MJ Metabolizable Energy Research Articles

Effects of feeding frequency on the performance and welfare of mature Hereford cows and their progeny

A study was conducted to assess the effects of daily feeding (D) vs. feeding every third day (3D) on the performance of suckler cows and calves. In treatment 3D, the cows received the entire three-day feed portion on the first feeding day. The feeding regimens were imposed during the indoor feeding period in cold circumstances with grass silage and hay offered in the proportions of 1 : 1 on an energy basis for the cows. Thirty-two mature Hereford cows with an initial live weight (LW) of 787 kg and body condition score (BCS) of 3.33 were selected for the experiment. The experiment consisted of a winter feeding period and a grazing period averaging 225 and 96 days, respectively. Indoors the cows received a daily average 94 MJ metabolizable energy. The in vivo digestibility of dietary organic matter was similar in both treatments. No significant differences between the treatments were observed in cow LW, BCS, milk production and calf LW. Thirty-one cows were observed to be pregnant after the mating period. In the 3D treatment the serum concentrations of urea and long-chain fatty acids were increased on the third day after feeding compared to first and second days throughout the experiment, possibly due to activation of lipolysis and proteolysis. The 3D cows spent on average more ( P < 0.001, 9.1% vs. 4.5%) time lying and less time ( P < 0.05, 32.9% vs. 40.1%) outdoors than the D cows. On the basis of the results, feeding every third day is an acceptable winter feeding strategy for mature suckler cows if the cows receive enough energy for maintenance and milk production.

Effects of ensiled forage legumes on performance of twin-bearing ewes and their progeny

Twenty-four twin-bearing mature Mule ewes were used to evaluate the effects of feeding ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or perennial ryegrass (Lolium perenne) during late pregnancy on subsequent ewe and lamb performance. Eight weeks prior to lambing the ewes were individually penned and offered one of the treatment forages ad libitum (no. = 8 per silage). All ewes were supplemented with molassed sugar-beet shreds to avoid dietary energy being a limiting factor and to ensure the responses were primarily attributable to the forage protein content. Individual intakes of the ewes were determined daily and weekly measurements of ewe live weight and body condition score were made. The ewes were also scanned weekly for depths of subcutaneous fat and longissimus dorsi (LD) muscle. Blood samples were taken at 6, 4, 2, and 1 week(s) before lambing, 24 h after lambing and at 3 weeks after lambing and were analysed for serum concentrations of total protein (TP), albumin, urea, beta-hydroxybutyrate (BHB) and plasma concentrations of glucose and non-esterified fatty acid (NEFA). After lambing all ewes and their lambs were turned out to graze together on a ryegrass sward. The lambs were weighed at birth and at weekly intervals thereafter until 12 weeks post partum. The lucerne silage offered had a higher dry matter (DM) content than the red clover and ryegrass silages (367, 305 and 314 g DM per kg fresh matter, respectively;P&lt; 0·001). Forage type significantly affected crude protein (CP) concentration (240, 215 and 182 g CP per kg DM for lucerne, red clover and ryegrass silages, respectively) and metabolizable energy (ME) density (11·1, 11·6 and 10·8 MJ ME per kg DM respectively). Ewes offered the legume silages had higher intakes of DM, CP and ME than ewes offered ryegrass silage (P&lt; 0·05), which was reflected in higher ewe live-weight gain (P&lt; 0·05) but not in litter birth weight (P&gt; 0·05). Silage treatment affected serum concentrations of TP, albumin, globulins and urea during the last 4 weeks of pregnancy (P&lt; 0·05). Lambs born from ewes offered lucerne and red clover silages prior to lambing had higher growth rates from birth to 3 weeks of age than those from ewes offered ryegrass silage (320, 323 and 282 g/day, respectively;P&lt; 0·05). Lamb live weight at 12 weeks of age was higher for lambs from ewes that had been offered the red clover silage, at 29·1 kg compared with 26·7 and 27·1 kg for lambs from ewes previously offered lucerne and ryegrass silages (P&lt; 0·05). In conclusion, the results showed that red clover and lucerne silages are better able to meet nutrient requirements of ewes in late pregnancy than grass silage.

