Levels Of Protein Supplementation Research Articles

Effects of replacing rapeseed meal with fava bean at 2 concentrate crude protein levels on feed intake, nutrient digestion, and milk production in cows fed grass silage-based diets.

The objective of this study was to evaluate the production and physiological responses of dairy cows to the substitution of fava bean for rapeseed meal at 2 protein supplementation levels in grass silage-based diets. We used 6 primiparous and 6 multiparous Finnish Ayrshire cows in a cyclic changeover trial with a 2×3 factorial arrangement of treatments. The experimental diets consisted of formic acid-treated timothy-meadow fescue silage and 3 isonitrogenous concentrates containing either rapeseed meal, fava bean, or a 1:1 mixture of rapeseed meal and fava bean at low and high inclusion rates, resulting in concentrate crude protein (CP) levels of 15.4 and 19.0% in dry matter. Silage dry matter intake decreased linearly when rapeseed meal was replaced with fava bean, the negative effect being more distinct at the high CP level than the low (-2.3 vs. -0.9kg/d, respectively). Similarly, milk and milk protein yields decreased linearly with fava bean, the change tending to be greater at the high CP level than the low. Yield of milk fat was lower for fava bean compared with rapeseed meal, the difference showing no interaction with CP level. Especially at the high CP level, milk urea concentration was higher with fava bean compared with rapeseed meal indicating better utilization of protein from the rapeseed meal. The apparent total-tract organic matter digestibility did not differ between treatments at the low CP level, but digestibility was higher for fava bean than for rapeseed meal at the high CP level. Plasma concentrations of essential amino acids, including methionine and lysine, were lower for fava bean than for rapeseed meal. Compared with rapeseed meal, the use of fava bean in dairy cow diets as the sole protein supplement decreased silage intake and milk production in highly digestible formic acid-treated grass silage-based diets.

Allergens and intestinal damage induced by soybean antigen proteins in weaned piglets

This study was conducted to investigate the effects of soybean antigen proteins on serum cytokine levels and claudin-1 distribution in the intestine of weaned piglets. Seventy piglets (24 d of age) were randomly divided into seven groups. Piglets in group A were fed a basal diet, in groups B, C and D were fed the basal diet supplemented with β-conglycinin; and in groups E, F, G were fed the basal diet supplemented with glycinin. Blood samples were collected and analysed for IFN-γ, IL-2, IL-4 and IL-6 levels on day 24, 26, 28 and 30. At the end of the trial, five piglets per group were sacrificed and the small intestine was collected to evaluate intestinal claudin-1 distribution and OD of the relative staining positivity. β-Conglycinin and glycinin decreased the growth performance in piglets by decreasing ADFI, ADG and increasing F/G. Serum levels of IL-2, IL-4 and IL-6 in β-conglycinin and glycinin groups ranged from 126.067 to 144.067 ng • L−1, 31.798 to 44.360 ng • L−1 and 36.360 to 40.482 ng • L−1 on day 24, 26 and 30. However, serum IFN-γ levels were negatively correlated with soybean antigen proteins supplementation levels ranged from 6.956 to 15.361 ng • L−1. The treatment groups had lower OD values of claudin-1 than those of the control group. The β-conglycinin groups had lower distribution and OD values than the glycinin groups at similar antigen protein supplementation levels. These results suggest that β-conglycinin and glycinin damage the intestinal mucosal immune barrier in weaned piglets.

Effects of Two Levels of Protein Supplementation on Intake, Apparent Digestibility and Ammonia Nitrogen in Growing Goats Fed Ammoniated Crop By-Products

Effects of Two Levels of Protein Supplementation on Intake, Apparent Digestibility and Ammonia Nitrogen in Growing Goats Fed Ammoniated Crop By-Products

Effect of feeding different levels of proteins on growth, blood biochemical and immunological parameters in laying Khaki Campbell ducks

