Effects of sex and dietary lysine on performances and serum and meat traits in finisher pigs

A total of 160 Duroc×(Landrace×Large White) pigs, 50% barrows and 50% gilts, of 28.3±4.52 kg of BW were used to study the effect of lysine (Lys) restriction in the finisher period, on growth performances and serum and carcass and meat quality traits. The grower diet (from 30 to 90 kg BW) was slightly Lys-restricted (7.8 g standardised ileal digestible (SID) Lys/kg) in accordance with results from a previous trial. During the finisher period (90 to 130 kg BW), four experimental diets with decreasing SID Lys contents (6.3, 5.6, 4.2 and 3.2 g/kg) were tested. Each of the eight treatments (two sexes×four levels of Lys) was replicated five times. Each replicate was a pen with four pigs allocated together. When animals achieved 129±2.59 kg were slaughtered and carcass and meat characteristics were evaluated. No significant interaction sex×diet was found. During the finisher period, barrows grew faster (P<0.001) and ate more feed (P<0.001) but tended to be less efficient (P=0.055) than gilts. The Lys restriction affected linearly (P<0.001) all productive performance traits; daily BW gain and feed intake decreased and feed conversion ratio increased. Also, the concentration of serum urea at slaughter tended to be higher in barrows than in gilts (P=0.065) and was reduced quadratically by the restriction of Lys in feed (P<0.001). Carcasses from barrows had higher backfat thickness (P<0.01) and lower weight of main trimmed lean cuts (ham+shoulder+loin; P<0.05) than those from gilts. The Lys restriction during the finisher period decreased carcass yield (quadratic; P<0.001) and the weight of major cuts (linear; P<0.001). Sex and diet had limited effect on meat characteristics; the Lys restriction decreased quadratically the proportion of protein (P<0.01) and increased linearly the intramuscular fat (IMF) content (P<0.001). We can conclude that dietary Lys restriction during finisher period in pigs impaired growth performances and was not successful to increase the carcass fat deposition, although it could have positive effects on IMF proportion of pork.     

Plane of nutrition during the rearing phase for replacement ewes of four genotypes: II - effects on performance during first pregnancy and to weaning,and of their progeny

Plane of nutrition (PN) offered to ewe replacements during the rearing phase (8 to 17 months) and first pregnancy may affect reproductive and progeny performance when replacements are joined at ~19 months. The effects of PN offered to spring-born ewe replacements during their first winter (winter_1), second summer (summer_2) and subsequent winter (mid and late pregnancy; winter_2) were evaluated, over 3 consecutive years, using 287 ewe lambs of four genotypes: Charmoise×Scottish Blackface (C×SBF), Belclare×SBF (Bel×SBF), Belclare (Bel) and Belclare×SBF (heterozygous for a gene, either FecG^H or FecX^G mutations, that increases ovulation rate: BelMG×SBF). Ewe lambs were offered, daily, a deferred-grazed herbage allowance (HA) of either 0.75 or 1.75 kg dry matter during winter_1. During summer_2 the replacements were set-stocked to maintain sward heights of 4 or 6 cm. Ewes were housed during mid and late pregnancy (winter_2) and offered either medium or high-feed-value grass silage, thus yielding a 2×2×2 factorial design. Increasing HA during winter_1 and residual sward height during summer_2 increased ewe BW post joining (P<0.001) and at lambing (P<0.01), but had no effect (P>0.05) on number of lambs reared. Increasing HA during winter_1 increased lamb BW at birth (P<0.05) and reduced carcass fat score (P<0.05). There was a significant interaction between PN offered during winter_1 and summer_2 for average daily gain (ADG) from birth to 5 weeks (P<0.01) and from 5 to 10 weeks (P<0.05): progeny of replacements that experienced either a high or low PN throughout the rearing phase had lower ADG than lambs born to the replacements that experienced a low PN only during winter_1 or summer_2. Increasing PN during winter_2 increased ewe BW (P<0.001), lamb BW at birth (P<0.001) and weaning (P<0.05) and reduced the proportion of ewes that failed to lamb (P<0.01). Ewe genotype had a significant (P<0.001) effect on litter size (1.48 to 2.45), number of lambs reared, lamb BW at birth and weaning, lamb ADG and age at slaughter. It is concluded that, among the nutrition treatments examined, increasing PN during mid and late pregnancy had the greatest effect on ewe and progeny performance. Although increasing PN offered during winter_1 increased lamb birth BW, PN offered during summer_2 had no effect on lamb performance. There were no significant interactions between PN and ewe genotype.     