Effect of whole-crop barley and oat silages on the performance of mature suckler cows and their progeny in outdoor winter feeding

This study was undertaken to assess during the winter feeding period the effects of replacing grass silage (G) with whole-crop barley silage (B) or whole-crop oat silage (O) on suckler cow and calf performance. Forty-eight Hereford cows with an initial live weight of 741 kg (S.D. 78.5) were selected for the experiment. The diet was either G, B or O as a sole feed. The aim was to offer the cows the same amount of energy in all diets. Therefore, the energy content of the silages was evaluated prior to the experiment by measuring the in vitro organic matter digestibility which resulted in 11.7 MJ metabolizable energy (ME)/kg dry matter (DM) for G and 9.9 MJ ME/kg DM for B and O. During the experiment, the digestibility of the silages was measured by both in vitro and in vivo methods. The ME values of G, B and O evaluated by the in vivo method were 11.2, 10.5 and 9.5 MJ/kg DM, respectively. The DM intake on diets G, B and O averaged 9.2, 10.5 and 10.3 kg which resulted in ME intakes of 102, 109 and 97 MJ ME/d, respectively. The type of roughage affected the in vivo apparent protein digestibility co-efficients which for G, B and O were 0.841, 0.698 and 0.498, respectively (G versus B, P < 0.05; G versus O and B versus O, P < 0.01). The initial cow body condition score (BCS) averaged 3.2 (S.D. 0.23). Pre-grazing the change of BCS and the live weight gain (LWG) for G, B and O cows was on average 0.23, 0.09 and −0.39 (G versus O and B versus O, P < 0.001) and −20, −9 and −56 kg (G versus O, P < 0.05; B versus O, P < 0.01), respectively. All calves were born before the grazing season and milk and grass were the sole feeds at pasture. The pre-weaning calf LWG was not affected by the diets averaging 1357 g/d. The daily milk yield on diets G, B and O averaged 11.4, 10.3 and 9.5 kg (G versus O, P < 0.05), respectively. Forty-two out of 48 cows entered the mating period of which all were observed to be pregnant. The interval from calving to conception averaged 89 days. B and O proved to be suitable winter feeds for mature suckler cows in cold winter circumstances. Especially O had a lower energy and protein content than G but fulfilled the energy and protein demands of mature, pregnant beef cows in good body condition.

Supplementation of waste tea fungal biomass as a dietary ingredient for broiler chicks

The waste tea fungal biomass produced during black tea fermentation was investigated as a dietary ingredient in poultry feeds. A small portion of fungal mat was used as starter culture for the next cycle while the major portion is discarded as waste. Hence a trial study was carried out to utilize the waste fungal biomass as a supplementary diet for broiler chicks. The fungal biomass contained 179.38 g of crude protein, 120 g crude fibre, 4.82 g phosphorus, 6.56 g of calcium and 8.92 MJ metabolizable energy per kilogram of biomass. The dried tea fungus showed phytase activity of 23 IU/mg protein. The supplementation of tea fungal inclusion (TFI) at 150 g/kg concentration in poultry feed increased the feed consumption, body weight, performance efficiency factor (PEF) and the carcass characters of test broilers significantly ( P = 0.01) over the control. The histopathological examination of liver showed no abnormalities and the mortality rate was zero.

Partitioning of limiting protein and energy in the growing pig: testing quantitative rules against experimental data

Literature solutions to the problem of protein and energy partitioning in the growing pig are quantitatively examined. Possible effects of live weight, genotype and food composition on the marginal response in protein retention to protein and energy intakes, on protein and energy-limiting foods are quantified. No evidence was found that the marginal response in protein retention to ideal protein supply, when protein intake is limiting, is affected by live weight, genotype or environmental temperature. There was good evidence that live weight does not affect the marginal response in protein retention to energy intake when protein intake is not limiting. Limited data for different genotypes suggested no effects on this response. A general quantitative partitioning rule is proposed that has two key parameters; e(p)* (the maximum marginal efficiency for retaining the first limiting amino acid) and R* (the maximum value of R, the energy to protein ratio of the food, MJ metabolisable energy (ME)/kg digestible crude protein (DCP), when e(p)* is just achieved). When R<R* the material efficiency of using ideal protein is (e(p)*/R*) x R. The value of e(p)* was determined to be 0.763 (SE 0.0130). There was no good experimental evidence that e(p)* is different for different amino acids. The best estimate of R* was 67.9 (SE 1.65) MJ ME/kg DCP. Live weight, genotype and temperature did not affect the values of either parameter. A more general understanding of partitioning, including the effects of 'stressors' such as disease, may be achieved by using the preferred rule as a starting point.

