Effect of growth rates on hormonal and pubertal status in Nellore heifers early weaned.

This study aimed to determine the effect of growth rates on the hormonal status and puberty onset. Forty-eight Nellore heifers were weaned at 3.0 ± 0.1 (means ± standard error of the mean) months old were blocked according to body weight at weaning (84 ± 2 kg) and randomly assigned to treatments. The treatments were arranged in 2 × 2 factorial according to the feeding program. The first program was high (H; 0.79 kg/day) or control (C; 0.45 kg/day) average daily gain (ADG) from 3rd to 7th month of age (growing phase I). The second program was also high (H; 0.70 kg/day) or control (C; 0.50 kg/day) ADG from the 7th month until puberty (growing phase II), resulting in four treatments: HH (n = 13), HC (n = 10), CH (n = 13), and CC (n = 12). To achieve desired gains, heifers in high ADG program were fed ad libitum dry matter intake (DMI), and the control group was offered around 50% of ad libitum DMI of high group. All heifers received a diet with similar composition. Puberty was assessed weekly by ultrasound examination, and the largest follicle diameter was evaluated every month. Blood samples were collected to quantify leptin, insulin growth factor-1 (IGF1) and luteinizing hormone (LH). At 7 months of age, heifers in high ADG were 35 kg heavier than the control. Heifers in the HH had greater DMI compared with CH in phase II. The puberty rate at 19 months old was greater in the HH treatment (84%) than in the CC (23%), but there was no difference between HC (60%) and CH (50%) treatments. Heifers from HH treatment had greater serum leptin concentration than others at 13 months old, and serum leptin was greater in HH compared with CH and CC at 18 months old. High heifers in phase I had greater serum IGF1 concentration than the control. In addition, HH heifers had a greater diameter of the largest follicle than CC. There was no interaction between phases and age in any variable relative to the LH profile. However, the heifers' age was the main factor that increased the frequency of LH pulse. In conclusion, increasing ADG was associated with greater ADG, serum leptin and IGF-1 concentration, and puberty onset; however, LH concentration was affected mainly by age of the animal. The increasing growth rate at younger age made heifers more efficient.

Sensitivity of breeding values for carcass traits of meat-type quail to changes in dietary (methionine + cystine):lysine ratio using reaction norm models.

Our objective was to evaluate changes in breeding values for carcass traits of two meat-type quail (Coturnix coturnix) strains (LF1 and LF2) to changes in the dietary (methionine + cystine):lysine ([Met + Cys]:Lys) ratio due to genotype by environment (G × E) interaction via reaction norm. A total of 7000 records of carcass weight and yield were used for analyses. During the initial phase (from hatching to day 21), five diets with increasing (Met + Cys):Lys ratios (0.61, 0.66, 0.71, 0.76 and 0.81), containing 26.1% crude protein and 2900 kcal ME/kg, were evaluated. Analyses were performed using random regression models that included linear functions of sex (fixed effect) and breeding value (random effect) for carcass weight and yield, without and with heterogeneous residual variance adjustment. Both fixed and random effects were modelled using Legendre polynomials of second order. Genetic variance and heritability estimates were affected by both (Met + Cys):Lys ratio and strain. We observed that a G × E interaction was present, with changes in the breeding value ranking. Therefore, genetic evaluation for carcass traits should be performed under the same (Met + Cys):Lys ratio in which quails are raised.

Genetic parameters for body weight in meat quail.

The aim of this study was to estimate genetic parameters for BW in meat quail at different ages. A total of 24,382 weight records from 3,652 quail, born between 2009 and 2011, were evaluated. Weekly BW was measured from hatch until 42 d of age. The genetic parameters were estimated by the restricted maximum likelihood method using a multivariate animal model. Heritability of BW ranged from 0.03 to 0.23. Genetic correlations were mainly high and positive. Selection for BW at 28 d of age yielded good indirect genetic progress in BW at 42 d of age.

Egg laying and egg quality in meat type quails in diallel crosses.

This study aimed to assess egg laying and egg quality in quail lines in diallel crosses. We evaluated 16 genetic groups obtained from crosses of four strains of meat quails (L1, L2, L3, and L4) in a complete diallel. We assessed weekly egg number (WEN), egg yield (EY), egg weight (EW), and Haugh unit (HU) for: 51-80, 81-110, 111-140, and 51-140 days (whole period) old. The general combining capacity (GCC) showed significance for WEN and EY, with the exception of the period of 111-140 days. In general, L3 had the highest positive GCC estimates. The additive genetic variability was significant for EW in all periods, as was HU, with the exception of the first period. The specific combining capacity was significant for HU, except in the second period. The largest estimates for GCC were submitted by L1 for EW, followed by L4, considering the whole period. For HU, L2 had the highest estimates for GCC. The more favorable cross for HU was L2xL3, in the whole period. In the third period, there was a significant reciprocal effect, where there was a positive estimate for the cross L2xL3.

Effect of glycerol on GHR and IGF-1 gene expression in breast muscle and on growth of Japanese meat quails.

