated by the faecal egg count reduction test (FECRT). Higher systemic exposure of both CLO and MXD was observed after the sc compared to the oral administration in lambs. The combined administration of CLO + MXD did not markedly alter their disposition kinetics. At 13 days post-treatment, the administration of both molecules as a single active principle reached efficacy levels ranging between 80% (MXDoral), 84% (CLOoral), 85% (CLOsc), and 92% (MXDsc). The combined oral and sc treatments reached 99% efficacy. No adverse effects were observed after the combined treatment of CLO + MXD, and their co-administration did not show any adverse pharmacokinetic interaction. The combined effect of CLO + MXD successfully restored the maximum efficacy levels, which were not reached by the individual active ingredients.

SNP associations and genetic-parameter estimation for nose and hoof pigmentation in Corriedale sheep

Context Quantity and quality of both meat and wool are important for selection programs of the dual-purpose Corriedale sheep. In Corriedales, black pigmentation of nose skin and hooves is preferred as part of the breed standard. However, within the breed, pigmentation can vary from none to complete pigmentation. Aims The aim was to discover single-nucleotide polymorphisms (SNPs) and genes associated with nose and hoof pigmentation and to estimate genetic parameters of nose and hoof pigmentation, wool traits and meat traits. Methods The phenotype and genotype data on Corriedale lambs (n = 764) produced from 44 sires (12 studs) and 300 ewes in 2017–2019 were used in this study. Lambs were slaughtered at 6–7 months of age. Nose pigmentation and hoof pigmentation were scored on a five-point scale, where no pigmentation was scored 0 and complete pigmentation was scored 5. Wool- and meat-quality traits were measured, including greasy fleece weight, fibre diameter, weaning weight, hot standard carcass weight and intramuscular fat percentage. The lambs were genotyped with the GGPOvine50K SNP chip. A genome-wide association study (GWAS) was conducted. Genetic parameters and bivariate analyses were estimated using ASReml-R. Results The lambs had a mean nose-pigmentation score of 3.69 and hoof-pigmentation score of 4.12. The nose pigmentation (h2 = 0.58) and hoof pigmentation (h2 = 0.51) were highly heritable and highly correlated (rG = 0.73). The GWAS identified a genome-wide significant SNP (OAR19_33278780.1) associated with nose pigmentation (q-value = 0.04). This SNP is positioned in a known pigmentation gene, melanocyte-inducing transcription factor (MITF). The same SNP was the sixth-most associated SNP for hoof pigmentation but did not reach significance level. OAR19_33278780.1 also had a significant effect on back conformation and weaning weight. Conclusions The results of these analyses have provided information and an understanding of the genetics for pigmentation of nose and hooves in Corriedale sheep. Implications Nose and hoof pigmentation are highly genetically correlated with each other, but with no negative effects on production traits.

PSIII-A-10 Effect of Grain Type and wet-Aging Time on Lamb Meat

Abstract Visual appearance is critical for the consumer perception of meat quality. Color, as well as juiciness are key factors in determining consumer choice. The objective of this study was to evaluate the effect of grain type and different wet-aging periods on lamb meat. Eighteen castrated Merino x Corriedale lambs (± 40 kg) were randomly assigned to three dietary treatments: 60% corn grain (CG), 60% oats grain (OG) or all fescue hay (Control); diets were isonitrogenous (13% CP). After slaughter, pieces of Longissimus thoracis muscle from each animal were aged during 1, 4, 8 and 16 d. Treatments were arranged as a 3x4 factorial experiment, and color and water-holding variables were measured. No interactions were found (p &amp;gt; 0.05) between type of grain and aging time. Meat from CG showed the highest values for lightness, redness and yellowness (p= 0.0240, 0.0119, 0.0077, respectively), while meat from OG had the lowest values for redness and yellowness. Expressible juice was lowest (p= 0.0307) for Control, intermediate for CG and higher for OG. Meat cooking loss (p= 0.0157) resulted highest for Control, intermediate for OG and lowest for CG. Cooking loss, drip loss (48h) and expressible juice showed differences among aging periods (p= 0.002, 0.0001, 0.0015, respectively); the highest loss was found for 1d-aging, but no differences were detected for the other aging periods. The effect of aging period was greater than type of grain for cooking loss (F: 7.82, 4.48) and expressible juice (F: 5.88, 3.71) respectively. Purge-thaw loss showed no differences for diet type (p &amp;gt; 0.16) or aging period (p &amp;gt; 0.11). A more intense color developed by CG than OG might favor consumer perception of meat quality. Additionally, water-loss seems to be independent of these diets, showing that a longer aging period would be more relevant to get juicier lamb meat.