A feeding experiment was carried out to study the effect of feeding different levels of protein during laying (20-40 weeks) on growth, feed consumption and mortality in Khaki Campbell ducks. 180 ducks were distributed randomly into three treatment groups viz. T1, T2 and T3 with three replicates of 20 ducks (15 females and 5 males) in each replicate. Birds were allotted to different groups in such a manner that there was no significant difference between the average 20th week body weight among the treatment groups. Between 20-40 weeks, ducks were provided with isocaloric diets with 16, 18 and 20 per cent crude protein in to groups T1, T2 and T3 respectively with ad lib provision of feed and water. Results indicated that supplementation of crude protein of about 18% in the ration during laying period might be sufficient with respect to growth trait in Khaki Campbell layer ducks. Further, the mortality ranged from 2 to 3.2% during laying stage, which was within normal range indicating that the different levels of protein supplementation in diet could not influence the health condition of ducks. The effect of different levels of protein supplementation in the diet during active stage of laying (30th week) was found to be non-significant, with respect to blood biochemicals like total protein, albumin, abumin:gobulin ratio, glucose, urea and creatinine concentration. The level of primary antibody in T1, T2 and T3 of female ducks were 6.00 ± 0.00, 5.33 ± 0.33 and 6.33 ± 0.33 and for combined sex they were 5.00 ± 0.52, 5.33 ± 0.33 and 5.67 ± 0.42, respectively.

Benefits of post-operative oral protein supplementation in gastrointestinal surgery patients: A systematic review of clinical trials.

To evaluate published trials examining oral post-operative protein supplementation in patients having undergone gastrointestinal surgery and assessment of reported results. Database searches (MEDLINE, BIOSIS, EMBASE, Cochrane Trials, Cinahl, and CAB), searches of reference lists of relevant papers, and expert referral were used to identify prospective randomized controlled clinical trials. The following terms were used to locate articles: "oral'' or "enteral'' and "postoperative care'' or "post-surgical'' and "proteins'' or "milk proteins'' or "dietary proteins'' or "dietary supplements'' or "nutritional supplements''. In databases that allowed added limitations, results were limited to clinical trials that studied humans, and publications between 1990 and 2014. Quality of collated studies was evaluated using a qualitative assessment tool and the collective results interpreted. Searches identified 629 papers of which, following review, 7 were deemed eligible for qualitative evaluation. Protein supplementation does not appear to affect mortality but does reduce weight loss, and improve nutritional status. Reduction in grip strength deterioration was observed in a majority of studies, and approximately half of the studies described reduced complication rates. No changes in duration of hospital stay or plasma protein levels were reported. There is evidence to suggest that protein supplementation should be routinely provided post-operatively to this population. However, despite comprehensive searches, clinical trials that varied only the amount of protein provided via oral nutritional supplements (discrete from other nutritional components) were not found. At present, there is some evidence to support routinely prescribed oral nutritional supplements that contain protein for gastrointestinal surgery patients in the immediate post-operative stage. The optimal level of protein supplementation required to maximise recovery in gastrointestinal surgery patients is effectively unknown, and may warrant further study.

Metabolismo nitrogenado em bovinos suplementados a pasto durante a transição águas seca

Objetivou-se com este estudo avaliar o consumo, a fermentação ruminal, síntese de proteina microbiana, balanço dos compostos nitrogenados e comportamento ingestivo de suplemento de novilhos mantidos a pasto, suplementados com níveis crescentes de proteína bruta. Foram utilizados 4 novilhos mestiços, com idade média de 24 meses, peso corporal médio de 400 kg, providos de cânula ruminal. Os animais foram mantidos em piquetes individuais, em delineamento quadrado latino 4 x 4. Os suplementos experimentais foram constituídos por diferentes níveis de proteína: T00= Suplemento mineral (controle); T20= Su-plemento concentrado com 20 % de PB; T40= Suplemento concentrado com 40 % de PB; T60= Suplemento concentrado com 60 % de PB. Não foi observado efeito sobre o consumo de matéria seca. Foi observado efeito sobre as concentrações de valerato, porém não foram observadas respostas lineares ou quadráticas. O tratamento T60 apresentou menor velocida-de de ingestão de suplemento em relação aos demais. Os níveis de suplementação proteica não influenciaram o consumo de matéria seca, síntese de proteína microbiana e balanço de compostos nitrogenados, porem influenciaram as concentrações de ácidos graxos de cadeia ramificada e a velocidade de consumo de suplemento proteico.