We evaluated messenger RNA (mRNA) expression of the growth-hormone (GHR) and insulin-like growth factor (IGF-1) genes in 28-day-old Japanese meat quails fed diets containing 0, 8, or 12% dietary glycerol in substitution of corn. Total RNA was extracted from the breast muscle and the DNA was amplified with specific primers using real-time PCR. Feed conversion ratio and feed intake were evaluated. The birds fed 8 and 12% glycerol presented higher IGF-1 mRNA expression [0.059 and 0.049 arbitrary units (AU), respectively] relative to those not fed with glycerol (0.029 AU), while 12% glycerol reduced GHR mRNA expression (0.022 AU). Dietary inclusion of 8% glycerol promoted similar performance results (feed conversion) as the diet with no glycerol. We conclude that inclusion of glycerol in the diet affects GHR and IGF-1 gene expression in Japanese meat quails. However, considering the performance results and the expression of the GHR and IGF-1 genes, 8% glycerol may be safely included in the diet of meat quails.

Expression of growth genes in response to glycerol use in Japanese quail diets.

Glycerol can be used as a substitute for corn for feeding poultry, but there are concerns about how it may affect growth performance and health of the birds. We evaluated the expression of mRNA of growth hormone (GH) and insulin-like growth factor I (IGF-I) in 35-day-old Japanese quails fed different glycerol levels (0, 4, and 8% dietary glycerol instead of corn). Total RNA was extracted from the breast muscle and cDNA was amplified with the use of specific primers for these genes using real-time PCR. Quails fed the diet with 8% glycerol supplementation had significantly lower GH mRNA and IGF-I mRNA expression than those fed no glycerol or 4% glycerol. No significant effect of the treatments was found on quail weight gain or feed intake. Feed conversion ratio was influenced by dietary glycerol levels: the group fed 8% glycerol displayed the worst feed conversion ratio (2.54) compared with that of quail fed the control diet (2.35) or 4% glycerol (2.36). Considering quail performance and the expression of the genes GH and IGF-I, a level of 4% glycerol can be used in quail feeding without any harmful effects.

Implications of growth rates and compensatory growth on puberty attainment in Nellore heifers.

This study investigated the effects of growth rates and compensatory growth on puberty attainment in Nellore heifers. Nellore heifers (n = 120), weaned at 8 ± 0.75 mo of age, were blocked by sire and BW (180 ± 8.6 kg) and assigned randomly to receive 1 of 4 treatments over a 10-mo period. Treatments included ad libitum feeding (high gain, HG), feed intake to gain 0.6 kg/d (medium gain, MG), restricted feeding (0.2 kg/d) for 4 mo followed by ad libitum feeding for 6 mo (compensatory gain, CG), and alternating periods of ad libitum and restricted feeding for 2 mo each throughout the trial (alternated CG, ACG). Puberty was assessed weekly by transrectal ultrasonography. Blood samples were collected at 8, 11, and 18 mo of age and at puberty to determine circulating concentrations of leptin. At 18 mo of age, nonpubertal heifers were treated with a puberty induction protocol using an intravaginal progestin device. There was no treatment effect (P = 0.17) on the percentage of heifers pubertal by 18 mo of age (HG: 66, MG: 40, CG: 58, and ACG: 52%), BW at puberty, and age at puberty. However, HG heifers had higher ADG (P < 0.01), dry matter intake (P < 0.01), and leptin concentrations (P = 0.03) than heifers from other groups. The response to the puberty induction protocol was similar (P = 0.90) among treatments. Regarding sire effects (genetic effects), there was an effect (P = 0.03) on the percentage of heifers pubertal by 18 mo of age and a tendency (P = 0.07) of sire effect in response to the puberty induction protocol. Compensatory growth appears to be an effective managerial approach to decrease feeding costs and stimulate puberty in Nellore heifers.

Carcass characteristics and meat quality of Nellore bulls submitted to different nutritional strategies during cow-calf and stocker phase.

There have been few studies realized that evaluate the effects of adopting different nutritional systems in more than one phase of cattle production on carcass and meat characteristics. This study was realized to evaluate carcass and meat characteristics from bulls submitted to different nutritional systems during two production phases. The experiment was conducted at Figueira's farm during two production phases: I (cow-calf) - 80 calves (99.6±2.72 days of age and 109.7±2.99 kg of BW) with their mothers were randomly assigned into two supplemental diets: cow-calf mineral supplement (n=40) or cow-calf creep-feeding (n=40); II (stocker) - the same 80 calves (201.2±2.11 days of age and 190.2±3.37 kg of BW) were redistributed into two production systems: stocker pasture (n=40) or stocker feedlot (SF; n=40). After, all 80 animals were kept on a pasture system (III) for 290 days, and then finished in a feedlot system (IV) for more 33 days. Then, they were slaughtered at an average 764.2±3.06 days of age and at 499.2±3.33 kg of final BW. After slaughter, the average daily gain was calculated, and the carcass and meat characteristics were measured. The statistical model design used was completely randomized in a 2×2 factorial arrangement (two treatment groups on cow-calf phase and two treatment groups on stocker phase). The single effects between the groups in each phase and the interactions between both phases (cow-calf v. stocker) were analyzed. The results were compared by Fisher's test, using the R statistical software. A cow-calf by stocker phases interaction occurred for carcass conformation and fiber diameter. For single effects, the greatest influences observed were in the stocker phase. The feedlot group was slaughtered 17 days earlier, with greater final BW (3.8%), hot carcass weight (5.7%), average daily gain (6.9%), dressing percentage (1.8%), carcass length (1.8%), carcass width (1.5%), longissimus muscle area (4.8%) and muscle depth (2.3%) than pasture group. The SF group also had influence on fat color; showing higher L* and lower b* values. These results reveal that bulls reared in feedlot at the stocker phase have higher muscle development and that the stocker phase has the greatest potential to influence carcass characteristics and meat quality.