Metabolic and biochemical changes in plasma of the periparturient rabbit does with different litter size

The aim of this study was to investigate the metabolic and biochemical changes in plasma that occur in the reproductive rabbit doe close to the parturition, as well as if the number of offspring affects the metabolism and the health status of the doe. At −3, 4 and 12 days from parturition (–D3, D4, and D12, respectively) nine rabbit does at their third parity from a commercial hybrid line (HYPLUS PS 19) selected for high prolificacy were weighted and blood was collected for a wide inflammometabolic profile. According to the number of offspring the does were retrospectively divided in two groups: high litter size group (HI; n=5) and low litter size group (LO; n=4). BW was higher (P<0.01) at –D3 and had the lowest values at D4. At D12, the BW was lower (P<0.05) in LO compared with HI. Several metabolites significantly changed from dry to lactation period. Glucose and cholesterol had the lowest levels at –D3; non-esterified fatty acid (NEFA) and aspartate aminotransferase had the highest values before parturition (P<0.05); creatinine and β-hydroxybutyrate (BHBA) were higher at –D3 with respect to D4 (P<0.05). The lowest value of paraoxonase was observed in does at –D3 (P<0.05), whereas at this time ceruloplasmin and total bilirubin had the highest concentration (P<0.05). The differences for blood profile parameters between does grouped according to litter size were mainly evident before parturition (–D3). In particular, BHBA, NEFA and total bilirubin had higher concentrations (P<0.05) in HI v. LO group, whereas albumin and PON were lower in HI group (P<0.01). After parturition there were no significant differences for the metabolic parameters between the two groups. The results show that for reproductive rabbit doe the last days of gestation are very stressful from a metabolic and inflammatory point of view. The genetic selection of does for higher litter size has increased their ability to mobilize body reserves in order to guarantee the nutrients to a high number of kits. This exposes them to a more severe metabolic and inflammatory challenge during the transition period. Consequently, feeding and managerial strategies for high prolificacy periparturient rabbit does should be revised.     

Effects of water restriction on growth performance,feed nutrient digestibility,carcass and meat traits of rabbits

The study investigates the effects of a post-weaning water restriction on performance, nutrient digestibility, carcass traits and meat quality of 84-day-old rabbits. A total of 1388 weaned rabbits (35 days) were randomly divided into two groups on the basis of BW and sex. The two groups were fed the same diets ad libitum both in the post-weaning (35 to 60 days) and fattening (61 to 84 days) periods. In the post-weaning period, one group (AL) also received drinking water ad libitum, whereas the other (WR) had a water restriction from 35 to 41 days 2 h/day; from 42 to 48 days 2.5 h/day; from 49 to 55 days 3 h/day; and from 56 to 60 days 4 h/day. During the fattening period, both groups had water-free access. Individual live weights and feed intake per cage were recorded weekly for 32 cages randomly chosen per group (64 rabbits) to calculate the BW gain, feed intake and feed conversion ratio (FCR). The apparent digestibility values of nutrients were measured using acid-insoluble ash. Carcass data were collected from 16 rabbits (8 males and 8 females) per group selected for similar final BW in both groups. Mortality from 35 to 60 days was higher in the AL group (10.1% v. 5.2%, for AL and WR, respectively, P < 0.0001). BW gain was higher for the AL group during both the post-weaning (+22.4%, P < 0.01) and the entire period (+7.5%, P < 0.05). Water restriction reduced feed intake both in the post-weaning (−17.4%, P < 0.0001) and in the entire period (−9.9%, P < 0.05). During the fattening period, FCR was lower for the WR group (5.15 v. 5.75 g/g, for WR and AL, respectively, P < 0.05). The apparent digestibilities of dry matter, organic matter, NDF, ADF and cellulose were greater in the restricted rabbits (+4.7%, +4.5%, +10.2%, +18.8% and +12.8%, P < 0.01, P < 0.01, P < 0.05, P < 0.01, P < 0.05, respectively). Perirenal and scapular fat percentages were higher in the AL rabbits (+30.7% and +116.6%, P < 0.01 and P < 0.001, respectively). Water restriction increased saturated fatty acids (C16:0, +12.9%, P < 0.05), lauroleic acid (C12:1, +75.0%, P < 0.01), n-3 polyunsaturated fatty acids (C20:5, +50.0%, P < 0.01 and C22:5, +16.6%, P < 0.05) and the n-3/n-6 ratio (+28.6%, P < 0.05). The applied water restriction between 35 and 60 days executed during the winter months improved the digestive health of rabbits, with no negative effects on carcass traits, or physical and chemical meat characteristics. However, from the animal welfare point of view, a water restriction can be criticized as a method to restrict feed intake.     

Effects of late gestation shearing on BW,feed intake and plasma metabolite concentrations in Rambouillet ewes managed outdoors during winter

The majority of lambs in the United States are born from late winter to early spring and pregnant ewes are generally sheared in the last third of pregnancy. Although there are benefits to shearing before parturition, shorn animals may be more vulnerable to the cold, highly variable climatic conditions associated with these seasons. The objective of this study was to determine if late gestation shearing induces differences in individual BW, dry matter intake (DMI) and plasma metabolite concentration of finewool ewes managed outdoors during winter. Thirty-six mature, pregnant Rambouillet ewes (3.8±0.45 years; 76.8±11.4 kg) were managed in a drylot with ad libitum access to pelleted alfalfa in bunks capable of measuring individual daily DMI. The treatment group consisted of ewes sheared at ~5 weeks before the estimated parturition date (shorn; n=18). Unshorn ewes (n=18) remained in full fleece throughout the experiment and were shorn on the last day of the experiment ~2 weeks before the estimated parturition date. Blood was collected on days 0 (before shearing shorn group), 7, 14 and 21 (before shearing unshorn group) of the trial, and plasma was isolated and analyzed for non-esterified fatty acid (NEFA), β-hydroxybutyrate (BHB) and glucose (GLU) concentrations. There was no effect of shearing on ewe DMI or BW during the trial (P⩾0.35). Plasma NEFA and GLU concentrations were similar (P⩾0.36) between shearing groups, though plasma BHB concentration was 103.7 μmol/l greater (24.1%; P<0.01) in unshorn ewes. Lamb BW at birth was not affected (P=0.30) by ewe shearing treatment. Under conditions of this study, no differences in economically important aspects of sheep production were observed between shorn and unshorn pregnant ewes.     

