Cláudio José Araújo da Silva

Adição de plasma seminal ao sêmen descongelado e taxa de prenhez de ovelhas inseminadas em tempo fixo

The effect of seminal plasma addition to thawed-frozen ram semen on the pregnancy rate of commercial herd ewes was evaluated. One hundred and seventy-four crossbred Texel sheep were allocated to four treatments: T1) cervical artificial insemination (CAI) using frozen-thawed semen (FTS) diluted in phosphate buffered saline solution (PBS); T2) CAI using FTS diluted in ovine seminal plasma; T3) control group I: CAI using fresh semen diluted in PBS; T4) control group II: laparoscopic insemination using FTS diluted in PBS. Estrus induction was performed with medroxiprogesterone acetate (MAP) impregnated sponges for 12 days, followed by intramuscular injection of 400 IU of eCG (Novormon®) and 37.5µg of sodium cloprostenol (Sincrocio®) on the day of sponge removal. Estrus was monitorated with vasectomized rams, beginning at the time of the sponge removal until the fixed time artificial insemination - 54 to 60 hours. The pregnancy rate of FTS diluted in seminal plasma treatment (7.0%) did not differ (P>0.05) for the treatment without addition of seminal plasma (4.3%), however it was lower (P<0.05) when compared to the pregnancy rate of the cervical inseminated control I group with PBS diluted fresh semen (50.0%) and laparoscopic inseminated control group II with PBS diluted FTS (39.4%). The cervical artificial insemination with the addition of seminal plasma to frozen-thawed semen did not increase the pregnancy rate at acceptable values to make this biotechnology useful on commercial herds.

Early weaning and concentrate supplementation on the performance and metabolic profile of grazing lambs

This study was designed to investigate the effect of early weaning and concentrate supplementation on performance and metabolic profile of lambs in four production systems on pasture: suckling lambs not supplemented until slaughter; suckling lambs supplemented with concentrate in creep feeding until slaughter; early weaned lambs not supplemented until slaughter; early weaned lambs supplemented with concentrate until slaughter. Performance was assessed by average daily gain (ADG) and body condition score (BCS) measurements. Metabolic profile was delineated by measuring serum albumin, urea, creatinine, cholesterol, glucose and aspartate aminotransferase. Weaning reduced ADG by 92 g/d and the ADG for weaned and suckling lambs were 113 g/d and 205 g/d, respectively. Supplementation increased ADG by 117 g/d and the ADG was 99 g/d for non-supplemented and 216 g/d for supplemented lambs. Body weight and BCS at the end of trial were lower in weaned and non-supplemented animals (20.7 kg and 1.5 points), and higher in those on creep feeding (35.3 kg and 3.3 points). Weaning decreased serum levels of albumin, cholesterol and aspartate aminotransferase. Supplementation increased serum albumin and decreased serum aspartate aminotransferase. Serum urea was not affected by weaning or supplementation and remained high during the trial. Serum creatinine and glucose were lower in weaned and non-supplemented lambs. Early weaning generates unsuitable metabolic profile and low performance and may not be recommended as single strategy to produce lambs on pasture. Concentrate supplementation has similar response to suckling on the performance and metabolic profile of animals, and may be considered an efficient strategy to improve the nutritional status of early weaned lambs.

Método FAMACHA para detectar anemia clínica causada por Haemonchus contortus em cordeiros lactentes e ovelhas em lactação

The control of gastrointestinal parasites in small ruminants has traditionally involved the indiscriminate use of anthelmintic drugs that resulted in a high parasite selection pressure for anthelmintic resistance. Selective methods (ex.: FAMACHA/FMC and faecal egg count/EPG), which have good sensitivity to identify animals that need drug treatment, are important alternative methods for parasite control. The objective of this study was to determine the sensitivity and specificity of the FMC method to detect clinical anemia caused by Haemonchus contortus in two highly susceptible categories of Suffolk sheep; suckling lambs and lactating ewes. The ocular conjunctivae of 42 suckling lambs and 35 lactating ewes were evaluated using the FMC method at 14 days interval for five months. Hematocrit (Ht) served as the gold standard for anemia evaluation. To calculate the sensitivity and specificity of the FMC method, different criteria were adopted: animals classified as 4 and 5, or 3, 4 and 5, were considered to be anemic (positive test), and animals classified as 1, 2 and 3, or 1 and 2 were considered to be non-anemic (negative test). Three standard values of Ht (≤22%, ≤19% or ≤15%) were used to confirm anemia. Among the prevalent genera of helminths H. contortus (61.5%) and Ostertagia sp. (21.3%) were the most predominant species in the coproculture. For both categories, the inclusion of FMC 3 as a positive test increased the sensitivity but decreased the specificity of the method. When FMC 3 was included as anemic, the percentage of false negative was close to zero, but a greater number of treatments were applied to non-anemic animals (false positive). Most of the lambs (73%) and ewes (57%) remained in categories 1 or 2 throughout the trial. Only 5% of the lambs and 8% of the ewes were classified as the two major stages of anemia (4 and 5). The results indicate that the FMC is a safe method to be used in lambs and lactating ewes with clinical anemia from H. contortusinfection. For both categories, it was necessary to include FMC 3 as a positive condition to increase the sensitivity of the method and to reduce the risk of death of undiagnosed anemic animals (false negatives).