A combination of nutrition and genetics is able to reduce age at puberty in Nelore heifers to below 18 months.

Nelore heifers usually begin their reproductive life at ⩾24 months of age mainly due to suboptimal nutritional conditions and genetics. This study aimed to determine the effect of expected progeny difference (EPD) for age at first calving and average daily gain (ADG) on puberty in Nelore (Bos taurus indicus) heifers. A total of 58 weaned heifers (initial BW=174±6 kg; age=9±1 months) were allocated into 28 feedlot pens. Heifers were born from four sires, of which two had low EPD for age at first calving (L; n=33) and two had high EPD for age at first calving (H; n=25). Then, heifers of each EPD were randomly assigned to high ADG (HG; 0.7 kg) or low ADG (LG; 0.3 kg), resulting in four treatments: heifers from L sires were submitted to either HG (LHG; n=17) or LG (LLG; n=16), and heifers from H sires were submitted to either HG (HHG; n=12), or LG (HLG; n=13). The HG heifers were fed a 75% grain diet, whereas the LG heifers received 93% of forage in their diet. Blood samples were collected at 9, 14, 18, 24 and 28 months of age for IGF1 and leptin determination. There was a treatment effect (P<0.01) on the proportion of heifers that attained puberty by 18 (62%, 0%, 0% and 0%), 24 (100%, 6%, 54% and 0%) or 36 (100%, 100%, 100% and 38%) months of age for LHG, LLG, HHG and HLG treatments, respectively. In addition, mean age at puberty was different across treatments (P<0.01). Heifers from the LHG achieved puberty at the earliest age when compared with cohorts from other treatments (18.1, 28.9, 23.9 and 34.5 months for LHG, LLG, HHG and HLG, respectively). Serum IGF1 concentrations were higher for L heifers compared with H cohorts at 9, 14, 18, 24 and 28 months of age (P<0.01; treatment×age interaction), whereas circulating leptin concentrations were higher (P<0.01; age effect) as heifers became older, regardless of the treatments. In conclusion, only Nelore heifers with favorable genetic merit for age at first calving were able to attain puberty by 18 months of age. In heifers with unfavorable genetic merit for age at first calving, supplementary feeding to achieve high ADG was unable to shift the age at puberty below 24 months.

Field study on nematode resistance in Nelore-breed cattle.

The present study evaluated Nelore cattle with different degrees of resistance to natural infections by gastrointestinal nematodes. One hundred weaned male cattle, 11-12 months of age, were kept on the same pasture and evaluated from October 2003 to February 2004. Faecal and blood samples were collected for parasitological, haematological and immunological tests. In February 2004, the 10 most resistant and the 10 most susceptible animals were selected based on individual means of nematode faecal egg counts (FEC). Such animals were slaughtered for worm burden determination and nematode species identification. The repeatability estimates for FEC (+/-S.D.), log-transformed FEC and packed-cell volume (PCV) in all animals were 0.3 (+/-0.05), 0.26 (+/-0.04) and 0.42 (+/-0.05), respectively. The resistant group showed lower FEC and worm burdens than the susceptible group (P<0.05). There were no significant differences between groups regarding mean body weight, weight gain, PCV and total serum protein values (P>0.05). The resistant group showed higher total serum IgE levels (P<0.05) and higher mean eosinophil blood counts. However, the latter was statistically significant only 42 days after the beginning of the study. Nematodes Cooperia punctata and Haemonchus placei were predominant and the correlation between Cooperia and Haemonchus burdens was 0.64 (P<0.05), which indicated that animals presenting increased numbers of one of those genera probably had increased numbers of the other. The current study provides further evidence of IgE active role in nematode immunity and suggests that total serum IgE level might serve as an additional marker to select Nelore cattle that are responsive to H. placei and C. punctata infections.

Crude glycerin decreases nonesterified fatty acid concentration in ewes during late gestation and early lactation.

