-The effects of overfeeding with protein of different degradability on body condition, plasma urea nitrogen and progesterone concentrations, ovulation number and follicular dynamics were assessed in Santa Ines ewes.Twelve ewes were assigned to a randomized block design according to body weight and received overfeeding with soybean meal or with corn gluten meal or maintenance diet for 28 days before ovulation and during the next estrous cycle. Blood samples were taken on days 7, 14, 21, and 28 after the beginning of treatments for analysis of plasma urea nitrogen and on days 3, 6, 9, 12, and 15 into the estrous cycle for analysis of plasma urea nitrogen and progesterone. Follicular dynamics was monitored daily by ultrasound during one estrous cycle. Dry matter and crude protein intake, weight gain, plasma urea nitrogen concentration before ovulation, number of ovulations, diameter of the largest follicle of the 1st and of the 2nd waves and the growth rate of the largest follicle of the 1st wave were higher in the ewes that received overfeeding. The growth rate of the largest follicle of the 3rd wave was higher in the ewes fed maintenance diet. The back fat thickness, plasma urea nitrogen before ovulation and progesterone concentrations, diameter of the largest follicle of the 2nd wave and growth rate of the largest follicle of the 3rd wave were higher in ewes that received overfeeding with soybean meal. The growth rate of the largest follicle of the 1st wave was higher in ewes that received overfeeding with corn gluten meal. Overfeeding with protein-rich feeds may increase the ovulation number and with soybean meal, it may be effective in increasing plasma progesterone concentration in ewes.
Efeito do nível nutricional antes e após a ovulação sobre a taxa de gestação e a prolificidade em ovelhas Santa Inês RESUMOQuarenta e três ovelhas foram distribuídas em quatro tratamentos em um delineamento de blocos casualizados. Os tratamentos consistiram no fornecimento de dietas de flushing, formuladas com farelo de soja (FFS) ou com glúten de milho e farelo de algodão (FGM+FA) por 28 dias antes da ovulação, seguido pelo fornecimento de dietas de flushing ou de uma dieta de mantença (DM) durante 28 dias após a ovulação: T1 -FFS antes e após a ovulação (n=12); T2 -FFS antes da ovulação e DM após (n=11); T3 -FGM+FA antes e após a ovulação (n=10); T4 -FGM+FA antes da ovulação e DM após (n=10). O ganho de peso e o peso final não diferiram (P>0,05) entre os animais dos tratamentos. O ECC final foi maior (P<0,05) nas ovelhas do tratamento T3 do que nas do tratamento T2. A concentração de N-ureico foi maior (P<0,05) nas ovelhas dos tratamentos T1 e T3 do que naquelas dos tratamentos T2 e T4. A taxa de gestação e a prolificidade não diferiram (P>0,05) entre os animais. As dietas de flushing antes da ovulação, seguidas pelo fornecimento destas mesmas dietas ou de uma dieta de mantença após a ovulação, não alteraram a taxa de gestação e a prolificidade.Palavras-chave: farelo de soja, glúten de milho, proteína degradável no rúmen, concentração plasmática de N-ureico ABSTRACT Forty-tree ewes were assigned to four treatments in a randomized block design. The treatments consisted of two flushing diets, composed of soybean meal (SMF) or corn gluten and cottonseed meal (CG+CMF) furnished for 28 days before ovulation, and feeding with flushing diets or a maintenance diet (MD) for 28 days after ovulation: T1 -(SMF) before and after ovulation (n=12); T2 -SMF before ovulation and a MD after (n=11); T3 -CG+CMF before and after ovulation (n=10); T4 -CG+CMF before ovulation and MD after (n=10
Flushing provides sheep a diet dense in nutrients before the breeding season to increase the ovulation rate and is usually accompanied by increase in body weight (BW) and body condition score (BCS). Although the effect of flushing with high-energy diets is documented, the influence of flushing with high-protein diets on ovulation rate and on plasma urea nitrogen (PUN) is not well established. The aim of this study was to evaluate the ovulation rate of Santa Ines ewes subjected to flushing with protein sources with different ruminal degradability. Forty-eight ewes were assigned to 2 treatments in a randomized block design, based on initial BCS (2.25 to 2.5; 2.75; and 3.0 to 3.25; scale 1 = thin and 5 = fat). The treatments consisted of 2 isonitrogenous (12% crude protein) and isocaloric (3.9 Mcal of metabolizable energy per day) diets, but with different proportions of rumen-degradable protein; one with soybean meal (SM, n = 24) and the other with corn gluten meal and cottonseed meal (CG + CM, n = 24), provided for 28 d before ovulation. The BW and BCS were