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Bioactive components in goat milk and plasma
No full textLeptin, ghrelin and IGF-1 were measured in sonicated defatted milk (morning and evening milkings) and in plasma (before feeding, 1 and 4 h after feeding) in 17 Saanen goats in midlactation. Leptin and ghrelin were positively correlated and were twice/thrice more concentrated in milk than in plasma. Plasma IGF-1 level was 7-fold higher than in milk with high correlation (r=+0.84; P<0.01). During the periprandial period (immediately prefeeding, 1 and 4-h postfeeding) plasma leptin and IGF-1 levels did not change significantly, while plasma ghrelin level was significantly lower 1 h after feeding
Influence of a nonforage diet on plasma leptin in dairy goats throughout lactation
Full text linkThe aim of this study was to compare the plasma level of leptin in lactating goats fed a traditional silage-based diet or a totally free forage diet, throughout lactation and during the pre and post-feeding state.
Conclusions: The opposite trend in the pattern of diet effects on DMI and plasma leptin, both in pre- and postfeeding state, induces to retain that in goats throughout
lactation the levels of leptin can be related to DM intake, as Barb (1999) proposed in other animal models.
Finally, it is interesting to note that also in lactating goats, as in other species, plasma leptin level increased during the post-feeding phase
Effect of grinding of maize and level of starch on digestibility and performance of Saanen goats
No full textThe purpose of this experiment was to evaluate the effects on intake, digestibility and lactational performance of goats when fed diets containing whole or ground maize grain at two different dietary starch levels through substitution of beet pulp for maize. Eight second parity Saanen goats in mid lactation were used in a digestibility trial. The experimental design was a duplicated 4x4 Latin square with a 2x2 factorial arrangement of treatments. The goats were fed four diets, with a forage:concentrate ratio of 40:60, containing: 33.5% (on dry matter basis) whole maize grain or 33.5% ground maize grain in the diets with high starch content; 22.5% dried beet pulp and 11.0% whole maize grain or 11.0% ground maize grain in the two diets with low starch content. The high starch diets significantly decreased DMI in comparison with the low starch diets (2333 and 2229 g/d, for low and high starch diets, respectively). Substitution of beet pulp for maize significantly improved NDF and ADF digestibility (56.4 and 55.5% and 42.2 and 38.9%, for low and high starch diets, respectively) due to the lower content of starch. Starch digestibility was influenced by the grinding of maize: whole grain (92.6%) was less utilized than ground grain (97.7%), despite not impairing total DM digestibility. The ground maize grain depressed feed intake and milk yield in the high starch content diets. The data obtained suggest that the grinding of maize is not likely to be worthwhile for lactating goats
Digestibility and milk performance of dairy goats fed two dietary starch concentration, with whole or ground maize
No full textThe purpose of this experiment was to evaluate the effects on intake, digestibility and milk performance of goats fed diets with whole or ground maize at two dietary starch concentration obtained substituting beet pulp for maize.
For this aim eight second parity Saanen goats (57.4 kg BW, on average) in mid lactation (83 DIM, on average), confined in individual metabolic cages, were utilized for a digestible trial in a duplicated 4 x 4 Latin square design balanced for carry-over effect with a 2 x 2 factorial arrangement of treatments. The goats were fed four diets, with a forage:concentrate ratio of 40:60, containing: 33.5% (on dry matter basis) whole maize grain (HSMG) or 33.5% maize meal (HSMM) in the diets with high starch content; 22.5% dried beet pulp and 11.0% whole maize grain (LSMG) or 11.0% maize meal (LSMM) in the two diets with low starch content. The other ingredients were (on DM): barley meal (13.3%), soybean meal (9.1%), maize gluten meal (3.0%) and mineral-vitamin complex (3.0%). The diets were isonitrogenous and with NDF and starch content (% on DM) of 32 and 33% or 40 and 17%, for high or low starch diets, respectively. The diets were offered ad libitum, allowing for about 5% orts. Individual data for DM intake, digestibility and milk production were statistically analysed using GLM procedure of SAS. Tukey’s test comparisons of treatment means was conducted if P<0.05 for interaction of main effects.
The animals made a strong feed selection leaving hay as the sole refusal. As a consequence, the forage:concentrate ratio (DM basis) of the ingested diet resulted to be 32:68 instead of the planned 40:60, on average for the four treatments. The DMI obtained during the experimental trials was not significantly different among treatments, despite a higher value registered by low starch diets (2333 and 2229 g/d, for low and high starch diets, respectively, P<0.05).