Crude glycerin is a gluconeogenic substrate in ruminants and may help to decrease the occurrence of pregnancy toxemia. The objective in this trial was to determine the effects of feeding a diet containing crude glycerin on DMI, milk yield, milk composition, and blood metabolites in periparturient ewes and lamb performance. One hundred eighteen 90 (±1.1)-d pregnant Santa Inês ewes were used. After lambing, 32 ewes (62.8 ± 1.3 kg BW) were allotted in a randomized complete block design defined by prelambing diet, BW, BCS, lambing date, type of birth (single or twin), and sex of offspring. Diets were isonitrogenous (13.0 ± 0.3% CP, DM basis), composed of concentrate and raw sugarcane bagasse (70:30 ratio, DM basis), and fed ad libitum daily. Crude glycerin (83.6% glycerol) levels were 0 or 10% (DM basis), corresponding to the experimental diets G0 and G10, respectively. From 8 until 56 d of lactation, DMI was determined. In the same period, once a week at 1000 h, the ewes were separated from the lambs and mechanically milked after intravenous administration of 10 IU of synthetic oxytocin. Three hours after the first milking, ewes were milked again and milk yield and composition were determined. Glucose, NEFA, and ß-hydroxybutyrate (BHBA) were determined at -14, -7, 0, 7, 14, 28, and 56 d relative to lambing and insulin was determined at -14, -7, 0, and 7 d. Crude glycerin did not affect DMI (2.2 kg/d for G0 vs. 2.2 kg/d for G10; = 0.93) or milk production (171 g/3 h for G0 vs. 164 g/3 h for G10; = 0.66). However, there was a decrease ( = 0.01) in milk fat percentage (8.1% for G0 vs. 7.0% for G10) for ewes fed glycerin. Ewes fed the G10 diet had decreased ( < 0.01) NEFA concentration (0.27 mmol/L for G0 vs. 0.18 mmol/L for G10). There was an interaction between diet × time for glucose ( = 0.04), insulin ( = 0.05), and BHBA ( = 0.01); feeding glycerin increased glucose (5.61 mmol/L for G0 vs. 7.42 mmol/L for G10; < 0.01) and insulin concentrations (10.5 µIU for G0 vs. 24.5 µIU for G10; < 0.01) at parturition compared with G0. The BHBA was less ( = 0.02) on the day of lambing (0.40 mmol/L for G0 vs. 0.29 mmol/L for G10) and it was greater ( < 0.01) on d 56 for ewes fed the G10 diet (0.46 mmol/L for G0 vs. 0.61 mmol/L for G10). There was no effect of diets fed to ewes on lamb growth from birth to weaning. Crude glycerin improved energy balance of periparturient ewes, suggesting a reduced risk of developing clinical metabolic-related disorders. Crude glycerin can be added at 10% of ewes' diets without affecting DMI and milk yield.

Effects of temperament on physiological, productive, and reproductive responses in beef cows.

This experiment evaluated the effects of temperament on physiological, productive, and reproductive responses in beef cows. A total of 953 lactating, multiparous, non-pregnant Nelore cows (age = 99 ± 2 mo; days post-partum = 51.4 ± 0.3 d; BCS = 5.34 ± 0.04; BW = 430 ± 2 kg) were allocated into 8 groups of approximately 120 cows each. Groups were assigned to an estrus synchronization + timed-AI protocol at the beginning of the breeding season. Concurrently with AI, blood samples were collected, hair samples were clipped from the tail switch, and cow temperament was evaluated via chute score and exit velocity. Individual exit score was calculated within each group by dividing exit velocity into quintiles and assigning cows with a score from 1 to 5 (1 = slowest; 5 = fastest cow). Temperament scores were calculated by averaging cow chute score and exit score, and used to define cow temperament ( ≤ 3 = adequate, = 726; ADQ; > 3 = excitable, = 227; EXC). Cows not pregnant to AI were assigned to a second timed-AI protocol ( = 184 ADQ and 72 EXC) or exposed ( = 269 ADQ and 90 EXC) to bulls for 60 d. Pregnancy status was verified 30 d after each AI and 45 d after the breeding season via transrectal ultrasound. Cow age, BW, BCS, and d post-partum at the beginning of the breeding season were similar ( ≥ 0.27) between ADQ and EXC cows. At first timed-AI, EXC had greater ( < 0.01) serum cortisol but similar ( ≥ 0.87) serum haptoglobin and hair cortisol concentrations compared with ADQ cows (49.1 vs. 39.1 ng/mL of serum cortisol, SEM = 1.0). Pregnancy rate to first timed-AI tended ( = 0.09) to be less in EXC vs. ADQ cows (41.0 vs. 47.3%; SEM = 3.6), whereas no treatment differences were detected ( ≥ 0.23) for subsequent pregnancy outcomes. Calving rate was less ( = 0.04) in EXC vs. ADQ cows (68.3 vs. 74.8%; SEM = 2.2), which can be attributed to the greater ( = 0.05) pregnancy loss detected in EXC cows (9.9 vs. 5.9%; SEM = 1.4). Weaning rate tended ( = 0.09) to be less, whereas calf weaning BW and age were less ( ≤ 0.05) in EXC vs. ADQ cows (63.9 vs. 69.4%, SEM = 2.4; 209 vs. 212 d, SEM = 1; 204 vs. 210 kg, SEM = 2). Hence, kg of calf weaned/cow exposed to breeding was reduced ( = 0.04) in EXC vs. ADQ cows (130 vs. 146 kg, SEM = 5). In summary, cows with excitable temperament had reduced reproductive performance and overall productivity compared to cohorts with adequate temperament when exposed to timed-AI + natural breeding.

Flint corn grain processing and citrus pulp level in finishing diets for feedlot cattle.

