Energy source and ionophore supplementation effects on lamb growth, carcass characteristics, visceral organ mass, diet digestibility, and nitrogen metabolism

Staphylococcus aureus mutants resistant to the feed-additive monensin show increased virulence and altered purine metabolism

Ionophores are antibacterial compounds that affect bacterial growth by changing intracellular concentrations of the essential cations, sodium and potassium. They are extensively used in animal husbandry to increase productivity and reduce infectious diseases, but our understanding of the potential for and effects of resistance development to ionophores is poorly known. Thus, given their widespread global usage, it is important to determine the potential negative consequences of ionophore use on human and animal health. In this study, we demonstrate that exposure to the ionophore monensin can select for resistant mutants in the human and animal pathogen Staphylococcus aureus, with a majority of the resistant mutants showing increased growth rates in vitro and/or in mice. Whole-genome sequencing and proteomic analysis of the resistant mutants show that the resistance phenotype is associated with de-repression of de novo purine synthesis, which could be achieved through mutations in different transcriptional regulators including mutations in the gene purR, the repressor of the purine de novo synthesis pathway. This study shows that mutants with reduced susceptibility to the ionophore monensin can be readily selected and highlights an unexplored link between ionophore resistance, purine metabolism, and fitness in pathogenic bacteria.IMPORTANCEThis study demonstrates a novel link between ionophore resistance, purine metabolism, and virulence/fitness in the key human and animal pathogen Staphylococcus aureus. The results show that mutants with reduced susceptibility to the commonly used ionophore monensin can be readily selected and that the reduced susceptibility observed is associated with an increased expression of the de novo purine synthesis pathway. This study increases our understanding of the impact of the use of animal feed additives on both human and veterinary medicine.

Review of Feeding Systems Affecting Production, Carcass Attributes, and Meat Quality of Ovine and Caprine Species

Growth rate, carcass attributes, and meat quality traits of small ruminants (i.e., sheep and goats) depend on various factors, among which the feeding system is one of the most important factors. However, how feeding systems affect these parameters differ between sheep and goats. Therefore, this review aimed to evaluate the differences in how different feeding systems affect the growth performance, carcass characteristics, and meat quality of sheep and goats. It also explored the effects of a new finishing strategy-time-limited grazing with supplements on these traits. Compared with stalled feeding, finishing lambs/kids on pasture-only feed reduced the average daily gain (ADG) and carcass yield, while supplemented-grazing lambs/kids had near-equivalent or higher ADG and carcass attributes. Pasture-grazing increased the meat flavor intensity and healthy fatty acid content (HFAC) of lamb/kid meat. Supplemental grazing lambs had comparable or superior meat sensory attributes and increased meat protein and HFAC compared to stall-fed ones. In contrast, supplemental grazing only improved the meat color of kids but had little effect on other meat qualities. Moreover, time-limited grazing with supplemental concentrates increased the carcass yield and meat quality in lamb meat. Overall, the effects of different feeding systems on growth performance and carcass traits were comparable between sheep and goats but differed in terms of the meat quality.

Effect of forage to concentrate ratio on growth performance and feeding behavior of Thalli lambs

The objective of the study was to evaluate the effect of forage to concentrate ratio (F:C) on growth performance and feeding behavior of Thalli lambs. For this purpose, twenty-one male Thalli lambs with initial live body weight (26.30 ± 3.02 kg) were selected and divided into three experimental groups in a randomized complete block design. The experimental duration was 12 weeks. The experimental diets were F:C (100:0), F:C (80:20), and F:C (60:40). Alfalfa hay was used as forage source. Lambs fed F:C (60:40) and F:C (80:20) diets showed higher dry matter intake (DMI), total dry matter intake (TDMI), organic matter intake (OMI), weight gain, growth rate, better feed conversion ratio, and feed efficiency as compared to the lambs fed F:C (100:0) (P < 0.05). The results also showed that crude protein (CP), ether extract (EE), and total digestible nutrient (TDN) intake were maximum in F:C (60:40)-fed lambs (P < 0.05). However, higher crude fiber (CF), neutral detergent fiber (NDF), and acid detergent fiber (ADF) intakes were seen in the F:C (100:0)-fed lambs (P < 0.05). The results of nutrient digestibilities revealed the improved OM, DM, CP, and ADF digestibilities in lambs fed with F:C (60:40) and F:C (80:20) (P < 0.05). The digestibility of NDF and CF were not affected by the all-dietary treatments (P > 0.05). Behavior results explored that eating time, and chewing time was higher in F:C (100:0)-fed lambs (P < 0.05), while standing time, lying time, and abnormal behavior were increased in lambs fed with F:C (60:40) and F:C (80:20) (P < 0.05). Based on the results, it is concluded that the addition of concentrate at 20% and 40% improves growth performance and increases DMI, TDMI, OMI, and nutrient digestibility. However, standing time, lying time, and abnormal behavior increase by feeding of the 20% and 40% concentrate. Therefore, it is suggested that the concentrate should be supplied in restricted amounts to improve lambs' welfare and normal behavior without influencing their performance.