Concerning DM digestibility, the interaction between the effects of starch concentration and type of maize was statistically significant (P<0.05); particularly, the DM of HSMG diet resulted better digested (71.6%) in comparison with HSMM diet (69.0%) and with LSMG diet (69.1%). Substitution of beet pulp for maize significantly improved NDF and ADF digestibility (56.4 and 55.5% and 42.2 and 38.9%, for low and high starch diets, respectively, P<0.001) due to the high content of pectins, confirming the results obtained by Voelker & Allen (2003) in a trial with dairy cows. Starch digestibility was influenced (P<0.001) by the physical form of maize: whole grain (92.6%) was less utilized than maize meal (97.7%), despite it did not impair total DM digestibility. Anyway, the high utilization of starch in diets with whole maize (94.2 and 90.9% for high starch and low starch, respectively) indicates a low passage of indigested grain trough the gut. This seems due to an extensive damage of maize kernels during mastication (Beuchemin at al., 1994) which determines a relevant grain utilization already at rumen level.
The milk production was not affected by the level of starch (4323 and 4328 g/d, for low and high starch diets, respectively): this was probably due to the higher DMI by goats fed the low starch diets. On the other hand, looking at the effect of the type of maize in the diets with high starch content, it is evident that maize meal depressed feed intake and milk yield (4075 and 4570 g/d, for HSMM and HSMG, respectively, P<0.05). Milk fat was not affected neither by starch level nor by maize type and its percentage for all treatments resulted lower than protein percentage (2.52 and 2.66%, for fat and protein content on average, respectively). This might be due to the low ether extract content of the diets (2.24%). The proportion of lactose was significantly influenced by the level of starch (4.49 and 4.39%, for high and low starch diets, respectively, P<0.001): this could be ascribed to the presumably higher rumen propionate production from amylolytic microbes.
In conclusion, substitution of beet pulp for maize in diets rich in concentrates significantly improved DMI and NDF and ADF digestibility due to their high content of soluble fibre. Moreover the utilization of whole grain instead of maize meal does not depress diet digestibility while increases milk yield. The data obtained suggest that the grinding of maize given to lactating goats is likely to be of no value
Trend of energy and nitrogen utilization of high fibre diets in pigs from 100 to 160 kg bodyweight
No full textScopo della ricerca è stato di indagare la capacità del suino pesante di utilizzare diete a elevato contenuto di fibra. Sono
stati utilizzati 8 suini castrati Landrace x Large White, alimentati con tre diete ad alto tenore in fibra (HF, mediamente
NDF 17,8% SS) e con una dieta di controllo (C, NDF 13,5% SS), inseriti in un disegno sperimentale a Quadrato Latino.
L’alimentazione è stata razionata, mentre l’acqua era a volontà. Ognuno dei 4 periodi includeva 21 giorni di adattamento
e 7 di digeribilità e calorimetria. Le 3 diete HF includevano crusca di frumento in scaglie o macinata e polpe di bietola
disidratate. Nei 4 periodi di digeribilità gli otto suini pesavano mediamente 105, 124, 140 e 158 kg. La digeribilità della
fibra delle diete HF è aumentata dal periodo 1 al periodo 4: 56,2, 56,6, 58,8 e 62,2% per l’NDF e 46,0, 47,1, 49,0 e 53,4% per l’ADF. Un andamento simile è stato rilevato anche per la digeribilità di sostanza secca, sostanza organica, proteine
grezze, estratto etereo ed energia. Confrontando la digeribilità media dei 4 periodi, si rileva una significativa
(P<0,05) maggior digeribilità della dieta C rispetto a quella delle diete HF per la sostanza secca (87,5 vs 84,9%), per la
sostanza organica (89,5 vs 87,0%) e per l’azoto (87,2 vs 83,4%), mentre per la fibra la tendenza si inverte senza raggiungere
differenze significative. Per le diete HF si è rilevato un incremento dell’energia persa come gas metano passando
dal periodo 1 al 4 (da 0,40 a 0,59% dell’energia ingerita, P<0,05) mentre non si sono registrate differenze significative
per il calore prodotto e l’energia ritenuta. I valori relativi a questi parametri sono risultati simili anche confrontando la
dieta C rispetto alle diete HF (media dei 4 periodi), confermando la buona capacità del suino pesante di utilizzare diete
con tenore di fibra particolarmente elevato. Passando dal periodo 1 al periodo 4 il bilancio dell’N per il trattamento HF ha
evidenziato che, a fronte di un miglioramento della digeribilità, vi è stato un aumento delle perdite di N urinario. Tale
perdita è risultata pari al 35,7% dell’N ingerito per il periodo 1 e al 51,9% per il periodo 4 (P<0,05). In valore assoluto
l’azoto escreto totale, a fronte di una riduzione dell’ingestione, è risultato simile nei 4 periodi (mediamente 0,98 g/PV 0,75).