Comparative evaluation of different animal models for genetic analysis of body weight traits in an organized Corriedale sheep population

The present study aimed to evaluate different animal models for their appropriateness to best fit the body weight data of Corriedale lambs at different ages and reared under temperate conditions. Data used in this study consisted of 24,907 body weight records on a total of 6162 lambs of Corriedale sheep population. The data pertained to body weight traits at different ages i.e., at birth (BW), weaning (WW), six months (SW), nine months (NW) and yearling age (YW). The (co)variance components of five traits were estimated using univariate analysis based on restricted maximum likelihood (REML) algorithm in WOMBAT program. Six different univariate animal models, with or without maternal genetic effect, maternal permanent environment effect and covariance between additive genetic and maternal genetic effects, were fitted on the body weight data of the Corriedale sheep population. All univariate animal models incorporated season (winter, spring) and period of lambing (8 periods, each of 5-year duration), and sex of lamb (male, female) as fixed effects. AIC, Log-likelihood and likelihood ratio test results were used to evaluate the best fit models for body weights at different ages. Model I, incorporating additive genetic effect of the individual as random effect, showed the minimum AIC estimate for BW. Model III showed the minimum AIC values for all other traits under consideration i.e., WW, SW, NW and YW. The direct additive genetic heritability for birth weight was 0.025 under the best fit model i.e., model I. The direct heritability estimates for WW, SW, NW and YW were 0.151, 0.216, 0.103 and 0.132, respectively under the best-fit models. Maternal genetic heritability ranged from 0.043 to 0.087 for different body weights, except BW for which model I was the best-fit. Most of the covariance and correlation estimates between direct additive genetic and maternal genetic effects were negative. Low estimates of heritability found in best-fit models in this research are suggestive of the less appropriateness of applying individual selection for this population as it may only result in slow progress for body weight traits in Corriedale sheep. Environmental factors played a significant role in generating the variation in body weight traits in Corriedale sheep.

ABC-transporter gene expression in ivermectin-susceptible and resistant Haemonchus contortus isolates

Mammalian efflux transporters of the ATP-binding cassette (ABC) regulate cellular levels of endo- and xenobiotics by transporting molecules across cell membranes and are involved in diverse biological processes. Over-expression of these ABC transporters has been involved in macrocyclic lactone resistance. The main goal of this work was to compare the gene expression of the whole ABC-transporter superfamily in isolates of the sheep nematode Haemonchus contortus with different degrees of susceptibility to ivermectin (IVM). Additionally, the effects of in vivo IVM treatment were evaluated in the resistant isolates. Parasite-free Corriedale lambs were artificially infected with either IVM-susceptible or IVM-resistant H. contortus isolates. The differential expression of ABC transcripts in H. contortus female worms with differential susceptibility to IVM were assessed by RNA-seq. Additionally, the transcription levels of ABC-transporter genes in IVM-resistant adult worms recovered from treated sheep at 12 and 24 h after IVM administration were compared to those of IVM-R worms collected from untreated sheep. The comparative analysis of the ABC-transcripts revealed some minor differences in the expression levels of HCON_00042800 (pgp-3), HCON_00020200.mod (ced-7c), HCON_00085890 (abt-4), HCON_00063000 (pmp-5) and HCON_00116670 (wht-8), indicating that, at transcriptional level, these ABC-genes alone cannot explain resistance in H. contortus. HCON_00130060 (pgp-9.2) was highly differentially expressed in resistant isolates compared to susceptible ones, which agrees with previous reports suggesting that pgp-9 may be one of the most relevant candidates contributing to the multi-genic nature of the IVM resistance trait.