Management factors affecting mortality,feed intake and feed conversion ratio of grow-finishing pigs

The aim of this study was to determine the effect of animal management and farm facilities on total feed intake (TFI), feed conversion ratio (FCR) and mortality rate (MORT) of grower-finishing pigs. In total, 310 batches from 244 grower-finishing farms, consisting of 454 855 Pietrain sired pigs in six Spanish pig companies were used. Data collection consisted of a survey on management practices (season of placement, split-sex by pens, number of pig origins, water source in the farm, initial or final BW) and facilities (floor, feeder, ventilation or number of animals placed) during 2008 and 2009. Results indicated that batches of pigs placed between January and March had higher TFI (P=0.006), FCR (P=0.005) and MORT (P=0.03) than those placed between July and September. Moreover, batches of pigs placed between April and June had lower MORT (P=0.003) than those placed between January and March. Batches which had split-sex pens had lower TFI (P=0.001) and better FCR (P<0.001) than those with mixed-sex in pens; pigs fed with a single-space feeder with incorporated drinker also had the lowest TFI (P<0.001) and best FCR (P<0.001) in comparison to single and multi-space feeders without a drinker. Pigs placed in pens with <50% slatted floors presented an improvement in FCR (P<0.05) than pens with 50% or more slatted floors. Batches filled with pigs from multiple origins had higher MORT (P<0.001) than those from a single origin. Pigs housed in barns that performed manual ventilation control presented higher MORT (P<0.001) in comparison to automatic ventilation. The regression analysis also indicated that pigs which entered to grower-finisher facilities with higher initial BW had lower MORT (P<0.05) and finally pigs which were sent to slaughterhouse with a higher final BW presented higher TFI (P<0.001). The variables selected for each dependent variable explained 61.9%, 24.8% and 20.4% of the total variability for TFI, FCR and MORT, respectively. This study indicates that farms can increase growth performance and reduce mortality by improving farm facilities and/or modifying management practices.     

Impact of feed restriction and housing hygiene conditions on specific and inflammatory immune response,the cecal bacterial community and the survival of young rabbits

Limiting the post-weaning intake of the young rabbit is known to improve its resistance to digestive disorders, whereas a degradation of its housing hygiene is assumed to have a negative impact on its health. This study aims at providing insights into the mechanism of digestive health preservation regarding both host (growth and immune response) and its symbiotic digestive microbiota. A 2×2 factorial design from weaning (day 28) to day 64 was set up: ad libitum intake or restricted intake at 70% of ad libitum, and high v. low hygiene of housing (n=105 per group). At day 36 and day 45, 15 animals/group were subcutaneously immunized with ovalbumin (OVA) to assess their specific immune response. Blood was sampled at 36, 45, 57 and 64 days of age to determine total and anti-OVA immunoglobulin type G (IgG) and haptoglobin levels. The cecal bacterial community was explored (18 per group) by 454 pyrosequencing of genes coding for the 16S ribosomal RNA, whereas cecal pH, NH₃ and volatile fatty acid (VFA) concentrations were measured to characterize fermentative activity. A 30% reduction in feed intake reduced the growth by only 17% (P<0.001), and improved the feed conversion ratio by 15% (P<0.001), whereas the degradation of hygiene conditions slightly decreased the feed intake in ad libitum fed rabbits (−3.5%, P<0.02). As poor hygiene conditions did not affect weight gain, feed conversion was improved from day 42 (P<0.05). Restricted feeding led to a lower mortality between day 28 and day 40 (P=0.047), whereas degraded hygiene conditions decreased overall morbidity (7.8% v. 16.6%; P<0.01). Both a reduced intake and low hygiene conditions of housing affected microbiota composition and especially dominant genera belonging to the Ruminococcaceae family (P<0.01). Moreover, low hygiene was associated with a higher Ruminococcaceae/Lachnospiraceae ratio (3.7 v. 2.4; P<0.05). Cecal total VFA and pH were increased (+19%; P<0.001) and decreased (−0.1 pH unit; P<0.05), respectively, in feed-restricted rabbits. Neither specific anti-OVA IgG nor haptoglobin was affected by treatments. Total IgG concentrations were the highest in animals raised in poor hygiene conditions after 8 days of restriction, but decreased after 19 days of restriction in high hygiene conditions (−2.15%; P<0.05). In conclusion, the degradation of hygiene conditions failed to induce a systematic specific and inflammatory response in rabbit, but reduced morbidity instead. Our results suggest that the microbiota composition would be a helpful source of biomarkers of digestive health.     