Feeding of Spinach or Sweet-potato Leaves and Growth Performance of Growing Pigs Kept on Smallholder Farms in Central Vietnam

We investigated whether the addition of either spinach or sweet-potato leaves to the diet of growing pigs, kept in small holdings in Central Vietnam, would improve growth performance. A control diet was formulated and mixed with each of the vegetables to a final concentration of 15% of the total dietary dry matter. The diets were fed to the pigs from 70 to 100 days of age on six different smallholder farms in Central Vietnam. There were three animals per treatment group per farm and biopsies of adipose tissue were analysed for their contents of alpha-linolenic, eicosapentaenoic and docosahexaenoic acids. The diets without and with vegetables contained on average 0.14 and 0.32 g alpha-linolenic acid per MJ metabolizable energy. The relative percentage of alpha-linolenic acid in adipose tissue was raised by the intake of the vegetables. Eicosapentaenoic acid was not detectable in adipose tissue and the level of docosahexaenoic acid was unchanged. There was a significant stimulatory impact of the intake of either spinach or sweet-potato leaves on growth performance of the growing pigs. It is suggested that an adipose tissue content of alpha-linolenic acid less than 1% of total fatty acids does not allow maximum growth in growing pigs.

The influence of calf rearing methods and milking methods on performance traits of crossbred dairy cattle in Thailand – 3. Calf performance

Abstract. The experiment to investigate the effect of restricted suckling (RS) and bucket rearing (BR) involved 40 calves from crossbred dairy cows with 75 % or 87.5 % Holstein-Friesian (HF) genes from 4 days after birth to weaning at 84 days of age. From days 4 to 84 of age restricted suckling calves were allowed to suckle their dams up to 15 minutes post milking. Bucket reared calves were fed a total of 236 kg whole milk and received concentrate supplementation after day 56. All calves were kept indoor, received Brachiaria ruziziensis grass ad libitum from day 56 and had free access to water. RS calves exhibited no losses and only 3 illnesses, whereas three BR calves died and nine developed illnesses. Up to 84 days of age RS calves had a highly significant faster average daily gain (ADG) than BR calves (620 g vrs. 390 g) and a significant larger heart-girth. RS and BR calves had an estimated adjusted daily metabolisable energy (ME) intake from milk of 18.9 ME and 12.6 ME and from the whole ration of 18.9 ME and 14.3 ME, respectively. Intake of milk fat, milk protein, Ca and P were highly significant higher in RS calves. Total protein intake from the whole ration was higher in BR calves. The daily intake of 18.9 MJ and 14.3 MJ ME for RS and BR calves exceeded the need for the realised ADG of 620 g and 390 g (average demand: 16.3 and 11.8 MJ ME) which suggest an oversupply of energy. Demand calculation for protein of 115 g and 103 g crude protein for RS and BR calves corresponded to an intake of 107.7 g and 118.9 g crude protein, respectively. This indicates that the efficiency in utilisation of crude protein seems to be grossly underestimated in suckling calves. Restricted suckling has been demonstrated to be an efficient method for calf rearing.

The effect of high dietary protein levels during late gestation on colostrum yield and lamb survival rate in singleton-bearing ewes

The study was carried out to determine the effect of crude protein (CP) levels in late pregnancy on the subsequent colostrum production and lamb survival rate. A total of 40 singleton-bearing Hampshire Down X Karayaka (F 1) crossbred ewes were allocated to two treatment groups ( n=20 for each group), namely a control (P) and high CP (1.4P) group. The ewes in the P group were fed a protein maintenance level for pregnant ewes (117 g CP and 10.5 MJ metabolizable energy (ME)/kg dry matter (DM)), while ewes in the 1.4P group were fed 1.4 times the protein requirement level for pregnant ewes (165 g CP and 10.5 MJ ME/kg DM). The high crude protein level (1.4P) offered to the ewes did not affect lamb body weight from birth to weaning, however, it increased the live weight changes of ewes (2.5±1.3 kg for P versus 6.4±1.5 kg for 1.4P; P<0.05), lambing difficulty (5% versus 30%; χ 2=4.33; P<0.05) and lamb birth weight (4.3±0.1 kg versus 4.9±0.1 kg; P<0.05). It also decreased the total colostrum yield (1700±165 g versus 1200±147 g; P<0.01) and lamb survival from birth to weaning (100% versus 80%; χ 2=4.44; P<0.05). These results indicate a high level of CP (1.4P) supplementation to singleton-bearing ewes during late gestation to increase lamb birth weight decrease colostrum yield, increase lambing difficulty and reduce lamb survival rate prior to weaning. In conclusion, because of the adverse effect of high dietary protein nutrition during late gestation on colostrum yield and lamb survival rate in singleton-bearing ewes, feeding of protein to pregnant ewes with a view to increase postnatal lamb growth performance and lamb survival rate, should be treated with caution.

