Carla Joice Härter

Mineral requirements for growth of wool and hair lambs

The present study was conducted to determine the body composition and the mineral requirements for growth of wool and hair lambs. A total of 34 castrated lambs with an initial body weight (BW) of 19.9±0.8 kg were used; 17 of these lambs were of the genotype Ideal × Ile de France and 17 were Santa Ines. Ten lambs (5 of each genotype) were slaughtered at the beginning of the experiment to establish their initial body composition. The remaining lambs were assigned to one of three diets (40% roughage and 60% concentrate, 60% roughage and 40% concentrate, or 80% roughage and 20% concentrate) in a 2 × 3 factorial arrangement of treatments. All of the diets were provided ad libitum. When the group under 40% roughage and 60% concentrate reached 35 kg BW, all of the animals were slaughtered. Linear regressions were used to determine the relationship between the shrunk BW and the empty body weight (EBW) for each genotype. These equations were compared and revealed differences between the genotypes. The allometric equations were calculated using the relationship between the amount of minerals and the EBW. The equations of a given mineral for each genotype were compared to verify if they were statistically different. The equations for calcium, phosphorus, magnesium and sodium differed between genotypes. The same equations were used to estimate the major body mineral composition per kilogram of EBW. The net requirement for gain of the fleece-free Ideal × Ile de France lambs ranged from 7.77 to 6.80 g Ca, 4.54 to 4.14 g P, 0.30 to 0.27 g Mg, 1.18 to 1.07 g K and 0.84 to 0.76 g Na per kg BW gain, and the requirements of the Santa Ines animals ranged from 9.57 to 8.37 g Ca, 5.39 to 4.91 g P, 0.36 to 0.33 g Mg, 1.18 to 1.07 g K and 0.90 to 0.81 g Na per kg BW gain for the lambs weighting 20 to 35 kg. Santa Ines lambs showed higher requirements for Ca, P, Mg and Na.

Mineral requirements for growth and maintenance of F1 Boer × Saanen male kids.

The objective of this study was to determine the net requirements of minerals for the growth and maintenance of intact male F1 Boer × Saanen goat kids in the initial phase of growth. The following 2 experiments were performed: Exp. 1 was performed to determine the net growth requirements for Ca, P, Mg, Na, and K by F1 Boer × Saanen goat kids from 5 to 25 kg of BW and Exp. 2 was performed to determine the maintenance requirements of F1 Boer × Saanen goats from 15 to 25 kg BW. In Exp. 1, 32 intact male goat kids were distributed in a completely randomized design and mineral body composition was fit to an allometric equation in the form of a nonlinear model. To determine the mineral requirements for maintenance in Exp. 2, 21 intact male goat kids were distributed in a randomized block design, where the goat kids were subjected to 3 levels of feed restriction (0, 30, and 60% feed restriction). At the onset of Exp. 2, 7 goat kids were harvested and used to estimate the initial body composition (15 kg BW). Initial body composition was used to calculate the retention of minerals. The maintenance requirements were estimated by regressions obtained from the retention of minerals in the empty body and the intake of the mineral. The concentration of Ca, P, Na, and K in the empty BW decreased by 11, 13, 26, and 23% with the increase in BW from 5 to 25 kg (P < 0.01). As a consequence, our results showed that net requirements of Ca, P, Mg, Na, and K for weight gain decreased by 27.5, 27.8, 4.25, 43.2, and 39.7%, respectively, with the increase in BW from 5 to 25 kg (P < 0.01). The net requirements (g/kg of ADG) decreased from 9.7 to 7.0 for Ca, 6.5 to 4.7 for P, 0.38 to 0.36 for Mg, 0.88 to 0.50 for Na, and 1.9 to 1.2 for K when BW increased from 5 to 25 kg. The daily net requirements for maintenance per kilogram of BW were 38 mg of Ca, 42 mg of P, 1.6 mg of Mg, 5.0 mg of Na, and 19 mg of K. These results for the nutritional requirements of minerals may help to formulate more balanced diets for F1 Boer × Saanen goat kids in the initial growth phase.

