RESUMEN
BACKGROUND: In the last years, difficulties occurring in corn cultivation (i.e., groundwater shortages, mycotoxin contamination) have been forcing dairy farmers to consider alternative silages. Some experiments conducted on lactating cows have proven that the total replacement of corn silage with sorghum silage did not reduce milk yield. However, this kind of substitution involves supplementing sorghum-based diets with grains, to compensate for the lower starch content of sorghum silage compared to corn silage. Change of silage type and inclusion of starch sources in the diet would influence rumen fermentations, with possible effects on milk composition (i.e., fatty acid profile) and coagulation properties. A worsening of milk coagulation properties would have a negative economic impact in Italy, where most of the milk produced is processed into cheese. This study was designed to compare milk composition and quality, with emphasis on fatty acid profile and coagulation properties, in dairy cows fed two diets based on corn or sorghum silage. RESULTS: The sorghum diet reduced milk yield (P = 0.043) but not 4% fat corrected milk (P = 0.85). Feeding sorghum silage did not influence milk contents of protein (P = 0.07) and lactose (P = 0.65), and increased fat content (P = 0.024). No differences emerged for milk concentrations of saturated (P = 0.61) and monounsaturated fatty acids (P = 0.50), whereas polyunsaturated fatty acids were lower (P < 0.001) for the sorghum diet. Concentrations of n-6 (P < 0.001) and n-3 fatty acids (P = 0.017) were lower in milk of cows fed the sorghum diet. Milk coagulation properties did not differ between the two diets, except the "a30" (the curd firmness, expressed in mm, 30 min after rennet addition), that was lower (P = 0.042) for the sorghum diet. CONCLUSIONS: Feeding a forage sorghum silage, properly supplemented with corn meal, as total replacement of corn silage maintained milk composition and did not influence negatively milk coagulation properties, which have a great economic relevance for the Italian dairy industry. Thus, silages obtained from forage sorghums could have a potential as substitute of corn silages in dairy cow diets.
RESUMEN
The present work is aimed at evaluating the behaviour of Italian Heavy Draught Horse (IHDH) foals reared in semi-covered stables and fed two isoenergetic total mixed rations with different dietary protein levels (13.2% and 10.6% of CP on dry matter). The study was prompted by the restrictions for nitrate emissions in farms of the European Nitrate Directive. One suggested solution is to reduce dietary protein while maintaining normal performance and welfare, but there is a lack of literature in studies of horses. The behaviours of 20 foals of 437±60 kg of BW, aged 379±37 days and stabled in four pens by sex (S) and diet (D) were video recorded and analysed to build a suitable ethogram including 18 behaviours in six categories: ingestion, resting, maintenance, movement, social activities, other. The percentage of the daily time spent in each behavioural category and single behaviours was analysed via a single traits GLM including S, D and their interaction. Daily activity was consistent with existing literature: foals spent about 33% of the day in ingestion activities and 41% in resting, whereas social interactions constituted 8% of the time and individual maintenance <2%. Concerning diet, foals fed high protein spent more time in movement (19.62±0.73% of day v. 10.45±0.73% in low-protein (LP) foals; P⩽0.001), whereas the LP group increased resting (43.42±1.12% v. 38.02±1.12%; P⩽0.001). No stereotypies were found, and daily activity followed the typical values for draught breeds for foals in both dietary groups, a result that suggests the maintenance of well-being after dietary protein reduction. This result, together with the findings of a companion study showing no changes in growth performances of foals, showed that a reduction of CP in foal diet is reconcilable with the maintenance of performance and welfare.
Asunto(s)
Alimentación Animal/análisis , Conducta Animal/efectos de los fármacos , Dieta/veterinaria , Proteínas en la Dieta/farmacología , Caballos/fisiología , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Proteínas en la Dieta/administración & dosificación , Relación Dosis-Respuesta a Droga , Femenino , Masculino , Actividad Motora/efectos de los fármacosRESUMEN
This study aimed at evaluating in vivo performance, growth parameters, intakes, dressing percentage, and blood parameters in Italian Heavy Draft Horse (IHDH) weanlings fed 2 CP levels up to the 2 typical ages of slaughter. Forty-one weanlings were grouped in 8 pens according to sex, age, and BW. After a transition period, animals were randomly assigned to 2 isoenergetic diets containing different CP levels: 10.6 and 11.2% CP in DM for low protein (LP) and 13.2 and 14.7% CP in DM for high protein (HP) diets in the first and second phase, respectively. About half of the animals (n = 22) were slaughtered when aged 13 mo (end of first phase); the remaining animals (n = 19) were slaughtered at 18 mo (end of second phase). Animals were weighed, measured for withers height, and scored in vivo for fleshiness and BCS at 3 wk intervals. Feed intake in each pen was measured weekly, and feed samples were collected every 2 mo. Blood samples from venous jugular were collected in both phases to analyze plasma protein, urea, glucose, bilirubin, hepatic enzymes, and mineral content. Growth parameters were estimated within phase by modeling BW as a function of age using fourth-degree Legendre polynomials. During the first phase, a different linear coefficient (P = 0.051) for the growth curve was observed between females fed a HP or a LP diet, while males showed differences only on quadratic and cubic Legendre coefficients. However, no significant differences were detected in ADG between the CP levels and sexes. In the second phase, Legendre coefficients were not different between treatments for the remaining weanlings, and once again no differences were found on ADG. The DM intake was influenced by diets in both periods, greater in the HP diet as compared with the LP diet (P < 0.001). No differences due to diet were observed for fleshiness or BCS scores at the end of each phase or in the dressing percentage at slaughter. As expected, plasma urea was greater (P < 0.001) in animals fed the HP diet but was within a normal range for healthy horses. In conclusion, a small dietary protein restriction (i.e., on average 3% of DM) did not change the in vivo performance of IHDH weanlings up to 13 or up to 18 mo of age.
