bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting lean meat yield in beef cattle using ultrasonic muscle depth and width measurements
Authors: Bergen R. , Crews D. H. , Miller Jr., S. P. , McKinnon J. J.
Published: April 2011

The value of live ultrasound longissimus dorsi depth and width measurements as predictors of estimated carcass lean meat yield of steers (CARLEAN-S) and bulls (CARLEAN-B) was studied. In trial 1, equations were developed to predict estimated lean meat yield of steers (n = 116) from carcass weight (Eq. 1) or liveweight (Eq. 2), fat depth and l. dorsi area or liveweight, fat depth and l. dorsi depth × width (Eq. 3). Equation 1 was most precise (RSD = 25.6 g kg-1), followed by Eq. 2 (RSD = 27.8g kg-1) and Eq. 3 (RSD = 30.2g kg-1). Equations 2 and 3 predicted CARLEAN-S with similar accuracy (SEP = 23.8 vs. 24.9 g kg-1, respectively) and were highly correlated with each other (r = 0.89) in an independent data set (n = 118). Repeatability and accuracy of pre-slaughter l. dorsi depth and width measurements were studied in yearling bulls (trial 2; n = 191). When ultrasound measurements were expressed as a percentage of the average ultrasound measurement, repeatabilities of l. dorsi depth (SER = 6.2 to 7.8%) and width (SER = 4.2 to 6.1%) measurements were similar to fat depth and l. dorsi area measurements (SER = 17.9 and 4.5%, respectively). When ultrasound measurements were compared to the corresponding carcass measurements, l. dorsi depth (SEP = 10.3 to 13.9%) and width (SEP = 6.7 to 8.5%) measurements were as accurate as fat depth and l. dorsi area measurements (SEP = 32.9 and 8.4%, respectively). Equations were developed to predict CARLEAN-B of yearling bulls (n = 82) from liveweight, 12th rib ultrasound fat depth and either l. dorsi depth × width measurements (Eqs. 4 and 5) or two l. dorsi depth measurements (Eq. 6). All equations had similar precision (RSD = 19.4 to 19.5 g kg-1) and predicted CARLEAN-B similarly (SEP = 25.0, 24.6 and 26.1g kg-1 for Eqs. 4, 5 and 6, respectively) in an independent data set (n = 109). All equations were highly correlated (r ≥0.97) with an equation using ultrasound fat depth and l. dorsi area in the independent data set. Longissimus muscle depth and width measurements were as valuable as l. dorsi area for predicting carcass composition of yearling beef bulls in the present study. Key words: Ultrasound, beef cattle, carcass traits
Effect of micronization of peas and enzyme supplementation on nutrient excretion and manure volume in growing pigs
Authors: Zhang Z. , Nyachoti C. M. , Arntfield S. , Guenter W. , Cenkowski S.
Published: April 2011

The effect of micronization of peas and enzyme supplementation on performance, nitrogen and phosphorus excretion as well as manure output was investigated in a study with 12 Cotswold gilts (26.9 ± 3.6 kg initial body weight). Three diets based on barley-raw peas (control), barley-micronized peas, or barley-micronized peas plus a multi-enzyme blend were used. The study was conducted in two blocks and within a block; each diet was randomly assigned to four pigs to give a total of eight observations per diet. Pigs fed micronized peas and micronized peas plus enzyme diets had higher (P < 0.05) feed conversion than the control. Compared with the control, micronization of peas reduced (P < 0.05) wet and dry fecal output by 33 and 25%, respectively. Urine volume was not influenced (P > 0.05) by dietary treatment. Total fecal phosphorus excretion was lower (P < 0.001) in gilts fed the micronized peas or micronized peas plus enzyme diets compared with the control. Micronization of peas reduced (P < 0.05) total nitrogen excretion in pig manure by 21.5% (17.39 vs. 13.65 g d-1). In conclusion, formulating pig grower diets with micronized peas improves nitrogen and phosphorus utilization and reduces total manure volume. Key words: Pigs, nitrogen, phosphorus, manure volume, micronized peas
A proposed methodology to standardize the determination of enzymic activities present in enzyme additives used in ruminant diets
Authors: Colombatto and K. A. Beauchemin D.
Published: April 2011

There is increasing interest in using enzymes that degrade plant cell walls in ruminant diets to enhance production efficiency. Despite strong evidence from several studies suggesting a beneficial effect of enzyme supplementation on nutrient utilization and animal performance, overall the results have been somewhat inconsistent. One of the main problems faced by researchers is the lack of adequate biochemical characterization of the products used, which leads to a poor understanding of their mode of action. Of these biochemical characteristics, enzyme activities are the most important, but they are not always evaluated prior to use. Furthermore, as many arbitrary units of expression for these activities coexist, direct comparisons among studies are essentially impossible. In this paper, we propose a methodology that we feel accounts for the requirements of accuracy, simplicity and safety of use. In addition, a rationale for the standardization of the assays as a function of the conditions under which the enzymes are expected to act is presented. The standardization of these assays will benefit researchers, the feed industry, regulatory organizations, and ultimately the consumer, as it will result in the development of better, safer and more consistent enzyme additives for use in ruminant diets. Key words: Cellulase, enzyme additives, methodology, ruminants, xylanase
Protein turnover—what does it mean for animal production?
Authors: Lobley G. E.
Published: April 2011