Effects of soybean meal or canola meal on milk production and methane emissions in lactating dairy cows fed grass silage-based diets

This study evaluated the effects of soybean meal (SBM) and heat-moisture-treated canola meal (TCM) on milk production and methane emissions in dairy cows fed grass silage-based diets. Twenty-eight Swedish Red cows were used in a cyclic change-over experiment with 4 periods of 21 d and with treatments in 2×4 factorial arrangement (however, the control diet without supplementary protein was not fed in replicate). The diets were fed ad libitum as a total mixed ration containing 600g/kg of grass silage and 400g/kg of concentrates on a dry matter (DM) basis. The concentrate without supplementary protein consisted of crimped barley and premix (312 and 88g/kg of DM), providing 130g of dietary crude protein (CP)/kg of DM. The other 6 concentrates were formulated to provide 170, 210, or 250g of CP/kg of DM by replacing crimped barley with incremental amounts of SBM (50, 100, or 150g/kg of diet DM) or TCM (70, 140, or 210g/kg of diet DM). Feed intake was not influenced by dietary CP concentration, but tended to be greater in cows fed TCM diets compared with SBM diets. Milk and milk protein yield increased linearly with dietary CP concentration, with greater responses in cows fed TCM diets compared with SBM diets. Apparent N efficiency (milk N/N intake) decreased linearly with increasing dietary CP concentration and was lower for cows fed SBM diets than cows fed TCM diets. Milk urea concentration increased linearly with increased dietary CP concentration, with greater effects in cows fed SBM diets than in cows fed TCM diets. Plasma concentrations of total AA and essential AA increased with increasing dietary CP concentration, but no differences were observed between the 2 protein sources. Plasma concentrations of Lys, Met, and His were similar for both dietary protein sources. Total methane emissions were not influenced by diet, but emissions per kilogram of DM intake decreased quadratically, with the lowest value observed in cows fed intermediate levels of protein supplementation. Methane emissions per kilogram of energy-corrected milk decreased more when dietary CP concentration increased in TCM diets compared with SBM diets. Overall, replacing SBM with TCM in total mixed rations based on grass silage had beneficial effects on milk production, N efficiency, and methane emissions across a wide range of dietary CP concentrations.

A comparison of ruminal or reticular digesta sampling as an alternative to sampling from the omasum of lactating dairy cows

The objective of this study was to develop and compare techniques for determining nutrient flow based on digesta samples collected from the reticulum or rumen of lactating dairy cows with estimates generated by the omasal sampling technique. Pre-experimental method development suggested, after comparing with the particle size distribution of feces, application of primary sieving of ruminal and reticular digesta from lactating cows through an 11.6-mm sieve, implying that digesta particles smaller than this were eligible to flow out of the rumen. For flow measurements at the different sampling sites 4 multiparous, lactating Nordic Red cows fitted with ruminal cannulas were used in a Latin square design with 4 dietary treatments, in which crimped barley was replaced with 3 incremental levels of protein supplementation of canola meal. Digesta was collected from the rumen, reticulum, and omasum to represent a 24-h feeding cycle. Nutrient flow was calculated using the reconstitution system based on Cr, Yb, and indigestible neutral detergent fiber and using 15N as microbial marker. Large and small particles and the fluid phase were recovered from digesta collected at all sampling sites. Bacterial samples were isolated from the digesta collected from the omasum. Several differences existed for digesta composition, nutrient flows, and estimates of ruminal digestibility among the 3 different sampling sites. Sampling site × diet interactions were not significant. The estimated flows of DM, potentially digestible neutral detergent fiber, nonammonia N, and microbial N were significantly different between all sampling sites. However, the difference between DM flow based on sampling from the reticulum and the omasum was small (0.13kg/d greater in the omasum). The equality between the reticulum and the omasum as sampling sites was supported by the following regression: omasal DM flow=0.37 (±0.649) + 0.94 (±0.054) reticular DM flow (R2=0.96 and root mean square error=0.438kg/d). More deviating nutrient-flow estimates when sampling digesta from the rumen than the reticulum compared with the omasum suggested that sampling from the reticulum is the most promising alternative to the omasal sampling technique. To definitively promote sampling from the reticulum as an alternative to the omasal sampling technique, more research is needed to determine selection criteria of reticular digesta for accurate and precise flow estimates across a range of diets.