Effects of grass and maize silage feed value,offering soybean meal with maize silage,and concentrate feed level in late pregnancy,on ewe and lamb performance

In many countries, daily herbage accumulation on pasture declines towards zero during the winter period; thus, many pregnant ewes are housed and offered conserved forages supplemented with concentrate prior to parturition. The effects of forage type and feed value (FV), offering soybean meal with maize silage during mid and late pregnancy, and concentrate feed level in late pregnancy on the performance of ewes and their progeny (to slaughter) were evaluated. Ewes (n = 151) were assigned to one of nine treatments from mid-pregnancy until lambing. Medium FV and high FV grass silages (metabolisable energy concentrations of 10.7 and 12.0 MJ/kg DM) were offered ad libitum supplemented with either 15 or 25 kg concentrate/ewe during late pregnancy. Low and high DM maize silages (starch concentrations of 80 and 315 g/kg DM) were offered ad libitum either alone or with soybean meal (200 g/d) and supplemented with 15 kg concentrate during late pregnancy. A final treatment consisted of high FV grass silage supplemented with 5 kg soybean/ewe over the final 4 weeks of pregnancy. Ewes and lambs were put to pasture in a rotational-grazing system within 3 days of lambing. There were no interactions (P > 0.05) between grass silage FV and concentrate feed level for ewe or lamb traits. Increasing grass silage FV increased food intake (P < 0.001) during late pregnancy, ewe BW and body condition score (BCS) at lambing (P < 0.001), lamb BW at birth (P < 0.001) and weaning (P < 0.05), and reduced age at slaughter (P = 0.06). Increasing concentrate feed level increased metabolisable energy (P < 0.05) intake during late pregnancy but had no effect (P > 0.05) on ewe or lamb performance. Increasing maize DM at harvest and offering soybean meal with maize silage increased food intake (P < 0.001) and ewe BW and BCS at lambing (P < 0.05 or P < 0.01). Offering soybean meal with maize silage increased lamb BW at birth (P < 0.01) and reduced age at slaughter (P < 0.05). Reducing supplementation of high FV grass silage to 5 kg of soybean meal had no effect (P > 0.05) on animal performance. Replacing grass silage with maize silage did not affect (P > 0.05) BW gain of lambs. It is concluded that increasing the FV of the grass silage offered during pregnancy had the greatest positive impact on ewe and lamb performance.     

Early feed restriction of lambs modifies ileal epimural microbiota and affects immunity parameters during the fattening period

Bacteria firmly attached to the gastrointestinal epithelium during the pre-weaning phase may show a significant impact on nutrient processing, immunity parameters, health and feed efficiency of lambs during post-weaning phases. Thus, the aim of this study was to describe the differences in the ileal epimural microbiota (e.g. total bacteria, Prevotella spp., Bifidobacterium spp. and Lactobacillus spp.) of fattening lambs promoted by early feed restriction during the suckling phase trying to elucidate some of the underlying mechanisms behind changes in feed efficiency during the fattening period. A total of 24 Merino lambs (average BW 4.81±0.256 kg) were used, 12 of them (ad libitum, ADL) kept permanently in individual pens with their mothers, whereas the other 12 lambs were separated from their dams for 9 h each day to be exposed to milk restriction (RES). After weaning (BW=15 kg) all the animals were penned individually, offered the same complete pelleted diet (35 g/kg BW per day) and slaughtered at a BW of 27 kg. During the fattening period, reduced gain : feed ratio (0.320 v. 0.261, P<0.001) was observed for the RES group. Moreover, increments of Prevotella spp. were detected in the ileal epimural microbiota of RES lambs (P<0.05). There were also higher numbers of infiltrated lymphocytes (T and B cells) in the ileal lamina propria (P<0.05), a higher M-cell labelling intensity in ileal Peyer’s patches domes (P<0.05) and a trend towards a thickening of the submucosa layer when compared with the ADL group (P=0.057). Some other immunological parameters, such as an increased immunoglobulin A (IgA) production (pg IgA/µg total protein) and increments in CD45+ cells were also observed in the ileum of RES group (P<0.05), whereas transforming growth factor β and toll-like receptor gene expression was reduced (P<0.05). In conclusion, early feed restriction during the suckling phase promoted changes in ileal epimural microbiota and several immunity parameters that could be related to differences in feed efficiency traits during the fattening period of Merino lambs.     

Evaluation of production efficiencies at pasture of lactating suckler cows of diverse genetic merit and replacement strategy

Feed costs account for the largest proportion of direct cost within suckler beef production systems. By identifying the cow type with enhanced capability of converting grazed herbage to beef output across lactations, suckler cow systems would become more efficient and sustainable. The objective of this study was to estimate grass DM intake (GDMI) and production efficiency among lactating suckler cows of diverse genetic merit for the national Irish maternal index (Replacement Index) which includes cow efficiency components such as milk yield and feed intake. Data from 131 cows of diverse genetic merit within the Replacement Index, across two different replacement strategies (suckler or dairy sourced), were available over two grazing seasons. Milk yield, GDMI, cow live weight (BW) and body condition score (BCS) were recorded during early, mid and late-lactation, with subsequent measures of production efficiency extrapolated. Genetic merit had no significant effect on any variables investigated, with the exception of low genetic merit (LOW) cows being 22 kg heavier in BW than high genetic merit (HIGH) cows (P < 0.05). Beef cows were 55 kg heavier in BW (P < 0.001), had a 0.31 greater BCS (P < 0.05) and 0.30 Unité Fourragère Lait (UFL) greater energy requirement for maintenance compared to dairy sourced beef × dairy crossbred (BDX) cows (P < 0.001). The BDX had 0.8 kg greater GDMI, produced 1.8 kg more milk (P < 0.001), had a 0.8 UFL greater energy requirement for lactation and produced weanlings that were 17 kg heavier in BW than beef cows (P < 0.05). Subsequent efficiency variables of milk per 100 kg BW (P < 0.001), milk per kg GDMI (P < 0.001) and GDMI per 100 kg BW (P < 0.001) were more favourable for BDX. The correlations examined showed GDMI had moderate positive correlations (P < 0.001) with intake per 100 kg BW, net energy intake per kg milk yield, RFI and intake per 100 kg calf weaning weight but was weakly negatively correlated to milk yield per kg GDMI (P < 0.001). No difference was observed across genetic merit for beef cows for any of the traits investigated. Results from the current study showed that, while contrasting replacement strategies had an effect on GDMI and production efficiency, no main effect was observed on cows diverse in genetic merit for Replacement Index. Nonetheless, utilising genetic indexes in the suckler herd is an important resource for selecting breeding females for the national herd and phenotypic performance generated from this study can be included in future genetic evaluations to improve reliability of genetic values.     