The dynamics of protein turnover confer great advantages for homeothermy, plasticity and metabolic function in mammals. The different roles played by the various organs have led to aspects of protein synthesis and degradation that aid the various functions performed. The so-called “non-productive” organs such as the gastro-intestinal tract and liver produce large quantities of export proteins that perform vital functions. Not all these proteins are recovered, however, and thus function can result in lowered net conversion of plant protein to animal products. The splanchnic tissues also oxidize essential amino acids (AA). For example, the gut catabolizes leucine, lysine and methionine, but not threonine and phenylalanine, as part of a complex interaction between AA supply and tissue metabolic activity. Losses by oxidation and endogenous secretions can markedly alter the pattern of absorbed AA. The fractional rates of extraction of total AA inflow to the liver are low and this allows short-term flexibility in controlling supply to peripheral tissues. Recent evidence suggests that the role of the liver in AA catabolism is more a response to non-use by other tissues rather than an immediate regulation of supply to the periphery. Neither arterial supply of AA nor the rate of transport into peripheral tissues limits protein gain, except when supply is very limited. Rather, control is probably exerted via hormone-nutrient interactions. Key words: Protein synthesis, amino acid, gastro-intestinal tract, liver, muscle, mammary gland
Effects of evening feeding and extended photoperiod on growth, feed efficiency, live animal carcass traits and plasma prolactin of beef heifers housed outdoors during two Manitoba winters
Authors: Kennedy A. D. , Bergen R. D. , Lawson T. J. , Small J. A. , Veira D. M.
Published: April 2011

The effects of evening feeding and extended photoperiod on feedlot performance, live animal carcass traits and plasma prolactin were investigated in crossbred beef heifers in two consecutive Manitoba winters (1998–1999; exp. 1 and 1999–2000; exp. 2) using a 2 × 2 factorial design. Heifers were fed in the morning (1000 exp. 1 and 0900 exp. 2) or evening (2000) and exposed to natural winter photoperiod (NP) of <15 h or extended winter photoperiod (EP) of 16–19 h (65 lux exp. 1, 51 lux exp. 2) in outdoor partially covered pens. Heifers (n = 48; 276.9 ± 19.4 kg, mean ± SD) in exp. 1 were given a 60% forage: 40% concentrate backgrounding ration for 56 d followed by a 25% forage: 75% concentrate finishing ration for 70 d. In exp. 2, heifers (n = 48; 228.8 ± 18.8kg) were given the backgrounding ration for 170 d. Mean ambient temperature during the backgrounding and finishing periods in exp. 1 was -13.7 and 0.5°C, respectively. During the backgrounding period of exp. 1, evening feeding increased (P = 0.05) growth rate 10.1%, and tended (P = 0.08) to improve feed efficiency by 9.0%; EP tended (P = 0.08) to improve feed efficiency by 9.0%. During the finishing period there was a time of feeding × photoperiod interaction (P = 0.02) for feed efficiency with a tendency for most efficient gains in the morning-fed NP heifers. There were no main or interaction effects of time of feeding and photoperiod on ultrasonically measured subcutaneous fat depth or longissimus dorsi muscle area in exp. 1. Plasma prolactin was elevated by EP on day 42 (photoperiod × day; P < 0.01) of exp. 1. Mean ambient temperature during exp. 2 was -5.1°C, and there were no main or interaction effects of time of feeding or photoperiod on weight gain, dry matter intake or feed efficiency. However, subcutaneous fat depth was reduced by EP on day 156 (photoperiod × day; P < 0.01). Plasma prolactin did not change during the first 107 d of exp. 2, but subsequently rose in all but the morning-fed EP treatment group. The results indicate that both evening feeding and extended photoperiod can impact growth and feed efficiency of beef cattle during winter-feeding. Key words: Feedlot heifers, beef cattle, evening feeding, extended photoperiod, light, prolactin
Chemical composition and ruminal nutrient degradabilities of fresh and ensiled Kura clover (Trifolium ambiguum M.B.)
Authors: Seguin and A. F. Mustafa P.
Published: April 2011

Kura clover is a perennial rhizomatous forage legume mainly used for grazing in permanent pastures. A study was conducted to determine the ensiling potential of Kura clover by comparing the chemical composition and ruminal nutrient degradabilities of fresh and ensiled forage of two cultivars (Cossack and Endura). Ensiling characteristics were determined by ensiling forages in mini-silos for 50 d. Ruminal nutrient degradabilities of fresh and ensiled forages were determined by the nylon bag technique using two lactating cows fitted with ruminal cannulas. Results showed that silages of both cultivars were well preserved as indicated by low pH and high lactic acid concentration. Cultivar had little effect on the chemical composition of Kura clover silage. However, ensiling increased (P < 0.05) soluble protein and non-protein nitrogen (NPN) and reduced (P < 0.05) neutral and acid detergent insoluble protein fractions. Ensiling increased NPN and reduced true protein by 87 and 29%, respectively. Results of the in situ study indicated that cultivar had no effect on effective ruminal degradability of dry matter (DM), crude protein (CP), an d neutral detergent fiber (NDF). Relative to fresh forage, ensiled Kura clover had similar effective ruminal degradability of DM (712 g kg-1 of DM) and NDF (417 g kg-1 of NDF) but a higher (P < 0.05) effective ruminal degradability of CP (806 vs. 725 g kg-1 of CP). It was concluded that Kura clover may be preserved as silage with minimal alterations in forage quality. These findings will increase the acceptability of Kura clover by widening possible utilizations. Key words: Forage quality, Kura clover (Trifolium ambiguum M.B.), protein fractions, ruminal degradability, silage
Estimating fat reserves in Rasa Aragonesa ewes: A comparison of different methods
Authors: Mendizabal J. A. , Delfa R. , Arana A. , Eguinoa P. , González C. , Treacher T. , Purroy A.
Published: April 2011