Protein metabolism, body composition and oxygen consumption in young bulls divergent in residual feed intake offered two contrasting forage-based diets

Protein metabolism and body composition have been identified as major determinants of residual feed intake (RFI) in beef cattle fed high-starch fattening diets. This study aimed to evaluate if these two identified RFI determinants in beef cattle are the same across two contrasting silage-based diets. During two consecutive years, an 84-day feed efficiency test (Test A) immediately followed by a second 112-day feed efficiency test (Test B) was carried out using a total of 100 animals offered either one of two diets (either corn silage- or grass silage-based) over 196 days. At the end of Test A, the 32 animals most divergent for RFI (16 extreme RFI animals per diet, eight low RFI and eight high RFI) were identified and evaluated during Test B for their i) N use efficiency (NUE; N retention/N intake) calculated either from a 10-d nitrogen balance trial or from estimations based on body composition changes occurring during the whole experiment (Test A and Test B; 196 days), ii) carcass and whole-body protein turnover rates analysed through the 3-methyl-histidine urinary excretion and the N isotopic turnover rates of urine, respectively, and iii) body composition measured at the slaughterhouse at the end of Test B. Oxygen consumption was measured during Test B for the 100 animals by two GreenFeed systems. Irrespective of the diet, efficient RFI animals tended (P = 0.08) to improve their NUE when N retention was estimated for 196 days or when considering their lower urinary urea-N to total N ratio (P = 0.03). In contrast, NUE calculated during the 10-d N balance showed no differences (P = 0.65) across RFI groups suggesting that this method may not be suitable to capture small NUE differences. Efficient RFI individuals presented higher dressing percentage and muscle deposition in the carcass (P = 0.003) but lighter rumen (P = 0.001), and a trend for lower oxygen consumption (P = 0.08) than inefficient RFI animals irrespective of the diet. Lower protein degradation rates of skeletal muscle and lower protein synthesis rates of plasma proteins were found in efficient RFI cattle but only with the corn silage-based diet (RFI × Diet; P = 0.02). The higher insulinaemia associated with the corn silage-based diet (P = 0.001) seemed to be a key metabolic feature explaining the positive association between protein turnover and RFI only in this diet. Feed N was more efficiently used for growth by efficient RFI animals regardless of the diet but lower protein turnover rates in efficient RFI animals were only observed with corn silage-based diets.

Digestion of bamboo compared to grass and lucerne in a small hindgut fermenting herbivore, the guinea pig (Cavia porcellus)

Bamboo is an enigmatic forage, representing a niche food for pandas and bamboo lemurs. Bamboo might not represent a suitable forage for herbivores relying on fermentative digestion, potentially due to its low fermentability. To test this hypothesis, guinea pigs (n = 36) were used as model species and fed ad libitum with one of three forages (bamboo, lucerne, or timothy grass) in a fresh or dried state, with six individuals per group, for 3 weeks. The nutrient composition and in vitro fermentation profile of bamboo displayed low fermentation potential, i.e. high lignin and silica levels together with a gas production (Hohenheim gas test) at 12 h of only 36% of that of lucerne and grass. Although silica levels were more abundant in the leftovers of (almost) all groups, guinea pigs did not select against lignin on bamboo. Dry matter (DM) intake was highest and DM digestibility lowest on the bamboo forage. Total short-chain fatty acid levels in caecal content were highest for lucerne and lowest for grass and bamboo. Bamboo-fed guinea pigs had a lower body weight gain than the grass and lucerne group. The forage hydration state did not substantially affect digestion, but dry forage led to a numerically higher total wet gut fill. Although guinea pigs increased DM intake on the bamboo diet, the negative effects on fermentation of lignin and silica in bamboo seemed overriding. For herbivores that did not evolutionary adapt, bamboo as an exclusive food resource can be considered as inadequate.