Effects of Different Levels of Protein Supplements in the Diet of Early-Weaned Yaks on Growth Performance, Intestinal Development, and Immune Response to Tuberculosis

This study was conducted to determine the effects of different levels of crude protein (CP) supplements to the diet of early-weaned yaks on their growth performance, intestinal development, and immune response. Forty 3-month-old weaned yaks were selected and assigned to four dietary groups (Control, 17, 19 and 21% CP). Dietary CP supplements had a significant effect on average daily gain (ADG), crypt depth (CD) (duodenum, jejunum and ileum), villous height (VH) (duodenum, jejunum and ileum) and CD/VH (jejunum and ileum). Average daily gain, CD (duodenum, jejunum and ileum) and VH (ileum) showed quadratic increases as the dietary CP increased, whereas CD/VH (jejunum and ileum) ratios showed quadratic decreases. Blood urea nitrogen (BUN), glucose (GLU), immunoglobulin G (IgG), IgM, interleukin-1 (IL-1), IL-2, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ concentrations increased significantly, whereas albumin (ALB), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) decreased significantly with dietary CP supplements. Dietary CP supplements significantly increased the concentrations of IL-6, TNF-α, IFN-γ and the nuclear factor of activated T cell transcription factor (NF-AT) for gene expression. As the dietary CP supplements increased, IL-6, IFN-γ and NF-AT gene expression showed quadratic increases. These results showed that the appropriate dietary CP supplementation improved the growth performance and intestinal development of early-weaned yaks and thus that the CP supplements were beneficial and enhanced the humoral immunity response of yaks.

Effects of feeding different levels of proteins on the performance in Khaki Campbell ducks during starter stage

The present study was conducted on the 225 unsexed day-old Khaki Campbell ducklings in the Regional Centre, CARI, Bhubaneswar during the period between March to June, 2013. The ducklings were randomly distributed into three treatment groups viz. T1, T2 and T3 supplemented with 18, 20 and 22 per cent crude protein respectively and three replicates in each group to study the effect of feeding different levels of proteins on the performance of the ducks during starter stage. It was found that the live weight of ducklings in different treatments group increased steadily up to 8 weeks of age attaining the lowest body weight of 1243.45±23.01 g in T1 and highest body weight of 1292.97±0.71 g in T3. Significantly (p£0.05) lower daily feed intake was observed in T3 during 3rd week of age than T1 and T2 and the intake was significantly (p£0.05) lower in T3 than T1 but not from T2 at 8th week of age. The apparent metabolisibility of dry matter in T1, T2 and T3 were 75.46±0.90, 77.70±0.30 and 79.38±0.89 per cent, respectively and there was a significant difference in the metabolisability of dry matter (per cent) among different treatments. The nitrogen intake was significantly (p£0.05) higher in T3 (3.63 g/day) than T1 (3.16 g/day), but the difference between T3 and T2 was found to be non-significant. The impact of different levels of protein supplementation in the diet of ducks was found to be non-significant with respect to blood glucose, total protein, albumin, globulin, albumin and globulin ratio, total cholesterol and creatinine concentration after 8 weeks of age. It can be concluded that with increase in the supplementation of protein in the Khaki Campbell ducks during the starter period significantly better impact the health and productive traits of the birds and thereby the overall economic status of the farm.

Dairy cow responses to graded levels of rapeseed and soya bean expeller supplementation on a red clover/grass silage-based diet