Efecto de la deficiencia subclínica de zinc en corderos sobre retención de nitrógeno, parámetros productivos y hematológicos

The objective of this trial was to study the effect of subclinical zinc (Zn) deficiency in lambs on productive variables, nitrogen (N) balance and hematological parameters. Ten Corriedale lambs, with an average weight of 10.09 kg, were randomly assigned to two groups: Basal (B, 10 ppm Zn) and Supplemented with 30 ppm Zn (Z). The trial lasted 20 weeks. The animals were weighed every 4 weeks. Also with this periodicity, they were bled by jugular venipuncture. In weeks 6 and 20 the apparent dry matter digestibility (ADMD) and N balance were evaluated. At the end of the test the wool production and quality were measured.The weight gain and wool quality were similar in both groups, while wool production was 37.4% higher in group Z. According to the first balance period, ADMD was similar in both groups, but the retention of N was significantly higher in group Z than in group B (5.53 vs 4.03 g/day). In the second balance period there was a similar trend. There were no differencies between groups on hematocrit, hemoglobin concentration, red blood cells, total leukocytes, lymphocytes andneutrophils number. These results suggest that subclinical Zn deficiency reduces wool production, which may be related to lower protein synthesis.synthesis.

Dietary carnosic acid and seleno-compounds change concentrations of fatty acids, cholesterol, tocopherols and malondialdehyde in fat and heart of lambs.

The aim of the current study was to evaluate the impact of carnosic acid (CA), selenised yeast (YSe) and selenate (VISe) supplemented to diets, including fish oil (FO) and rapeseed oil (RO), on the content of fatty acids, total cholesterol (TCh), tocopherols and malondialdehyde in the fat located between the thigh muscles and the heart in lambs. Twenty-four male Corriedale lambs were divided into 4 groups of 6 animals. Animals were fed a diet with FO and RO (the control diet) or experimental diets containing RO, FO and CA with/without Se (as YSe or VISe). The experimental diets without/with YSe or VISe changed concentrations of fatty acids in the fat and heart compared to the control. All experimental diets increased the levels of c11c14C20:2, c5c8c11c14C20:4, c5c8c11c14c17C20:5 and the sums of long-chain polyunsaturated fatty acids (LPUFA) and conjugated linoleic acid isomers in the fat compared to the control. The experimental diet containing YSe or VISe increased the content of Se, TCh, c11c14C20:2, c8c11c14C20:3, c5c8c11c14C20:4, c5c8c11c14c17C20:5, c7c10c13c16c19C22:5, c4c7c10c13c16c19C22:6 and the concentration sum of n-3LPUFA, n-6LPUFA and tocopherols in the heart in comparison with the control diet and the diet containing only CA. Experimental diets reduced the concentration of malondialdehyde in the fat and heart in comparison with the control diet. Our dietary intervention has great potential for future practical and commercial implementations.

Evaluation of protection in grazing lambs immunised with different doses of Haemonchus contortus gut membrane glycoproteins in Southern Brazil

A vaccine containing doses ranging from 2 μg to 50 μg of integral membrane proteins from Haemonchus contortus intestinal cells (H11 and H-gal-GP complex) has been shown to be effective for lambs. A vaccine for H. contortus was tested in two-month old grazing Corriedale lambs during an eight-month trial on the outskirts of Bagé, Rio Grande do Sul, Brazil. The animals were kept in a single paddock and allocated to five similar groups according to weight, sex and faecal egg counts (FEC). Vaccinated lambs received 0, 2, 5, 10 or 50 μg of the same antigen diluted in QuilA adjuvant. Vaccine injections were given at days 0, 21, 49, 91, 133, and 175. Lambs were sampled weekly for FEC, packed cell volume (PCV), and plasma ELISA antibody titre. Lambs with PCVs ≤15 % were drenched with levamisole (7.5 mg/kg body weight) as a salvage treatment. During days 77–98 an artificial challenge was administered to increase parasite transmission. Post-artificial challenge (from day 98–217), the FEC of the vaccinated lambs were 59.3 % lower than those of the control lambs. Antigen dose correlated with changes in PCV (r = 0.387 p-value < 0.001). Vaccinated lambs also had higher PCV than controls (p < 0.001; contrast analysis). Salvage treatment was needed in 16.7 % of vaccinated lambs and 88 % of control lambs.