Four pre-slaughter measurements, liveweight (LW), body condition score (BCS) and fat thickness, measured by ultrasound, in the lumbar (FTL) and sternal regions (FTS), and four post-slaughter measurements, empty liveweight (ELW), hot carcass weight (HCW) and diameter of adipocytes in subcutaneous (DSC) and omental (DOM) fat depots¸ were used to predict the weight of fat in the omental (OM), mesenteric (MES), perirenal (PR), subcutaneous (SC) and intermuscular (IM) depots of ewes. Linear and multiple regressions were fitted to data from 42 adult, non-pregnant and non-lactating Rasa Aragonesa ewes, with liveweights between 29.8 and 79.2 kg and body condition scores between 0.75 and 4.5. Using a single parameter, ELW and HCW gave the most accurate predictions of the total depot fat (R2 = 0.88 and 0.90, RSD = 1.571 and 1.484 kg, respectively). Multiple regressions predicted total weight of fat depots from the pre-slaughter variables LW, BCS and FTS with an R2 value of 0.92 (RSD=1.317 kg). This result confirms the utility of using in vivo measures as fat reserve predictors in Rasa Aragonesa ewes. Key words: Fat tissue, liveweight, body condition score, adipocytes, ultrasound, ewes
Endocrinology and mammary development of lactating Genex-Meishan and Large White sows
Authors: Farmer C. , Palin M. F. , Sorensen M. T.
Published: April 2011

Endocrine and metabolic data as well as mammary tissue composition were obtained in Genex-Meishan (GM, containing 50% Chinese Meishan genes) and Large White (LW) lactating sows. Jugular vein cannulae were used to collect serial blood samples from 9 LW and 8 GM sows for 4 h every 15 min on days 6 and 19 of lactation. Concentrations of prolactin and cortisol were determined on all samples while those of insulin-like growth factor-I (IGFI), growth hormone (GH), glucose and free fatty acids (FFA) were measured in hourly samples. Milk samples were obtained from 19 GM and 16 LWsows on day 23 of lactation and all sows were slaughtered on day 25. Mammary glands were excised and analyzed for tissue composition and for number and affinity of prolactin receptors. Concentrations of plasma IGF-I were lower (P < 0.01) and plasma FFA greater (P < 0.001) in GM than in LW sows. On day 6 of lactation, serum prolactin (P < 0.05) and cortisol (P < 0.01) concentrations were greater and glucose values lower (P < 0.001) in GM than in LW sows. The concentration of IGFI in lactoserum was lower (P < 0.001) while that of prolactin was greater (P < 0.05) in GM compared to LW sows on day 23 of lactation. There was less (P < 0.001) residual milk and more (P < 0.05) parenchymal RNA in mammary glands from GM compared to LW sows. The affinity of prolactin receptors was also greater (P < 0.05) in GM than in LW sows. The better emptying of mammary glands by litters from GM sows and the greater circulating concentrations of prolactin in early lactation as well as the greater affinity of mammary prolactin receptors may be related to the great milking potential of Meishan-derived sows. Key words: Hormones, lactation, mammary gland, Meishan, prolactin, sows
Study of carcass, organ, muscle, fat tissue weight, and concentration in rats fed CLA or its precursors by principal component analysis
Authors: Goonewardene L. A. , Mir P. S. , Wang Z. , Okine E. K. , Mir Z. , He M.
Published: April 2011

Carcass, organ and muscle weight, and fat tissue data were obtained from 30 weaned male Wistar rats fed one of three diets, (10 rats/diet) over a period of 60 d. The diets were base with synthetic conjugated linoleic acid (CLA), sunflower oil or beef enriched CLA. The CLA diet contained the base diet and 18.2 g kg-1 of synthetic CLA (53% cis 9, trans 11 and 44% trans 10, cis 12) replacing 26% of the soybean oil, the sunflower oil diet contained the base plus 70 g kg-1 of sunflower oil replacing all the soybean oil, and the CLA-enriched diet contained the base plus 200 g kg-1 of beef enriched bio-formed CLA replacing the casein. Data were subjected to a principal component analysis (PCA). The first principal component (PC) extracted carcass weight, organ and muscle weight variables and accounted for 41.3% of the total variation. The second principal component included all of the fat tissue variables and accounted for 20.5% of the total variation. The rats fed the synthetic CLA diet were associated with high carcass, liver, kidney, heart, gastrocnemius and soleus muscle weights, and low retroperitoneal and inguinal fat weights, and adipocyte numbers in the fat tissues. In rat models, short periods of synthetic CLA feeding may have a greater impact on decreasing fat accretion in selected fat tissues than feeding CLA-enriched meat. The PC analysis provides means of combining into one or a few components traits that have similar responses, each component being orthogonal to all other components, whereas, in a conventional univariate analysis of variance each dependent variable is analyzed separately in relation to one or more independent variable. Key words: Conjugated linoleic acid, feeding, principal component analysis, fat, muscle, accretion
Alternative fall and winter feeding systems for spring calving beef cows
Authors: McCartney D. , Basarab J. A. , Okine E. K. , Baron V. S. , Depalme A. J.
Published: April 2011

