Paola Prevedello

Effect of dietary supplementation with different sources of selenium on growth response, selenium blood levels and meat quality of intensively finished Charolais young bulls

The study aimed at comparing three strategies of supplementing selenium (Se) during the finishing period of Charolais young bulls: (1) administration of sodium selenite throughout the finishing (NaSe); (2) administration of an Se-enriched yeast strain (Saccharomyces cerevisiae NCYC R397) throughout the finishing (Se-Y); (3) administration of sodium selenite for 140 days replaced by Se-enriched yeast during the last 70 days of finishing (Switch). Eighty-four young bulls (mean initial BW=434.2±31.9 kg; mean age=382±52 days) were stratified by live weight and equally assigned to one of three Se treatments. Experimental groups were fed the same diets and the inclusion rate of the different treatments was targeted to achieve 0.3 mg of Se/kg of dry matter (DM) in the complete feed. The average daily gain of bulls was 1.36 kg/d and no differences due to Se treatment were recorded. Dry matter intake and feed conversion ratio were not affected by Se treatment resulting in, on average, 10.3 kg/d and 7.65, respectively. Repeated blood samples were taken at days 0, 120, 180 and 210 of finishing to assess the Se status of the animals. As compared to NaSe, both organic Se treatments (Se-Y and Switch) increased plasma Se in the last two sampling sessions according to a significant treatment×time interaction (P<0.001). A similar trend was observed for serum total antioxidant status of the young bulls, whereas there was only a significant time effect (P<0.001) on glutathione peroxidase activity that was raised by all Se treatments. The finishing period lasted 210 days and at the abattoir there were no differences across Se treatments in carcass weight and dressing percentage. A higher Se content in the Longissimus thoracis (LT) muscle was instead observed in Se-Y samples as compared with NaSe (0.85 v. 0.47 mg/kg DM; P<0.05). Meat quality evaluation was carried out on LT samples after 6 and 11 days of ageing under a vacuum package. Regardless of ageing time, meat from young bulls supplemented with Se yeast had higher colour lightness (L*) values than those receiving NaSe (38.1 v. 36.6; P<0.01) and showed a significant decrease in shear force (3.69 v. 4.22 kg/cm2; P<0.01). The outcomes of the study suggest that the provision of Se yeast throughout the finishing period is a strategy to increase the benefits of the replacement of sodium selenite with organic selenium in beef cattle.

Effects of the provision of large amounts of solid feeds to veal calves on growth and slaughter performance and intravitam and postmortem welfare indicators

Polish Friesian male calves (n = 78) were used to investigate the effects of innovative feeding plans based on the provision of large amounts of solid feeds on growth performance, welfare, and carcass characteristics of veal calves. Groups of calves (initial BW 71.5 ± 3.7 kg) were fed 1 of 3 treatments (26 calves/treatment): 1) milk replacer plus corn grain (CG), 2) milk replacer plus an 80:20 mixture (as-fed basis) of corn grain and wheat straw (CGS), or 3) milk replacer plus a 72:20:8 mixture (as-fed basis) of corn grain, wheat straw, and extruded soybean, respectively (CGSES). All the treatments provided at least 170 kg DM/calf from solid feed throughout the 206 d of fattening. Type and concentration of milk replacer were the same for all calves throughout fattening. Calves fed CGSES received 96% of the daily amount of milk replacer delivered to CG and CGS to balance the dietary CP content. No differences (P ≥ 0.063) among treatments were observed for growth performance and DMI. Health status of CG calves was less than CGSES calves, as indicated by the greatest (P < 0.001) proportion of milk replacer refusal events and the greatest (P < 0.001) incidence of treatments for respiratory disorders. Inclusion of straw and soybean in the solid feeds increased (P < 0.001) the daily intake of iron in CGS and CGSES as compared with CG; however, blood hemoglobin concentrations measured at d 5 and 31 were greater (P < 0.05) than when measured on d 80, 122, and 206 of fattening. Feeding treatment did not (P ≥ 0.107) affect HCW, dressing percentage, or carcass color. Calves fed CG had heavier (P < 0.001) reticulorumens and more (P < 0.001) developed rumens than CGS and CGSES calves, but 84% and 68% of CG rumens (P < 0.001) showed overt signs of hyperkeratinization and plaques, respectively. These alterations of rumen mucosa were not detected in CGSES calves, and only 8% of CGS calves had rumen plaques. Regardless of feeding treatment, postmortem inspection recorded a prevalence of more than 84% abomasal lesions. When feeding veal calves with large amounts of solids, it is advisable to avoid the provision of corn grain alone and replace part of the cereal with a roughage source to improve calf health and prevent rumen mucosa alterations.