Protein requirements for maintenance and growth of Corriedale lambs

The protein requirements of lambs for growth and fiber production can be breed specific. The Corriedale is a dual-purpose lamb breed, suitable for fleece and meat production; however, there is no information regarding the specific protein requirements for its growth and maintenance. In this study, we aimed to determine the protein requirements of castrated Corriedale lambs for maintenance, weight gain, and wool growth. Purebred Corriedale lambs with average body weights (BW) of 28, 33, and 38 kg were distributed into three respective trial groups. Their requirements of net protein for maintenance (NPm), metabolizable protein for maintenance (MPm), net protein for weight gain (NPg), net protein for wool growth (NPw), metabolizable protein for weight gain (MPg), metabolizable protein for wool growth (MPw), and their efficiencies for metabolizable protein use were determined. The NPm and MPm of the Corriedale lambs with 28–38 kg BW were 1.44 ± 0.58 g/d/kg0.75 and 3.07 ± 1.28 g/d/kg0.75 of their fasting BW, respectively, and the MP efficiency use for maintenance was 0.47. The NPg and NPw increased with the lambs’ weight gain (from 100 to 250 g/day) and ranged from 9.53 ± 0.001–21.8 ± 0.003 and 7.13 ± 0.038–24.4 ± 0.079 g/d, respectively, in the lambs with 28–38 kg BW. The partial MP efficiencies for the maintenance use of a fleece-free body and wool protein retention were 0.72 and 0.27, respectively. The MPg and MPw ranged from 13.2 ± 0.002–30.3 ± 0.004 g/d and 26.4 ± 0.14–90.4 ± 0.29 g/d, respectively, in the lambs with 28–38 kg BW and an average daily weight gain of 100–250 g. The findings of this study can help feeding systems to improve their protein requirement recommendations for Corriedale sheep in the future.

Feed conversion efficiency in sheep genetically selected for resistance to gastrointestinal nematodes

Context It has been indicated that there might be an antagonism between selection for gastrointestinal nematode resistance and high productivity and feed conversion efficiency in ruminants. Aims This study aimed to determine whether genetic selection for resistance to gastrointestinal nematodes would alter the feed intake and feed efficiency of sheep with or without an infection of Haemonchus contortus. Methods Sixty-seven Corriedale lambs (357 ± 14 days old) derived from flocks genetically selected to be resistant (n= 29) or susceptible (n = 38) to gastrointestinal nematodes (GIN) were evaluated for individual dry-matter intake (DMI), feed conversion ratio (FCR) and residual feed intake (RFI). Considering bodyweight (BW), GIN line and sires, males were allotted to one of three outdoor pens and females to one of two, each pen being equipped with five automated feeding systems and two automatic weighing platforms to record individual feed intake and BW. Feed (lucerne haylage, crude protein 20.5%, metabolisable energy 9.2 MJ/kg DM) and water were offered ad libitum. The experiment was conducted in two periods. First, animals were maintained worm-free (14 days of acclimatisation and 44 days of records) and then, in Period 2 (42 days), animals were artificially infected with 6000 L3 of Haemonchus contortus. Worm egg counts were recorded on Days 9, 23, 27, 30, 42 post-infection. While DMI, FCR, average daily gain and BW were analysed using a generalised linear model including dams age, pen and GIN line as fixed effects, RFI was analysed including only GIN line. Key results In both periods, GIN line did not have a significant (P &gt; 0.05) effect on DMI, FCR, RFI, average daily gain or BW. Worm egg count was different (P &lt; 0.05) on Day 23 post-infection (Period 2), being higher in susceptible line. Conclusions The most important finding of this study is that breeding GIN-resistant animals would not have a negative effect on feed conversion efficiency when evaluated as FCR or RFI in 1-year old lambs fed ad libitum with a high-protein diet. Implications Breeding for resistance to internal nematodes does not affect feed efficiency or productivity.