Mineral Metabolism in Singleton and Twin-pregnant Dairy Goats

During pregnancy, the maternal body undergoes significant physiological changes. The present study assessed the changes on calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na) and potassium (K) metabolism in singleton and twin-pregnant dairy goats. The 42 goats used (49.5 kg±7.6 body weight [BW]) were assigned at random to treatments that were factorially arranged to account for 2 breeds (Oberhasli and Saanen), 2 pregnancy types (singleton and twin) and 3 gestation periods (80, 110, and 140 days). Digestibility trials were performed at 80, 110, and 140 days of gestation. Mineral retention during pregnancy was determined in the maternal body, femur, uterus, mammary gland, fetus and fetal fluid. Blood samples were taken during pregnancy before and after a meal, and Ca, P, Mg, Na, K ions and alkaline phosphatase activity determined in serum. Bone mineral density was determined in the right femur. Statistical analyses were performed using the SAS MIXED procedure. Dry matter intake decreased linearly up to 140 days of gestation. Maternal BW gain, and Ca, P, and Mg retention (g/kg) decreased linearly with the advance of gestation days. Macromineral retention in maternal body (g/kg) was greater in Oberhasli than Saanen goats, and their fetuses had higher Ca, P, and Mg deposition (mg/g). Mineral retention (mg/g) increased in fetuses according to pregnancy development, with no differences between singleton and twin pregnancy. In the mammary gland, the retention of all minerals (g) increased with the days of pregnancy. In conclusion, related to Ca, P, and Mg metabolism can be divided into two stages. Up to 80 days of gestation, was characterized by the preparation of the maternal body reserves for future mineral demands. From 80 days of gestation onward, was characterized by the transfer of maternal body reserves for fetal development and colostrum production. Na and K supply was provided by adjustments in endogenous excretion and an increase in intestinal absorption. Finally, mineral metabolism was specific to each genotype and, except for Na, was not affected by the number of fetuses.

What is the best additive to use at the ensiling of sugarcane SP81-3250?

Our objective was to determine the best additive to use for the ensiling of sugarcane SP81-3250 based on the nutritional properties and aerobic stability of the silages. The additives evaluated were (1) and (2): salt (NaCl) at rates of 1.0 or 2.0 kg/100 kg fresh sugarcane (as-is basis), respectively; (3) and (4): quicklime (CaO) at rates of 1.0 or 2.0 kg/100 kg fresh sugarcane, respectively; (5) and (6): commercial inoculants Silobac® and Maize All®; and a control treatment. The addition of quicklime reduced the NDF and ADF contents of the silages by 11% compared with the control treatment, but did not increase the digestibility. On the other hand, after 24 h of in vitro fermentation, the application of 1.0 and 2.0% salt reduced the gas production by 34.15 and 33.55 mL/g OM, respectively, and the IVOMD was reduced 5.74 and 5.90%, respectively, compared with the untreated silage. Moreover, the addition of quicklime elevated the pH of the sugarcane silages, with a trend towards an increase in the DM recovery. In contrast, the bacterial inoculants did not alter the pH values, but there was an upward trend for a DM recovery. After the silos were opened, the silages that were treated with salt (independent of the dose) and 1.0% quicklime exhibited greater stability. We recommend applying 1.0 kg of quicklime to each 100 kg of sugarcane at the time of ensiling to improve the nutritional characteristics of sugarcane silage variety SP81-3250.

Inovações tecnológicas na caprinocultura

The Brazilian agribusiness has being passed through intensive growth and it has been stimulating transformations of the productive systems both in intensification and professionalization of animal production. In this regard, producers are seeking the use of strategies to better attend the new challenges of the animal production. Among the strategies stands out the technological innovations, which should result in real benefit to the activity by increasing productivity, improving product’s quality and providing protection to the environment. As other segments of the Brazilian agribusiness, in goat production there is an increased demand for the application of technological innovation once this system needs to be more competitive in the global market. Among the technological innovations applied for goat production, this review addressed the most relevant in the reproduction (from methods for estrus induction to transgenic practice), animal breeding (biogenetic), health management (innovation on diagnosis and prevention of the most prevalent diseases), nutrition (feeding systems innovations) and waste treatment (reduction of environment contamination) areas. The joint use of the technological innovations in the different segments linked to the goat production chain can contribute to improve herd’s quality as well as the generated produces.

Net energy and protein requirements for pregnancy differ between goats and sheep.