This study evaluated the effects of early (EW) and late (LW) weaning on calf post-weaning growth performance and carcass characteristics. It also quantified the effects of EW and LW in combination with three winter feeding strategies on cow growth, reproductive performance and cost of production. EW calves were weaned in late August, while LW calves were weaned 56 d later in late October. The three cow winter feeding strategies were: (1) traditional (TD), or straw fed ad libitum and barley (Hordeum vulgare L.) silage fed every day; (2) alternate day (AD), or straw fed ad libitum and equivalent amounts of barley silage fed every second day (AD); and (3) swath graze (SG), or swath grazing whole-plant barley, cut in the soft dough stage. The study was conducted over three production cycles (1997/1998, 1998/1999 and 1999/2000). EW calves weighing 213 kg and fed a backgrounding diet (82% barley silage: 18% concentrate) for 56 d, grew 0.36 kg d-1 (EW = 0.61 ± 0.02 kg d-1; LW = 0.97 ± 0.02 kg d-1; P < 0.001) slower from early to late weaning than LW calves (210 kg) on pasture nursing their mothers. Over the next 124–128 d, EW and LW calves fed the backgrounding diet grew similarly at 0.95 ± 0.01 and 0.93 ± 0.02 kg d-1, respectively. Both groups of calves also grew similarly during the finishing phase (EW = 1.56 ± 0.04 kg d-1; LW = 1.53 ± 0.05 kg d-1; P = 0.62), such that at slaughter, EW and LW calves were the same age (461 ± 4 vs. 455 ± 5 d, P = 0.326) and weight (522 ± 5 vs. 515 ± 6 kg, P = 0.390), with similar levels of carcass backfat, yield and quality grade. EW cows weighed 12 to 15 kg more (P < 0.01) in mid-November (first winter feeding), mid-February (pre-calving) and late-May (prebreeding) and tended to have a shorter calving span (49 vs. 62 d, P = 0.07) than the LW cows. Calving interval, calving pattern and cumulative open and cull rates, monitored over three consecutive production cycles, were similar for EW and LW cows. Differences (P < 0.05) in body weight were observed between winter feeding treatments. SG cows had the lowest weight (605 kg) and backfat thickness (4.5 mm) at pre-breeding; AD cows were intermediate (623 kg and 5.1 mm); and TD cows were heaviest (639 kg) with the most backfat (6.4 mm). Calving interval, length of the calving span, calving pattern and cumulative open and cull rates were similar among the winter feeding strategies for cows monitored over three production cycles. Swath grazing required 38.4% less labour than traditional feeding and 20.9% less labour than alternate day winter feeding. Total cash cost over the first 100 d of winter feeding for the SG winter feeding strategy was $70.00 cow-1 less than TD (45.5%) and $56.70 cow-1 less than AD (40.4%) winter feeding strategies. On average, 300 and 314 cow swath grazing d ha-1 were required to cover the cost of feed in the TD and AD winter feeding strategies, respectively. Key words: Beef cows, Western Canadian Parkland, swath grazing, alternate day, early and late weaning
Frequency of concentrate supplementation for cattle fed barley straw. 2. Ruminal dilution rates, pH and metabolite concentrations
Authors: Tellier R. C. , Mathison G. W. , Okine E. K. , McCartney D. , Soofi-Siawash R.
Published: April 2011

Five ruminally cannulated crossbred steers (474 ± 30 kg) were fed diets containing 70% barley straw and 30% concentrate in an unbalanced 5 × 5 Latin square design experiment to in vestigate the effects of frequency of feeding concentrate (daily, alternate days or every third day) with different dietary protein concentrations (7.9 and 11.5%) on ruminal liquid and particulate dilution rates, pH and metabolite concentrations. Dilution rates of cobalt-ethylene diamine tetraacetic acid (Co- EDTA) and chromium-mordanted fibre did not differ when low- and high-protein concentrates were fed. Supplemental protein increased (P < 0.05) mean ruminal ammonia concentrations (3.3 vs. 1.6 mM), but had no influence on ruminal concentrations of organic acids. Frequency of concentrate feeding had no influence on dilution rate of digesta markers, pH or on mean ruminal concentrations of ammonia, lactic acid, propionic acid, isobutyric acid, valeric acid and isovaleric acid. Mean concentrations of total volatile fatty acids, acetic acid and butyric acid were, however, reduced (P < 0.05) when steers were fed concentrates on alternate days. The reduced (P < 0.01) ruminal acetic:propionic acid ratios observed in steers fed concentrates on alternate days were consistent with reduced heat productions. Positive relationships (P < 0.05) were obtained between heat production of steers and ruminal concentrations of isobutyric and valeric acids. It was concluded that the low-protein diet did not provide sufficient protein to meet microbial requirements and that under controlled feeding conditions cattle can be fed concentrate on alternate days or every third day without the occurrence of lactic acidosis. Additional research is warranted to examine the relationships between reduced heat production of steers fed concentrates on alternate days and ruminal concentration and production of organic acids. Key words: Cattle, straw, protein, feeding frequency, rumen metabolites, lactic acid
Effect of wheat cultivar and enzyme supplementation on nutrient availability and performance of laying hens
Authors: Rafuse J. L. , Silversides F. G. , Bedford M. R. , Simmins P. H.
Published: April 2011

This study examined the effect of four wheat cultivars (Belvedere, Glenlea, Norboro, and Walton) grown in the Maritime provinces of Canada and dietary enzyme supplementation on apparent metabolizable energy (AME), digestibility of crude protein (CP), and performance of laying hens, and compared these values to those obtained using a corn-based diet. Forty groups of three adjacent battery cages, each housing two hens, were fed each diet which included the wheat samples (61.0%) or locally obtained corn (65.1%), with or without commercial enzymes containing a mixture of xylanase, protease, and amylase for corn-based diets and a mixture of xylanase and protease for wheat-based diets. Excreta samples were collected at 17 d for analysis of nutrient retention. The diet that the hens consumed had no significant effect on performance. The feed conversion ratio of hens was lowest (1.79) in the final week of the experiment when egg production was highest (97.0%) and feed intake lowest (109 g bird-1 d-1). The diet significantly affected both AME and digestibility of CP. The wheat cultivar influenced the AME and digestibility of CP when these diets were fed to laying hens, with enzyme supplementation reducing the AME and digestibility of CP for diets containing three (Belvedere, Glenlea, and Walton) of the four wheat cultivars. The significant improvement with enzyme supplementation of the corn-based diet is promising and should be the basis of future studies. Key words: Wheat, layers, apparent metabolizable energy, enzyme
Use of recorded nursing grunts during lactation in two breeds of sows. I. Effects on nursing behaviour and litter performance
Authors: Fisette K. , Laforest J. P. , Robert S. , Farmer C.
Published: April 2011