Single nucleotide polymorphisms from candidate genes associated with nematode resistance and resilience in Corriedale and Pampinta sheep in Argentina.

Selective breeding of genetically resistant animals is considered a promising strategy to face the problem of nematode resistance to anthelmintics and mitigate concerns about the presence of chemical residues in animal food products and the environment. Gastrointestinal nematode resistance is a complex, multifactorial trait related to host immunity. However, the mechanisms underlying host resistance and response to infection remain to be fully elucidated. In this context, the objective of this study was to provide insight into the chromosomal regions determining nematode resistance and resilience in Corriedale and resistance in Pampinta sheep breeds. A total of 170 single nucleotide polymorphisms (SNP) from 76 candidate genes for immune response were studied in 624 Corriedale and 304 Pampinta animals. Lambs underwent artificial or natural challenges with infective larvae mainly from Haemonchus contortus. Fecal egg counts, estimated breeding values for fecal egg counts, and rate of packed cell volume change and FAMACHA© score change over the challenge were used, when available, as indicators of host parasite resistance or resilience. Phenotype-genotype association studies were conducted and significance values obtained were adjusted for multiple testing errors. Eight SNPs, located on OARs 3, 6, 12, and 20, reached significance in Corriedale sheep under artificial challenge. Those SNP represent allelic variants from the MHC-Ovine Lymphocyte Antigen-DRA, two C-type lectin domain families, the Interleukin 2 receptor β, the Toll-like receptor 10, the Mannan binding lectin serine peptidase 2, and the NLR family, CARD domain containing 4 genes. On Pampinta lambs under natural challenge, we found three significant SNPs, located in the TIMP metallopeptidase inhibitor 3, the FBJ murine osteosarcoma viral oncogene homolog, and the Interleukin 20 receptor alpha genes, on OARs 3, 7, and 8, respectively. The results obtained herein confirm genomic regions previously reported as associated with nematode resistance in other sheep breeds, reinforcing their role in host response to parasites. These findings contribute to gain knowledge on parasite resistance and resilience in Corriedale sheep and report for the first time SNPs associated with resistance to gastrointestinal parasite infections in Pampinta breed.

Photovoltaic panels as shading resources for livestock

Based on our search, we believe that this is the first paper to evaluate the use of photovoltaic panels as shade resources for livestock. Photovoltaic panels can provide artificial shades to protect livestock against intense solar radiation while serving as a clean energy source, reducing CO2 emission, and providing an additional source of income to farmers. These benefits foster sustainable livestock farming practices. In this study, we (1) determined livestock shade preference for photovoltaic panels and the classical 80%-blockage cloth material, and (2) quantified the reduction in radiant heat load provided by these shade structures. To determine the shade preference, the behavior of five Corriedale lambs and six Corriedale ewes were observed in a paddock with two shade structures (one with photovoltaic panels and another with an 80%-blockage cloth). The following behavioral activities were determined using the instantaneous scan sampling method each 10-min from 07:00 h to 17:00 h: grazing, ruminating, idling, lying, standing, under the sun, under the shade from photovoltaic panels, and under the shade from cloth. To correlate animal behavior with environmental conditions and to quantify the reduction in radiant heat load provided by these shade structures, the following meteorological variables were recorded: solar radiation (total and short-wave), air temperature, relative humidity, wind speed, and black-globe temperature (in the shades and in the sun). We observed that the animals spent less than 1% of their time under the shade from cloth compared to 38% under the shade from photovoltaic panels and 61% exposed to the sun. Sheep preference for shade projected by photovoltaic panels might be explained by the reduced radiant heat load (approximately lower by 40 W m−2) compared to that from the cloth. When the intensity of solar radiation increased from 250 to 850 W m−2, the time the animals spent outside the shades decreased from 96.7 ± 3.6% to 30.2 ± 6.3%, which was coupled with a similar increase in the time spent in the shade from photovoltaic panels (from 13.0 ± 3.3% to 69.3 ± 6.2%). For the same increase in solar radiation, the energy generated (integrated over 5-min) by the photovoltaic panels increased from 38.8 ± 5.9 to 197.9 ± 3.8 kWh. Over a period of one year, an electric energy of 5.19 MWh (monthly average of 432.33 kWh) was generated and 2.77 tons of CO2 were not emitted to the atmosphere. In economic terms, the electric energy generated in one year was equivalent to a saving of $740.