Asunto(s)
Alimentación Animal/análisis , Dieta/veterinaria , Proteínas en la Dieta/farmacología , Caballos/fisiología , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Bilirrubina , Nitrógeno de la Urea Sanguínea , Composición Corporal , Proteínas en la Dieta/administración & dosificación , Femenino , Glucosa , Caballos/crecimiento & desarrollo , Masculino , UreaRESUMEN
This study compared measured gas production (GP) and computed CH4 production values provided by closed or vented bottles connected to gas collection bags. Two forages and 3 concentrates were incubated. Two incubations were conducted, where the 5 feeds were tested in 3 replicates in closed or vented bottles, plus 4 blanks, for a total of 64 bottles. Half of the bottles were not vented, and the others were vented at a fixed pressure (6.8 kPa) and gas was collected into one gas collection bag connected to each bottle. Each bottle (317 mL) was filled with 0.4000 ± 0.0010 g of feed sample and 60 mL of buffered rumen fluid (headspace volume = 257 mL) and incubated at 39.0°C for 24 h. At 24 h, gas samples were collected from the headspace of closed bottles or from headspace and bags of vented bottles and analyzed for CH4 concentration. Volumes of GP at 24 h were corrected for the gas dissolved in the fermentation fluid, according to Henry's law of gas solubility. Methane concentration (mL/100mL of GP) was measured and CH4 production (mL/g of incubated DM) was computed using corrected or uncorrected GP values. Data were analyzed for the effect of venting technique (T), feed (F), interaction between venting technique and feed (T × F), and incubation run as a random factor. Closed bottles provided lower uncorrected GP (-18%) compared with vented bottles, especially for concentrates. Correction for dissolved gas reduced but did not remove differences between techniques, and closed bottles (+25 mL of gas/g of incubated DM) had a greater magnitude of variation than did vented bottles (+1 mL of gas/g of incubated DM). Feeds differed in uncorrected and corrected GP, but the ranking was the same for the 2 techniques. The T × F interaction influenced uncorrected GP values, but this effect disappeared after correction. Closed bottles provided uncorrected CH4 concentrations 23% greater than that of vented bottles. Correction reduced but did not remove this difference. Methane concentration was influenced by feed but not by the T × F interaction. Corrected CH4 production was influenced by feed, but not by venting technique or the T × F interaction. Closed bottles provide good measurements of CH4 production but not of GP. Venting of bottles at low pressure permits a reliable evaluation of total GP and CH4 production.
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Bovinos/fisiología , Gases/metabolismo , Técnicas In Vitro/métodos , Metano/biosíntesis , Rumen/metabolismo , Animales , Femenino , FermentaciónRESUMEN
The aim of the study was to investigate whether the addition of extruded flaxseed (EF) in dairy cow diets had an effect on milk fat and individual fatty acids (FA) recovery in cheese after 90 d of ripening. Eighteen Holstein-Friesian cows, divided into 3 experimental groups (6 cows/group), were fed 3 isonitrogenous and isoenergetic diets with 0 (CTR), 500 (EF500), or 1,000 g/d (EF1000) of EF in 3 subsequent periods (2 wk/each), following a 3 × 3 Latin square design. Dry matter intake (DMI) and milk yield were recorded daily. Individual milk samples were collected on d 7 and 13 of each period to determine proximate and FA composition. Eighteen cheese-making sessions (2 for each group and period) were carried out, using a representative pooled milk sample obtained from the 6 cows of each group (10L). At 90 d of ripening, cheeses were analyzed for proximate and FA composition. Cheese yield was computed as the ratio between the weights of ripened cheese and processed milk. Recoveries of fat, individual FA, and grouped FA were computed as the ratio between the corresponding weights in cheese and in milk. Inclusion of EF did not affect DMI, milk yield, or milk composition. Compared with CTR, the 2 diets containing EF increased the proportion of C18:3n-3 and total n-3 FA, in both milk and cheese. Cheese yield and cheese fat percentage did not differ among diets. Likewise, milk fat recovery in cheese was comparable in the 3 treatments and averaged 0.85. The recoveries of individual FA were, for the most part, not dissimilar from fat recovery, except for short-chain saturated FA (from 0.38 for C4:0 to 0.80 for C13:0), some long-chain saturated FA (0.56 and 0.62 for C20:0 and C21:0, respectively), and for C18:3n-6 (1.65). The recovery of saturated FA was lower than that of monounsaturated FA, whereas recovery of polyunsaturated FA was intermediate. Compared with medium- and long-chain FA, short-chain FA were recovered to a smaller extent in cheese. No differences in recovery were found between n-6 and n-3 FA. In conclusion, FA have different recoveries during cheese-making, with lower values for the short-chain compared with long-chain FA, and for saturated FA compared with unsaturated FA. The addition of EF in dairy cow diets did not influence cheese yield or fat recovery in cheese, irrespective of the inclusion level. The experiment confirmed that feeding cows with EF represents a successful strategy for improving the FA profile of dairy products, through an increase of n-3 FA.