PC47 IMPACT OF MATERNAL UNDERNUTRITION DURING EARLY-MID GESTATION ON RESULTING ADULT OFFSPRING IN SHEEP

Introduction: Suboptimal maternal nutrition during pregnancy is associated with increased risk of diseases in resulting adult offspring. Maternal undernutrition during placental growth produced a longer fetus at term with a disproportionately larger placenta and increased fat deposition. This study aimed to determine the long term consequences of early-mid gestation maternal undernutrition on blood pressure and plasma leptin concentration in young adult offspring. Methods: Seventeen male singleton bearing Scottish Black-face ewes of similar liveweight and body condition were individually housed from day of mating. Nine ewes were nutrient restricted (NR) consuming 4.0 MJ of metabolisable energy (ME) per day (50% ME requirements for maintenance and growth of conceptus) until 95 days gestation with 8 controls (C) consuming 8.0 MJ/day. After 95 days gestation until term (147 days) all ewes consumed 100% of requirements. At term lambs were delivered spontaneously and at 3 years old, the jugular vein and carotid artery were surgically catheterised for blood pressure (BP) measurement and blood sampling. Plasma was collected before and after a noradrenaline (NA) infusion with dose increases (2–48 ng/kg/min) at 10-minute intervals, and leptin concentration analysed. Animals were then humanely euthanased by barbiturate overdose to allow tissue sampling. Results are presented as mean ± standard error. Results: Between groups offspring body weight was similar at birth and 3 years of age but the NR group had larger fat (omental, perirenal and subcutaneous) deposits compared to controls. Basal BP prior to feeding was significantly higher in the NR offspring compared to controls (eg. diastolic 65 ± 3; NR 74 ± 2 mmHg (P<0.05)). Following NA infusion BP was similar between groups and rose with increasing NA concentration. With controls heart rate simultaneously decreased but this response was blunted in the NR group. The NR but not C offspring exhibited a significant increase in plasma leptin following NA infusion (C pre NA 3.22 ± 1.9; Post NA 3.16 ± 1.7; NR pre NA 3.47 ± 0.9; Post NA 4.5 ± 1.3 ng/ml (P<0.05)). Conclusion: Nutrient restriction between early-mid gestation produced hypertensive offspring with a blunted heart rate response to a vasoconstrictor challenge, with more fat and higher plasma leptin levels. Altering maternal nutrition during gestation may contribute to reprogramming of adult blood pressure and fat deposition contributing to hypertension and obesity in later life.

An estimate of the leucine requirement for young pigs

AbstractThree pig trials were done to estimate an objective requirement of young (10 to 20 kg) pigs for leucine (Leu). Within each trial, four or five replicates of five pigs were given ad libitum access to their experimental diet for a period of 21 (trial 1) or 19 days (trials 2 and 3). A Leu-deficient diet (177 g crude protein per kg) based on maize, peanut meal, lactose, sucrose, dried whey, maize starch, soya-bean meal (SBM), and gelatin was used in these trials. Trial 1 showed that the Leu-deficient diet supplemented with Leu produced responses in weight gain and gain/food ratio that were similar (P &gt; 0·10) to that obtained from a maize-SBM-whey positive-control diet containing 213 g crude protein (CP) per kg. Trials 2 and 3 utilized graded levels of crystalline L-Leu to determine the minimal Leu requirement in young pigs. Both trials showed linear increases (P &lt; 0·05) in weight gain and gain/food as a result of Leu supplementation. Closer examination of the data revealed no significant change in gain/food or PUN responses above 11·2 g/kg total Leu in trial 2, or in weight gain or PUN values above 11·5 g/kg total Leu in trial 3. These data indicate that the Leu requirement of young pigs is probably not greater than 11·5 g/kg (10·5 g/kg true digestible), which equates to approximately 0·72 g true digestible Leu per MJ metabolizable energy. The ideal ratio of Leu to Lys appears to be close to 1: 1 for pigs in the weight range of 10 to 20 kg.