Synthetic rubber surface as an alternative to concrete to improve welfare and performance of finishing beef cattle reared on fully slatted flooring

The aim of this study was to compare a fully slatted concrete floor (concrete slatted (CS)) with the same floor on which synthetic rubber slats were placed on the concrete slats (rubber slatted (RS)) as housing solution for finishing beef cattle. The present study involved five commercial beef cattle farms in which the floor of at least three pens was kept as fully slatted, and in an equal number of pens a rubber cover was placed on the floor, tightly matching the gap profile of the concrete slats to allow the drainage of manure. A total of 326 finishing beef bulls were used (153 on CS and 173 on RS), and regardless of the floor treatment animals were housed in groups of 6 to 12 bulls/pen with a space allowance of 3.1 ± 0.2 m2/bull. Bulls had similar initial live weights (422.3 kg on CS and 425.0 kg on RS), but bulls on RS were heavier at the end of the finishing period with a higher average daily gain than bulls kept on CS (1.53 v. 1.46 kg/day; P<0.05). The proportion of bulls treated for locomotor problems was lower in RS pens compared with CS. Rubber covering prevented the occurrence of bursitis, but it increased the odds for hoof overgrowth at end of the finishing period. Hoof overgrowth detected in vivo in bulls on RS was confirmed at the slaughterhouse by the longer dorsal wall and diagonal lengths of the hoof as well as by a more acute toe angle. Compared with bulls on CS, bulls on RS showed less inactivity and resting time, increased social interactions, decreased abnormal lying down and unsuccessful attempts to lie down, as well as shortened the time for lying down. Bulls in RS pens were dirtier compared with those in CS pens, likely due to the draining gaps being reduced to 11.6 ± 1.2% of the total pen surface compared with the 16.9 ± 1.7% in CS pens. This study gave further evidence about the positive effects of the RS floor on growth performance and welfare of finishing beef cattle, although compromising cleanliness and hoof overgrowth.

Effects of pen floor and class of live weight on behavioural and clinical parameters of beef cattle

Abstract The study compared behaviour and clinical parameters of beef cattle housed on two different types of floor (fully slatted vs. deep litter) considering animals belonging to 2 live weight classes (less vs. more than 350 kg). The assessment of behavioural and clinical parameters was carried out in 20 intensive farms, all rearing imported bulls. Floor type had no effect on cattle behaviour except for the duration of the lying down sequence, which lasted more for bulls kept on slats. Slatted floor increased also the likelihood of occurrence of hair and skin lesions and lameness. On the other hand, bulls cleanliness was more likely to be impaired on bedded floor. Regarding the class of live weight, behavioural observation showed lighter animals performing more antagonistic interactions, while horning resulted more frequent in heavier bulls. Avoidance distance test indicated that bulls >350 kg were more fearful of humans. About health status, light animals were more affected by respiratory disease and hairless patches, likely because they are more sensitive to the stressful situations imposed by their transfer and adaptation to the new housing environment of the fattening unit. The risk of skin lesions and dirtiness increased instead in heavier bulls.

Effects of the provision of solid feeds enriched with protein or nonprotein nitrogen on veal calf growth, welfare, and slaughter performance

The study compared the effects of enriching a basic solid feed mixture made of corn grain and straw with a protein source (extruded pea) or with urea on growth, health, behavior, and carcass quality of veal calves. Seventy-nine calves, divided according to their initial body weight (59.8 ± 6.9 kg) into 3 groups (5 pens of 5 or 6 animals per group), were allotted to 1 of 3 experimental feeding treatments: milk replacer plus an 85:15 (as-fed basis) mixture of corn grain and wheat straw (CGS); milk replacer plus a 72:15:13 mixture of corn grain, wheat straw, and extruded pea (CGS-EP); or milk replacer plus an 83.3:16:0.7 mixture of corn grain, wheat straw, and urea (CGS-U). All feeding treatments were targeted to provide 140 kg of dry matter (DM)/calf of solid feed during the 201-d fattening cycle, and the greater crude protein content of the mixtures supplemented with protein or urea was balanced by restricting to 96% the daily amount of milk replacer delivered to CGS. Results did not differ among feeding treatments for average daily gain or solid feed intake but, net of meal refusal events, the average daily intake of milk replacer was 1.73, 1.66, and 1.60 kg of DM/calf for CGS, CGS-EP, and CGS-U, respectively. The overall mean hemoglobin values from samples taken at d 11, 40, 83, 126, and 196 were lower for CGS-U calves (9.1 ± 0.2 g/dL) compared with CGS (9.8 ± 0.2 g/dL), whereas those of CGS-EP were intermediate (9.4 ± 0.2 g/dL). Behavioral observations showed a frequency of oral stereotypes <1.2% for all feeding treatments. Longer eating and chewing or ruminating time was recorded for CGS-U calves compared with CGS and CGS-EP calves. All carcasses had satisfactory color for the veal market and none of the carcass traits were affected by the feeding treatments. The proportions of tongues and lungs with signs of lesions, forestomach development, abomasal lesions, and rumen plaques did not differ among feeding treatments. Hyperkeratinization of rumen papillae was observed only in CGS-U calves with a prevalence of 11.3%. Based on these findings, providing a corn grain and straw solid feed mixture enriched with extruded pea or urea was an effective strategy to reduce milk replacer consumption, lowering total feeding cost per calf by 3.0 to 3.4% and 6.9 to 7.2%, respectively. This economic advantage was supported by the lack of detrimental effects on calf growth performance, behavior, and carcass quality. However, the occurrence of rumen papillae hyperkeratosis may raise some concerns about the use of urea.