Esprimendo i dati in percentuale dell’N ingerito, infatti, si è passati dal 54,6% del periodo 1 al 68,2% del periodo 4
(P<0,05). Questo ha portato a una deposizione proteica (N x 6.25) pari a 155 g/d nel periodo 1 e a 126 g/d nel periodo
4 (P<0,05). Al contrario, la deposizione lipidica è aumentata passando dal periodo 1 al periodo 4, rispettivamente 315,
359, 374 e 394 g/d.The aim of the experiment was to investigate the ability of the heavy pig to utilize diets rich in fibre. Eight Landrace x
Large White fattening barrows were fed 3 high fibre (HF) diets (on average 17.8% NDF on DM) and a traditional (C) diet
(13.5% NDF) in a Latin Square design. Feeding was restricted. Each of the 4 periods included 21 days adaptation and 7
days digestibility/calorimetry. The HF diets included wheat bran (coarse or milled) or beet pulp. In periods 1, 2, 3 and 4
the eight pigs weighed, on average, 105, 124, 140 and 158 kg. Fibre digestibility (%) of HF diets increased from period
1 to period 4: 56.2, 56.6, 58.8, 62.2 for NDF and 46.0, 47.1, 49.0, 53.4 for ADF. A similar trend was registered for the
digestibility of DM, OM, CP, EE and energy. Comparing the digestibility of diet C with HF diets, independently of the periods,
diet C always had significantly higher digestibility (e.g. DM=87.5 vs 84.9%) except for fibre which gave similar coefficients.
Methane energy losses increased significantly from period 1 to period 4 for HF diets (0.40 vs 0.59% of the intake
energy, IE, P<0.05), while heat production and retained energy (% of IE), did not differ significantly between periods.
Retained energy of diet C (37.1% IE) and of HF diets (35.3%) considered as the average of the four periods, were similar,
confirming that the heavy pig can utilize fibre to a good extent. Considering the N balance of treatment HF, passing
from period 1 to period 4 concomitantly with a lower faecal excretion a significantly greater urinary excretion was recorded:
35.7 and 51.9% of intake N in periods 1 and 4, respectively (P<0.05). Total N excretion was similar in the four periods
(on average 0.98 g/BW0.75). However, expressing the data as % of the intake N, total N excretion increased from period
1 (54.6%) to period 4 (68.2%) (P<0.05). As a consequence, protein deposition (N*6.25) decreased from 155 to 126
g/d from period 1 to period 4 (P<0.05). On the contrary, fat deposition increased, as expected, in the four periods: 315,
359, 374 and 394 g/d
EFFECT OF THE STAGE OF MATURITY ON THE NUTRITIVE VALUE OF WHOLE CROP WHEAT SILAGE
No full textAn in vivo digestibility and calorimetric experiment was performed on eight adult wethers to determine the digestibility and net energy content of wheat silages obtained from whole plants cut at different stages of maturity. Wheat (Triticum aestivum L., var. Eridano) was harvested at the boot (B), midbloom (MB), milk (M) and dough (D) stages of maturity. The wethers were fed ad libitum in a 4 × 4 latin square digestibility trial. Each collection period lasted eight days with 3 × 24 h-cycles of respiration trials (indirect calorimetry in respiration chambers). In vitro organic matter digestibility (IVOMD) was determined on dried samples of whole wheat cut from the same field at 10 different stages between boot and dough. Silage quality parameters were optimum for all stages. DM, OM and energy intake were significantly higher in the first and last stages of maturity (B and D) than in the medium stages (MB and M). DM, OM and energy digestibility decreased significantly from B to M stage but did not change between the last two stages. In contrast, CF, NDF and ADF digestibility decreased significantly with maturity. IVOMD had a quadratic trend of variation as a function of the stage of maturity, similar to the in vivo data, with the lower value at the M stage. Metabolizability (q = ME/GE) followed the same trend of energy digestibility. NE1 decreased with increasing stage of plant growth but the difference was significant only between the first stage and the last three stages. The nutritive values of the whole-crop wheat silages was very high for the B stage and decreased with successive stages of maturity (7.74, 6.41, 5.69 and 5.39 MJ NE1/kg DM at the B, MB, M and D stages). In contrast, DM yield was minimum at the B stage (3.3 t/ha) and increased with increasing maturity up to 9.6 t/ha at the D stage. As a consequence, a satisfactory compromise between yield and nutritive value would involve harvesting whole-crop wheat just before the milk stage
Valore nutritivo di insilati di loiessa (lolium multiflorum lam.) : confronto tra il doppio taglio e il taglio unico
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