Current feeding systems for goats estimate the energy and protein requirements for pregnancy using data from sheep. The objective of this study was to predict the NE and net protein requirements for pregnancy in goats carrying single and twin fetuses and to compare these requirements with those of sheep. Data were compiled from 2 studies with dairy goats and 3 studies with sheep. These studies measured the energy content (EC) and protein content (PC) of the gravid uterus and of the mammary gland using the comparative slaughter technique. The current study was performed as a meta-analysis using an exponential model, comparing species (sheep versus goats) and litter size (single versus twin) from 50 to 140 d of pregnancy. Total EC and total PC in the gravid uterus were similar in goats and sheep carrying a single fetus. Energy and protein contents of the gravid uterus of sheep carrying twins were, on average, 29% greater than that of goats with twins from 80 to 140 d of pregnancy. During pregnancy, EC and PC of the mammary gland in goats carrying singles and twins were, on average, greater than those of sheep by 9 and 24%, respectively, for EC and by 25% for PC for both litter sizes. In conclusion, the gravid uterus and the mammary gland of goats and sheep require different amounts of energy and protein. Sheep carrying twins have the greatest daily NE and net protein requirements for pregnancy followed by goats carrying twins and both species carrying a single fetus. Therefore, it is inappropriate to adopt data from sheep to predict the net pregnancy requirements of goats, and the results found in this study could be relevant to the nutritional management of dairy goats.

Replacement of aruana grass by gliricidia (Gliricidia sepium) on silage quality

Our objective was to investigate the effect of the replacement of aruana grass by gliricidia on the fermentative losses, chemical composition, and aerobic stability of silages. For ensiling, whole-crop aruana grass (75 d of growth) was chopped (275 g kg-1 dry matter - DM) and ensiled alone or associated with gliricidia (270 g kg-1 DM; 150 d of growth). For gliricidia, we used only the leaves and stalks to ensile. The evaluated treatments were different ratios of aruana grass to gliricidia (100:0, 75:25, 50:50, 25:75, and 0:100), with four replicates (mini-silos). The silage composed only of gliricidia exhibited a lower pH than the other silages. Dry matter recovery was not affected by the treatments, although effluent losses were affected. The replacement of aruana grass by gliricidia 50% at ensiling resulted in a higher lactic acid bacteria count. The aruana grass silages displayed lower protein contents and a higher neutral detergent fiber content than the gliricidia silages after 40 d of fermentation. Consequently, the silage consisting of 100% gliricidia showed higher in vitro DM digestibility, presenting an increase of 8.13% after 40 d of fermentation compared with 100% of aruana grass silage. After silo opening, the gliricidia silage was very stable (>72 h). The low quality of aruana grass silage is improved by replacing this grass with significant amounts of gliricidia (approximately 75%).

Energy and protein requirements for maintenance of dairy goats during pregnancy and their efficiencies of use

It has been suggested that maintenance requirements are similar among animals of different physiological stages; however, important physiological changes occur in the maternal body during pregnancy. Therefore, the aim of this study was to determine the energy and protein requirements for the maintenance of pregnant dairy goats and to estimate their efficiency of energy and protein utilization for maintenance and pregnancy. We used 66 multiparous pregnant goats having 49.0 ± 1.59 kg initial BW (around the third or fourth parturition) arranged in a randomized block design with a 3 × 3 factorial scheme including slaughter at different days of pregnancy (DOP; 80, 110, and 140 d) and feed restriction (0, 20, and 40% feed restriction). The comparative slaughter technique was used to estimate energy and protein maintenance requirements. Goats slaughtered at 140 DOP were subjected to digestibility trials at around 80, 110, and 140 DOP to estimate diet metabolizability and N balance (NBAL). Metabolizability decreased with feed restriction and was 63.3 ± 2.16, 55.7 ± 2.35, and 58.2 ± 2.30% at 0, 20, and 40% of feed restriction, respectively ( < 0.01). There was no effect of DOP on NE or the requirements of ME for maintenance (ME), which were 197 and 315 kJ/kg empty body weight (EBW), respectively, and the efficiency of ME utilization for maintenance (k) was 0.63. Similarly, DOP did not affect thedaily net protein requirements for maintenance (NP) estimated using the comparative slaughter technique (1.38 ± 0.512 g/kg EBW; = 0.003) or the NP estimated using NBAL (2.49 ± 0.594 g/kg EBW; < 0.01). The MP requirement for maintenance (MP) estimated using the comparative slaughter technique was not affected by DOP and was 3.22 g MP/kg EBW ( < 0.01). The efficiency of MP utilization for maintenance (k) was 0.43. The efficiency of ME utilization for pregnancy (k) increased with the progress of pregnancy and was 0.058, 0.10, and 0.19 at 80, 110, and 140 DOP, respectively. Similarly, the efficiency of MP utilization for pregnancy (k) increased with DOP and was 0.12, 0.21, and 0.43 at 80, 110, and 140 DOP, respectively. There was no evidence that pregnancy affected NE, ME, NP, and MP or k and k, which were also unaffected by DOP. However, k and k increased with pregnancy progress as a response to the physiological changes that pregnant females are subjected to.