The impact of exposing lactating sows and their litters to recorded sow nursing grunts played at different intervals during lactation was studied. Yorkshire × Landrace (YL) and 25% Meishan (MH) primiparous sows were divided into three groups (n = 14): (1) no playback, (2) playbacks at 35-min intervals (GR35), and (3) playbacks at 40-min intervals (GR40). Recordings were played from day 110 of gestation to day 27 of lactation. Nursing behaviours, incidence of nursings without milk ejection (NPN), nursing interval and proportion of nursings induced by playbacks were measured on days 6, 18 and 26 of lactation. Litter size was standardized to 10 ± 1 piglets within 48 h of birth and piglets were weighed weekly. Mean nursing intervals, excluding NPN, were shorter for MH than for YL sows (P < 0.001). The increase in mean nursing interval between days 6 and 18 was greater in GR40 than in GR35 or controls (P < 0.01) and, when excluding NPN, the mean nursing interval decreased in GR35 on day 18 (P = 0.01). The occurrence of NPN decreased as lactation advanced (P < 0.001) and was lower for MH than YL sows on day 26 (P < 0.001). Between days 6 and 18, the proportion of nursings initiated by playbacks increased (P < 0.05) and the duration of milk ejection decreased (P < 0.001). In MH sows, controls had longer milk ejections than GR35 (P < 0.05) whereas, in YL sows, controls had shorter milk ejections than GR40 (P < 0.05) and GR35 (P = 0.06). Piglet growth was not affected by treatments or breed (P > 0.1). In conclusion, exposing sows and their litters to recorded sow nursing grunts played at 35-min intervals reduced nursing intervals on day 18 of lactation only, without affecting piglet performance. Key words: Auditory stimulus, behaviour, lactation, litter performance, Meishan, sows
Limitations of intensive meat rabbit production in North America: A review
Authors: Lukefahr S. D. , Cheeke P. R. , McNitt J. I. , Patton N. M.
Published: April 2011

This paper documents underlying causes for the poor track record of the commercial meat rabbit industry in North America, relative to the success of several other species (cattle, swine, chickens and turkeys). For over half a century, efforts have been ongoing to develop a viable commercial meat rabbit industry. The progress has not been significant; rather, an accumulation of serious obstacles has targeted the species (e.g., high labor demand, no tradition of rabbit meat consumption, and nutritional limitations and behavioral constraints). Critical biological behaviors associated with the doe rabbit [e.g., short gestation and (or) underdeveloped neonates, cannibalism, territorialism, and pseudo-pregnancy] require that does be permanently placed into individual cages. These behaviors underpin the inability of management to offset labor by employing cost-effective automated feeding and management systems. As a consequence, labor costs per rabbit are high; rabbit meat is generally not competitive with more widely consumed meats. A proposed alternative solution is a redirected focus on rabbits as a “microlivestock” species — reared in small numbers as a family enterprise to enhance quality of life in rural and periurban areas, as well as in lesser developed countries — as opposed to further exploitation of the species as a commercial agricultural commodity. Key words: Rabbit, commercial, contemporary issues, industry, production
Performance of growing-finishing pigs fed barley-based diets containing graded levels of number 1 wheat screenings
Authors: Thacker P. A.
Published: April 2011

This experiment was conducted to determine the effect of graded levels of number 1 wheat screenings on performance, nutrient digestibility and carcass traits when fed to growing-finishing pigs. Forty crossbred pigs (Camborough 15 Line female × Canabred sire) weighing an average of 19.7 ± 2.8 kg were assigned to one of five dietary treatments in a 5 × 2 factorial design experiment. The main effects tested included level of wheat screenings and sex of pig (barrows and gilts). The levels of inclusion were 0, 18, 36, 54 and 72% in the grower diet and 0, 20.5, 41, 61.5 and 82% in the finisher diet. Screenings were added largely at the expense of barley. A botanical analysis was preformed and it indicated that the screenings contained approximately 88.5% whole or cracked wheat with the most prevalent weed seeds being wild buckwheat (6.7%), canola seed (2.8%) and cleavers (0.96%). There was a linear (P = 0.001) increase in the digestibility of dry matter, crude protein and gross energy with increased incorporation of wheat screenings in the diet. Over the entire experimental period (19.7–105.1 kg), there was no change in growth rate due to feeding wheat screenings, but feed intake declined in a linear (P = 0.044) fashion while feed conversion improved linearly (P = 0.014) as the inclusion level of screenings increased. There were no sex effects on pig performance. Dietary inclusion of wheat screenings had no significant effects on any carcass traits including dressing percent, carcass value index, lean yield, loin fat or loin lean. The carcass value index for gilts was higher than that of barrows (P = 0.038). The overall results of this experiment indicate that number 1 wheat screenings can be successfully uti lized as an energy source for use in growing-finishing diets and can be fed at levels as high as 72% for growing pigs and 82% for finishing pigs with no negative effects on pig performance or carcass quality. However, should the level of weed seeds increase or the type of weed seeds contaminating the screenings change appreciably from those reported here, then it may be necessary to reduce the incorporation level of screenings in the diet. Key words: Pigs, wheat screenings, performance, digestibility, carcass
Hydroxycinnamic acids and ferulic acid esterase in relation to biodegradation of complex plant cell walls
Authors: Yu P. , McKinnon J. J. , Christensen D. A.
Published: April 2011