Four trials were conducted to evaluate the effects of flint corn processing and the replacement of corn with citrus pulp (CiP) in diets for Nellore feedlot cattle. In a 103-d finishing trial, 216 Nellore bulls (350 ± 24 kg initial BW) were used in a randomized complete block design with a 2 × 4 factorial arrangement of treatments. Factors included 2 processing methods, either ground corn (GC) or steam-flaked corn (FC), with CiP replacing each corn type at 4 levels (0, 25, 50, and 75% of DM). All diets contained 12% sugarcane bagasse and 88% concentrate (DM basis). Treatments were also evaluated in metabolism trials, in which 10 ruminally cannulated Nellore steers (389 ± 37 kg) were assigned to 2 independent but simultaneous 5 × 5 Latin squares, each using 1 method of corn processing (GC and FC). Interactions ( < 0.05) between corn processing and CiP inclusion level were observed for final BW, DMI, ADG, G:F, and HCW. With FC-based diets, added CiP linearly decreased final BW ( = 0.04), whereas with GC-based diets, added CiP quadratically increased final BW ( = 0.002). With FC-based diets, the inclusion of CiP linearly increased DMI ( = 0.03) and linearly decreased ADG ( = 0.03) and G:F ( = 0.001). Increasing CiP in GC-based diets quadratically increased DMI ( = 0.001), ADG ( = 0.005), and HCW ( = 0.003). In FC-based diets, CiP inclusion had no effect on HCW ( = 0.21). Dressing percent, LM area, and 12th-rib fat were not affected by diet ( ≥ 0.05). For steers fed GC diets, CiP inclusion in the diet quadratically decreased the molar proportion of isovalerate ( = 0.001) but linearly increased ruminal butyrate ( = 0.006). No differences ( ≥ 0.16) were observed for total VFA concentrations, acetate:propionate ratio, and ruminal NH-N as CiP replaced GC. For steers fed FC diets, the molar proportion of acetate linearly increased ( = 0.002) whereas the proportion of propionate was linearly decreased ( < 0.001), resulting in a linear increase ( = 0.001) in the acetate:propionate ratio. Replacing corn with CiP linearly reduced NEm ( = 0.001) and NEg ( < 0.001) of FC-based diets but did not affect ( = 0.15) NE values of CG-based diets. Steam flaking flint corn improved cattle performance in this trial more than has been reported for dent corn in the published literature.

Post-artificial insemination supplementation with calcium salts of soybean oil influences pregnancy establishment factors in beef cows.

The objective of this experiment was to compare hormonal, uterine, and conceptus factors associated with pregnancy establishment in beef cows supplemented or not with Ca salts of soybean oil (CSSO) for 21 d beginning after timed AI. One hundred lactating multiparous Nelore cows were allocated to 20 groups of 5 cows/group and timed inseminated on d 0 of the experiment. After AI, groups were randomly assigned to receive (as-fed basis) 100 g of protein-mineral mix + 100 g of ground corn per cow per day, in addition to 1) 100 g/cow daily of CSSO ( = 10) or 2) 100 g/cow daily of kaolin (CON; rumen-inert indigestible substance; = 10). Groups were maintained in 4 pastures (5 groups from the same treatment within each pasture) with ad libitum access to forage. Groups were segregated daily and individually offered treatments from d 0 to 21. Blood samples were collected and transrectal ultrasonography was performed to verify ovulation and corpus luteum (CL) volume immediately before AI (d 0) and on d 7 and 15. After ultrasonography on d 15, 60 cows (30 cows/treatment and 3 cows/group) diagnosed without the presence of a CL on d 0 but with a CL greater than 0.38 cm3 in volume on d 7 and 15 were assigned to conceptus collection via transcervical flushing with PBS followed by endometrial biopsy in the uterine horn ipsilateral to the CL. Additional blood samples were collected for whole-blood RNA extraction (d 20), and pregnancy status was verified by transrectal ultrasonography (d 30) in cows not assigned to conceptus collection. Cows receiving CSSO had greater ( ≤ 0.04) mean plasma linoleic acid concentration, plasma linoleic:linolenic acid ratio, plasma progesterone (P4) concentration, and CL volume during the experiment compared with CON cows. Moreover, CSSO supplementation increased ( ≤ 0.04) length and mRNA expression of and by the conceptus as well as blood mRNA expression of interferon-stimulated genes on d 20 in gestating cows. No treatment differences were detected ( ≥ 0.30) for endometrial mRNA expression of and . In summary, post-AI CSSO supplementation to B. indicus beef cows increased plasma concentration of linoleic acid and enhanced pregnancy establishment factors, which included CL development and plasma P4 concentration, conceptus growth, and mRNA expression of as well as blood mRNA expression of interferon-stimulated genes.