Effect of Barley Variety on Feed Intake, Digestibility, Body Weight Gain and Carcass Characteristics in Fattening Lambs

Twenty lambs (18 ± 0.22 kg initial weight) were blocked by weight and individually assigned into pens to evaluate the effects of barley straw variety on digestibility, growth performance and carcass characteristics. The following four treatments were tested: (1) a local barley straw (as control), (2) HB1963 (high grain and straw yields), (3) Traveller (high straw yielder), and (4) IBON174/03 (high grain yielder). A concentrate (50:50 wheat bran and noug seed cake) was offered constantly (300 DM g), whereas the straw was offered ad libitum. The digestibility trial lasted 22 days (15 days to adapt to dietary treatments and 7 days for sampling). The growth performance trial lasted 90 days. At the end, all of the lambs were slaughtered, and their carcasses were evaluated. The IBON174/03 variety had a higher (p < 0.05) intake of organic matter and crude protein, a higher dry matter and organic matter digestibility than the control, and a faster growth than the control. The feed-to-gain ratio was similar among treatments. The slaughter and empty body weights of lambs in the IBON174/03 group were higher than the control variety (p < 0.05). The present study showed that the feeding value of barley straw can differ substantially between varieties and therefore must be considered in the choice of a barley variety.

Evaluation of tree lucerne (Chamaecytisus palmensis) dried leaves as a substitution for concentrate mixture on biological performance and socioeconomic of Washera sheep fed on desho grass hay

Background

The experiment was conducted to evaluate the effect of tree lucerne dried leaves (TLDL) as a substituting supplement for noug seed cake, and wheat bran concentrate mixtures (CM) on feed intake, digestibility, growth, carcass characteristics and economic benefits using Washera sheep fed desho grass hay as a basal diet.

Methods

Twenty‐five male Washera sheep with an initial body weight of 16 ± 4.01 kg (mean ± SD) were used for both growth and digestibility trials which lasted for 90 and 10 days, respectively The experiment was conducted using a randomized complete block design having five blocks with five treatments (T1 = 0% TLDL + 100% CM; T2 = 25% TLDL + 75% CM; T3 = 50% TLDL + 50% CM; T4 = 75% TLDL + 25% CM and T5 = 100% TLDL + 0% CM).

Results

Significant (p < .05) differences were observed among treatments in total dry matter (DM), nutrients and metabolizable energy (ME) intake; as the level of TLDL increases total DM and nutrient intake decreased (p < .05) except neutral detergent fibre intake (NDFI) and acid detergent fibre intake (ADFI). Digestibility of DM, organic matter (OM) and crude protein (CP) were significantly reduced (p < .001) among the treatments increasing the substitution level of TLDL for local concentrate mixture, but non‐significant for fibre fractions digestibility. Similarly, body weight, average daily gain and feed conversion efficiency were significantly different (p < .01) and highest in T1 than other treatments, whereas lowest values of the same parameters were observed for T5. Non‐significant difference among treatments was observed in almost all of the carcass characteristics except for rib‐eye area that showed significant difference among treatment and was highest in T1 and T2 (low level of TLDL inclusion). The economic analysis showed that supplementation TLDL was economically feasible in which the net return of the treatments were 31.66 (T1), 30.68 (T2) and 30.34 (T3), 27.88 (T4) and 26.32 (T5) USD (United States Dollar).

Conclusions

It was concluded that TLDL could be used as alternative feed source by replacing concentrate mixture up to 75% (T4) which enhanced nutrient intake, digestibility and growth performance of Washera sheep. Finally, TLDL supplementation is recommended as replacement of CM up to 75% for its biological and economic feasibility.