Mineral metabolism of pregnant goats under feed restriction

We examined the effects of feed restriction on calcium, phosphorus, magnesium, sodium and potassium metabolism in Oberhasli and Saanen goats during gestation. The 63 goats were distributed into groups that were divided into three levels of feed restriction (0%, 20% and 40% restriction) and slaughtered at different pregnancy stages (80, 110 and 140 days of gestation), in a randomised block design with a 2 × 3 × 3 factorial arrangement. The mineral balance was determined at ~80, 110 and 140 days of gestation. The serum levels of minerals and alkaline phosphatase activity were determined during pregnancy. Mineral retention in the maternal body, femur, empty uterus, mammary gland, fetus and fetal fluid was also determined during gestation. Bone mineral density was measured in the femur. Mixed models with days of gestation, levels of feed restriction, breed and their interactions as fixed effects and blocks as random effect were used for data analysis. In response to the reduction in feed intake, the maternal body uses its mineral reserves to maintain gestation. Physiological adjustments of the goats subjected to 20% feed restriction avoided a decrease in fetal mineral deposition. More severe feed restriction, however, compromised concentrations of phosphorus, sodium and potassium in the fetus, which were the main minerals used by the maternal body, whereas calcium and magnesium deposition in fetuses remained unaffected. At 40% feed restriction, the retention of all minerals in the body decreased, and the fetal dry mass was on average also less than those fetuses from goats without feed restriction. The fetal deposition of phosphorus, sodium and potassium was also lower during 40% restriction.

Growing goats of different sexes have distinct metabolic responses to continuous feed restriction

The objective of the present study was to investigate the effect of sex on the hormonal and metabolic changes in growing goats subjected to levels of feed restriction. We used 72 Saanen kids, including 24 intact males, 24 castrated males and 24 females with initial bodyweight of 15.76 ± 0.174 kg and initial age of 108.4 ± 18.86 days respectively. A split-plot design was employed (3 sexes = intact males, castrated males, and females; 3 levels of feed restriction = 0% (ad libitum), 25% and 50%). Groups of three goat kids were formed by sex (each goat eating one level of feed restriction); goats of each group were slaughtered when animals fed ad libitum reached 30 kg bodyweight. Fat and protein deposition were calculated by the difference between the determinations performed on samples of homogenates of control animals slaughtered at the start of the experiment and the experimental animals. Blood samples were collected every 10 days to evaluate glucose, total protein, albumin, urea, creatinine, cholesterol, non-esterified fatty acid, β-hydroxybutyrate, aspartate aminotransferase, gamma glutamyltransferase, creatine kinase, triiodothyronine (T3), thyroxine and insulin-like growth factor. Females presented greater fat deposition than did castrated and intact males, regardless of feed restriction (P < 0.0001). Protein body retention (kg) was affected only by feed restriction (P < 0.0001). In females, aspartate aminotransferase activity was greater in those subjected to 50% feed restriction (83.83 ± 4.96 U/L). Regardless of sex, the greatest serum β-hydroxybutyrate concentration was observed when animals were subjected to 50% feed restriction (P < 0.0149). Plasma concentration of insulin-like growth factor 1 was similar in castrated and females, being lower than in intact males. Intact males showed lower plasma T3 concentration than did females (P < 0.05). Females changed their glycolytic metabolism to retain fat deposition even under feed restriction, whereas males mainly changed their protein metabolism to retain protein synthesis, and were less affected by feed restriction.