Effect of thyme essential oil on rumen parameters, nutrient digestibility, and nitrogen balance in wethers fed high concentrate diets / Efeito do óleo essencial de tomilho sobre os parâmetros ruminais, a digestibilidade dos nutrientes e o balanço de nitrogênio em borregos alimentados com elevado teor de concentrado

This trial aimed to evaluate the effects of thyme essential oils (EO) on rumen parameters, nutrient digestibility and nitrogen balance in wethers fed with high-concentrate diet. Twenty rumen-cannulated wethers were blocked according to body weight (BW= 64.0±2.1kg), and received one of the following treatments: 25mg of monensin/kg of dry matter (DM; MON) or doses of thyme EO (1.25, 2.50 or 3.75g/kg of DM). The diet was composed of 90% concentrate. Thyme EO was composed mainly by thymol (46.6% of DM) and p-cymene (38.9% of DM). The nutrient intake and apparent digestibility were similar among treatments. The inclusion of 3.75g of thyme EO tended (P= 0.07) to increase butyrate compared to MON and 1.25OE and wethers fed with 1.25g of thyme EO tended (P= 0.07) to decrease ruminal pH on the 14th day compared to MON. The treatments did not affect acetate:propionate ratio, total short chain fatty acids (SCFA) and nitrogen retention. Results from this study suggest that adding thyme EO to high-concentrate diets may be used as an alternative to monensin as feed additive in feedlot lambs.(AU)

O objetivo do estudo foi avaliar os efeitos do óleo essencial (OE) de tomilho nos parâmetros ruminais, na digestibilidade e no balanço de nitrogênio em borregos alimentados com elevado teor de concentrado. Vinte borregos providos de cânulas ruminais foram blocados de acordo com o peso corporal (PC=64,0±2,1kg) e receberam um dos tratamentos: 25mg de monensina/kg de matéria seca (MS; MON) ou doses de OE de tomilho (1,25; 2,50 ou 3,75g/kg de MS). A dieta foi composta por 90% de concentrado. A composição do OE de tomilho foi principalmente timol (46,6% da MS) e p-cimeno (38,9% da MS). A ingestão e a digestibilidade dos nutrientes foram semelhantes entre os tratamentos. A inclusão de 3,75g de OE de tomilho tendeu (P=0,07) a aumentar o butirato em relação aos tratamentos MON e 1,25OE. Os borregos alimentados com 1,25g de OE tenderam (P=0,07) a apresentar menor pH ruminal no 14º dia comparado a MON. No entanto, os tratamentos não afetaram a relação acetato:propionato, concentração total de ácidos graxos de cadeia curta e retenção de nitrogênio. Os resultados sugerem que a adição de OE de tomilho em dietas com elevado teor de concentrado pode ser uma alternativa à monensina como aditivo alimentar para cordeiros em confinamento.(AU)

Encapsulated nitrate and cashew nut shell liquid on blood and rumen constituents, methane emission, and growth performance of lambs.

Nitrate can be a source of NPN for microbial growth at the same time that it reduces ruminal methane production. The objective of this study was to evaluate the effects of 2 encapsulated nitrate products used as urea replacers on blood and rumen constituents, methane emission, and growth performance of lambs. Eighteen Santa Inês male lambs (27 ± 4.9 kg) were individually allotted to indoor pens and assigned to a randomized complete block design with 6 blocks and 3 dietary treatments: control (CTL) = 1.5% urea, ENP = 4.51% encapsulated nitrate product (60.83% NO3(-) in the product DM), and ENP+CNSL = 4.51% ENP containing cashew nut shell liquid (60.83% NO3(-) and 2.96% cashew nut shell liquid [CNSL] in the product DM). Diets were isonitrogenous with 60:40 concentrate:forage (Tifton 85 hay) ratio. The experiment lasted for 92 d and consisted of 28 d for adaptation (a weekly 33% stepwise replacement of CTL concentrate by nitrate-containing concentrates) and 64 d for data collection. The ENP and ENP+CNSL showed greater (P < 0.05) red blood cell counts than CTL. Blood methemoglobin (MetHb) did not differ (P > 0.05) among treatments, with mean values within normal range and remaining below 1.1% of total hemoglobin. There was an increase (P < 0.05) in total short-chain fatty acids concentration at 3 h postfeeding for ENP, with an additional increase (P < 0.05) observed for ENP+CNSL. No treatment effects (P > 0.05) were observed on acetate to propionate ratio. Methane production (L/kg DMI) was reduced (P < 0.05) with nitrate inclusion, recording 28.6, 19.1, and 19.5 L/kg DMI for CTL, ENP, and ENP+CNSL, respectively. Addition of CNSL did not result (P > 0.05) in further reduction of methane production when compared with ENP. Final BW, DMI, ADG, and feed efficiency were similar (P > 0.05) among treatments. Values for DMI were 1.11, 1.03, and 1.04 kg/d and for ADG were 174, 154, and 158 g for CTL, ENP, and ENP+CNSL, respectively. In conclusion, encapsulated nitrate products showed no risks of toxicity based on MetHb formation. The products persistently reduced methane production without affecting performance. Inclusion of cashew nut shell liquid in the product formulation had no additional benefits on methane mitigation.

Energy efficiency of growing ram lambs fed concentrate-based diets with different roughage sources.

