A. L. Schaefer

The effect of conjugated linoleic acid on fat to lean repartitioning and feed conversion in pigs

The repartioning effect of CLA was evaluated using 108 pigs (54 gilts and 54 barrows) fed from 61.5 to 106 kg liveweight. Pigs were fed a cereal-based basal diet containing either 2% CLA or 2% sunflower oil (a rich source of α-linoleic acid). Irrespective of gender, pigs fed CLA tended to have reduced feed intakes (−5.2%, P = 0.07), improved feed conversion efficiences (−5.9%, P = 0.06) and similar rates of gain relative to sunflower oil fed pigs. In addition, pigs fed CLA deposited less subcutaneous fat (−6.8%, P = 0.01) and gained more lean (+2.3%, P = 0.03) than pigs fed sunflower oil. These data suggest CLA can be used as a repartioning agent in pigs and that further research to optimize the repartitioning effect is warranted. Key words: Pig, pork, swine, conjugated linoleic acid, CLA, repartioning

Distributions of conjugated linoleic acid (CLA) isomers in tissue lipid classes of pigs fed a commercial CLA mixture determined by gas chromatography and silver ion-high-performance liquid chromatography

Pigs were fed a commercial conjugated linoleic acid (CLA) mixture, prepared by alkali isomerization of sunflower oil, at 2% of the basal diet, from 61.5 to 106 kg live weight, and were compared to pigs fed the same basal diet with 2% added sunflower oil. The total lipids from liver, heart, inner back fat, and omental fat of pigs fed the CLA diet were analyzed for the incorporation of CLA isomers into all the tissue lipid classes. A total of 10 lipid classes were isolated by three-directional thin-layer chromatography and analyzed by gas chromatography (GC) on long capillary columns and by silver-ion high-performance liquid chromatography (Ag+-HPLC); cholesterol was determined spectrophotometrically. Only trace amounts (<0.1%; by GC) of the 9,11–18∶2 cis/trans and trans, trans isomers were observed in pigs fed the control diet. Ten and twelve CLA isomers in the diet and in pig tissue lipids were sepatated by GC and Ag+-HPLC, respectively. The relative concentration of all the CLA isomers in the different lipid classes ranged from 1 to 6% of the total fatty acids. The four major cis/trans isomers (18.9% 11 cis, 13 trans-18∶2; 26.3% 10 trans, 12 cis-18∶2; 20.4% 9 cis, 11 trans-18∶2; and 16.1% 8 trans, 10 cis-18∶2) constituted 82% of the total CLA isomers in the dietary CLA mixture, and smaller amounts of the corresponding cis,cis (7.4%) and trans,trans (10.1%) isomers were present. The distribution of CLA isomers in inner back fat and in omental fat of the pigs was similar to that found in the diet. The liver triacylglycerols (TAG), free fatty acids (FFA), and cholesteryl esters showed a similar patterns to that found in the diet. The major liver phospholipids showed a marked increase of 9 cis,11 trans-18∶2, ranging from 36 to 54%, compared to that present in the diet. However, liver diphosphatidylglycerol (DPG) showed a high incorporation of the 11 cis,13 trans-18∶2 isomer (43%). All heart lipid classes, except TAG, showed a high content of 11 cis,13 trans-18∶2, which was in marked contrast to results in the liver. The relative proportion of 11 cis,13 trans-18∶2 ranged from 30% in the FFA to 77% in DPG. The second major isomer in all heart lipids was 9 cis,11 trans-18∶2. In both liver and heart lipids the relative proportions of both 10 trans,12 cis-18∶2 and 8 trans,10 cis-18∶2 were significantly lower compared to that found in the diet. The FFA in liver and heart showed the highest content of trans,trans isomers (31 to 36%) among all the lipid classes. The preferential accumulation of the 11 cis,13 trans-18∶2 into cardiac lipids, and in particular the major phospholipid in the inner mitochondrial membrane, DPG, in both heart and liver, appears unique and may be of concern. The levels of 11 cis,13 trans-18∶2 naturally found in foods have not been established.

The effects of feeding conjugated linoleic acid on subsequent pork quality

Feeding conjugated linoleic acid (CLA) has recently been shown to repartition fat to lean in pigs. The present study was undertaken to determine if feeding CLA affects pork quality. Pigs were fed a cereal-based diet containing either 2% CLA or 2% sunflower oil. Fifty-four pigs (27 gilts and 27 barrows) were fed per diet, and diets were fed from 61.5 to 106 kg liveweight. Diet did not affect postmortem longissimus thoracis (LT) glycogen utilization, lactate accumulation, or pH decline. Conjugated linoleic acid fed pigs had slightly higher LT temperatures at 3 h postmortem (+1.15 °C; P < 0.05), but subsequent LT shear force, drip loss and soluble protein levels were unaffected. Diet did not affect subjective LT scores for structure or color, but objective color measurements indicated LT from CLA-fed pigs had slightly higher chroma (color saturation) values (+0.84; P < 0.05). Longissimus thoracis from CLA-fed pigs also had increased subjective marbling scores (P < 0.01) and increased petroleum-ether-extracta...