evaluated weekly. Estrus synchronization was initiated on Day 17 after beginning the treatment diets. An intravaginal sponge with 60 mg of medroxyprogesterone acetate (MAP-60®, Tecnopec, São Paulo, Brazil) was used for 11 d, and an injection of 300 IU of eCG (Novormon®, Syntex SA, Buenos Aires, Argentina) and 50 μg of cloprostenol (Prolise®, ARSA S.R.L., Buenos Aires, Argentina) was given 9 d after beginning the protocol. Estrus was monitored twice daily. The ovulation rate was evaluated by transrectal ultrasonography and was characterized by the disappearance of dominant follicles in the ovaries. Blood samples for determination of PUN were collected on Days 7, 14, 21, and 28 after the start of flushing. Quantitative data were subjected to ANOVA and the rate of estrus detection was analyzed by chi-square test. Treatment differences were considered significant if P < 0.05. The sheep consumed the equivalent to 1.60 times the metabolizable energy requirement for maintenance and 1.86 times the requirement of protein for maintenance. Estrus detection rate (95.83 v. 83.33%), BW (3.14 ± 0.55 v. 2.94 ± 0.61 kg) and BCS (0.04 ± 0.05 v. 0.10 ± 0.06) gain before ovulation, BW (54.46 ± 1.31 v. 53.36 ± 1.44 kg) and BCS (2.78 ± 0.05 v. 2.85 ± 0.05) on the 28th experimental day, PUN (17.25 ± 0.60 v. 16.23 ± 0.66 mg dL-1), ovulation rate (2.25 ± 0.16 v. 2.24 ± 0.18) and ovulatory follicle diameter (6.61 ± 0.17 v. 6.72 ± 0.19 mm) did not differ (P > 0.05) between ewes feed SM or CG + CM, respectively. Flushing with protein sources with different ruminal degradability did not alter the ovulation rate or the ovulatory follicle diameter in Santa Ines ewes. Funded by FAPEMIG, CNPq, TECNOPEC.
Protein excess in diet and or rumen degradable protein (RDP) has been associated with elevated concentrations of N-urea in blood and reduction of the concentration of progesterone (P4) in plasma. The objective of this study was to evaluate the overnutrition (flushing) effects of diets containing different rates of RDP on the plasma concentrations of N-urea and P4 in Santa InÊs ewes. Twelve ewes were assigned in a randomized block design formed by 4 body weight bands. Two isocaloric (3.10 and 2.89 Mcal/day) and isonitrogenous (13.15 and 13.46% crude protein; CP) diets with different proportions of RDP (8.43 and 6.60%) containing soybean meal and corn gluten meal, respectively, and 1 maintenance diet (1.91 Mcal/day; 11.30% CP and 6.31% of RDP) were provided for 28 days before ovulation and during the next estrous cycle. Hence, 3 treatments were compared and 4 replicates were done. On Day 17 after starting the diet treatments, intravaginal sponges containing 60 mg of medroxyprogesterone acetate (MAP-60®, Tecnopec, São Paulo, Brazil) were inserted for 11 days. Nine days after sponge insertion, 240 IU of eCG (Novormon®, Syntex S.A., Buenos Aires, Argentina) and 50 μg of cloprostenol (Prolise®, ARSA S.R.L., Buenos Aires, Argentina) were administered i.m. Blood samples for determination of N-urea were collected on Days 7, 14, 21, and 28 after starting the diets and on Days 3, 6, 9, 12, and 15 after ovulation. Blood samples collected during the postovulatory interval were also analyzed for P4. Data were analyzed by ANOVA and treatment means were compared by orthogonal contrasts, where theF-testwas significant. Contrast 1 =T1 andT2 v. T3, and contrast 2 = T1 v. T2. The N-urea and P4 concentrations in plasma were analyzed according to split plot in time scheme. The sheep dry matter (DM) and CP consumption that were recorded in the flushing diet was higher (P < 0.01) than in ewes receiving the maintenance diet. The DM and CP consumption of ewes did not differ between treatments T1 and T2. The plasma N-urea concentration was not different (P > 0.05) between the ewes that consumed the flushing diet and ewes that received the maintenance diet, but it was higher (P < 0.01) in ewes that were fed the flushing diet containing soybean meal (25.09 mg dL-1) as compared with that of ewes fed the flushing diet containing corn gluten meal (20.81 mgdL-1). The P4 concentration in plasma did not differ (P > 0.05) among animals that received the flushing diet and those that received the maintenance diet, but there was a significant difference (P = 0.05) between flushing diets containing soybean meal (7.28 ngmL-1) compared with those containing corn gluten meal (4.46 ngmL-1). In summary, the nutritional level (flushing v. maintenance) did not alter the concentrations of N-urea and P4 in plasma of ewes, but the supply of a greater protein degradability source did increase their concentrations. Funded by FAPEMIG, CNPq, and TECNOPEC.
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