Ferulic acid (3-methoxy-4-hydroxycinnamic acid), present in complex plant cell walls, is covalently cross-linked to polysaccharides by ester bonds and to components of lignin mainly by ether bonds. Ferulic acid has also been shown to occur in dimer- and trimerized forms through oxidative coupling between esterified and/or etherified ferulic acid residues. These cross-links are among the factors most inhibitory to digestion of complex plant cell walls in ruminants. Recently obtained information on ferulic acid and ferulic acid esterases in relation to complex plant cell wall biodegradation is reviewed. A focus of the review is on structural characteristics of plant cell walls associated with ferulic acid, physicochemical properties of ferulic acid esterase and synergistic interaction between ferulic acid esterase and other accessary cell wall degrading enzymes on the release of ferulic acid and plant cell wall biodegradation. Key words: Ferulic acid, hydroxycinnamic acid, feruloyl esterase, interaction effects, polysaccharide, feruloyl-polysaccharides, plant cell walls, biodegradation
Performance and carcass characteristics of growing-finishing pigs fed barley-based diets supplemented with Linpro (extruded whole flaxseed and peas) or soybean meal
Authors: Thacker P. A. , Racz V. J. , Soita H. W.
Published: April 2011

The objective of this experiment was to determine the effects of feeding graded levels of Linpro (a 50:50 combination of extruded full-fat flax seed and peas) on pig performance and carcass traits, particularly the fatty acid composition of backfat. Eighty crossbred pigs (Camborough 15 Line female × Canabred sire, Pig Improvement Canada Ltd., Airdrie, AB) weighing an average of 22.7 ± 2.2 kg were assigned on the basis of sex, weight and litter to one of five dietary treatments in a 5 × 2 factorial arrangement (treatment × sex). The experimental diets were based on barley and soybean meal and contained 0, 7.5, 15, 22.5 or 30% Linpro during the growing period (22.7–69.7 kg) and 0, 6, 12, 18 or 24% Linpro during the finishing period (69.7–111.1 kg). Digestibility coefficients for dry matter were not significantly affected by incorporation of Linpro in the diet. Digestibility coefficients for crude protein (P = 0.01) and gross energy (P = 0.04) exhibited a cubic effect due to Linpro incorporation with the highest digestibility coefficients observed for pigs fed 7.5% Linpro. Over the entire experimental period (22.7–111.1 kg), daily gain was affected both linearly (P = 0.02) and quadratically (P = 0.04) by Linpro inclusion. The most rapid gains were obtained by pigs fed 7.5% Linpro (6% in finisher), while pigs fed 30% Linpro (24% in finisher) gained weight the slowest. Feed intake was not significantly affected by Linpro inclusion, while feed conversion exhibited a quadratic effect (P = 0.02) with pigs fed the highest and lowest levels o f Linpro showing the poorest feed conversion. Linpro inclusion, had no significant effects on carcass traits including slaughter weight, carcass weight, dressing percent, carcass value index, lean yield, loin fat or loin lean. Inclusion of 30% Linpro (24% in finisher) significantly (P < 0.05) increased the levels of linolenic acid in backfat and this increase could provide significant health benefits for consumers of pork. Linpro would appear to be an acceptable alternative to soybean meal as a protein supplement for use in growing-finishing swine diets and can be incorporated at levels as high as 22.5% in the grower period and 18% in the finisher period without detrimental affects on pig performance. Key words: Swine, extrusion, flax, peas, digestibility, growth, backfat
Gene expression of leptin, leptin receptor, prolactin receptor and whey acidic protein in mammary glands of late-pregnant gilts from two breeds
Authors: Palin M. F. , Beaudry D. , Farmer C.
Published: April 2011

In order to identify genes which are essential for pig mammary gland development, mRNA levels of prolactin receptor (PRL-R), leptin, leptin receptor and whey acidic protein (WAP) were measured in parenchymal tissue of 110-d-pregnant gilts. Thirteen Upton-Meishan (UM) and 14 Large White (LW) pregnant gilts and 5 non-pregnant control gilts (2 LW and 3UM) were used. PRL-R and WAP mRNA levels were higher in pregnant than in non-pregnant gilts (P < 0.05). Leptin mRNA levels were higher in UM than in LW gilts (P < 0.05), but this breed effect was not seen when leptin mRNA levels were corrected for percent fat in parenchyma. Correlations were found between concentrations of IGF-I in plasma and PRL-R (P < 0.01) and WAP (P < 0.05) mRNA levels in UM gilts. Serum prolactin (PRL) was correlated with leptin mRNA levels in the overall (P < 0.05) and LW (P < 0.05) populations of gilts, while estradiol was associated with leptin receptor mRNA in UM gilts (P < 0.05). The mRNA levels of all studied genes were positively correlated with mammary parenchymal and extra parenchymal weights in UM gilts, whereas these variables were only correlated with PRL-R and WAP gene expression in LW gilts. The presence of leptin and leptin receptor mRNA in parenchymal tissue suggests a paracrine role for leptin in mammary tissue of late-pregnant gilts. These results also suggest that the PRL signalling pathway is fully active at the transcriptional level in the mammary gland of gilts at 110 d of pregnancy. Key words: Genetics, pig, mammary glands, Meishan, mRNA
Barley- versus protein-supplemented corn-based diets for feedlot cattle evaluated using the NRC and CNCPS beef models
Authors: Koenig Karen M. , Beauchemin Karen A.
Published: April 2011

A study was conducted to evaluate the effects of supplementing a corn-based finishing diet [10.0% crude protein (CP), 6.2% degradable intake protein (DIP), dry matter basis, no protein supplementation] with DIP in the form of urea (13.0% CP, 9.1% DIP) or canola meal and urea (12.8% CP, 8.6% DIP) on dry matter intake (DMI) and average daily gain (ADG). Animal performances were compared with those obtained by feeding a barley-based diet (13.9% CP, 9.6% DIP). Crossbred beef steers (398 ± 28 kg) were allocated to 24 pens and six pens were assigned to each diet. There were no differences (P > 0.05) in DMI and ADG between cattle fed the barley diet and those fed the corn diets supplemented to provide a concentration of DIP similar to that supplied by the barley diet. However, ADG was 10% lower and DMI was 8% lower for cattle fed the corn diet with no protein supplementation (P < 0.05). The NRC and CNCPS models predicted the substantially lower gain of cattle fed the corn diet with no protein supplementation, but underestimated the improvement in performance when the corn diet was supplemented with urea or canola meal and urea to supply the requirement for DIP. Key words: Feedlot cattle, protein, corn, barley, growth, models
Feedlot cattle diets based on barley or corn supplemented with dry corn gluten feed evaluated using the NRC and CNCPS beef models
Authors: Beauchemin Karen A. , Koenig Karen M.
Published: April 2011

