R.M. Caldeira

Daily variation in blood enzymes and metabolites in ewes under three levels of feed intake

Daily variations in the concentration of albumin, creatinine, non-esterified fatty acids, globulins, glucose, total lipids, total protein, triglycerides, urea, β-hydroxybutyrate, and in the activity of alkaline phosphatases, aspartate aminotransferase, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase and pyruvate kinase were evaluated in the serum or plasma of ewes fed 30, 100 and 200% of theoretical maintenance energy requirements. A daily profile was observed in almost all variables, which may be of importance when interpreting data for these blood indicators. Daily variations were found even for albumin and total protein serum concentrations, showing a significant decrease of their levels after the meal. In order to maximize the diagnostic value of these indicators, the most suitable times for blood collection seem to be 16 h after the meal and (or) just before the meal. Collection 16 h after the meal apparently allows the characterisation of a relatively steady meta...

Interrelationship between body condition and metabolic status in ewes

Abstract Blood samples were collected in four groups of mature, dry, non-pregnant ewes showing different body condition (BC) scores. In the first experiment, animals were fed differently to achieve four stabilized body weights and BC. In the second, only groups with highest and lowest weights and BCs were maintained on the experiment. The high group was fed to allow a gradual decrease to the lowest mean weight and BC, while the low group was fed to achieve the opposite. Free fatty acids (FFA), triglycerides (Tg), total cholesterol (TCh), phospholipid (Phl) concentrations and enzymatic activities of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) were determined in serum. Ewes were weighed and assessments of BC made weekly. Change of mean BC scores from 0.64 to 3.93 and from 4.14 to 1.00 took 24 and 46 weeks, respectively. Ewes with stabilized but different BC score had similar FFA, Tg, TCh, Phl concentrations, and GOT, GPT enzymatic activities. BC was related to small differences. For the increasing BC state (IBC), concentrations and activities had all increased gradually except FFA which decreased. For the decreasing BC state (DBC), mean FFA and Tg concentrations greatly increased at the beginning of food restriction, but gradually decreased afterwards. Phl and TCh concentrations remained constant while GOT and GPT activities decreased after food restriction; gradually increasing afterwards as animals were loosing BC. Results demonstrate that animals in the same BC may be in different metabolic states. Concentrations of FFA are a good predictor of animal energy status, GOT and GPT activities are good indicators of mobilization of body protein reserves when animals are in negative energy balance.

Effects of body condition and leptin on the reproductive performance of Lusitano mares on extensive systems

The aim of this study was to investigate the effects of body condition (BC), BC changes, and plasma leptin concentrations on the reproductive performance of Lusitano broodmares on extensive systems. Data from 119 mares (ranging from 4 to 22 years of age) were collected over a period of four consecutive breeding seasons. Each case was considered as one foaled mare bred in 1 year. Body condition changes at conception (ΔBCScon) showed a strong effect on fertility at the first two postpartum estrous cycles and a significant interaction with body condition score at conception (BCScon) was observed (P < 0.01). The best fertility results were obtained with positive and greater ΔBCScon. The best predictive value of fertility (91%) was achieved when the BCScon was 3.0 and ΔBCScon was 0.375. Global foaling rate for the 4-year period was 74.5%. Mean foaling interval and gestation length were, respectively, 368.0 ± 2.8 and 340.3 ± 1.0 days. Gestation length was influenced by the month of foaling (P < 0.05) and decreased as mares got older (P < 0.01). The number of estimated estrous cycles per live foal was 1.78 ± 0.12, including foal heat ovulation. Leptin was correlated with BCS (0.41; P < 0.001), but in the present study, plasma leptin concentrations on late gestation and early lactation did not influence fertility results. At 90 days of age, lower growth performances were obtained in foals which dams presented negative BCS changes on the first 3 months of lactation (P < 0.05). In conclusion, BC changes at early postpartum period influence the reproductive efficiency of broodmares and the growth of their suckling foals. These findings are important to help breeders on management options concerning feeding strategies in the Lusitano production systems and others under similar conditions.

Effects of foaling season on growth and development of Lusitano suckling foals raised on extensive grazing systems

Most Lusitano stud farms in Portugal are based in extensive grazing systems. In these systems, mares and foals are bred outdoors throughout the year, being pasture an important part of their diets. However, grass production is highly dependent on Mediterranean climatic conditions, with hot and dry summers. Therefore, a field study was conducted in order to evaluate the effects of foaling season on growth and development of the Lusitano suckling foal. One hundred and eight foals from four stud farms (A, n=39; B, n=33; C, n=12; D, n=24) were monitored from birth to six months of age, throughout three (A and B) and two (C and D) years. Monthly, foals were weighed (BW) and withers height (WH), girth (G) and cannon circumference (CC) were measured. According to birth date, two main foaling seasons were considered: February-March and April-May. A mixed linear model allowing for repeated measures on time was used to assess the effect of foaling season, stud farm, gender and their interactions on body weight, withers height, girth and cannon circumference. Quadratic effect of time was included in the model. The effect of foaling season was significant for withers height and girth (P<0.05) with higher values for foals born in February-March. Differences between stud farms were observed (P<0.001) for BW, WH, G and CC, which are probably linked with feeding options and pasture quality. The effect of gender was only significant on CC (P<0.05) with lower values registered in fillies. In the present study, foals born in February-March seem to have better development performances compared with foals born in April-May. Since pasture production and quality usually decreases from the end of May, these results suggest that April-May foaling mares may need a supplement to dry pasture, in order to support milk production and to promote an adequate foals’ growth and development.

