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Context. Mitigating urinary nitrogen (N) losses is an important target of sustainable cattle nutrition concepts. One option to achieve this may be dietary inclusion of tanniferous herbs. Aims. Aim of the study was to investigate herbs with different profiles of tannins for their efficiency to abate urinary N losses. Small burnet (Sanguisorba minor) with high concentrations of total tannins, plantain (Plantago lanceolata) with low concentrations and birdsfoot trefoil (Lotus corniculatus) with expectedly high concentrations of condensed tannins were included in the treatments. Methods. The test plants were mixed in dried form into a grass-maize-silage diet at 80 g/kg of dietary dry matter. They replaced dried perennial ryegrass (control). Twenty-four multiparous dairy cows were randomly allocated to the four diets. Intake, eating time, rumination time, and milk yield were recorded individually, and representative samples of milk and excreta were collected and analysed six times within 14 days, following 10 days of adaptation. The diets with ryegrass, birdsfoot trefoil, plantain or burnet contained, per kilogram of dry matter, 0, 1.8, 1.2 and 1.9 g condensed tannins, 0.1, 1.9, 1.7 and 15.5 g total tannins, and 26.2, 28.5, 27.5 and 26.6 g N. Key results. Milk yield and composition were not affected by treatment, apart from a decline in milk protein content when feeding plantain. Milk urea concentration was reduced with burnet by more than 30%, compared with the control and plantain. Birdsfoot trefoil also reduced milk urea concentration, but to a lesser degree. Furthermore, the burnet treatment substantially shifted N excretion from urine to faeces (about 30% lower urine N losses). All treatments lowered the proportion of fine particles of <1.0 mm in faeces, what might be due to high fibre content of the control. Conclusions. At dietary proportion of 80 g/kg, burnet is a forage herb with potential to reduce ruminal ammonia generation as indicated by reduced urinary N and milk urea. Plantain and birdsfoot trefoil had no or negligible effects. Implications. The study indicated that small burnet could have potential as a feed additive for dairy cows in terms of N-use efficiency, lower emissionsto the environment, and reduced animal metabolic stress. [ABSTRACT FROM AUTHOR]

High prolificacy of sows and increased fetal survival lead to greater incidence of intrauterine crowding (IUC), which may then affect pre- and post-natal development of the progeny. The aim of the study was to assess the impact of IUC, using unilaterally hysterectomized-ovariectomized gilts (UHO), on organ and muscle development of their progeny at birth. In the study, 7 UHO and 7 intact control (Con) Swiss Large White gilts were used. At farrowing, if available, 3 male and 3 female progeny with a low (>0.8 and 1.2 and 1.6 kg) birth weight (BtW) were killed. Internal organs and brain were weighed, and semitendinosus (STN), psoas major (PM), and rhomboideus (RH) muscles were collected. Histological analyses were performed in PM, RH, and STN (dark and light portion) using myofibrillar ATPase staining after preincubation at pH 10.3. Myosin heavy chain (MyHC) polymorphism was determined in the PM using SDS-PAGE gel electrophoresis. Despite that only one-half of the uterine space was available, litter size was smaller (P < 0.01) only by 35% in UHO compared with Con gilts. However, UHO progeny tended (P = 0.06) to be lighter than Con progeny. The average BtW of the selected piglets did not differ (P = 0.17) between the 2 sow groups, whereas PM and kidneys tended to be lighter (P < 0.07) in UHO than in Con progeny. Compared with Con progeny, the PM and the [STN.sub.dark] of UHO progeny had fewer (P [less than or equal to] 0.05) secondary and total myofibers as well as fewer (P = 0.10) primary myofibers in the PM. In the RH, the secondary-to-primary myofiber ratio was smaller (P < 0.01) in UHO than in Con progeny, whereas the total number of myofibers did not (P = 0.96) differ. The relative abundance of fetal MyHC was less (P = 0.02) and that of type I MyHC tended (P = 0.09) to be greater in UHO than in Con offspring. With increasing BtW, organ and brain weights increased (P < 0.01). Muscle cross-sectional area and total number of myofibers in the light portion of the STN were greater (P < 0.05) in high and medium than in low piglets. In conclusion, IUC reduced hyperplasia of secondary and total myofibers in the [STN.sub.dark] and PM. These effects were independent of the BtW and sex. Key words: birth weight, intrauterine crowding, myogenesis, pig doi: 10.2527/jas.2010-2867