Integration of energy and protein transactions in the body to build new tools for predicting performance and body composition of ruminants

Increased market pressure to improve meat yield and quality require improved methods of predicting body composition in growing animals. Current systems of animal nutrition based on nutrient supply and animal characteristics predict animal growth from nutrient inputs, but, as of yet, do not accurately predict body composition. The present paper explores the evidence and data required to support an existing model of the effects of energy intake on visceral and muscle protein mass and energy expenditure to predict heat production, growth and body composition of sheep. While parameters of the model related to energetic costs of protein in muscle and viscera can be supported by independent studies, parameters associated with energetic costs of protein gain, particularly in viscera, are harder to reconcile with independent measurements. The range of available data on systematic changes in visceral organ mass over time in response to feed intake is limited, which may constrain generalisation of the parameters of the model with regard to the wide range of production situations faced by the sheep and cattle industries. However, sufficient data exist in the literature to test, and if required, revise the current framework.

Effect of forage to concentrate ratio and duration of feeding on growth and feed conversion efficiency of male lambs

Rations (DM basis) for spring-born male lambs consisting of concentrates ad libitum (CON), 50:50 (50% concentrate:50% forage), and forage ad libitum (FORG) were evaluated across feeding periods of three durations (36, 54, and 72 d). Lambs on CON diets were offered ad libitum access to concentrate along with 400 g of fresh weight silage (daily), while 50:50 diets were offered 0.9 and 3.0 kg of concentrate and silage, respectively. Lambs on FORG were offered ad libitum access to 25.5% DM silage. These rations were fed to 99 spring-born male Texel cross Scottish Blackface lambs which were assigned to a 3 × 3 factorial arrangement. Lambs were slaughtered following completion of their respective treatments. Lambs fed CON diets had greater ADG, FCE, and carcass weight (P < 0.001) and carcasses with greater conformation score (P < 0.001) than lambs fed 50:50 or FORG diets. Duration of feeding had no effect on production variables across all three concentrate inclusion levels. It was concluded that the inclusion of concentrates is needed to adequately finish lambs fed indoors. Feeding lamb’s 50:50 diets resulted in modest responses and may be a viable option for finishing lambs or to maintain growth in lambs when the cost of concentrate feed is high relative to the financial return on the lamb meat.

Microanatomy of the digestive tract, hooves and some visceral organs of addax antelope (Addax nasomaculatus) following a concentrate or forage feeding regime

Subacute ruminal acidosis is a common disease in captive non-domesticated ruminants and is mainly diagnosed by rumen fluid pH and rumen histology. Furthermore, differences in ruminant gastrointestinal histology have been hypothesized to correlate with the browser-grazer continuum. Twelve surplus addax antelope (Addax nasomaculatus) were divided into two groups, fed either their usual diet, consisting of a concentrate feed with a limited amount of hay, or a diet of unlimited hay only, for 3 months. After culling, descriptive and morphometric histology and pH measurements were compared between groups. Significant variations in cellular subpopulations were noted between groups, with roughage-fed individuals presenting primarily with balloon cells of the Stratum corneum and living layer cell vacuolization, whereas parakeratosis and intermediate-type cells were more frequent in the concentrate-fed group. Lesions typical of subacute ruminal acidosis were significantly more pronounced in concentrate-fed individuals. Ruminal pH measurements did not differ significantly, but were more consistent in forage-fed individuals, indicating a more stable reticuloruminal environment. The results indicate that ruminal histology may be more appropriate in assessing ruminal health compared to a single post-mortem pH measurement. It is proposed that Stratum corneum balloon cells may indicate cell maturation and not, as previously assumed, hyperfunction. Concentrate-fed individuals scored higher on the presence of inflammatory cells on hoof corium histology. The study further emphasizes the adaptability of ruminant digestive tract microanatomy in adult animals even after a short period of time and the positive effects an increased roughage diet may have in populations of captive grazing ruminants.