Muscle-specific metabolic, histochemical and biochemical responses to a nutritionally induced discontinuous growth path

AbstractAn experiment was conducted with 42 Montbéliard steers to determine if nutritionally induced interrupted growth could influence muscle characteristics of steers and hence meat quality. A restriction/refeeding path was designed in order to induce a discontinuous growth path. At 9 months of age, 21 steers were given a restricted amount of diet for 3 months and were then slaughtered (R steers; no. = 10; intake: 5·28 kg dry matter (DM) per day) or subjected to a 4-month ad libitum refeeding period (R/F steers; no. = 11; intake: 8·99 kg DM per day) with the same diet (11·03 to 11·12 MJ metabolizable energy (ME) per kg DM) prior to slaughter. An additional 21 control steers were offered the same diet but in amounts that allowed them to gain continuously between 9 and 12 months of age, and were then slaughtered (C steers; no. = 10; intake: 7·08 kg DM per day) or maintained on a continuous feeding protocol through to 16 months of age prior to slaughter (C/C steers; no. = 11; intake: 8·07 kg DM per day). M. semitendinosus (ST), m. longisssimus thoracis and m. triceps brachii (TB) were collected for biochemical and histochemical analyses. R steers had a lower average daily gain (ADG; P 0·001), a lower final weight (P 0·01) and a leaner carcass (P 0·01) than C steers. Upon refeeding, R/F steers had a higher ADG than C/C steers (P 0·05) and underwent compensatory growth resulting in compensation of body weight and composition at 16 months. In muscles, glycolytic lactate dehydrogenase activity was lower in R steers (P 0·01) and restored in R/F steers compared with control steers. Among oxidative enzymes, cytochrome-c oxidase activity was higher in the TB of R/F compared with C/C steers (P 0·001) indicating a muscle-specific metabolic adaptation to the feeding level. There was little effect of the nutritional treatment on muscle fibre size and type except for an increase in the frequency of hybrid fibres in R and R/F groups (P 0·05). Total and insoluble collagen content were affected by restriction (P 0·001) in a muscle-specific manner: insoluble collagen content was lower in ST, but total and insoluble collagen contents were higher in TB of R compared with C animals at 12 months of age. No differences were recorded in lipid contents nor in proteasome activities. The data suggest that an alternation of relatively mild nutritional restriction and ad libitumfeeding had only a small effect on muscle characteristics. However, muscles respond differentially to changes in feeding level.

Growth performance and carcass traits of Large White, Mukota and Large White ✕ Mukota F1crosses given graded levels of maize cob meal

AbstractA study was conducted to compare the performance of Mukota, Large White (LW) and LW ✕ Mukota F1pigs given increasing levels of maize cob meal. Sixteen female weaners of each genotype were given, ad libitum, diets containing 0, 100, 200 and 300 g maize cob meal per kg of diet for 14 weeks. The diets were designed to contain similar levels of protein (ca. 160 g crude protein per kg) and energy (ca. 9 MJ metabolizable energy per kg). Average daily food intake per unit metabolic body weight (ADFI per kg M0·75), average daily gain (ADG) and food conversion ratio (FCR) were determined. The pigs were slaughtered and cold dressed mass (CDM) and backfat thickness were determined for each pig. The ADFI per kg M0·75was similar among the four diets for the three genotypes. The rate of decline in ADG was higher (P &lt; 0·05) in the LW than in the other two genotypes. The FCR in the Mukota was poorer (P &lt; 0·05) than that in the LW and the F1crosses. The Mukota had the highest (P &lt; 0·05) backfat thickness (K5 and K7·5) values of the three genotypes across the four diets, followed by the F1crosses. The CDM values for the LW and the F1crosses were similar and were higher (P &lt; 0·05) than those for the Mukota. The findings indicate that F1crosses and the Mukota were better able to utilize diets containing high levels of maize cob meal than LW pigs.

Nitrogen utilisation and rumen function in Menz rams supplemented with foliages of Lablab purpureus or graded levels of Leucaena pallida 14203 and Sesbania sesban 1198

Thirty-five male Menz rams (19.3 ± 0.87 kg, mean ± s.d.) fed on a basal diet of tef (Eragrostis tef) straw were used in a randomised block design to study the effects of supplementing with one level of Lablab purpureus (lablab), at 1.2% LW (230 g DM/day), and 3 graded levels of Leucaena pallida 14203 or Sesbania sesban 1198 at 0.9% LW (170 g DM/day), 1.2% LW (230 g DM/day), and 1.5% LW (290 g DM/day) on nitrogen (N) intake, microbial N yield, N retention, levels of rumen pH, and ammonia N. Five rams were used in each of the 7 treatments. The rams were adapted to treatment feeds for 3 weeks, followed by the collection of faeces and urine for 7 days by keeping them in metabolic cages. Graded levels of L. pallida resulted in lower (P &lt; 0.001) daily microbial N yield and lower (P &lt; 0.001) efficiency of microbial N yield per kg organic matter digested in the rumen and per MJ metabolisable energy than graded levels of S. sesban. Urinary N excretion was higher (P &lt; 0.001) in S. sesban and Lablab supplemented animals than those supplemented with L. pallida, and the opposite was true for faecal and total N excretion. However, these did not result in treatment differences in N retention. L. pallida promoted lower (P &lt; 0.001) mean rumen NH3-N level and higher mean rumen pH than the other supplement feeds. It is concluded that the lowest level of either L. pallida or S. sesban supplementation was adequate to promote comparable N retention to the 2 higher levels of supplementation.