Veal calves' clinical/health status in large groups fed with automatic feeding devices.

Abstract Aim of the current study was to evaluate the clinical/health status of veal calves in 3 farms that adopt large group housing and automatic feeding stations in Italy. Visits were scheduled in three phases of the rearing cycle (early, middle, and end). Results showed a high incidence of coughing, skin infection and bloated rumen particularly in the middle phase while cross-sucking signs were present at the early stage when calves’ nibbling proclivity is still high. Throughout the rearing cycle, the frequency of bursitis increased reaching 53% of calves at the end. The percentage of calves with a poorer body condition than the mid-range of the batch raised gradually as well, likely due to the non-proportioned teat/calves ratio that increases competition for feed and reduces milk intake of the low ranking animals. The remarked growth differences among pen-mates and the mortality rate close to 7% showed by the use of automatic feeding devices for milk delivery seem not compensating the lower labour demand, therefore its sustainability at the present status is doubtful both for the veal calves’ welfare and the farm incomes.

Trend overtime of total haemoglobin, iron metabolism and trace minerals in veal calves fed high amounts of two different solid feeds

Abstract Fifty Polish Friesian veal calves were administrated high amounts of two different solid feeds (maize grain and a mix diet containing 10% of straw and 8% of soy) in addition to the traditional milk replacer diet. Compared to the mix diet, maize grain had a lower content of iron, copper and zinc and a minor fibre level. Effects of the two diets on calves’ blood haemoglobin, iron, iron metabolism parameters, copper and zinc concentrations were studied. Haemoglobin concentration resulted higher at the end of the fattening for calves fed the mix diet, as expected. Values remained, however, within ranges that allowed acceptable carcass paleness. Haematic iron, unsaturated iron binding capacity (UIBC) and total iron binding capacity (TIBC) levels were not significantly different between the two solid feeds. Lower copper and zinc blood concentrations resulted for calves fed the mix diet were likely due to the feed fibre interfering with the bioavailability of the two minerals, according to what happens for iron.

Nutrient Digestibility of Veal Calves Fed Large Amounts of Different Solid Feeds During the First 80 Days of Fattening

The study aimed at evaluating nutrients apparent digestibility in veal calves fed 3 feeding plans based on milk-replacer plus large amounts of solid feeds differing in their composition during the first 80 days of fattening. Twelve Polish Friesian male calves (70.6±1.9 kg) were randomly assigned to one of the following feeding treatments: i) milk-replacer plus corn grain (CG); ii) milk-replacer plus 80:20 mixture (as fed basis) of corn grain and wheat straw (CGS); and iii) milk-replacer plus 72:20:8 mixture of corn grain, wheat straw and extruded soybean (CGSES). Calves received the same milk-replacer but the daily amount was restricted (96%) for CGSES calves to balance dietary protein. Total dry matter intake from milk-replacer and solid feeds was similar among treatments, but CGSES calves showed better growth performance than CG ones. Calves were introduced into a metabolism stall (1/pen) during week 9 of fattening for a 3-day adaptation period and a 4-day digestibility trial. Calves fed CG showed the greatest DM, NFC, and ash digestibility while CGSES calves showed the lowest CP digestibility. Haemoglobin concentrations measured at day 5, 31 and 80 were similar among feeding treatments and significantly decreased over time. In CGSES treatment, the combination of milk-replacer with solid feed closer to a complete diet for ruminants led to better calves’ growth performance. However, the reduced protein digestibility with CGSES indicates that protein quality becomes a key factor when formulating diets for veal calves using alternatives to dairy sources.

Administration of high amounts of two solid feeds to veal calves: effects on growth performance and slaughter traits

Abstract The study aimed at assessing the effects on growth performance and slaughter traits of two type of solid feeds (Maize grain vs. Mix) administrated to veal calves in amounts exceeding the minimum recommended by the welfare legislation. Fifty Polish Friesian calves, housed in 5 group pens per each experimental treatment, were fed the same milk replacer diet twice a day. After milk distribution a growing amount of solid feed was distributed through the fattening period. The type of solid feed did not affect calves final body weight and average daily gain although intake of solid feed was higher i calves fed the Mix diet. Carcass weight and dressing percentage were no significantly affected by the two diets. Despite the higher haemoglobin level resulted with the Mix diet, no relevant differences between the two feeding treatments were observed regarding carcass colour parameters that were suitable for the meat market.