ANIMAL BEHAVIOR AND WELL-BEING SYMPOSIUM: The Common Swine Industry Audit: Future steps to assure positive on-farm animal welfare utilizing validated, repeatable and feasible animal-based measures

The Common Swine Industry Audit (CSIA) was developed and scientifically evaluated through the combined efforts of a task force consisting of university scientists, veterinarians, pork producers, packers, processers, and retail and food service personnel to provide stakeholders throughout the pork chain with a consistent, reliable, and verifiable system to ensure on-farm swine welfare and food safety. The CSIA tool was built from the framework of the Pork Quality Assurance Plus (PQA Plus) site assessment program with the purpose of developing a single, common audit platform for the U.S. swine industry. Twenty-seven key aspects of swine care are captured and evaluated in CSIA and cover the specific focal areas of animal records, animal observations, facilities, and caretakers. Animal-based measures represent approximately 50% of CSIA evaluation criteria and encompass critical failure criteria, including observation of willful acts of abuse and determination of timely euthanasia. Objective, science-based measures of animal well-being parameters (e.g., BCS, lameness, lesions, hernias) are assessed within CSIA using statistically validated sample sizes providing a detection ability of 1% with 95% confidence. The common CSIA platform is used to identify care issues and facilitate continuous improvement in animal care through a validated, repeatable, and feasible animal-based audit process. Task force members provide continual updates to the CSIA tool with a specific focus toward 1) identification and interpretation of appropriate animal-based measures that provide inherent value to pig welfare, 2) establishment of acceptability thresholds for animal-based measures, and 3) interpretation of CSIA data for use and improvement of welfare within the U.S. swine industry.

Growth performance and development of internal organ, and gastrointestinal tract of calf supplementation with calcium propionate at various stages of growth period

To investigate the effects of calcium propionate (CaP) supplementation on performance, the development of the internal organ, and gastrointestinal tract of calves at various stages of growth period, 54 male Jersey calves (age = 7 ± 1 d, body weight(BW) = 23.1 ± 1.2 kg) were randomly allocated to three treatment groups. While control calves were fed basis dietary with no additives (0CaP), other treatment calves were fed basis dietary supplementation with CaP at 50 (5CaP) or 100 (10CaP) g kg-1 dry matter. The experiment lasted 160 d and was divided into three feeding stages: Stage 1 (d 0 to 30), Stage 2 (d 31 to 90), and Stage 3 (d 91 to160). Six calves from each group were randomly selected and slaughtered on days 30, 90, and 160 when at the conclusion of each experimental feeding stage. The BW of calves increased with 10CaP after feeding 90 d, whereas it increased with 5CaP and 10CaP at feeding 120d and 160d compared to 0CaP. The 10CaP group improved average daily gain (ADG) of calves at stage 2, and d120-160 of stage 3 compared with the 0CaP group. The ADG of 5CaP was greater than the 0CaP group only at 120-160 d of stage 3 compared with the 0CaP group. The results of feed efficiency were in agreed with ADG as no dry matter intake difference at all stages of growth period. The 10CaP treatment exhibited the greatest spleen weight among the treatment at the end of the experiment; the liver weight of the 5CaP and 10CaP calves at feeding 90 d and of the 10CaP calves at feeding 160 d and were greater than those of the 0CaP animals. The CaP at the tested doses increased the rumen weight after feeding 90d of Jersey calves, and also improved the development of intestine. In conclusion, dietary supplementation with calcium propionate at the tested doses caused a beneficial effect in the growth performance and gastrointestinal tract traits of Jersey calves, thus to add 10% CaP before feeding 90 days was better and 5% CaP supplementation was expected at the period for feeding 90 to160 d.

Effects of dietary calcium propionate on growth performance and carcass characteristics of finishing lambs

The objective of this study was to evaluate the effects of the addition of two levels of calcium propionate on lamb performance and some carcass characteristics. Twenty-one male Creole lambs with an initial weight of 25.3 ± 3.3 kg were randomly assigned to one of the following treatments: 0, 10, and 20 g of calcium propionate/kg of diet (dry matter basis). Intake, daily gain, feed conversion, carcass weight, and rib eye area were not affected (P < 0.05) by calcium propionate addition. Ruminal fermentation was not altered (rumen pH, volatile fatty acids concentration, and fermentation pattern), and ruminal ammonia-N presented a quadratic response (P < 0.05). In fat from the longissimus dorsi muscle, oleic acid showed a linear decrease (P < 0.05) and α-linolenic presented a linear increment (P < 0.05). The addition of 10 or 20 g of calcium propionate in diets containing 350 g/kg grain and 100 g/kg molasses did not modify the productive performance of lambs or ruminal fermentation, and minor changes were detected in long-chain fatty acid in intramuscular fat.