The objective of the study was to test the hypothesis that birth weight (BtW) influences growth, carcass characteristics, meat quality, and postmortem (pm) proteolysis differently when pigs originate from small (S) or large (L) litters. Swiss Large White barrows (60) used in this study originated from 20 litters with either less than 10 (S) or more than 14 (L) piglets born per litter. Within each of the S and L litters, 3 barrows were selected at birth: the lightest (L-BtW), the heaviest (H-BtW), and the one with a BtW nearest to the average BtW of the litter (M-BtW). The BW and total feed intake of the individually penned pigs were determined weekly. At slaughter, carcass characteristics were assessed. Meat quality traits were determined in the LM and dark portion of semitendinosus muscle. Titin, nebulin, desmin, and integrin proteolysis were evaluated by SDS-PAGE and Western blot technique, and p- and m-calpain activities were monitored using casein zymography. Litter size affected BtW of L-BtW and M-BtW but not of H-BtW barrows (BtW x litter size interaction; P = 0.07). From weaning to slaughter, L-BtW barrows grew slower (P < 0.01), ingested less feed (P < 0.01), and were less efficient (P < 0.01) than H-BtW and M-BtW barrows. The carcass yields were greater (P < 0.01), and livers and kidneys were lighter (P < 0.01) in L-BtW compared with H-BtW barrows. Regardless of BtW, barrows from S litters had greater percentages of shoulder (P = 0.02) and lower percentages of omental fat (P = 0.06) than barrows from L litters. Compared with the LM of H-BtW barrows, the LM of L-BtW barrows was redder (P < 0.01). The semitendinosus muscle of M-BtW barrows was more (P < 0.01) tender than that of L-BtW and H-BtW barrows. The extent of titin and nebulin proteolysis at 24 and 72 h pm was greater (P [less than or equal to] 0.07) in the LM of H-BtW than in L-BtW barrows. At 72 h pm, integrin of the LM had been less (P = 0.08) degraded in barrows originating from S than from L litters. These results confirm the known effect of BtW on growth performance, whereas its effect on carcass characteristic and meat quality traits could only be partially demonstrated. Although litter size affected average BtW of the L-BtW and M-BtW barrows, its effect on growth performance, carcass characteristics, and meat quality was minor. The almost complete absence of significant BtW x litter size interaction indicates that litter size affects swine growth and carcass and meat quality through its inverse relationship with BtW. Key words: birth weight, litter size, meat quality, pig, proteolysis

On steep slopes, grazing is associated with elevated physical activity. This is assumed to influence muscle metabolism, carcass and meat quality in beef cattle. However, there is a lack of experiments which allow distinguishing between physical activity and other factors of influence. In the present experiment, a setup was applied which excluded other factors as best as possible. Two groups of 12 Angus-sired suckling calves were each kept on high altitude pastures with either steep (whole area with about 40% inclination; S-calves) or with flat areas (0% inclination; F-calves). The two areas offered forage of similar nutritional quality. The calves, initially 18 ± 2·5 weeks old, were kept with their dams on the pastures for 11 weeks in a rotational grazing system. The calves were equipped with pedometers and rumination sensors to record physical activity and feeding behaviour, respectively. Slaughter took place on two dates immediately after the grazing period and carcass quality was assessed. Muscle fibre types were classified according to their contractile metabolism and post mortem (p.m.) protein degradation was quantified. The meat, aged for 21 days, was subjected to various physicochemical analyses and sensory evaluation. S-calves walked more steps and spent more time lying down than F-calves, whereas feeding behaviour was not affected by pasture inclination. The daily gains of S-calves were 10% lower compared with those of F-calves. Carcass characteristics were not influenced by pasture inclination. S-calves had a larger proportion of fast-twitch type IIX/B muscle fibres than F-calves. The opposite was observed for intermediate type IIA muscle fibres, whereas the proportion of slow-twitch type I muscle fibres was unaffected. Occasional differences were observed between S- and F-calves regarding indicators of p.m. proteolysis. In S-calves, compared with F-calves, meat from the longissimus thoracis muscle was juicier and showed a tendency to be of lighter colour, whereas meat from the biceps femoris muscle had a smaller shear force (24·5 v. 27·5 N in F-calves). In conclusion, 11 weeks’ exposure to environments forcing calves to exhibit different physical activities in a hypoxic environment was sufficient to cause adaptations in muscle metabolism and several, though small, differences in meat quality. [ABSTRACT FROM PUBLISHER]