A study was conducted to evaluate the effects of supplementing feedlot finishing corn diets with dry corn gluten feed (CGF). Animal performance and carcass traits were compared with those obtained by feeding a barley-based diet typical of diets fed commercially in western Canadian feedlots. The second objective of the experiment was to evaluate the diets using the 1996 National Research Council (NRC) Beef (level 1 and 2) and Cornell Net Carbohydrate and Protein System (CNCPS, version 5.0) models to determine how well the models predict animal response. Crossbred beef steers (248) weighing 423 ± 20.5 kg were allocated to 24 pens and then six pens were assigned to each of four diets: (1) barley grain (13.8% crude protein, CP), (2) corn grain (9.2% CP), (3) corn grain supplemented with a low level (7%, DM basis) of CGF (CGF-low, 9.7% CP), and (4) corn grain supplemented with a high level (23%) of CGF (CGF-high, 11.7% CP). The barley grain was steam-rolled and the corn grain was dry-rolled. All diets contained 8% barley silage (DM basis). The cattle were adapted from a backgrounding diet to the experimental diets over a period of 28 d and then fed for a period of 136 d. During the adaptation phase cattle fed unsupplemented corn grew slower (P < 0.05) than the cattle fed the other diets (1.23 vs. 1.52 kg d-1). However, after day 42 of the study, cattle fed unsupplemented corn grew very rapidly such that gain for the entire feeding period was similar for cattle fed unsupplemented corn and barley diets (1.62 vs. 1.58, P > 0.05). Furthermore, growth rate was higher (P < 0.05) for cattle fed barley or unsupplemented corn than for cattle fed low or high levels of CGF (1.48 and 1.45 kg d-1, respectively). The dry matter intake (DMI) averaged 11.4 kg d-1 during the feeding period and was not affected (P > 0.05) by diet. Feed:gain ratio (kg DM:kg gain) was similar (P > 0.05) for cattle fed barley (7.09) and unsupplemented corn (7.38), but was higher (P < 0.05) for cattle fed CGF-high (7.92), and intermediate (P > 0.05) for those fed CGF-low (7.52). There were no differences in carcass composition between barley and corn-fed cattle, but those fed low and high levels of CGF had carcasses that were fatter with lower lean meat yield. The three models underestimated DMI of all four diets. When DMI was set to observed intake in the models, CNCPS accurately predicted ADG and F:G ratio for cattle fed corn diets, but all models underestimated ADG of cattle fed barley. All models correctly predicted that gain during the feeding period was not limited by protein supply. The results from this study indicate that rolled-corn diets containing about 9.5% CP, with 50% of the CP as DIP are adequate for feedlot cattle weighing more that 500 kg. Substituting dry CGF for corn grain reduces feed efficiency and gain due to the lower digestible energy content of CGF. Key words: Grain, barley, corn, corn gluten feed, feedlot cattle, protein, models
The effects of enzyme and phosphate injections on the quality of beef semitendinosus
Authors: Janz J. A. M. , Pietrasik Z. , Aalhus J. L. , Shand P. J.
Published: April 2011

In light of palatability concerns with beef semitendinosus (ST), its resistance to tenderization by more conventional methods, and its large content of elastin, investigation into the efficacy of enzyme injection was undertaken. Pancreatin, an enzyme cocktail for cheese making, was chosen for its content of elastase, amongst other enzymes, making it a suitable choice for use in the ST. To compare with uninjected controls, samples were prepared to contain a conservative level (0.01% delivered) of pancreatin, salt/phosphate brine, or a combination of enzyme with brine, injected to 105 or 110% green weight. Injection treatment significantly affected several meat quality attributes, while injection level did not. Where water alone was used as the enzyme carrier for injection, an excessive amount of drip loss was observed, with no improvement in tenderness. Salt/phosphate improved brine retention, increased pH, and resulted in darker meat colour. A significant reduction in shear was observed following injection with the enzyme/brine combination, results indicating that ST tenderness can be improved by 9–15% with the modest level of pancreatin used in this injection treatment. Further investigation is recommended to evaluate the tenderization potential using higher enzyme levels, and to examine the safety and sensory aspects of pancreatin use. Key words: Enzyme, moisture enhancement, phosphate injection, elastase, beef semitendinosus
Effect of water source (ground versus surface) and treatment on nursery pig performance
Authors: Nyachoti C. M. , Patience J. F. , Seddon I. R.
Published: April 2011

In a commercial-scale study involving 7200 piglets, performance of nursery pigs offered surface water from a dugout was equal to that of piglets offered well water (P > 0.10). Coagulation, acidification, and high chlorination (2 ppm free chlorine) of surface water were without effect on performance (P > 0.10). Key words: Nursery pig performance, Surface water, Well water
Milk production and milk composition of dairy cows fed Lac100® or whole flaxseed
Authors: Cavalieri F. B. , Santos G. T. , Matsushita M. , Petit H. V. , Rigolon L. P. , Silva D. , Horst J. A. , Capovilla L. C. , Ramos F. S.
Published: April 2011