High concentrate:forage ratio diet inhibiting omasal epithelium growth is associated with decreased cyclin D1 and CDK4 expression in growing goats

The hypothesis that different concentrate : forage ratio diets alter omasal epithelium proliferation of growing goats via cyclins and regulation of the cell cycle was tested. Growing goats were fed with a high concentrate (HC, n = 8) or a low concentrate (LC, n = 8) diet for 42 days. The concentrate : forage ratio was 40:60 in the HC group and 0:100 in the LC group. In the HC group, the relative weight and DNA content of the omasal epithelium were lower, but the protein : DNA ratio was higher. Flow cytometry revealed that HC omasal cell numbers were smaller in S- and G2 /M-phases of the cell cycle and higher in the G0 /G1 -phases and were accompanied by reduced expression of cyclin D1 and CDK4 mRNA and protein. These data are consistent with morphologic observations in the HC that cell density decreased in the stratum spinosum (SS) plus stratum granulosum (SG) and stratum basale, and that cell density was lower in the SS plus SG. Thus, high-concentrate : forage ratio diet retards omasal epithelial growth by slowing the G1 to S phase transition of the cell cycle and is associated with decreased cyclin D1 and CDK4 expression in growing goats.

Desempenho de cordeiros em confinamento alimentados com dieta exclusiva de concentrado com diferentes porcentagens de proteína

O presente experimento foi realizado com o objetivo de avaliar o desempenho de cordeiros em confinamento alimentados com dieta exclusiva de concentrado com diferentes porcentagens de proteína. Foram utilizados 24 cordeiros mestiços da raça Santa Inês, não castrados, com aproximadamente 180 dias de idade, peso vivo médio de 25kg, confinados, num delineamento experimental inteiramente ao acaso, com quatro tratamentos e seis repetições. O consumo voluntário de matéria seca, matéria orgânica, proteína bruta e nutrientes digestíveis totais, além do ganho de peso diário e total, da conversão e da eficiência alimentar dos cordeiros, não foram influenciados (P>0,05) pela porcentagem de proteína na dieta. As dietas com 18 e 20% de proteína bruta apresentaram menores custos de produção, entretanto o menor custo foi obtido com a ração contendo 18% de PB.

Prepartum dietary energy source fed to beef cows: II. Effects on progeny postnatal growth, glucose tolerance, and carcass composition

Mature Angus-cross beef cows (n = 228) were used to evaluate effects of prepartum dietary energy source on postnatal growth and carcass composition of progeny in a 2-yr study. Starting at approximately 160 d of gestation, cows were fed diets consisting of 1 of 3 primary energy sources: grass hay (HY), corn (CN), or dried corn distillers grains with solubles (DG). The CN and DG diets were limit-fed to achieve similar energy intakes as cows fed HY. Following parturition, cows were fed a common diet and managed as a single group. Calves were weaned at an average of 185 ± 6 d of age and backgrounded for 28 d. A subset of progeny (n = 134) was individually fed a common finishing diet until slaughter, when each calf reached 1.2 ± 0.05 cm of backfat. A glucose tolerance test (GTT) was conducted in year 2 on 4 calves/treatment after 41 and 111 d on the finishing diet (DOF). Calf birth weights were greater (P = 0.002) in calves from cows fed CN and DG than calves from cows fed HY, and weaning BW (P = 0.08) was less for calves from cows fed HY vs. CN. Receiving BW, final BW, and HCW did not differ (P ≥ 0.16) among treatments. No difference (P ≥ 0.28) in ADG, morbidity, and mortality from birth to slaughter was observed among treatments. In response to a GTT, increased DOF resulted in greater (P ≤ 0.005) fasting insulin, faster glucose disappearance rate, and greater insulin:glucose area under the curve ratio. Glucose disappearance rate was greater (P = 0.01) in calves from cows fed CN than in calves from cows fed HY or DG. A greater initial insulin response (P = 0.005) was observed in calves from cows fed CN or DG than in calves from cows fed HY. Carcass traits used to measure yield grade did not differ (P ≥ 0.19) among treatments. Calves from dams fed CN had the lowest marbling score (P = 0.03) and intramuscular fat content (P = 0.07). These results indicate that prepartum maternal dietary energy source can alter fetal adipose tissue development and insulin sensitivity resulting in long-term effects on progeny's intramuscular fat deposition. Moreover, present findings suggest that increasing the number of days on a corn-based finishing diet increases insulin resistance in beef cattle.