Poor-quality roughages are widely used as fiber sources in concentrate-based diets for ruminants. Because roughage quality is associated with the efficiency of energy use in forage-based diets, the objective of this study was to determine whether differing the roughage source in concentrate-based diets could change the energy requirements of growing lambs. Eighty-four 1/2 Dorper × 1/2 Santa Inês ram lambs (18.0 ± 3.3 kg BW) were individually penned and divided into 2 groups according to primary source of dietary roughage: low-quality roughage (LQR; sugarcane bagasse) or medium-quality roughage (MQR; coastcross hay). Diets were formulated to be isonitrogenous (2.6% N) and to meet 20% of physically effective NDF. After a 10-d ad libitum adaptation period, 7 lambs from each group were randomly selected and slaughtered (baseline). Twenty-one lambs in each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg BW. The remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction: 70% or 50% of the ad libitum intake. Retentions of body fat, N, and energy were determined. Additionally, 6 ram lambs (44.3 ± 5.6 kg BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to establish the ME content of the 2 diets at the 3 levels of DM intake. There was no effect of intake level on diet ME content, but it was greater in the diet with LQR than in the diet with MQR (3.18 vs. 2.94 Mcal/kg, respectively; P < 0.01). Lambs fed the diet with LQR had greater body fat (g/kg of empty BW) and energy concentrations (kcal/kg of empty BW) because of a larger visceral fat deposition (P < 0.05). Using a low-quality roughage as a primary source of forage in a concentrate-based diet for growing lambs did not change NEm and the efficiency of ME use for maintenance, which averaged 71.6 kcal/kg(0.75) of shrunk BW and 0.63, respectively. On the other hand, the greater nonfibrous carbohydrate content of the diet with LQR resulted in a 17% better efficiency of ME use for gain (P < 0.01), which was associated with a greater partial efficiency of energy retention as fat (P < 0.01). This increased nutritional efficiency, however, should be viewed with caution because it is related to visceral fat deposition, a nonedible tissue.

Thyme essential oil for sheep: effect on rumen fermentation, nutrient digestibility, nitrogen metabolism, and growth / Óleo essencial de tomilho para ovinos: efeito na fermentação ruminal, na digestibilidade dos nutrientes, no metabolismo de nitrogênio e no crescimento

Two experiments were conducted to evaluate the effect of thyme (Thymus vulgaris) essential oil (EO) doses on rumen fermentation, nutrient digestibility, and nitrogen metabolism, as well as performance and coccidia oocyst discharge. In experiment I, 20 rumen-cannulated wethers received the experimental diets containing 80% dry matter (DM) of haylage and 20% DM of concentrate. Treatments were 25mg of monensin/kg DM or doses of 1.25, 2.50, or 3.75g of thyme EO/kg DM. In experiment II, 50 ewe lambs received the same diets from experiment I, including a diet without feed additives. Wethers fed with diets containing 1.25g/kg DM of thyme EO had higher molar proportion of propionate (P= 0.03) and butyrate (P< 0.01), and lower (P= 0.04) acetate to propionate ratio than other treatments. Adding thyme EO to diets increased (P= 0.02) nitrogen retention compared to monensin. The performance of ewe lambs was not affected (P≥ 0.05) by treatments. However, lambs fed monensin had a lower (P= 0.04) number of coccidia oocyst discharge than others. Adding 1.25g/kg DM of thyme EO in high-forage diet improved ruminal fermentation. Thyme EO enhanced nitrogen metabolism, however, it did not improve performance.(AU)

Dois experimentos foram conduzidos para avaliar o efeito de doses de óleo essencial (OE) de tomilho (Thymus vulgaris) sobre a fermentação ruminal, a digestibilidade de nutrientes e o metabolismo de nitrogênio, bem como sobre o desempenho e a descarga de oocistos de coccídeos. No experimento I, 20 ovinos canulados receberam dietas experimentais contendo 80% de matéria seca (MS) de pré-secado e 20% de MS de concentrado. Os tratamentos foram 25mg de monensina/kg de MS ou doses de 1,25, 2,50 ou 3,75g de OE de tomilho/kg de MS. No experimento II, 50 borregas receberam as mesmas dietas do experimento I, incluindo uma dieta sem aditivos. Os animais alimentados com dietas contendo 1,25g de OE de tomilho apresentaram maior proporção molar de propionato (P=0,03) e de butirato (P<0,01) e menor (P=0,04) relação acetato/propionato do que outros tratamentos. A adição de OE de tomilho nas dietas aumentou (P=0,02) a retenção de nitrogênio em comparação com a monensina. O desempenho de cordeiros não foi afetado (P≥0,05) pelos tratamentos. No entanto, cordeiros alimentados com monensina apresentaram menor (P=0,04) número de oocistos de coccídeos. A adição de 1,25g/kg de MS de OE de tomilho na dieta forrageira melhorou o perfil da fermentação ruminal. O OE de tomilho aumentou a retenção de nitrogênio, no entanto não melhorou o desempenho.(AU)

Desempenho e características de carcaça de três genótipos comerciais de frangos de corte alimentados com diferentes dietas / Performance and carcass traits of three commercial broiler genotypes fed different diets