Early detection and prediction of infection using infrared thermography

Early detection and/or prediction of disease in an animal is the first step towards its successful treatment. The objective of this study was to investigate the capability of infrared thermography as a non-invasive, early detection method for identifying animals with a systemic infection. A viral infection model was adopted using 15 seronegative calves whose body weight averaged 172 kg. Ten of these calves were inoculated with Type 2 bovine viral diarrhoea virus (strain 24515) and five were separately housed and served as uninfected controls. A simultaneous comparison of infrared characteristics in both infected and control animals was conducted over approximately 15 d. In addition, measures of blood and saliva cortisol, immunoglobulin A, blood haptoglobin and clinical scores were obtained. Infrared temperatures, especially for facial scans, increased by 1.5°C to over 4°C (P < 0.01) several days to 1 wk before clinical scores or serum concentrations of acute phase protein indicated illness in the infected...

The use of infrared thermography as an early indicator of bovine respiratory disease complex in calves

Abstract Bovine respiratory disease (BRD) complex causes considerable distress to domestic livestock and economic hardship to the beef industry. Furthermore, the resulting extensive use of antimicrobial treatments is a growing concern from the perspective of facilitating antibiotic resistant microbes. The earlier detection of BRD would enable an earlier, more targeted treatment regime and earlier isolation of infected individuals. The objective of the present study was to investigate the use of non-invasive infrared thermography in the early detection of BRD in cattle. Studies were conducted on 133 head of weaned calves. Data demonstrated that infrared thermography was able to identify animals at early stages of illness, often several days to over one week before clinical signs were manifest. Data indicated that 4–6 days prior to the onset of clinical symptoms of BRD, greater positive and negative predictive values and test efficiency for infrared thermography (80%, 65% and 71%, respectively) compared to the industry standard practice of clinical scoring (70%, 45% and 55%, respectively).

Feedlot performance, carcass composition and meat quality of free-range reared pigs

The effects of the housing system (confinement versus free-range) and season (summer versus winter) on growth performance, carcass composition and meat quality were determined from commercial pigs with known NN genotype at the halothane locus. Free-range-housed pigs reared from 25 to 105 kg required 16 ± 1.2 (SEM) more days to reach market weight compared with confinement-housed pigs. Housing did not affect feed requirements during the summer, but food consumption increased by 13.7% for free-range pigs during the winter. Confinement-reared pigs had a 0.75 ± 0.28 kg heavier commercial carcass weight than free-range-reared pigs. While there was no difference in carcass fat thickness, muscle depth was 2.4 ± 1.02 mm greater in free-range-reared pigs with increased predicted lean yield from 59.1 ± 0.24% to 59.8 ± 24%. Free-range-reared pigs had heavier butts, loins and hams, and lighter bellies, which increased their wholesale carcass value by 2.9%. Furthermore, they had greater dissected lean in the picnic (2...

The effect of environment enrichment on aggression in newly weaned pigs.

Abstract The effect of environment enrichment on aggressive behavior in newly weaned pigs was studied in two experiments. In the first experiment, 132 6-week old gilts were divided into two treatment groups and housed at 6 per pen. Into each pen was placed either a car tire suspended on a chain ∼ 15 cm above the floor or alternatively, no device at all (control). Between 11 and 12 weeks of age, time-lapse video tapes of animal behavior were recorded and an analysis revealed that pigs offered the tire and chain device displayed a lower frequency of total aggressive acts (948 for all pigs with tires per 24 h vs. 1107 for control pigs). Most notable was the reduced frequency of head to head knocks (64 for all pigs with tires per 24 h vs. 202 in controls ( P ≤0.05)). In Experiment 2, 180 newly weaned pigs ∼ 28 days of age and equally represented by barrows and gilts were used. The pigs were assigned to one of three treatments at 15 per pen. The treatments were either: control (no device), a pacifier (sugar-mineral block suspended in a metal basket), or a teeter-totter (metal bar with rubber belts on the ends). Time-lapse video tapes were again collected on all pigs after a 7 day adjustment period. Analysis of these tapes again revealed that pigs offered a play device committed fewer total aggressive acts (46 per pig per 24 h in control vs. 22 per pig per 24 h in the teeter-totter group and 30 per pig per 24 h in the pacifier group, P ≤0.01). This was particularly notable for the frequency of head to head and head to body knocks. These studies suggest that aggression frequency inintensively raised pigs can be modified by enriching their environment with play objects.