Não constituintes da carcaça de cordeiros em distintas condições sexuais

Resumo O estudo foi realizado com objetivo de avaliar os efeitos da condição sexual nos pesos e rendimentos dos não constituintes da carcaça de cordeiros cruza Texel x Corriedale. Foram utilizados 46 machos divididos em três grupos: não castrados (n=15), castrados (n=17) e induzidos ao criptorquidismo (n=14). Foi adotado o delineamento experimental inteiramente casualizado com três tratamentos e número variável de repetições. Foi realizada análise de variância para avaliar o efeito da condição sexual sobre as características estudadas. Cordeiros castrados atingiram as condições estipuladas para o abate mais precocemente. Não castrados e induzidos ao criptorquidismo apresentaram pesos superiores de cabeça (kg), pele (kg), pênis (kg) e fígado com vesícula (kg). Não castrados apresentaram valores Como citar - disponível no site, superiores do conjunto pulmões com traqueia (kg) em relação na página do artigo. a animais castrados. Conclui-se que cordeiros não castrados e induzidos ao criptorquidismo apresentam pesos superiores de alguns componentes corporais quando terminados em campo nativo recebendo suplementação de 1% do peso corporal. Proporcionalmente, a condição sexual não interfere nos rendimentos dos componentes corporais de cordeiros Texel x Corriedale.

Body mass index, energy reserves, and tissue composition of cuts of Corriedale lambs

Abstract: The objective of this work was to identify relationships of the body mass index (BMI) with the body energy reserves and tissue composition of shoulder and leg cuts of Corriedale lambs. Twenty-two sheep with average age of 18 months were used. Linear regressions were determined between the studied characteristics. The mean body mass, body condition score (BCS), and BMI were 49.09±7.8 kg, 2.69±0.81, and 10.66±0.99, respectively. The BMI was correlated with the BCS (r = 0.51) and internal fat (r = 0.81). Multiple linear equations, involving BMI and BCS, yielded correlation coefficients between 0.50 and 0.76, with significant values for all studied characteristics. The body mass index allows estimating the body energy reserves of Corriedale sheep.

Efficacy of antiparasitic drugs in control of gastrointestinal helminthiasis in naturally colored and white lambs from southern Brazil

Parasitic infections and the efficiency of different drugs were evaluated considering efficacy percentages, reduction in count of eggs per gram of feces (EPG) and larval culture in 60, 30 white and 30 naturally colored Corriedale lambs. Each phenotypic group was subdivided into six groups of five animals, each of which was administered one of the active ingredients: albendazole, levamisole hydrochloride, dysophenol, nitroxynil and moxidectin, in addition to a control group, unmedicated. Helminths were considered susceptible to nitroxinil and resistant to albendazole, levamisole, moxidectin (moderately effective) and to dysophenol (insufficiently active). In the culture of larvae, levamisole, nitroxinil and moxidectin were totally efficient (100%) against Oesophagostomum spp., moxidectin was totally efficient against Trichostrongylus spp. and nitroxinil was efficient (97%) against Haemonchus spp. Evaluating the EPG means of the phenotypic groups, it was observed higher parasitic infections in white ewes (p&lt;0.05), in pre- and post-treatment. Therefore, it was concluded that the drug nitroxinil was the only effective for the reduction of the total parasite load of both phenotypic groups, being indicated for use in the herd in question. The genus Haemonchus spp. was the most prevalent and resistant to the drug action. Naturally colored Corriedale lambs, from the herd, showed increased resistance to gastrointestinal nematode infections.