Prepartum dietary energy source fed to beef cows: I. Effects on pre- and postpartum cow performance

Mature Angus-cross beef cows (n = 144) were used to determine effects of late gestation dietary energy source on pre- and postpartum cow performance in a complete randomized block design experiment. Cows were adapted to diets starting at 167 +/- 9 d of gestation and fed until 1 wk before expected calving date. Cows were fed 1 of 3 dietary energy sources: grass hay (HY), corn (CN), or dried distillers grains (DDGS). Cows allotted to HY were allowed ad libitum access to round-bale grass hay, and average hay disappearance was 12.4 kg/d. Limit-fed corn and DDGS diets contained 5.3 kg of whole-shelled corn or 4.1 kg of DDGS, respectively, plus 2.1 kg of hay, and 1.0 kg of supplement to meet cow nutritional needs during late gestation and to allow for an energy intake similar to HY. Every 21 d, BW, BCS, and ultrasound measurement of backfat between the 12th and 13th ribs were collected. At 210 d in gestation, jugular blood samples were collected from cows at 0, 3, 6, and 9 h postfeeding and were analyzed for glucose, insulin, NEFA, and blood urea N (BUN) concentrations. After parturition, cows were fed a common diet and managed similarly. Milk production was determined by weigh-suckle-weigh procedure on d 31, 100, and 176 postpartum. Cows fed DDGS during late gestation gained more (P = 0.04) BW than cows fed HY or CN; however, no difference in BCS change was detected (P = 0.28) among treatments. Plasma glucose concentrations were similar among treatments (P = 0.64), whereas insulin concentrations at 3 h postfeeding were greater (P = 0.002) for cows fed DDGS than those fed HY or CN. Plasma BUN concentrations were greater (P < or = 0.02) for cows fed DDGS vs. CN or HY up to 6 h postfeeding. Birth weight was greater (P < 0.001) for calves from cows fed CN and DDGS than for those fed HY, but this did not result in any differences in frequency of dystocia (P = 0.21). Prepartum energy source did not affect conception rates (P = 0.79), milk production (P > or = 0.51), or milk composition (P > or = 0.39). Maternal dietary energy source in late gestation did not affect pre- or postpartum cow performance, but did change plasma hormones and metabolites during gestation. Heavier birth weights in calves from cows fed CN or DDGS indicate the changes in maternal metabolism affected energy partitioning of nutrients to the fetus and subsequent fetal growth.

Supplementation with linseed (Linum usitatissimum) cake and/or wheat bran on feed utilization and carcass characteristics of Arsi-Bale sheep

Thirty yearling male intact Arsi-Bale sheep with initial body weight (BW) of 15.5 +/- 0.21 kg (mean +/- SD) were used in 90 days feeding trial, 10 days digestibility trial followed by evaluation of carcass parameters at Bokoji, Ethiopia. The objectives were to evaluate effects of supplementation with linseed (Linum usitatissimum) cake (LSC), wheat bran (WB), and their mixtures at 2:1 and 1:2, respectively on feed intake, digestibility, daily BW gain, and carcass parameters. The five treatments included ad libitum feeding of natural pasture hay (control) and with daily supplementation of 300 g dry matter (DM) sole LSC, 2LSC:1WB mix, 1LSC:2WB mix, and sole WB. Six sheep were randomly assigned to each treatment using randomized complete-block design. Four sheep in each treatment were randomly selected and used for determination of digestibility and carcass characteristics using a completely randomized design. The intake of hay DM was higher (P < 0.001) for the non-supplemented sheep compared with the supplemented ones, but the contrary was true for total DM intake. Sheep in the control treatment lost BW (-1.5 g/day), while the supplemented ones gained 69.0-104.1 g BW/head/day. Digestibility of CP was higher (P < 0.001) for supplemented sheep as a result of higher (P < 0.001) CP intake. Slaughter weight, empty BW, and hot carcass weight were lower (P < 0.001) for sheep in the control treatment compared with the rest. Sheep supplemented with LSC and its mixtures with WB had better (P < 0.001) performance in daily BW gain than sole WB supplemented ones indicating the advantages of using supplements as mixed rations. Moreover, supplementation proved to be profitable, whereas feeding hay alone led to economic loss.