The effects of rapeseed and soya bean expeller (SBE) supplementation on digestion and milk production responses in dairy cows were investigated in an incomplete Latin square design using five cows and four 3-week periods. The experimental diets consisted of five concentrate treatments fed at a rate of 9 kg/day: a mixture of barley and oats, which was replaced with rapeseed or SBE at two levels (CP concentration (g/kg dry matter (DM)) of 130 for the control concentrate and 180 and 230 for the two protein supplemented levels). A mixture of grass and red clover silage (1:1) was fed ad libitum and it had a CP concentration of 157 g/kg DM. Supply of nutrients to the lower tract was measured using the omasal canal sampling technique, and total digestion from total faecal collection. Protein supplementation increased omasal canal amino acid (AA) flows and plasma concentrations of AA, and was also reflected as increased milk production. However, N use efficiency (NUE) decreased with increased protein supplementation. Rapeseed expeller (RSE) tended to increase silage DM intake and elicited higher milk production responses compared with SBE and also resulted in a higher NUE. The differences between the protein supplements in nitrogen metabolism were relatively small, for example, there were no differences in the efficiency of microbial protein synthesis or omasal canal flows of nitrogenous components between them, but plasma methionine concentration was lower for soya bean-fed cows at the high CP level in particular. The lower milk protein production responses to SBE than to RSE supplementation were at least partly caused by increased silage DM and by the lower methionine supply, which may further have been amplified by the use of red clover in the basal diet. Although feed intake, diet digestion, AA supply and milk production were all consistently improved by protein supplementation, there was a simultaneous decrease in NUE. In the current study, the milk protein production increased only 9% and energy-corrected milk production by 7% when high level of protein supplementation (on average 2.9 kg DM/day) was compared with the control diet without protein supplementation showing that dairy production could be sustained at a high level even without external protein supplements, at least in the short term. The economic and environmental aspects need to be carefully evaluated when decisions about protein supplementation for dairy cows are taken.

Effects of Increasing Rumen‐Undegradable Protein Supplementation Levels on Early Weaned Calves Grazing Stargrass

Early weaned beef calves (Bos spp.) grazing warm‐season grasses may benefit from increasing levels of rumen‐undegradable protein (RUP) supplementation due to the limited RUP supplied by the forage and their high nutrient requirements. The objective of this study was to test the effects of increasing levels of RUP supplementation on performance of early weaned calves grazing stargrass (Cynodon nlemfuensis Vanderyst) pastures. The experiment was conducted in Ona, FL, from May to August 2007 and 2008. Treatments were 1.5 g kg−1 body weight (BW) of three levels of supplemental RUP from soybean [Glycine max (L.) Merr.] meal (SBM) (350 g kg−1 RUP), Soyplus (SP) (600 g kg−1 RUP) (a modified expeller SBM) (West Central, Ralston, IA), or a 50:50 mixture of SBM and Soyplus (SBMSP) (475 g kg−1 RUP). Pasture size was 0.51 ha and four early weaned calves were assigned to each pasture. There was no effect of the treatments on mean herbage mass (HM; 2.7 Mg ha−1), forage crude protein (CP) (171 g kg−1), in vitro digestible organic matter (IVDOM) concentration (640 g kg−1), or calf average daily gain (0.56 kg d−1). Increased RUP supplementation did not affect forage dry matter intake (mean = 2.0% BW); however, there was a linear decrease in apparent dry matter digestibility from 640 to 600 g kg−1. Increasing levels of RUP supplementation may not increase performance of early weaned calves grazing stargrass pastures when forage CP is not limiting.

Parâmetros ruminais e síntese de proteína metabolizável em bovinos de corte sob suplementação com proteinados contendo diversos níveis de proteína bruta

Avaliaram-se os efeitos dos níveis de nitrogênio de suplementos proteicos sobre as concentrações de nitrogênio amoniacal (N-NH3) e ácidos graxos voláteis (AGV) e o pH em bovinos de corte em pastagem de capim-marandu (Brachiaria brizantha, cv. Marandu). Foram realizadas estimativas da síntese microbiana, do aporte de proteína nãodegradável no rúmen (PNDR) e proteína endógena e das suas contribuições no pool de proteína metabolizável (PM). Quatro bovinos Nelore com 395 ± 9 kg, fistulados no rúmen, foram utilizados nas medidas dos parâmetros ruminais e nas avaliações da degradabilidade, da cinética ruminal e das estimativas de síntese microbiana em um delineamento quadrado latino 4 ×4. Suplementos com 30, 40 ou 50% de proteína bruta (PB) foram fornecidos na quantidade de 400 g/animal.dia para comparação a um grupo controle, sem suplementação proteica. Os animais foram mantidos em pastagens de Brachiaria brizantha, cv. Marandu, distribuídos em quatro piquetes com área de 1,0 ha cada, com oferta do suplemento e retirada das sobras, realizada diariamente. As concentrações de N-NH3 nos animais que receberam o suplemento com 50% PB foram superiores às observadas naqueles sob suplementação com 40% PB e no grupo controle, mas foram semelhantes às observadas no grupo sob suplementação com 30% PB. As concentrações de AGV no grupo sob suplementação com 30% PB foram superiores às observadas no grupo controle e semelhantes às obtidas com suplementação com 40 e 50% PB. O pH não diferiu entre os grupos. A estimativa de oferta de proteína microbiana e de PNDR foi maior para os animais sob suplementação com proteína em relação à observada no grupo controle.