Collagen, glycosaminoglycans and matrix metalloproteinase-2 and metalloproteinase-9 in the cervix of the ewe during prepubertal development.

The tortuous nature of the ovine cervix restricts the transcervical passage of the cannula, and many studies have aimed to understand the endocrine mechanism of the remodelling of cervical tissue in adult ewe. However, little is known about the remodelling of the cervical tissue during the prepubertal development of the lambs. To obtain histochemical and biochemical evidence about the nature of the prepubertal development of the cervix of the ewe, cervices of Corriedale lambs obtained at 0, 1, 2, 4, 6 and 8months of age (n=5 to 6 in each) were processed. Neutral and acidic glycosaminoglycans (by PAS-Alcian stain) were weakly in the cervical stroma and not shown change during the development, whereas the percentage volume of fibrillar collagen (by van Gieson stain) increases throughout the experimental period in the superficial fold stroma and deep wall stroma (p<0.05). The relative cervical weight (g/kg of body weight) and the collagen concentration (by spectrophotometry, mg/mg wet tissue) showed an early decreasing phase from months 0 to 4 and a later increasing phase from months 4 to 8 (p<0.05). The latent form of matrix metalloproteinase-2 (MMP-2) detected by gelatin zymography (ng/mg protein) decreased from months 0 to 2 and increased from months 4 to 8, whereas the activated form decreased from months 0 to 2, remained low until month 6 and then recovered on month 8 (p<0.0001). Data suggest that the relative cervical weight biphasic pattern during the development is related to MMP-2-dependent changes in the collagen content.

Effects of sire genotype on lamb performance at weaning in extensive sheep systems

A low finishing weight and poor carcass characteristics are major causes of lower incomes in extensive sheep flocks; however, the use of terminal sire crossbreeding would improve lamb performance and carcass traits under these conditions. The aim of this study was to evaluate sire breed effects on the performance of lambs born to Corriedale ewes in extensive sheep systems in Western Patagonia. A total of 10 Corriedale, 10 Dorset, nine Suffolk and seven Texel sires, 16 of which were under a genetic recorded scheme and 20 selected from flocks not participating in genetic improvement programmes, were used across six commercial farms for 2 successive years. Data were collected from 685 lambs of the four resulting genotypes. Overall, Corriedale lambs were 0.47 kg lighter at birth than crossbred lambs (P<0.001). Suffolk and Texel sired lambs required more assistance (P<0.01) at birth than Corriedale or Dorset sired lambs, with Suffolk sired lambs requiring the most assistance (8%). Ewes sired with Suffolk rams had larger (P<0.05) litters than ewes sired with Texel or Corriedale rams. Lamb live weight gain from birth to weaning was higher (P<0.001) in crossbred lambs compared with Corriedale lambs, therefore, crossbred lambs averaged 2.9 kg heavier BW (P<0.001) than Corriedale lambs. A significant sire breed x sire source interaction was detected for lamb live weight gain (P<0.05) and lamb live weight at weaning (P<0.01), showing that the heaviest lambs were from recorded sires, except for Suffolk crossbred lambs. Mortality rate to weaning was increased (P<0.05) in Suffolk cross lambs (31%), with Corriedale lambs showing the lowest (17%) mortality. Terminal sire breeds increased (P<0.001) cold carcass weight, with 13.8, 16.0, 15.2 and 14.9 kg for the Corriedale, Dorset, Suffolk and Texel sired lambs, respectively. Carcass length, kidney knob and channel fat, fat grade, grade rule and fat depth measurements were not affected by sire breed (P>0.05). Carcass conformation was higher in Texel sired lambs compared with Corriedale lambs (P<0.05), with Dorset and Suffolk sired lambs being intermediate. Crossbred lambs showed a greater (P<0.001) eye muscle than Corriedale. Commercial cuts were affected by sire breed, as a result of the Corriedale lambs being smaller and having lighter carcass than crossbred lambs. Significant improvement in lamb weights at weaning and carcass traits could be expected when using a terminal sire on Corriedale ewes in Western Patagonia. However, no advantages were detected with the use of recorded sires under these production systems.