Influence of age,body weight and body condition score before mating start date on the pubertal rate of maiden Holstein–Friesian heifers and implications for subsequent cow performance and profitability

The aim of this study was to assess the influence of age, body weight (BW) and body condition score (BCS) of maiden Holstein–Friesian heifers before mating start date (MSD) on the rate of puberty, subsequent production and longevity and their implications with regard to farm profitability. Data were available on 871 Holstein–Friesian heifers from 48 herds. BW was recorded electronically and BCS was recorded by a single operator on a scale of 1 to 5. Heifer age was calculated as the number of days from birth to the day of visit. All of the independent variables of interest were grouped into three or four categories. Three age categories (thirtiles), four BW categories (quartiles) and four BCS categories (⩽2.75, 3.00, 3.25 and ⩾3.50) were formed. Heifers with an identifiable corpus lutuem (CL) in the presence or absence of large follicles and peri-ovulatory signs and with a plasma progesterone (P4) concentration ⩾1 ng/ml were classified as pubertal. In addition, heifers without an identifiable CL in the presence or absence of large follicles and peri-ovulatory signs but with a P4 concentration ⩾1 ng/ml were also classified as pubertal. Age, BW and BCS at MSD were all found to be significantly associated with pubertal rate (P < 0.05). Age was shown to have no practical implications on subsequent cow performance. BW at MSD was favourably associated with subsequent calving date (P < 0.05), subsequent cow BW (P < 0.001) and potential (305 days) milk fat plus protein yield (P < 0.001). BCS at MSD was found to be favourably associated with milk fat plus protein yield potential (P < 0.05) and BCS (P < 0.001) during lactation. The economic analysis undertaken indicated that larger, well-grown heifers will be more profitable because of superior production potential, all else being equal. However, because of the finding of poorer reproductive efficiency in heifers grown to more than 343 kg at MSD, heifers at ∼330 kg at MSD are deemed optimal. This will correspond to mature cow BW of ∼550 kg.     

Effect of dietary amounts of inorganic and organic zinc on productive and physiological traits of White Pekin ducks

The effects of different dietary amounts of organic and inorganic Zn were studied in male White Pekin ducks (WPD) from 1 to 56 days of age. The control diet (26 ppm of Zn from raw ingredients) was supplemented with 30, 60 and 120 ppm of Zn from both inorganic and organic sources, for a total of seven treatment groups, each containing five replicates of nine 1-day-old ducklings each. BW, feed intake and feed conversion ratio (FCR) were recorded at 1, 28 and 56 days of age. At 56 days of age, five birds per group were used in a digestibility trial to measure Zn retention and excretion. At the end of the trial, five birds per treatment were slaughtered and carcass traits as well as Zn content in tibia and liver were measured. Samples of blood from five birds per treatment were used to measure plasma concentration of Zn and Cu. BW gain during the entire period of the trial increased (P < 0.001) by 30 and 60 ppm of Zn. Increasing Zn contents progressively increased (P < 0.001) the tibia and the liver Zn contents as well as the plasma Zn and Cu contents. The concentration of 120 ppm of Zn increased (P < 0.001) tibia ash and decreased (P < 0.001) abdominal fat in the carcasses. In the period 1 to 56 days, Zn oxide increased (P < 0.001) growth rate and improved (P < 0.03) FCR compared with organic Zn, whereas organic Zn increased (P < 0.003) the dressed carcass percentage. Organic Zinc increased (P < 0.001) Zn and Cu concentration in the plasma. A level of 30 ppm of Zn from an inorganic source was adequate for male WPD during 1 to 56 days of age, based on positive effects of growth rate and Zn excretion.     

