I. Casasús

Lucerne grazing compared with concentrate-feeding slightly modifies carcase and meat quality of young bulls

Carcase and meat quality of young bulls raised on one of three fattening strategies from 224 to 450 kg were compared. One group was fed concentrates (CON), another group grazed on lucerne plus 1.8 kg DM barley/day (LUC) and the last group had the same management as LUC young bulls for 3 months and was then finished on concentrates for 2 months. Among carcase traits, only tissue composition differed, with LUC young bulls having more muscle and less subcutaneous and intermuscular fat than their counterparts. Concerning meat quality, most attributes did not differ among fattening strategies but LUC young bulls had the lowest intramuscular fat, which presented greatest n-3 PUFA content. It can be concluded that lucerne grazing can be a good alternative to concentrates for young bulls, with similar carcase and meat quality but with lower fat content and healthier fatty acid composition than young bulls fed concentrates during the finishing period.

Effect of age at weaning on the physiological stress response and temperament of two beef cattle breeds

The study was conducted to evaluate the effect of age at weaning and breed on the stress response of calves to weaning and their temperament. At calving, 14 Parda de Montaña calves and 14 Pirenaica calves were randomly assigned to either early weaning (at 90 days) or traditional weaning (at 150 days) treatment. During nursing, calves were allowed to suckle their dams twice a day for 30 min. After weaning, calves were placed in an adjacent barn without access to their dams, where they remained for 7 days. On day 8 after weaning, they were transported to a feedlot where they received an intensive diet. Blood samples were taken 168 h before weaning (baseline) and 6, 24, 48 and 168 h after weaning for cortisol, fibrinogen and haematology analyses, and temperament was measured 90 and 180 days after weaning with the flight speed test. Cortisol concentration increased after weaning, irrespective of age at weaning. Early-weaned calves had a lower fibrinogen baseline and a greater increase in fibrinogen concentrations 48 h after weaning than traditionally weaned calves. Moreover, fibrinogen concentration returned to baseline values 168 h after weaning in traditionally weaned calves, whereas it remained high in early-weaned calves. Concerning breed effects, Pirenaica calves had higher cortisol concentration and fibrinogen increments after weaning than Parda de Montaña calves. Slight alterations occurred after weaning in haematology, but all parameters returned to baseline values 168 h after weaning, with no significant effects of age at weaning or breed. Despite the absence of clinical signs, early-weaned calves of both breeds suffered marginal anaemia, according to haemoglobin values. Regardless of age at weaning, Pirenaica calves had greater reactivity to human presence than Parda de Montaña calves, according to their higher flight speed values measured. Finally, early-weaned calves were lighter than traditionally weaned calves at weaning, but had similar weight gains in the feedlot. Consequently, they needed an additional 40 days to reach the target weight, irrespective of breed. Therefore, age at weaning had no major effects on the stress response to weaning or temperament, but early weaning increased the length of the feedlot period. On the other hand, Pirenaica calves were more reactive than Parda de Montaña calves to the stress of weaning and human presence.

Influence of management and nutrition on postpartum interval in Brown Swiss and Pirenaica cows

Abstract Data on productive and reproductive events of 549 cows (Brown Swiss and Pirenaica breeds) were collected in the Spanish Pyrenees from 1987 to 1998, in order to determine the factors that could be associated with the postpartum interval (PPI). Blood was collected 3 times per week during lactation; PPI was established by progesterone radioimmunoassay. Eighteen variables traditionally related to PPI were initially considered. Multiple Correspondence Analysis (MCA) was used to analyse the variables. PPI was associated with four factors that explained 59% of the total inertia and were defined as follows: “Prepartum feeding level” (19% of the inertia), “Postpartum feeding level—Parity” (16.4%), “Suckling frequency” (13%) and, as a supplementary variable, “Calving difficulty” (10.5%). These factors were introduced in a cluster analysis that identified five homogeneous groups of cows with respect to the management, defined by body condition score (BCS) at calving and PPI as follows: “Primiparous cows” (BCS=2.77; PPI=54 days), “Twice-daily suckling” (BCS=2.63; PPI=33 days), “Ad libitum suckling—Brown Swiss” (BCS=2.48; PPI=111 days), “Autumn calving season” (BCS=2.75; PPI=31 days) and “Spring calving season” (BCS=2.34; PPI=66 days). Cow breed was not related to PPI, although the cluster analysis associated the suckling-induced prolonged PPI with Brown Swiss animals. PPI was longer in the spring than in the autumn due to nutritional differences rather than to a seasonal effect.