Omasal sampling technique in estimation of the site and extent of mineral absorption in dairy cows fed rapeseed and soybean expellers

The effects of rapeseed and soybean expeller on digestion of sodium, potassium, calcium, magnesium, phosphorus and sulphur in dairy cows were investigated in a study conducted as an incomplete Latin square. The experimental diets consisted of five concentrates fed at a rate of 9 kg d-1: a mixture of barley and oats (control), which was replaced either with rapeseed or soybean expeller both at two levels (130, 180 and 230 g crude protein per kg dry matter). A mixture of grass and red clover silage (1:1) was fed ad libitum. No mineral supplements except for NaCl and trace minerals were used. Ruminal digestion was estimated by omasal sampling technique and total digestion from total faecal collection. Intake of all minerals except sodium increased with the level of protein supplementation and it was generally higher when rapeseed compared with soybean expeller diets were offered. Reticulo-rumen was the major site of net absorption of magnesium, whereas calcium, phosphorus, sodium and potassium were absorbed postruminally. Net absorption of sulphur took place both in the rumen and postruminally. Omasal flow of sodium and phosphorus indicated substantial secretion of these minerals into the rumen via saliva. Compared with the published data based on duodenal sampling, the results indicated that omasum has an important role in the absorption of minerals, especially sodium and phosphorus. Omasal sampling technique is a useful tool in studying ruminal mineral metabolism.;

Nutritive Value of Maize Stover Harvested at Two Stages of Maturity and Mixed with Different Types and Levels of Protein Supplements

Ouda, J.O. and Nsahlai, I. V. 2007. Nutritive value of maize stover harvested at two stages of maturity and mixed with different types and levels of protein supplements. J. Appl. Anim. Res., 32: 89–95. Studies were conducted on maize stover harvested at grain milk (MM) or dry (MB) stages and mixed with graded ratios (20, 40, 60, 80%) of protein supplements (PS) including lucerne hay (LH), lespedeza hay (LPZ) and sunflower seed cake (SC). Automated in vitro, gas production technique (IVGPT) was used. The degradability (Deg) was higher (P<0.001) in MM than MB (775.9 vs 720 g/kg BM). Also, MM rations had higher (P<0.001) gas production (GP) than MB. Only ST × PS interaction had effect (P<0.001) on the Deg:GP ratio i.e. the partitioning factor (PF), in which MD:LPZ rations had highest values apparently as a result of suppressed GP. The rate of GP from fibre fraction (b1) was increased (P<0.001) by PS although the margins were small across the rations. Supplementation of LPZ increased (P<0.01) lag time, which was highest in MD:LPZ rations. Among the PS, LH and SC had similar but superior nutritive effects relative to LPZ. It is suspected that the presence of tannins in LPZ might be responsible for the poor nutritive attributes observed. The results suggest that supplementation of the stover with at most 40% DM contributed by LH or SC would optimize their utilization.

Body condition and protein supplementation positively affect periovulatory ovarian activity by non LH-mediated pathways in goats