Influences of the number of fetuses and levels of CP and ME in gestation and lactation supplements on performance of Spanish does and kids during suckling and post-weaning

Forty-eight mature US Spanish does (40 kg BW), from a herd selected for cashmere fiber growth, were used to investigate influences of the number of fetuses and levels of ME and CP in supplements during gestation and lactation on doe and kid performance. At 60 days of gestation, does with single or twin fetuses consumed mature Bermudagrass hay ad libitum and 1% BW (DM basis) of supplements with 18.6% or 28.5% CP (LP and HP, respectively) and 2.2 or 2.8 Mcal/kg ME (DM basis; LE and HE, respectively). The HE-HP supplement was offered at 1.5% BW (DM basis) for 15 days after birth, and does received the same supplement treatments as in gestation thereafter until weaning at 50 days after parturition. For a 50-day post-weaning period, kids consumed ad libitum the HE-LP supplement. BW at 90 days of gestation (41.4 vs 38.4 kg; P<0.10), BW before parturition (46.1 vs 41.7 kg; P<0.05), BW loss from parturition to day 21 of lactation (8.38 vs 5.25 kg; P<0.05), litter birth weight (5.47 vs 2.75 kg; P<0.05) and plasma concentrations of β-hydroxybutyrate (0.33 vs 0.29 mM; P<0.05) and NEFA (538 vs 434 mEq/l; P<0.05) were greater for does with twin vs single kids. BW at weaning was similar between single and twin kids (P>0.10; 8.31 and 7.63, respectively). Kid BW and cashmere fiber weight after the post-weaning period were affected by interactions (P<0.05) between number of fetuses and supplement ME level; kid BW was 12.3, 14.7, 14.6 and 13.2 kg (SE = 1.12 and 0.68 kg for singles and twins, respectively), and kid cashmere weight was 86, 109, 106 and 102 g (SE = 8.5 and 5.0 g for singles and twins, respectively) for single-HE, single-LE, twin-HE and twin-LE, respectively. In conclusion, effects of supplements differing in levels of ME and in ingredient composition for US Spanish does in gestation and lactation had dissimilar impacts on post-weaning BW and cashmere weight of single and twin kids. However, because of the limited number of observations and the high variability among animals in measures such as cashmere fibre growth, further experimentation concerning the potential for effects of nutritional plane of does on cashmere growth by kids is warranted.     

The repeatability of feed intake and feed efficiency in beef cattle offered high-concentrate,grass silage and pasture-based diets

Breeding values for feed intake and feed efficiency in beef cattle are generally derived indoors on high-concentrate (HC) diets. Within temperate regions of north-western Europe, however, the majority of a growing beef animal’s lifetime dietary intake comes from grazed grass and grass silage. Using 97 growing beef cattle, the objective of the current study was to assess the repeatability of both feed intake and feed efficiency across 3 successive dietary test periods comprising grass silage plus concentrates (S+C), grazed grass (GRZ) and a HC diet. Individual DM intake (DMI), DMI/kg BW and feed efficiency-related parameters, residual feed intake (RFI) and gain to feed ratio (G : F) were assessed. There was a significant correlation for DMI between the S+C and GRZ periods (r = 0.32; P < 0.01) as well as between the S+C and HC periods (r = 0.41; P < 0.001), whereas there was no association for DMI between the GRZ and HC periods. There was a significant correlation for DMI/kg BW between the S+C and GRZ periods (r = 0.33; P < 0.01) and between the S+C and HC periods (r = 0.40; P < 0.001), but there was no association for the trait between the GRZ and HC periods. There was a significant correlation for RFI between the S+C and GRZ periods (r = 0.25; P < 0.05) as well as between S+C and HC periods (r = 0.25; P < 0.05), whereas there was no association for RFI between the GRZ and HC periods. Gain to feed ratio was not correlated between any of the test periods. A secondary aspect of the study demonstrated that traits recorded in the GRZ period relating to grazing bite rate, the number of daily grazing bouts and ruminating bouts were associated with DMI (r = 0.28 to 0.42; P < 0.05 - 0.001), DMI/kg BW (r = 0.36 to 0.45; P < 0.01 - 0.001) and RFI (r = 0.31 to 0.42; P < 0.05 - 0.001). Additionally, the number of ruminating boli produced per day and per ruminating bout were associated with G : F (r = 0.28 and 0.26, respectively; P < 0.05). Results from this study demonstrate that evaluating animals for both feed intake and feed efficiency indoors on HC diets may not reflect their phenotypic performance when consuming conserved forage-based diets indoors or when grazing pasture.     

Effect of pre-slaughter handling,exercise and the presence of a dog on lamb welfare and meat quality

Before slaughter, lambs may experience several stressors such as feed and water deprivation, handling and transport that have the potential to negatively impact welfare and meat quality. The objective of this study was to evaluate the effect of pre-slaughter handling, exercise and the presence of a dog on the behaviour and physiology of lambs and meat quality at slaughter. At 6 months of age, 60 lambs (n=20 lambs/replicate; three replicates) were allocated to one of the two treatment groups (n=30 lambs/treatment): low (LOW) intensive handling or high (HIGH) intensive handling. LOW lambs were moved short distances, quietly and without the use of a dog before transport. HIGH lambs were moved quickly, long distances and with a dog present before transport. Lamb behaviour (standing, lying, rumination and panting) was recorded for 1 h before (post-treatment) and after transport (post-transport), and for 30 min before slaughter (pre-slaughter). Blood samples were collected before (baseline), after transport (post-transport) and at exsanguination (at slaughter) to assess cortisol, lactate and non-esterified fatty acid (NEFA) concentrations. At slaughter, lamb carcases (M. longissimus lumborum) were evaluated for pH levels, drip and cook loss, and tenderness. HIGH lambs spent more time standing (P<0.001) and panting (P<0.001) and less time lying (P<0.001) and ruminating (P<0.001) post-treatment than LOW lambs, but more (P<0.001) time ruminating post-transport. All lambs spent more time standing (P<0.001) and less time lying (P<0.001) and panting (P<0.001) post-transport and pre-slaughter than post-treatment. Cortisol concentrations were greater (P<0.001) in lambs post-transport and at slaughter compared with baseline values. Lactate concentrations were lower (P=0.002) in HIGH than LOW lambs. In addition, NEFA concentrations were higher (P<0.001) post-transport and at slaughter in HIGH compared with LOW lambs. Ultimate pH was higher (P<0.001) in HIGH than LOW lambs and pH declined quicker (P=0.012) in LOW than HIGH lambs. Cook loss, drip loss and shear force were lower (P⩽0.05) in HIGH than LOW lambs. The HIGH intensive pre-slaughter handling regime used in the present study caused stress in lambs and increased ultimate pH that could potentially negatively impact welfare, product quality and consistency.     