Este estudo teve como objetivo avaliar o desempenho e as características de carcaça de frangos de corte de três genótipos comerciais do nascimento aos 35 dias de idade. Utilizou-se um total de 2.970 pintos de três genótipos de aves comerciais (Cobb 500, Hubbard Flex e Ross 308). Os programas nutricionais foram dieta basal, dieta com 10% mais e 10% menos de aminoácidos do que a dieta basal. As aves foram distribuídas em delineamento inteiramente ao acaso, em esquema fatorial 3x3x2 (genótipo x dieta x sexo), com cinco repetições e 33 aves por unidade experimental. Conversão alimentar, ganho de peso diário, ingestão da dieta e peso corporal aos 35 dias de idade foram registrados. Duas aves de cada unidade experimental foram amostradas e abatidas aos 35 dias de idade para avaliar as seguintes características de carcaça: peso corporal no momento do abate, peso da carcaça e rendimento, e peso e rendimento dos cortes (peito, pernas e asas). Houve uma interação significativa entre o genótipo e sexo para GPD e PC35. Os machos apresentaram melhores desempenhos e características de carcaças do que as fêmeas.(AU)

This study aimed to evaluate performance and carcass traits of three commercial broiler genotypes from hatch to 35 days of age. A total of 2,970 sexed one day old chicks of three commercial broiler genotypes (Cobb 500, Hubbard Flex and Ross 308) were used. The nutritional programs were basal diet, diet with 10% more and 10% less amino acids than the basal diets. Birds were distributed in a completely randomized experimental design in a 3x3x2 (genotype x diet x sex) factorial scheme, with five replicates and 33 birds per experimental unit. Feed conversion, daily weight gain, diet intake and body weight at 35 days of age were recorded. Two birds from each experimental unit were sampled and slaughtered at 35 days of age to evaluate the following carcass traits: slaughter body weight, carcass weight and yield, and main cuts (breast, legs and wings) weight and yield. There was a significant interaction between genotype and sex for ADG and BW35. Males fed basal diets presented higher performance and carcass traits in comparison to females.(AU)

Comportamento ingestivo de bovinos leiteiros alimentados com farelo de crambe / Ingestive behavior of dairy catle fed crambe bran

O objetivo deste trabalho foi estudar os efeitos da utilização de farelo de crambe em substituição ao farelo de soja sobre o comportamento ingestivo de bovinos leiteiros. Foram utilizados quatro machos castrados Holandês x Zebu, fistulados no rúmen, com peso vivo médio de 664kg, distribuídos em delineamento quadrado latino 4 x 4. Os tratamentos consistiram em quatro dietas isoproteicas e isoenergéticas, formuladas com relação volumoso:concentrado 60:40 com base na matéria seca (MS). O volumoso foi composto de silagem de milho (51% MS) e feno de Tifton (49% MS), e o concentrado formulado com níveis crescentes de substituição do farelo de soja pelo farelo de crambe em 0%, 2,8%, 6,4% e 11,0% na MS da dieta. O comportamento ingestivo foi avaliado por meio do método direto de avaliação visual, em intervalos de 10 minutos, durante períodos de 24 horas. Registraram-se a frequência de alimentação, a ruminação e o ócio, bem como a posição do animal (em pé ou em decúbito). As variáveis em pé e em decúbito não diferiram entre os tratamentos, assim como os tempos gastos em alimentação, ruminação e ócio. O consumo de matéria seca e de FDN expressos em g/dia e gFDN/dia, respectivamente, a eficiência de ruminação expressa em gMS/min, a eficiência de ruminação expressa em gFDN/dia e o tempo de mastigação total não diferiram significativamente. No entanto, a eficiência de alimentação (gMS/min) variou de forma linear decrescente com a inclusão do farelo de crambe. Os períodos do dia influenciaram todas as atividades. O maior tempo de alimentação foi observado nos períodos após o fornecimento da dieta, e a maior atividade de ruminação foi verificada no período noturno. A substituição de farelo de soja por farelo de crambe não afetou o comportamento ingestivo, exceto para o parâmetro eficiência de alimentação. Nesse sentido, considerando o comportamento ingestivo, recomenda-se a substituição do farelo de soja por farelo de crambe para alimentação de bovinos leiteiros.

The aim of this work was to study the effects of the use of crambe meal replacing soy bean meal on the ingestive behavior of dairy cattle. Four male Holstein x Zebu rumen, with average live weight of 664 kg distributed in a 4x4 latin square design. The treatments consisted of four isonitrogenous and isocaloric diets, formulated with a roughage:concentrate ratio of 60:40 based on dry matter (DM). The forage was corn silage (51% DM) and Tifton grass hay (49% DM), and the concentrate was formulated with increasing levels of substitution of soy bean meal by crambe meal at 0%, 2.8%, 6.4% and 11.0% of the diet DM. The feeding behavior was evaluated using the direct method of visual assessment in 10 minute intervals during a 24 hour period. The frequency of feeding, idling time and the animal's position (standing or supine) were recorded. The variables standing and supine did not differ between treatments as well as time spent feeding, ruminating and idling times. The consumption of dry matter and NDF expressed in g/day and gNDF/day respectively, the efficiency of rumination expressed in gDM/min, the efficiency of rumination expressed in gNDF/day and the total chewing time did not differ significantly. However, the efficiency of power (gDM/min) decreased linearly with the inclusion of crambe meal. Periods of the day influenced all the activities. The longer feeding time was observed in the periods after the diet intake and greater rumination activity was observed at night. The replacement of soy bean meal by meal crambe did not affect feeding behavior, except for the feeding efficiency parameter. In this sense, considering the feeding behavior, the replacement of soy bean meal by crambe meal to feed dairy cattle is recommended.