Effects of rumen undegradable intake protein (UIP) supplementation on ovarian activity and serum insulin, GH, and LH were evaluated in goats having low or high body condition (BC). Goats with either low BC ( n = 16, 28.7 ± 0.8 kg BW, BC = 2.1 ± 0.3) or high BC ( n = 16, 38.4 ± 0.8 kg, BC = 3.2 ± 0.3) received, during 40-days, one of the two protein supplementation levels: without UIP or with UIP (120 g goat −1 d −1). Oestrus was synchronized with two i.m. doses of PGF 2α, and jugular blood samples were collected from 36 to 42 h after the second prostaglandin injection at 15 min intervals. Serum concentrations of insulin, LH, and GH were measured The number of preovulatory follicles and the number of corpora lutea (CL) were evaluated by transrectal ultrasonography at 1 and 4 days after the second prostaglandin dose, respectively. Does with higher BC had more CL than those in the lower condition group (2.8 ± 0.2 versus 1.8 ± 0.2, P < 0.05). Similarly, goats receiving UIP supplementation had more follicles (2.6 ± 0.2 versus 1.9 ± 0.2, P < 0.05) and tended to have more CL (2.6 ± 0.2 versus 2.0 ± 0.2, P = 0.05) than does not receiving UIP. Neither BCS nor UIP supplementation affected serum GH or LH concentrations, pulsatility, or area under the curve. High BC does produced more insulin (1.92 ± 0.17 versus 0.81 ± 0.17 ng/mL, P < 0.01 ng/mL) than lower BC goats; the same for UIP-supplemented (1.69 ± 0.18 versus 1.04 ± 0.18, P < 0.05). Results suggest that the increased ovarian activity observed in both UIP-supplemented and higher BC goats was not the result of changes in LH or GH, suggesting effects at a local level, through changes in insulin in a non-GnRH-gonadotrophin dependent manner.

Effects of Body Condition and Protein Supplementation on LH Secretion and Luteal Function in Sheep

In ruminants, nutrition is one of the exogenous inputs affecting reproductive function at different levels of the hypothalamic-hypophyseal-gonadal axis. However, the exact mechanisms or even the identification of the signalling metabolic compounds by which nutrition affects reproductive function still need further clarification. The role of static body condition (BC) and its interaction with a short-term protein supplementation (PL), on secretion of metabolic hormones [growth hormone (GH), insulin and insulin-like growth factor-1 (IGF-1)], as well as on secretion of LH and progesterone (P4) was evaluated in sheep. Twenty-four Rambouillet ewes divided into two groups, with lower (LBC) and higher body condition (HBC), were randomly assigned within BC to one of two PL levels: low (LPL, 24% of crude protein; 14 g/animal/day), and high (HPL, 44% of crude protein; 30 g/animal/day). The secretion of GH, insulin, IGF-1 and LH was evaluated on day 10 of the oestrous cycle; appearance and timing of oestrous behaviour were previously detected using rams. Progesterone secretion was evaluated on day 13 of the same cycle. No differences were found (p > 0.05) between PL groups on serum GH concentrations during the sampling period (overall mean of 4.0 +/- 0.3 ng/ml), but a trend for lower values in HBC sheep was found (3.6 +/- 0.4 vs 4.4 +/- 0.4 ng/ml, p = 0.06). A BC effect was observed (p < 0.05) on serum IGF-1 level, with higher values in HBC sheep (p < 0.05). Neither BC nor PL affected (p > 0.05) secretion of LH and the number of corpora lutea, nor serum P4 and insulin concentrations. Results indicate a predominance of the static component of nutrition on sheep metabolic hormone responses, GH and IGF-1, with no effect of short-term PL on secretion of pituitary and ovarian hormones as well as luteal number and activity.

The influence of pre- and post-mating protein supplementation on reproductive performance in ewes maintained on rangeland

The effect of short-term changes in level of protein supplementation during pre- and post-mating on non-return rate, lambing rate and litter size was investigated in ewes grazing on rangeland during early autumn. Groups of ewes were fed diets providing either 58 g (low, L) or 113 g (high, H) crude protein per day per ewe grazing on rangeland. Diets were calculated on a dry matter bases to provide 0.7 and 1.3 times protein requirements for maintenance. Following the first detected estrus, a total of 130 adult ewes were allocated into either L ( n = 67) or H ( n = 63) treatment until next estrous (pre-mating). At the second estrus, the ewes were mated, and again randomly allocated to either the L or H allowance until day 15 (post-mating; mating = day 0). Hence, there were four nutrition treatments; LL ( n = 35), LH ( n = 32), HL ( n = 32) and HH ( n = 31). Non-return rate, lambing rate tended to be higher in ewes fed the LH diet (0.88 and 81.3%) than the HL diet (0.69; P < 0.07 and 59.4%; P < 0.06). A similar effect of the LH diet (81.3%) was observed for lambing rate compared to the LL diet (60.0%; P < 0.06). The mean litter size and fecundity were higher in the LH (1.31 and 1.06) compared to the LL (1.09 and 0.66; P < 0.05). The mean litter size of ewes in HL (1.32) and HH (1.42) diets was higher than those in the LL (1.09; P < 0.05) diet. It was concluded that short-term (15–17 days) changes in level of protein supplementation especially post-mating can have a beneficial effect on non-return rate and lambing rate to first estrus and litter size in ewes grazed on rangeland.