Impact of feed restriction on the performance of highly prolific lactating sows and its effect on the subsequent lactation

A total of 50 mixed parity sows of a high-prolificacy genetic line were used to evaluate the impact of feed restriction during lactation on their production and reproductive performance and their performance in the subsequent lactation. From day 7 of lactation, sows were distributed according to a completely randomized experimental design into two treatments. In treatment 1, sows were fed 8.0 kg feed/day (control) and in treatment 2, sows were fed 4.0 kg/day. The same suckling pressure was maintained until weaning on day 28 of lactation. Average minimum and maximum temperatures measured during the experimental period were 32.1°C and 16.5°C, respectively. Control sows presented significantly higher feed intake (P<0.001) compared with the restricted sows (6.43 v. 4.14 kg/day, respectively). Treatments influenced BW and backfat thickness losses (P<0.001). Control sows lost less BW than the restricted-fed sows (7.8 v. 28.2 kg). Restricted-fed sows lost more backfat thickness than those in the control group (3.97 v. 2.07 mm; P<0.01). Restricted-fed sows tended (P<0.10) to be lighter at weaning compared with the control sows (211 v. 227 kg). The composition of BW loss was influenced by the treatments (P<0.001), as the restricted-fed sows lost more body protein, lipids and energy compared with the control sows (3.90 v. 0.98 kg, 11.78 v. 4.83 kg and 584 v. 224 MJ, respectively). Litter weight gain was greater (P<0.05) in control sows than in restricted-fed sows (2.70 v. 2.43 kg/day). Daily milk production was 19% higher (P<0.01) in the control sows compared with the restricted-fed sows (8.33 v. 6.99 kg/day). However, restricted-fed sows presented a higher (P<0.05) lactation efficiency than the sows of the control group (82.30% v. 72.93%). No differences were detected (P>0.10) in weaning-to-estrus interval and averaged 4.3 days. No effect of the treatment (P>0.10) was observed on any of the studied performance traits in the subsequent lactation, except for litter size at birth that tended (15.2 v. 14.1; P<0.10) to be lower for the restricted sows. In conclusion, the present study demonstrated that feed restriction during lactation leads to intense catabolism of the body tissues of sows, negatively affecting their milk production, and the litter weight gain and possibly number of piglets born in the next litter. On the other hand, restricted-fed sows are more efficient, producing more milk per amount of feed intake.     

Plane of nutrition during the rearing phase for replacement ewes of four genotypes: I – effects on growth and development,and on ovulation rate at first joining

Plane of nutrition (PN) offered to ewe replacements during the rearing phase (8 to 17 months) affects BW at joining and may affect reproductive performance when joined at ~19 months. The effects of PN offered to ewe replacements during their first winter (winter_1) and second summer (summer_2) were evaluated over 3 consecutive years, using 287 spring-born ewe lambs, representing four genotypes (Belclare (Bel), Charmoise×Scottish Blackface (C×SBF), Bel×SBF (Bel×SBF), Bel×SBF that were heterozygous either FecG^H or FecX^G mutations that increase ovulation rate (OR) (BelMG×SBF)). During extended (deferred) grazing in winter_1 (November to March) the lambs were offered herbage DM allowances (HA) of 0.75 (L) or 1.75 (H) kg/day. During summer_2 (March to August) the replacements were set stocked to maintain sward heights of 4 (L) or 6 (H) cm, thus yielding a 2×2 factorial design for the nutrition treatments (71 to 73 animals/treatment). Increasing HA during winter_1, and residual sward height during summer_2, increased (P<0.001) BW and body size at joining (19 months) but had no effect (P>0.05) on OR. Mean BW at joining was 53.3, 56.8, 56.6 and 61.7 (SEM 0.74) kg for ewes offered the LL, LH, HL and HH treatments, respectively. Mean OR of C×SBF and BelMG×SBF differed (P<0.001) from that of Bel×SBF by −0.58 and +0.47, respectively. Correlations between linear measurements (LMs) of body size and BW at 7, 12 and 17 months were all positive and significant (P<0.001). The precision of the set of LMs as a predictor of BW at joining improved with age (R² 0.46, 0.54 and 0.74 at 7, 12 and 17 months) but BW at a given age was a better predictor at all age time points. Chest girth was the best predictor, among the LMs, of BW at joining and its explanatory power increased with age. Equations developed using LMs at 7, 12 or 17 months, to predict BW at joining exhibited biases of −2.1, −1.5 and +0.9 kg, respectively. It is concluded that whilst altering PN during the rearing phase changed BW by 16% it had no effect on OR. There was no interaction (P>0.05) between the PN offered during winter_1 and summer_2, or PN and ewe genotype for BW at joining or OR. LMs, either at 7, 12 or 17 months of age, are useful predictors of BW at joining.     