Electronic and visual identification devices for adult goats reared in semi-intensive system

This study intended to evaluate three identification devices for adult goats reared in semi-intensive system. They were (1) the ruminal bolus, electronic identification device composed of non-toxic ceramic and weighing 74.4 g; (2) small ear tag on left ear, visual identification device with dimensions of 50 × 15mm; and (3) big ear tag on right ear, also a visual identification device with dimensions of 42 × 48 mm. Twenty-two crossbred Boer female goats with mean age of 4 years and mean body weight (BW) of 52.6 kg were used. The identification devices were applied on all animals. Time spent for administration/application, readability and retention rate of devices were assessed. Problems during and after the application of devices, as well as device losses were recorded. Evaluations were performed one day and one week after application, then, monthly, for six months. The time spent for administration/application of the devices showed mean of 21 s and was similar between the evaluated devices. One big ear tag was lost, which decreased the retention rate of this device to 95.5%. The other devices showed retention rate of 100%. The readability was 100% for all studied devices. Small ear tags and ruminal boluses used in this study are recommended for adult goats. Production systems, environment, and ear tags with large dimensions may affect the retention rates of these visual identification devices.

Moxidectin residues in tissues of lambs submitted to three endoparasite control programs

The indiscriminate and continuous use of anthelmintic drugs has promoted the selection of resistant parasites population, the presence of drug residues in food products, and heavy environmental contamination. The aim of the present study was to determine the presence of antiparasitic drug residues in 42-days old lamb serum and tissues, submitted to three endoparasite control programs: preventive treatment (PT) using moxidectin (MOX) at every 28days; selective treatment (FEC) using MOX when fecal egg count was greater than or equal to 700; and selective treatment (FMC), using MOX when FAMACHA/FMC score was 3 and above. For this purpose, MOX residues were quantified in serum, muscle, fat, liver and kidney. Lambs were slaughtered when reaching 30kg of body weight, and after a 28-day MOX withdrawal period. Before slaughter, blood was collected to determine the concentration of MOX in serum. Tissues and organ samples were collected at slaughter. The quantitation of MOX residues was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS). From the 756 tissue samples analyzed, only one sample of fat from the PT group showed residue levels (586.3μg/kg) above the maximum residue limit (MRL) of 500μg/kg. No treated lambs presented traces of MOX residues in fat and liver, suggesting possible environmental contamination. In conclusion, all weaned lambs, produced in continuous grazing and subjected to gastrointestinal parasite control programs via selective (FEC and FMC) or preventive (PT) treatment, displayed a low risk (<1%) of MOX residues above the MRL in muscle, fat, kidney, and liver.