Instrumental meat quality of veal calves reared under three management systems and color evolution of meat stored in three packaging systems.

This study evaluated the meat quality of grazing suckling calves (GR), suckling plus supplemented calves (SUP) and weaned calves finished on concentrates (FIN) and the color evolution of meat packaged in film (FILM), modified atmosphere packaging (MAP) and vacuum packaging (VAC). Intramuscular fat was quite low for all treatments and GR meat had greater percentages of PUFA and lower SFA, MUFA and n6/n3 than SUP and FIN. FIN and SUP meat had more L* and was more tender when aged than GR. GR meat was tough and dark. The packaging system was more influential on meat color than the feeding management. VAC had the lowest values of metmyoglobin when aged. MAP had the greatest L* and hue angle and the lowest redness after 13 d of aging, thus MAP was the packaging with the shortest shelf life.

Livestock Grazing Impacts on Herbage and Shrub Dynamics in a Mediterranean Natural Park

Abstract Shrub encroachment can be explained by the abandonment of extensive livestock farming and changes to land use, and it is a common problem in the Mediterranean mountain pastures of Europe, with direct effects on biodiversity and landscape quality. In this paper, the effects of livestock exclusion vs. grazing on the dynamics of shrub and herbaceous vegetation were analyzed in a Spanish natural park located in a dry Mediterranean mountain area over a 5-yr period. Twelve 10 × 10 m exclosures were set up in six representative pasture areas of the park (with two replicates per location). Each year, the shrub number, volume, and biomass were measured in April, and the herbage height, biomass, and quality were measured in April and December (which represent the start and end of the vegetative growth season). A sustained increase of the shrub population and individual biomass was observed throughout the study, which was reflected in total shrub biomass per ha. Growth was greater in nongrazed exclosures (2 563 kg dry matter [DM] · ha−1 · yr−1), but it also happened in the grazed control areas (1 173 kg DM · ha−1 · yr−1), with different patterns depending on the location and shrub species. Herbage biomass did not change when grazing was maintained, but it did increase in places where grazing was excluded (291 kg DM · ha−1 · yr−1), mostly as a consequence of the accumulation of dead material, with a concomitant reduction in herbage quality. It was concluded that at the current stocking rates and management regimes, grazing alone is not enough to prevent the intense dynamics of shrub encroachment, and further reductions in grazing pressure should be avoided.

Effects of pre-weaning concentrate feeding on calf performance, carcass and meat quality of autumn-born bull calves weaned at 90 or 150 days of age

A study was conducted to evaluate the effect of pre-weaning concentrate feeding in early-weaned (EW, day 90) or traditionally weaned (TW, day 150) autumn-born beef calves on growth, feed intake and feed efficiency, and carcass and meat quality. Twenty-eight male calves were either EW or TW, and offered a starter concentrate (S) or no additional feed (NS) during the pre-weaning period. Therefore, four management strategies were tested: EWS, EWNS, TWS and TWNS. Growth patterns were affected by management strategy. From day 90 to 150, TWNS calves presented a substantially lower average daily gain (ADG) than their counterparts, which had similar performance. During the finishing phase (from day 150 to slaughter at 450 kg live weight), EWS calves had the lowest ADG. Daily feed intake or efficiency in the finishing phase was unaffected by previous management. Serum IGF-I concentrations at day 90 and slaughter did not differ with management strategy, but early weaning and pre-weaning concentrate feeding increased IGF-I concentrations at day 150. Circulating leptin concentrations were unaffected by age at weaning and pre-weaning concentrate feeding, except for leptin concentrations at slaughter, which were higher in S calves than in NS calves. Total concentrate intake from birth to slaughter and the concomitant feed costs were higher for EWS and EWNS calves than for TWNS and TWS ones. However, cow feed costs were lower for cows whose calves had been early weaned. Concerning carcass quality, early weaning improved dressing percentage and increased fatness score, and particularly TWNS calves presented a poorer conformation. Meat quality was not affected by management strategy. Considering the economic performance, TWS, EWNS and EWS strategies yielded a similar economic margin, whereas TWNS would be the least advisable strategy when calves are fattened in the farm until slaughter.