Effect of energy and protein nutrition in late gestation on immunoglobulin G in the colostrum of dairy cows with varying body condition scores

An experiment considered whether nutrition of dry cows or their body condition (thin or fat) affected the concentration of immunoglobulin (Ig) G in the colostrum produced by freshly calved dairy cows. Three diets were offered during the last 3-4 weeks before expected calving date: 1) a total mixed ration (TMR) containing maize silage, barley grain, canola meal and hay, fed at 1.5% of body weight (control diet), 2) the TMR plus 4 kg of pellets (energy diet), and 3) the TMR plus 3.5 kg of soyabean meal (protein diet). On average, the thin cows were 111 kg lighter (561 v. 672 kg; P 0.05). In all treatments, IgG concentrations were highest at the first milking and diminished exponentially. There was little effect of any treatment on colostral IgG concentration or yield. The main exception was that IgG at the first milking was significantly decreased by feeding the control diet to cows with low body condition. When regression analysis was undertaken, this effect of body condition on the IgG concentration in colostrum from the first milking ([IgG]) was not significant, but those of energy (total MEI; MJ/cow.day) and protein (total CPI; kg/cow.day) intake during the last month of gestation were, as described in the following weak significant regression equation: [IgG] = 50.4 - 0.36 (±0.127) total MEI + 10.0 (±3.87) total CPI [100 r2 = 11.1 (P = 0.022); r.s.d. = 11.1; c.v. = 37.4%; n = 68This regression indicates that each additional MJ of metabolisable energy consumed by cows was associated with a reduction of 0.4 g of IgG per kg of colostrum and that each additional kg of crude protein in the diet increased IgG concentrations by 10.0 g/kg.

Effect of undegradable protein supply on testicular size, spermiogram parameters and sexual behavior of mature Assaf rams

Eighteen mature Assaf rams were used to study the effect of undegradable protein (UDP) supply on testicular size, sperm production and quality, testosterone secretion and reproductive behavior. Animals were allocated to three groups of six animals each and fed during 10 weeks with different diets which were designed to supply approximately 0.5 MJ of metabolisable energy (ME)/kg LBW 0.75 and 9 g of effective rumen degradable protein (ERDP)/MJ of fermentable ME to all animals and to induce differences in rumen UDP intake (0.97, 1.72 and 3.08 g of UDP/kg LBW 0.75 for LP, MP and HP diets, respectively). Neither plasma testosterone concentration nor reproductive behavior parameters (number of services, number of mounts without ejaculation and reaction time to first mount) were affected ( P>0.05) by protein intake. Nevertheless, there were significant ( P<0.05) differences between diets in both testicular size and sperm production. Scrotal circumference was lower in LP compared to MP and HP groups, no significant differences being observed between these latter two groups at any time. In relation to sperm production, the lowest and the highest values were always observed in LP and HP groups, respectively. MP group showed intermediate values, significantly different from those of LP and HP groups on Week 5 and only from those of LP group on Week 9. The present results provide a better understanding of the effect of protein nutrition and suggest that UDP should be supplied to Assaf rams during the mating season to improve their reproductive performance.

Increased butyrate formation in the pig colon by feeding raw potato starch leads to a reduction of colonocyte apoptosis and a shift to the stem cell compartment