Influence of nutrient restriction and melatonin supplementation of pregnant ewes on maternal and fetal pancreatic digestive enzymes and insulin-containing clusters

Primiparous ewes (n=32) were assigned to dietary treatments in a 2×2 factorial arrangement to determine effects of nutrient restriction and melatonin supplementation on maternal and fetal pancreatic weight, digestive enzyme activity, concentration of insulin-containing clusters and plasma insulin concentrations. Treatments consisted of nutrient intake with 60% (RES) or 100% (ADQ) of requirements and melatonin supplementation at 0 (CON) or 5 mg/day (MEL). Treatments began on day 50 of gestation and continued until day 130. On day 130, blood was collected under general anesthesia from the uterine artery, uterine vein, umbilical artery and umbilical vein for plasma insulin analysis. Ewes were then euthanized and the pancreas removed from the ewe and fetus, trimmed of mesentery and fat, weighed and snap-frozen until enzyme analysis. In addition, samples of pancreatic tissue were fixed in 10% formalin solution for histological examination including quantitative characterization of size and distribution of insulin-containing cell clusters. Nutrient restriction decreased (P⩽0.001) maternal pancreatic mass (g) and α-amylase activity (U/g, kU/pancreas, U/kg BW). Ewes supplemented with melatonin had increased pancreatic mass (P=0.03) and α-amylase content (kU/pancreas and U/kg BW). Melatonin supplementation decreased (P=0.002) maternal pancreatic insulin-positive tissue area (relative to section of tissue), and size of the largest insulin-containing cell cluster (P=0.04). Nutrient restriction decreased pancreatic insulin-positive tissue area (P=0.03) and percent of large (32 001 to 512 000 µm²) and giant (⩾512 001 µm²) insulin-containing cell clusters (P=0.04) in the fetus. Insulin concentrations in plasma from the uterine vein, umbilical artery and umbilical vein were greater (P⩽0.01) in animals receiving 100% requirements. When comparing ewes to fetuses, ewes had a greater percentage of medium insulin-containing cell clusters (2001 to 32 000 µm²) while fetuses had more (P<0.001) pancreatic insulin-positive area (relative to section of tissue) and a greater percent of small, large and giant insulin-containing cell clusters (P⩽0.02). Larger insulin-containing clusters were observed in fetuses (P<0.001) compared with ewes. In summary, the maternal pancreas responded to nutrient restriction by decreasing pancreatic weight and activity of digestive enzymes while melatonin supplementation increased α-amylase content. Nutrient restriction decreased the number of pancreatic insulin-containing clusters in fetuses while melatonin supplementation did not influence insulin concentration. This indicated using melatonin as a therapeutic agent to mitigate reduced pancreatic function in the fetus due to maternal nutrient restriction may not be beneficial.     

Productive performance,meat quality and fatty acid profile of steers finished in confinement or supplemented at pasture

Thirty Aberdeen Angus crossbred steers (281±16 kg) were used to test the effect of finishing feeding system on growth performance, meat quality and fatty acid (FA) profile in intramuscular fat. Steers were fed in confinement (forage:concentrate ratio of 50 : 50; DM basis) or with different levels of energy supplementation (0, 0.4, 0.8 and 1.2% BW) at pasture (Avena strigosa Schreb and Lolium multiflorum L.). There were no differences between treatments for ADG (average=1.60 kg/day), hot carcass weight (HCW) (average=229 kg) and subcutaneous fat depth (average=3 mm). Dressing % (P=0.06; tendency) and carcass ADG (P=0.02) linearly increased with level of supplementation for pasture steers. No differences were observed between treatments for tenderness, marbling, pH, color b*, or cooking loss and drip loss in samples of Longissimus dorsi. However L* increased linearly (P=0.05) with level of supplementation. The concentrations of myristic, palmitic, estearic and linoleic FA did not differ among treatments. The concentration of n-3 FA increased (P<0.001) in steers at pasture compared with confinement, but n-6 FA concentrations did not differ between feeding system. Supplementation up to 0.4% BW increase (P<0.001) conjugated linoleic acid (CLA) and linolenic FA concentrations in intramuscular fat when compared with confinement. The level of supplementation on pasture linearly decreased (P<0.001) n-3 and CLA and linearly increased (P=0.001) the n-6 : n-3 ratio. Finishing of steers grazing winter pasture with energy supplementation or in confinement fed a medium-concentrate diet did not affect meat quality (tenderness, marbling, parameter b* on the CIE L*a*b* scale, cooking and drip losses) except for a* and L*. However, intramuscular fat of animals finished at pasture with moderate level of supplementation compared to animals fed in confinement had greater concentration of CLA, linolenic, and n-3, and lower n-6 : n-3 in intramuscular fat.