Grazing lucerne as fattening management for young bulls: technical and economic performance and diet authentication.

Three fattening systems were evaluated from weaning to slaughter in order to find alternatives to grain feeding in young bulls, and to test the reliability of carcass subcutaneous fat colour to discriminate among them. After weaning (224 kg), one group of animals was fed concentrates and straw until they reached the target slaughter weight (450 kg; Feedlot), another group grazed rotationally on lucerne supplemented with 1.8 kg DM/day barley until slaughter (LUC), and the third group had the same management as LUC animals for 3 months (period 1) and thereafter was finished on concentrates and straw until slaughter (period 2; LUC + Feedlot). Animals were weighed weekly and sampled monthly for serum IGF-I and leptin, and plasma non-esterified fatty acids and carotenoid pigment concentration analyses. Carcass characteristics and subcutaneous fat colour were recorded after slaughter. In period 1, Feedlot animals had slightly greater weight gains than their grazing counterparts (P < 0.10), and at the end of period 1 they had 66% greater IGF-I and 35% greater leptin concentration (P < 0.01). Plasma carotenoid pigments were undetectable in Feedlot animals, but increased during grazing in LUC and LUC + Feedlot treatments. In period 2, weight gains were lowest for LUC, intermediate for Feedlot and greatest for LUC + Feedlot animals (P < 0.001), conditioning the time taken to reach slaughter weight (73, 58 and 47 days, respectively; P < 0.05). Leptin and IGF-I concentrations increased in all management systems during period 2. Plasma carotenoid pigment concentration reached its maximum at the end of period 2 in LUC animals, but it decreased sharply in LUC + Feedlot animals in this period. Management did not affect carcass traits except for subcutaneous fat colour. Yellowness, Chroma (C*) and the value of the integral of the translated reflectance spectrum (SUM), estimator of carotenoid pigment content in fat, were higher in LUC than in LUC + Feedlot and Feedlot animals (P < 0.001). Two logistic regressions were obtained to discriminate carcasses from LUC treatment: P (LUC) = (1 + e(18.8-5.6 × lightness-36.9 × redness + 0.3 × SUM + 29.8 × C*))(-1) and LUC + Feedlot treatment: P (LUC + Feedlot)=(1 + e(833.7-11.8 × lightness + 4.7 × redness + 0.2 × SUM-2.5 × C*))(-1). The economic margin, calculated as income achieved minus costs, was greatest for LUC, intermediate for LUC + Feedlot and lowest for Feedlot treatment. Therefore, grazing lucerne supplemented with barley was an interesting alternative for fattening young bulls in these conditions, producing carcasses of similar quality, which could be accurately traced by measuring subcutaneous fat colour.

Performance and nursing behaviour of beef cows with different types of calf management

The aim of this experiment was to evaluate the effect of calf management during lactation on dam performance and nursing behaviour. Thirty-six multiparous beef cows (aged 7.5 ± 0.52 years) of Parda de Montaña breed (mean live-weight (LW) at calving 566 ± 9.3 kg) with a moderate body condition (mean 2.6 ± 0.02 on a 1 to 5 scale), were assigned to three nursing frequencies from the day after parturition: Once-daily restricted nursing during a 30 min period at 0800 h (RESTR1), twice-daily restricted nursing during two 30 min periods at 0800 and 1530 h (RESTR2) and ad libitum nursing (ADLIB). Cows were fed throughout the experiment 80 MJ/day of metabolizable energy. Cow-calf behaviour recordings were performed on days 30 and 66 of lactation in each treatment. Blood samples were collected fortnightly to analyse non-esterified fatty acids (NEFA) by an enzymatic colorimetric method, and twice weekly to determine progesterone concentrations by radioimmunoassay. Cow LW losses (P < 0.05), fat-corrected milk yield (P < 0.05) and calf average daily gain (P < 0.01) during lactation were higher in ADLIB. Nursing frequency affected the mean serum concentrations of NEFA, being lower in RESTR1 (0.18 mmol/l; P < 0.05) than in RESTR2 and ADLIB cows (0.29 and 0.25 mmol/l, respectively). The highest occurrence of nursing bouts was observed in ADLIB, leading to greater nursing duration per day (not statistically compared) in this treatment (58.8 ± 5.84 min) than in their restricted nursing counterparts (22.2 ± 1.42 and 34.3 ± 1.16 min, in RESTR1 and RESTR2, respectively). The nursing system did not affect the proportion of cows cycling within 3 months post partum (58%, 46% and 55% in RESTR1, RESTR2 and ADLIB, respectively; P > 0.05). The majority of cows in all treatments showed a short oestrus cycle after first ovulation (75%, 100% and 83%; P > 0.05). In conclusion, the post-partum luteal function in cows managed under continuous access to calves was similar to restricted nursing frequencies, despite the greater suckling intensity of the formers. Restricting calf presence does not enhance the resumption of ovarian activity when suckler cows are managed in moderate nutritional conditions.