The non-invasive and automated detection of bovine respiratory disease onset in receiver calves using infrared thermography

Abstract Bovine respiratory disease complex (BRD) causes considerable economic loss and biosecurity cost to the beef industry globally and also results in significant degradation to the welfare of affected animals. The successful treatment of this disease depends on the early, timely and cost effective identification of affected animals. The objective of the present study was to investigate the use of an automated, RFID driven, noninvasive infrared thermography technology to determine BRD in cattle. Sixty-five calves averaging 220kg were exposed to standard industry practices of transport and auction. The animals were monitored for BRD using conventional biometric signs for clinical scores, core temperatures, haematology, serum cortisol and infrared thermal values over 3weeks. The data collected demonstrated that true positive animals for BRD based on a gold standard including core temperature, clinical score, white blood cell number and neutrophil/lymphocyte ratio displayed higher peak infrared thermal values of 35.7±0.35°C compared to true negative animals 34.9±0.22°C (P <0.01). The study also demonstrated that such biometric data can be non-invasively and automatically collected based on a system developed around the animal’s water station. It is concluded that the deployment of such systems in the cattle industry would aid animal managers and practitioners in the identification and management of BRD in cattle populations.

The effect of ractopamine on myofibre distribution and morphology and their relation to meat quality in swine

One hundred and twenty-eight purebred Lacombe pigs (equal number of barrows and gilts) were assigned to one of four treatments at 64 kg and fed a commercial grower-finisher diet ad libitum to which ractopamine (RAC) was incorporated (0, 10, 15 or 20 mg kg(-1)). Pigs were slaughtered at 100 kg. Histological samples were collected from the semimembranosus (SM) and the psoas major (PM) muscles from the 0 and 20 mg kg(-1) RAC groups. Meat quality and muscle composition data were collected for all pigs. A significant 3-way interaction for muscle weight involving treatment, muscle and gender (P = 0·01) indicated that for the SM, gilts appeared to respond to RAC at a lower level of incorporation (10 mg kg(-1)) than barrows. Despite these differences in response at the gross muscle level, responses were similar at the cellular level for both muscles. The proportion of red fibres did not change (P = 0·21), the proportion of intermediate fibres decreased (P = 0·01) and the proportion of white muscle fibres increased (P = 0·02) in the mg kg(-1) RAC group compared to the controls. In addition, when compared to controls, average fibre diameters in the 20 mg kg(-1) RAC group remained constant in the red fibres, and increased significantly in both the intermediate and white fibres (P = 0·01 and 0·02, respectively). Over both muscles Kramer Press values were significantly higher (P = 0·030 in the RAC-fed pigs than in the controls. Incorporation of RAC into the diet did not result in any changes to crude protein or total and soluble hydroxyproline levels. Crude fat tended to increase in the 15 mg kg(-1) RAC treatment in the SM and decreased in the 20 mg kg(-1) RAC treatment in the PM. The shift in fibre type, and the associated changes in fibre size, may contribute to the increased shear values found in RAC-fed pigs.

Effects of feeding different levels of conjugated linoleic acid and total oil to pigs on live animal performance and carcass composition

The effects of feeding different dietary levels of conjugated linoleic acid (CLA) and total oil (TO) were evaluated using 216 barrows fed from 36 to 115 kg body weight. A 3 × 2 factorial design was used with three levels of dietary CLA (0, 0.25, and 0.5%), two levels of dietary TO (2 and 5% made up with canola oil) and 12 pens of three barrows fed per diet. Pigs on all diets gained weight at the same rate from 0 to 4 wk (36 to 61 kg) and from 4 wk to slaughter (61 kg to 115 kg) (P > 0.05). Pigs fed 5% versus 2% TO had 6.6% lower feed intake from 0 to 4 wk (P = 0.02) and 5.9% lower feed intake from 4 wk to slaughter (P < 0.003), while feeding CLA had no effect on feed intake (P = 0.70). A CLA by TO interaction for feed intake was not found for 0 to 4 wk but from 4 wk to slaughter a tendency for an interaction (P = 0.06) was found indicating 0.25% CLA may depress feed intake at 2% TO while stimulating intake at 5% TO. Increasing TO and CLA increased the lean content in commercial cuts by 1.6% (P = 0.06) and...