Cows were fed whole flaxseed or calcium salts of soybean oil as a fat source. Cows fed flaxseed had lower (P < 0.01) milk yield and higher (P < 0.01) percentages of fat and protein than cows fed calcium salts. Feeding whole flaxseed and calcium salts of soybean oil increased, respectively, the concentrations of alpha-linolenic acid and conjugated linoleic acid in milk. Key words: Flaxseed, fatty acids, fat supplement
Effects of chlortetracycline and Synovex-S® on growth rate and on plasma growth hormone and thyroid hormone concentrations following administration of thyrotropin-releasing hormone and GH-releasing hormone in beef steers
Authors: Kitts S. E. , Matthews J. C. , Schillo K. K. , Rumsey T. S. , Elsasser T. H. , Kahl S. , Baldwin, VI R. L. , McLeod K. R.
Published: April 2011

Twenty-four Angus steers (365 kg ± 4) were assigned randomly to a 2 × 2 factorial arrangement of treatments of either 0 or 350 mg chlortetracycline d-1, with or without Synovex-S to test the effects of chlortetracycline (CTC) and estrogenic implant on release of growth hormone (GH) and thyroid hormones. Steers received ad libitum a concentrate-forage diet over a 112-d feeding study, and growth and carcass characteristics were determined. On days 30, 56, and 106, steers received an injection, via jugular catheter, of 1.0 µg kg-1 BW thyrotropin-releasing hormone (TRH) + 0.1 µg kg-1 BW GH-releasing hormone (GHRH) and blood was collected from -30 to 360 min post-injection. Overall, compared with non-implanted steers, Synovex-S increased (P ≤ 0.009) rate and efficiency of gain, decreased (P = 0.05) time to peak for GH concentrations, whereas baseline concentrations of thyroid-stimulating hormone (TSH) were increased (P = 0.03). Additionally, the TSH response curve (P ≤ 0.05) and magnitude of triiodothyronine (T3; P = 0.01) response were greater following TRH + GHRH challenge for implanted versus nonimplanted steers. There were no main effects of CTC; however, CTC attenuated (P ≤ 0.05) the effects of implant on T3 release, slaughter weight, and carcass composition. In conclusion, Synovex-S alone increased BW gain and enhanced the response of GH, TSH, and T3 to a TRH + GHRH challenge, whereas CTC alone did not affect rate and composition of gain or release of pituitary and thyroid hormones. However, CTC appeared to mitigate the effects of implant on T3 release and carcass composition. Key words: Growth hormone, thyroid, estrogen, chlortetracycline, bovine, growth
The possible influence of intra-ruminal sulphur hexafluoride release rates on calculated methane emissions from cattle
Authors: Vlaming J. B. , Brookes I. M. , Hoskin S. O. , Pinares-Patiño C. S. , Clark H.
Published: April 2011

Estimates of methane (CH4) production from grazing animals are routinely made using the sulphur hexafluoride (SF6) tracer technique. While this technique is generally regarded as useful, some investigators report a higher variability in measurements when compared with calorimetry. The SF6 technique is a marker dilution method in which a known release rate of SF6 from an intra-ruminal permeation tube is used to calculate CH4 emissions from the ratio of SF6:CH4 in expired breath. The release rate of SF6 is unique for each tube, and although calculated CH4 emissions should be independent of SF6 release rate, an analysis of research conducted in New Zealand has suggested a possible influence of SF6 release rate upon calculated CH4 emissions. A modified cross-over design, with two groups of six steers given either one (2.878 mg SF6 d-1) or two (7.336 mg SF6 d-1) permeation tubes and offered either energy maintenance (M) or 2 × M levels of feed intake was undertaken to determine the effect of SF6 release rate and intake on calculated CH4 emissions. A high SF6 release rate elevated the calculated CH4 emission per day (P < 0.001) and per kg dry matter intake (kg DMI) by 19% (P < 0.001) irrespective of the level of intake. Release rate of SF6 can affect the calculated CH4 emissions from animals when employing the SF6 tracer technique. Key words: Methane, SF6 tracer technique, cattle, variability, feeding level
Evaluation of bacterial diversity in the gut of piglets supplemented with probiotics using ribosomal intergenic spacer analysis
Authors: Gagnon N. , Talbot G. , Ward P. , Roy D. , Dupuis M. , Farnworth E. , Tompkins T. A. , Lessard M.
Published: April 2011

In this study, ribosomal intergenic spacer analysis (RISA) was used to monitor changes of intestinal microbiota of piglets treated at birth with or without Pediococcus acidilactici (PA) and/or Saccharomyces cerevisiae ssp. boulardii (SCB) and weaned piglets fed with control diet supplemented with PA and/or SCB or antibiotic. During lactation, probiotics were given orally to piglets three times a week. At weaning (day 21), probiotics and the antibiotic, tiamulin, were added to the diet. Fifteen piglets per treatment were slaughtered at day 18 and day 24. The tracking of each probiotic from colonic samples was done using PCR primers specific for PA targeting the 16S rRNA gene or a specific culture medium for enumeration of SCB. The results showed the presence of probiotics in colonic samples of piglets supplemented with probiotics. Dendograms (UPGMA and Ward’s method), and non-metric multidimensional scaling analysis showed that the variability of RISA profiles in colonic microflora between individual piglets within a treatment was too high to obtain a grouping based on probiotic supplementation. Based on the relative frequency of internal transcribed spacers from RISA profiles (indicator species analysis) and diversity indices (Shannon, richness and evenness), both PA and the antibiotic treatments reduced the bacterial diversity in the gut of piglets after weaning compared with preweaning, while diversity was slightly increased postweaning compared with preweaning in control without antibiotic and SCB groups. In conclusion, all dietary additives differently affected postweaning microbial community composition; however, both antibiotic and PA reduced postweaning microbial diversity suggesting a possible benefit of PA supplementation during the postweaning transition period. Key words: Intestinal flora, piglet, PCR, probiotic, RISA profile, weaning