Effect of two Spanish breeds and diet on beef quality including consumer preferences

BACKGROUND Farmers in dry mountain areas are changing their management strategies to improve livestock farming efficiency, by using different forages or different breeds. The effect of breed (Parda de Montaña vs. Pirenaica) and finishing diet (grazing on meadows vs. a total mixed ration (50% alfalfa, 40% maize grain, 10% straw)) on carcass characteristics and meat quality of steers was studied. RESULTS Parda de Montaña had a greater (P < 0.01) amount of intramuscular fat than Pirenaica. The finishing diet did not influence carcass fat color, but fatty acid composition was slightly affected. Finishing steers on a total mixed ration increased the percentage of fat of the 10th rib (P < 0.001). Supplementation with concentrates increased the diet energy concentration and also increased the dressing percentage. CONCLUSIONS Both breeds had similar carcass characteristics. Consumers preferred beef from the Pirenaica breed because of its greater tenderness. Consumers did not differentiate between beef from animals fed different finishing diets. However, consumers who like meat very much preferred meat aged in a cooler at 4 °C for 15 days rather than 8 days.

Metabolic, endocrine, and reproductive responses of beef heifers submitted to different growth strategies during the lactation and rearing periods

The effects of different feeding strategies (0.7 kg/d target ADG [LO] and 1.0 kg/d target ADG [HI] during the lactation period (LACT; 0-6 mo) and the rearing period (REAR; 6-15 mo; HI-HI, HI-LO, LO-HI, and LO-LO treatments) on the growth and reproductive parameters of beef heifers bred by fixed-time AI at 15 mo were analyzed. Animal weights were recorded weekly (from birth to 18 mo), and size measures were recorded at 6 and 15 mo. Heifers were bled to determine the onset of puberty and the metabolic and endocrine (IGF-I and leptin) status. During lactation, calves in the high lactation treatment (LactHI) had greater weight ( < 0.001), weight gain ( < 0.001), and body size ( < 0.001) than calves in the low lactation treatment (LactLO). The greater energy balance of LactHI heifers at weaning was reflected in greater concentrations of plasma glucose ( < 0.001), urea ( < 0.001), and IGF-I ( < 0.001); plasma levels of NEFA were lower ( < 0.001). During REAR, LactLO heifers had a greater growth rate than did LactHI heifers ( < 0.001), partially overcoming the lower gains during lactation. The differences in size measurements registered at weaning were also compensated, with the exception of LO-LO heifers. The IGF-I profile was highly correlated with animal performance traits and metabolic profiles, providing a useful indicator of growth, nutritional, and metabolic status at key points in development. By contrast, the function of leptin as an indicator of growth and reproductive development of heifers was less clear. All treatments had similar weights at puberty onset (55.9% mature BW), although LactLO ( < 0.01) and the low rearing treatment (RearLO; < 0.001) heifers were older than the others. The animals with greater glucose and IGF-I levels at weaning and greater cholesterol concentrations during REAR reached puberty earlier. The fertility rate (86%) was similar among treatments. The heifers in the high rearing treatment (RearHI) required more AI services to become pregnant and were older at conception ( < 0.05). The age of conception was positively correlated with glucose ( = 0.57, < 0.01) and cholesterol ( = 0.68, < 0.001) at 9 mo. Our results show that a 0.7 kg/d gain from birth allowed the first breeding at 15 mo, 6 mo earlier than usual for these conditions, without any negative effect on heifer reproductive performance.