Nutritional status of Lusitano broodmares on extensive feeding systems: body condition, live weight and metabolic indicators

The present research aimed to evaluate the effects of foaling season and feeding management in extensive systems on the nutritional status of Lusitano broodmares throughout the gestation/lactation cycle, by assessment of body condition (BC), body weight (BW), and some blood metabolic indicators. Four groups of Lusitano broodmares (A, B, C, D) were monitored during four years, in a total of 119 gestation/lactation cycles. All mares were kept on pasture, and A and B mares were daily supplemented. Monthly, mares were weighed and BC evaluated. Suckling foals from these mares were also monitored for BW and withers height. Glucose, non-esterified fatty acids, urea and albumin concentrations were determined in blood. BW changes were influenced by reproductive stage and foaling season (P<0.001), reflecting also pasture availability. Changes on BC were observed (P<0.05), although with small amplitudes within each group. Higher scores were reached at the end of spring, decreasing 0.25 point until late summer. Early foaling had also a marked effect, hindering the recovery of BC along the cycle. Glucose values decreased from late gestation to early lactation (P<0.05) and lower levels were recorded during the summer months. Uremia was mainly influenced by the reproductive stage (P<0.05). Under nutrition was not detected. Foals born in February-March had higher average daily gain than those born in April-May (P<0.05), probably reflecting differences in milk production of the mares. BC and BW changes and, particularly, blood indicators showed an overall balanced nutritional status, reflecting an adaptation to feed availability and climate.

Morphological Aspects and Expression of Estrogen and Progesterone Receptors in the Interdigital Sinus in Cyclic Ewes

Many species that belong to Artiodactyls order show an interdigital sinus (IS), as it occurs in sheep, in all four extremities. These are considered to be scent glands responsible for sexual communication having strong attractiveness to mature males at the peak of the breeding season. The aim of this study was to evaluate, in IS in cyclic ewes, the microscopic and ultrastructure (scanning and transmission electron microscopy) anatomy, secretion composition, and mRNA and protein expression of estrogen receptors α and β and progesterone receptors. Glandular sebaceous structures occupy a superficial area of the pouch. The other glands present in the IS show a coiled tubular structure and tall and polyhedral secretory cells with irregular luminal surface resulting from the secretory process. Protein and mRNA gene transcription studies were performed to determine the presence of ER (α and β) and P4r in IS. At the follicular phase, IS cell populations analyzed using flow cytometry expressed higher levels of ERβ compared with ERα (P < 0.05), whereas no difference was observed between them in the luteal phase. The IS amount of secretion was the highest in the follicular phase compared with luteal phase (P < 0.05) or pregnancy (P < 0.001).To the best of our knowledge, for the first time, the presence of ER (α and β) within the IS was demonstrated. As estrogen action is mediated by specific receptors in target cells, the presence of these receptors in IS might be needed to trigger signaling pathways involved in conspecific chemical (sexual) communication attributed to this area. Microsc. Res. Tech. 77:313–325, 2014.

Effects of Condensed and Hydrolyzable Tannins on Rumen Metabolism with Emphasis on the Biohydrogenation of Unsaturated Fatty Acids

The hypothesis that condensed tannins have higher inhibitory effect on ruminal biohydrogenation than hydrolyzable tannins was tested. Condensed tannin extract from mimosa (CT) and hydrolyzable tannin extract from chestnut (HT) or their mixture (MIX) were incorporated (10%) into oil supplemented diets and fed to rumen fistulated sheep. Fatty acid and dimethyl acetal composition of rumen contents and bacterial biomass were determined. Selected rumen bacteria were analyzed by quantitative real time PCR. Lower ( P < 0.05) rumen volatile fatty acids concentrations were observed with CT compared to HT. Moreover, lower concentration ( P < 0.05) of Fibrobacter succinogenes, Ruminococcus flavefaciens, Ruminococcus albus, and Butyrivibrio proteoclasticus were observed with CT compared to HT. The extension of biohydrogenation of 18:2n-6 and 18:3n-3 did not differ among treatments but was much more variable with CT and MIX than with HT. The trans-/ cis-18:1 ratio in bacterial biomass was higher ( P < 0.05) with HT than CT. Thus, mimosa condensed tannins had a higher inhibitory effect on ruminal metabolism and biohydrogenation than chestnut hydrolyzable tannins.