Comparison of characteristics of lambs fed concentrate or grazed on ryegrass to traditional or heavy slaughter weights. I. Production, carcass, and organoleptic characteristics

The objectives of this study were to determine the effects of finishing lambs on concentrate (C) or by grazing ryegrass forage (F) to slaughter end weights of 52 (N) or 77 kg (H) on carcass characteristics and organoleptic properties. This experiment included 64 Targhee x Hampshire lambs (average BW = 24 +/- 1 kg) in a 2 x 2 x 2 factorial arrangement of treatments to compare wethers vs. ewes, C vs. F, and N vs. H slaughter weights. No interactions (P > 0.10) were observed between gender and other main effects. Hot carcass weight and dressing percent were greater (P < 0.001) for C- than for F-fed lambs. Backfat thickness also was greater (P < 0.001) for lambs fed C than for those fed F. Moreover, USDA lean quality score and USDA yield grades were higher (P < 0.001) for C- than for F-fed lambs, as well as for lambs slaughtered at H vs. N market weights. There was a higher (P < 0.005) incidence of off odors and off flavors in cooked muscle from F- vs. C-fed lambs, and also from H vs. N slaughter-weight lambs. The heavy C-fed lambs had juicier (P < 0.001) meat than other treatment combinations. Cooked meat from C-fed lambs received higher (P < 0.001) overall acceptability scores. Concentrate-finished lambs produced fatter carcasses and more palatable meat than forage-finished lambs; however, forage finishing allowed for slaughter at heavier weights without excessive fat deposition.

The effect of dietary restriction, pregnancy, and fetal type in different ewe types on fetal weight, maternal body weight, and visceral organ mass in ewes

Our objectives were to evaluate maternal body changes in response to dietary restriction or the increased nutrient requirement of fetal growth. In Exp. 1, 28 mature crossbred ewes (61.6 +/- 1.8 kg initial BW) were fed a pelleted forage-based diet to evaluate effects of pregnancy and nutrient restriction on visceral organ mass. Treatments were arranged in 2 x 3 factorially, with dietary restriction (60% restriction vs. 100% maintenance) and reproductive status (nonpregnant [NP], d 90 or d 130 of gestation) as main effects. Dietary treatments were begun at d 50 of gestation, and restricted ewes remained at 60% of maintenance throughout the experiment. Nonpregnant and d-90 ewes were fed dietary treatments for 40 d and slaughtered. The d-130 ewes were fed dietary treatments for 80 d and then slaughtered. In Exp. 2, four Romanov ewes were naturally mated (Romanov fetus and Romanov dam; R/ R), and two Romanov embryos were transferred to each of four Columbia recipients (Romanov embryos and Columbia recipient; R/C). Three Columbia ewes were naturally mated (Columbia fetus and Columbia recipient; C/C). In both experiments, maternal organ weights were reported as fresh weight (grams), scaled to empty body weight (EBW; grams per kilogram) and maternal body weight (MBW; grams per kilogram). In Exp. 1, ewe EBW and fetal mass were decreased (P < 0.02) with restriction compared with maintenance. Dietary restriction decreased liver mass (16.7 vs. 14.5 g/kg EBW or 18.8 vs. 16.4 g/kg MBW; P < 0.01), but dietary restriction did not affect total digestive tract mass. In Exp. 2, ewe BW was less for the R/R compared with R/C and C/C (44.8 vs. 110.4 and 98.1 +/- 7.9 kg, respectively; P < 0.01). Fetal weight at d 130 was less for the R/R than for R/C and C/C (2.2 vs. 3.3 and 4.7 +/- 0.3 kg, respectively; P < 0.01) when measured as individual fetuses; however, when measured as total fetal mass carried in each ewe, there was no effect of ewe type. These data suggest that the gastrointestinal tract, along with other maternal organs, responds to both level of dietary intake and nutrient requirements for gestation, and that fetal weight is decreased as a result of a 40% decrease in nutrients offered.