Effect of partially replacing silage with straw-barleysoybean meal mixtures on cow-calf performance

Forty-eight multiparous, medium-framed cows, calving between Jan. 02 and Mar. 05 were used in a 3 × 2 factorial experiment with three totally mixed ration (TMR) formulations and two levels of protein supplementation. The TMRs were formulated to contain 75, 50 or 25% silage (DM basis). The balance of the diet comprised barley, barley straw, soybean meal and urea, such that all TMRs were formulated to be isoenergetic and isonitrogenous. Supplemental protein was supplied as soybean meal at either 0 or 0.44 kg DM d-1. Diets were fed from Jan. 11 to turnout on May 26. Intake and performance were monitored during this period, and performance at pasture was recorded until weaning on Sep. 03. The only interactions between TMR and protein supplementation were a positive response to protein for DM intake (P &lt; 0.05) at the 50% silage level and for blood urea N (P &lt; 0.05) at the 25% silage level. Reducing the amount of silage in the TMR had no effects on calf performance or milk production, except that milk protein concentration was higher when the TMR contained 50% silage (quadratic effect; P &lt; 0.04). However as the percentage of silage in the TMR declined, cows lost less body weight (linear effect; P &lt; 0.001) and appeared to improve in condition. The interval between calving and conception increased linearly as the percentage of silage in the TMR declined (P &lt; 0.05). Supplemental protein had no major effects on performance, but limited the loss of body condition during the feeding period (P &lt; 0.03), although this was offset by increased loss of condition on pasture (P &lt; 0.01). There were no effects of protein supplementation on calf performance or reproductive efficiency. It is concluded that silage can be successfully replaced with other ingredients in winter beef rations, provided the nutrient concentration is balanced. Supplemental protein had little effect on any parameters of performance. Key words: Beef cow, cow-calf, silage, straw, gains, weaning weight, reproduction

The sequential analysis of local inflammatory cells during abomasal nematode infection in periparturient sheep.

A technique to take sequential tissue biopsy samples in multiparous, periparturient ewes from the abomasal mucosa is described, developed in parallel in Scotland and New Zealand. Samples were extracted via abomasal cannulae inserted into the wall of the abomasum and exteriorised through dorso-ventral laparotomy. Animals recovered quickly post-surgery, and tolerated the cannula and sampling without any adverse signs of pain or discomfort. The technique was deployed in two pilot studies to investigate the sequential mucosal inflammatory cell responses in well-defined parasitological models, during the periparturient relaxation of immunity in ewes infected with gastrointestinal nematodes and subjected to different feeding treatments. One experiment (Moredun Research Institute, Scotland) involved the infection of twin-bearing ewes with Teladorsagia circumcincta L3 either before, or after lambing. By feeding ewes with different levels of protein supplementation, preliminary data on the impact of nutrition on the eosinophil, mucosal mast cell and globule leucocyte responses during this period were investigated. A similar study was also performed at Lincoln University, New Zealand, to investigate these cell responses in sheep fed relatively high or low protein diets during pregnancy, and infected with a combined immunisation regime of T. circumcincta and Trichostrongylus colubriformis L3. These studies confirmed the phenomenon termed the periparturient relaxation in immunity (PPRI) where a transitory increase in faecal egg counts is observed during late pregnancy and lactation, and this effect was exacerbated during protein undernutrition. Although the number of animals was low in each experiment and the cell responses variable, the results together suggest a reduction in the number of mucosal mast cells and globule leucocyte during the PPRI when protein supply was restricted. The present paper thus describes a successful technique to monitor ovine mucosal cell populations during local immune responses in normal and pregnant sheep. It is envisaged that this technique will be a powerful adjunct to investigations into mucosal immune mechanisms and disease pathogenesis, and will be employed to confirm the influence of dietary protein on the local inflammatory cell responses during the PPRI.