Whereas butyrate is well known to induce apoptosis in transformed colon cells in vitro, evidence exists that it inhibits apoptosis of colon crypt cells in vivo. In this study, pigs were fed with resistant potato starch to increase microbial butyrate formation in the colon and to investigate its effects on mitosis and apoptosis. In addition, apoptosis regulating proteins were determined by immunocytochemistry, such as proapoptotic Bak, antiapoptotic Bcl-2, and the epidermal growth factor (EGF), which is synthesized by goblet cells and functions as a survival factor. Two groups of 6 barrows were both supplied with 381 g crude protein and 31 MJ metabolizable energy (ME) daily over a 19-day experimental period. The rations differed in the carbohydrate composition. The controls received gelatinized starch as the main carbohydrate, whereas the experimental group (butyrate group) received a ration with raw potato starch (low ileal digestibility). In the feces, butyrate concentration and pH were monitored daily. After killing the pigs, colon tissue was obtained for histologic and immunocytochemical evaluation, which was performed separately in the luminal, middle, and stem cell compartment of the crypts. In the butyrate group, the total number of apoptotic cells was reduced by 34% (P ≤ .001) compared with controls, whereas the mitotic rate was not altered. The crypt depth was only moderately increased by 15%. Apoptosis in the luminal compartment of the butyrate group was reduced by 18.8%, but was increased by 21.7% in the stem cell compartment. The effect of butyrate on apoptosis was paralleled by an increased number of Bcl-2 positive cells mainly in the luminal compartment (butyrate: 2.6 cells; controls: 1.2 cells, P ≤ .001), which was more pronounced compared with the number of Bak positive cells in the same compartment. Bak activity in the stem cell compartment was 3.4-fold increased compared with controls (P ≤ .001). The size of EGF-positive stained mucus-droplets from the goblet cells was increased in the butyrate group (P ≤ .001). We conclude that butyrate inhibits apoptosis of colonocytes in vivo. An excessive proliferation of crypts is counteracted by a shift of the remaining apoptosis towards the stem cell compartment.

Effects of oilseed meals and grain–urea supplements fed infrequently on digestion in sheep: 2. Cereal straw diets

An experiment examined the intake, growth responses and rumen digestion of young sheep fed ad libitum oat or barley straws alone or supplemented with approximately isonitrogenous amounts of barley grain and urea (Bar/N), safflower seed meal (SAF) or linseed meal (LIN) supplements provided at 3 day intervals. The supplements comprised 15–22% of total dry matter (DM) intake. Sheep offered either of the straws alone consumed 35.0–37.2 g DM/kg liveweight (LW 0.75) per day of straw and an estimated 2.03–2.07 MJ metabolizable energy (ME) per day, and lost 85–97 g LW per day. Supplements increased ( P<0.05 or <0.001) voluntary intake of straw and of total DM, and the organic matter (OM) digestibility of the entire diet. Each of the supplements increased ( P<0.001) the estimated ME intake to a similar extent and changed the rapid LW loss of sheep fed straw alone to approximate LW maintenance. Rumen ammonia concentrations in sheep fed barley and oat straws alone (12 and 24 mg NH 3/l, respectively) were expected to be deficient for microbial activity, but were increased ( P<0.001) by provision of the supplements. Digestion of straw in synthetic fibre bags incubated in the rumen was markedly increased ( P<0.01 or <0.001) when supplements were provided. Rumen pH was depressed briefly to pH <6.0 by the Bar/N, but not by the LIN or SAF, supplements. In young sheep fed cereal straws and losing LW rapidly the oilseed meal supplements increased wool growth more than the barley grain–urea supplements, but both types of supplement increased ME intake similarly and were equally effective to reduce the extent of LW loss.

Effects of oilseed meal and grain-urea supplements fed infrequently on digestion in sheep: 1. Low quality grass hay diets

An experiment examined intake, growth response and rumen digestion of young sheep fed ad libitum low quality grass hay alone or supplemented with approximately isonitrogenous amounts of barley grain and urea (Bar/N), safflower meal (SAF) or linseed meal (LIN) provided at 3 days intervals. Supplements comprised 13–20% of total DM intake. Sheep fed grass hay alone consumed 60.2 g DM/kg LW 0.75/day of hay and an estimated 6.09 MJ metabolizable energy (ME)/day, and were in liveweight (LW) maintenance. Hay intake was decreased ( P<0.05) by the Bar/N supplement with a substitution rate of 0.9, but was not changed by the oilseed meal supplements. Each of the supplements increased ( P<0.05) estimated ME intake to a similar extent, but LW gain and wool growth were lower ( P<0.05) in sheep supplemented with Bar/N than those supplemented with LIN. Rumen degradabilities of the SAF and LIN CP were estimated to be 0.72 and 0.62, respectively. Rumen ammonia concentrations in sheep fed hay alone (average 97 mg NH 3/l) were expected to be adequate for microbial activity. Fractional outflow rate (FOR) of liquid from the rumen measured with Co-EDTA (mean 0.109 h −1) was greater than that of Cr-mordanted supplements (mean 0.056 h −1), which was in turn greater than the FOR of Cr-mordanted hay (mean 0.031 h −1). Diet did not affect these FOR. Supplemented sheep accommodated increased DM intake on Day 1 of the 3 day supplementation cycle by increasing rumen digesta load rather than by increasing rate of passage of digesta. Results show that the LW gain of young sheep fed low quality hay was increased more by either oilseed meal than by equivalent amounts of barley grain/urea supplement, apparently due to more efficient utilization of ME for LW gain.