Electronic bolus design impacts on administration

Electronic identification of animals has become increasingly important worldwide to improve and ensure traceability. In warm and hot climates, such as Brazil, boluses can have advantages over ear tags as the internal devices reduce the risks of ear tag losses, tissue damage, and lesions on the ear. Electronic boluses, however, are often perceived as having negative characteristics, including reported difficulties of administration in small ruminants. This paper describes the factors associated with bolus design that affect the swallowing of a bolus in sheep. Other factors that might influence bolus swallowing time have also been considered. In addition, the effect of bolus design on its performance was evaluated. A total of 56 Suffolk ewes were used to assess the ease of administration and retention of 3 types of electronic ruminal boluses (mini, 11.5 × 58.0 mm and 21.7 g; small, 14.8 × 48.5 mm and 29.5 g; standard, 19.3 × 69.8 mm and 74.4 g) during a whole productive year, including pregnancy and lamb suckling. Ewe age (5.6 ± 2.3 yr) and weight (85.07 ± 8.2 kg BW) were recorded, as well as time for bolus swallowing. The deglutition of the bolus and any resulting blockages in the esophagus were monitored by visual observations. Retention and readability of the boluses were regularly monitored for d 1, wk 1, mo 1, and every mo until 1 yr. Time for bolus swallowing differed substantially with bolus type and was greater (P < 0.05) for the standard bolus (32.8 ± 6.9 s) when compared to small and mini boluses, which did not differ (8.5 ± 2.0 vs. 9.2 ± 2.7 s; P > 0.05). The bolus o.d. and length were positively correlated with swallowing time (P < 0.01). The ewe weight was negatively correlated with swallowing time (P < 0.05). At 6 mo all electronic boluses showed 100% retention rate, and at 12 mo, bolus retention was 100%, 94.5%, and 100% for mini, small, and standard boluses, respectively (P > 0.05). At 12 mo, all boluses showed 100% readability, except for small boluses, which had a readability of 94.5%. In conclusion, bolus design affected swallowing time and bolus readability. A reduction in boluses length and o.d. needs to be carried out to provide ease of administration and for boluses to be used as an effective means of electronic identification. Therefore, this study shows that adequately designed boluses are safe and suitable for identifying adult sheep and can therefore be used in hot climates.

Viabilidade econômico-financeira de sistemas de produção de cordeiros não desmamados em pastagem com suplementação em cocho ou pasto privativo

The objective was to analyze production costs and profitability of grazing sheep productions systems under three strategies of lambs supplementation: (1) white clover on creep grazing; (2) creep feeding; and (3) not supplemented. Two methods of financial analyses where used: annual (short term) and cash flow (long term). Costs were classified into variable, fixed, operational and total. Results showed that feeding and opportunity cost over investment was the most important production factors at variable and total costs, respectively. System with creep grazing supplementation did not show greater economic financial results over creep feeding supplementation system.

Consumo alimentar residual e sua relação com medidas de desempenho e eficiência e características in vivo da carcaça de cordeiros

The residual feed intake (RFI) and the feed conversion ratio (FCR) of 20 lambs was evaluated in order to estimate the correlations between these traits and performance measures and with in vivo carcass characteristics. The animals had their dry matter intake (DMI) measured over 65 days and they were weighed every 13 days to determine the average daily weight gain (ADG). Initial body weight (IBW), final body weight (FBW), metabolic weight (MW), ADG, relative growth rate (RGR), Kleiber ratio (KR), FCR, DMI and DMI in BW percentual (BWDMI) were considered. The carcass evaluation was performed by ultrasound. The RFI was correlated with the DMI (+0.81), BWDMI (+0.90) and with FCR (+0.63). Significant correlations were found between FCR and ADG; FCR and RGR; and FCR and KR; and FCR and IBW (-0.63, -0.74, -0.75 and +0.51 respectively). The RFI and the FCR were not correlated with carcass traits and similarly there was no difference between the RFI-classes for these variables. It was proved the RFI has potential as a measure of feed efficiency for housed lambs, without the existence of relations with weight gain and body size of animals and without changes in carcass composition.

Early weaning and concentrate supplementation strategies for lamb production on Tifton-85 pasture

The influence of early weaning and concentrate supplementation strategies on sward characteristics, forage chemical composition and lamb productivity were evaluated in four production systems on Tifton-85 pasture: suckling lambs not supplemented until slaughter; suckling lambs supplemented with concentrate in creep feeding until slaughter; early-weaned lambs not supplemented until slaughter; and early-weaned lambs supplemented with concentrate until slaughter. Structural, morphological and productive characteristics of pasture were measured. The forage was chemically analyzed to estimate its composition. Lambs average daily gain and productivity were calculated. Sward height, forage and morphological components mass were lower in systems without weaning. Forage production was higher in systems with supplementation. Higher levels of neutral and acid detergent fiber were observed in forage ingested by lambs in creep feeding and by weaned and unsupplemented lambs. Average daily gain was higher for lambs in creep feeding (275 g/d) and lower for the weaned and unsupplemented animals (57 g/d). Productivity was higher for weaned and supplemented lambs (21 kg lamb body weight, BW gain/ha/d). Lower productivity was observed in systems without supplementation (5 kg lamb BW gain/ha/d on average). Ewes modify the sward conditions improving the pasture characteristics and the quality of forage produced. Changes in sward conditions affect the chemical composition of forage ingested by lambs. Early weaning may be an alternative to maximize pasture utilization in small areas. Concentrate supplementation may increase lamb performance and productivity in grazing systems. If the objective is to improve lamb individual performance, creep feeding should be used.