Nutritional effects on the pituitary-ovarian axis during the early post-partum period in autumn-lambing ewes

AbstractUsing primiparous autumn-lambing ewes, this study investigated nutritional effects on (i) pulsatile LH secretion, (ii) responsiveness of the pituitary-ovarian axis to exogenous GnRH, and (iii) oestrus and ovarian cyclicity during the early post-partum period. At lambing (25 October ± 0·3 days), 32 primiparous ewes rearing 2·1 ± 0·04 lambs were equally allocated to four dietary treatments in a 2 ✕ 2 factorial designed experiment. Diets comprised ad libitum hay and 1·5 kg per ewe per day of one of four concentrates (12·5 MJ metabolizable energy per kg dry matter) containing either fibrous (F) or starchy (S) ingredients with (P) or without (O) the inclusion of 120 g/kg fish meal. Throughout the study (lambing to 17 December) ewe body condition score was assessed and ewes and their lambs were weighed at weekly intervals. Blood samples were obtained from all ewes to measure circulating concentrations of progesterone and oestrous behaviour was monitored using vasectomized rams. On day 12 post partum, blood samples were obtained from all ewes at 2-h intervals (09:00 to 17:00 h) to measure concentrations of insulin and urea nitrogen, and at 15-min intervals (09:00 to 21:00 h) to measure pulsatile LH secretion. All ewes received 25 i. v. injections of GnRH (250 ng GnRH in 2 ml 0·9% saline) at 2-h intervals commencing 4 h before the end of the 15-min blood sampling period and their ovaries were examined via laparoscopy on day 17 post partum. There was no effect of dietary treatment on ewe live weight or body condition score throughout the study but inclusion of fish meal in the ewe diet increased lamb growth (FP/SP 255 (s.e. 8·9) v. FO/SO 234 (s.e. 8·2) g/day, P &lt; 0·05). Circulating concentrations of insulin on day 12 post partum were lower in ewes given the fibrous compared with the starchy diets (P &lt; 0·05) while dietary inclusion of fish meal increased (P &lt; 0·001) urea nitrogen. Pulsatile LH secretion on day 12 post partum was not affected by dietary treatment. For ewes on diets F P, FO, SP and SO, the numbers that experienced an LH surge during the period of GnRH administration were 1, 2, 1 and 0, and that ovulated by day 17 post partum were 3, 5, 0 and 5 (FP/SP v. FO/SO, P &lt; 0·05) respectively. Dietary treatment did not affect the intervals from parturition to the onset of ovarian cyclicity or oestrus (overall means were 23 (s.e.1·0) days and 38 (s.e.1·6) days respectively) but ewes on the fibrous compared with the starchy diet had a higher (P &lt; 0·05) incidence of short (≤ 10 days) first ovarian cycles. Results of this study, which involved young growing animals, demonstrate that (i) inclusion of fish meal in the ewe diet influenced the sensitivity of the pituitary-ovarian axis to exogenous GnRH, and (ii) a fibrous compared with a starchy diet was associated with an increased incidence of premature luteal regression.

Architecture of a harmonized model of the growing pig for the determination of dietary net energy and protein requirements and of excretions into the environment (IMS Pig)

AbstractThe model incorporates, amongst its novel components, variable efficiency coefficients in the simulation of the responses of growing pigs to nutrient inputs, and thereby increases the accuracy and efficacy of control of feeding and nitrate excretion. The model determines (rather than is presented with) net energy and required amino acid level and balance. The estimation of protein turn-over as a function of rate of protein retention, protein mass and the maturity of the pig was found to be central to both the energy (ATP) and protein economy. Protein turn-over varied from around 0·14 to 0·08 of the protein mass depending upon the size of the pig. Efficiencies of energy yield from lipid, starch (and sugar), protein and (fibre-derived) volatile fatty acids were calculated to be 0·98, 0·86, 0·56 and 0·58 for ATP production and 0·90, 0·70, 0·50, and 0·44 for lipid retention, respectively. The maximum efficiency of use of ileal digestible amino acids was determined as around 0·85. The energy cost of protein synthesis was equivalent to 4·2 MJ metabolizable energy (ME) per kg, and the efficiency of use of ME for protein retention varied from 0·55 to 0·40 depending on the protein mass of the pig. The components of the model and the biochemical drivers are described in detail, and proof of principle of the main elements is presented. The model is different in its architecture to other published simulation models, and is considered to add to the present knowledge base in this discipline.