Asunto(s)
Alimentación Animal/análisis , Queso/análisis , Ácidos Grasos Omega-3/química , Lino/química , Ácidos Linoleicos Conjugados/química , Leche/química , Animales , Bovinos , Simulación por Computador , Dieta/veterinaria , FemeninoRESUMEN
A trial was carried out on double-muscled Piemontese bulls to evaluate the effects of two rations differing in crude protein density (HP=14.5% DM and LP=10.8% DM) and top dressed or not with 80 g/d of rumen protected CLA (rpCLA) for a long period (336 d) on meat quality traits and CLA content. Forty-eight bulls were fed one of the four experimental diets based on corn silage and cereals and were slaughtered at an average age and body weight (BW) of 562 ± 18 d and 668 ± 56 kg, respectively. After slaughter the 5th rib cut was dissected into Longissimus thoracis (LT), other muscles (OM), inter-muscular fat (IF), cover fat (CF), and bones. Muscles and fatty tissues were analyzed for proximate composition and fatty acid (FA) profiles. Rib was composed by 81.1, 3.7, 1.6 and 13.6% of muscles, IF, FC and bone, respectively; LT and OM contained only 0.8 and 1.4% of lipid, respectively. The treatments did not influence these values, but rpCLA increased, compared to control, both c9,t11-CLA and t10,c12-CLA concentrations in all the tissues (P<0.01); t10,c12-CLA concentration was increased much more in muscles (+20 times) than in fatty tissues (from +0.2 to +0.9 times). This suggests that in the muscle this isomer is preferentially stored and/or less combusted with respect to other fatty acids. Low protein rations did not exert any influence on carcass and meat quality, as on growth performance, but reduced nitrogen excretion, their use for improving the environmental impact (process quality) of this meat production system is recommended.
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Tejido Adiposo/química , Bovinos/crecimiento & desarrollo , Dieta/veterinaria , Ácidos Linoleicos Conjugados/farmacología , Carne , Músculo Esquelético/química , Tejido Adiposo/metabolismo , Alimentación Animal , Animales , Composición Corporal/efectos de los fármacos , Peso Corporal , Cruzamiento , Grasas de la Dieta/farmacología , Proteínas en la Dieta/farmacología , Ácido Graso Desaturasas/metabolismo , Ácidos Grasos/análisis , Isomerismo , Masculino , Músculo Esquelético/anatomía & histología , Músculo Esquelético/efectos de los fármacos , Rumen/metabolismoRESUMEN
This study was conducted to estimate the nutritional value of diets given to stallions of different breeds during the reproductive season, and comparing allowances with requirements. The systems compared were the French INRA, the 1989 NRC, and the 2007 NRC. Data on reproductive activity, daily exercise, BW, BCS, feed intake, and feed composition during 4 mo (from March to June) were recorded on 12 stallions used for commercial AI programs. Stallions belonged to 3 different breeds: Italian Haflinger (IH, n=4), Holstein (HOL, n=4), and Italian Heavy Draft horse (IHDH, n=4). Data recorded were used to estimate the actual energy and protein intakes and theoretical requirements of the stallions using the aforementioned systems. A deviation index [DI = (intake - requirement)/intake × -1] was calculated to allow a comparison among methods as a proportion of under- or overestimates of theoretical requirements. All data were statistically analyzed with a mixed model for repeated measurements. The reproductive activity of the stallions was affected by month (less in March and greater in subsequent months; P<0.05). Daily exercise was generally low during the middle breeding season, and the intensity and kinds of exercise differed according to the breeds. Changes of BW and BCS of the stallions were not statistically significant (P=0.69 and P=0.17, respectively) during the experimental period, and therefore diets could be considered balanced to support all animal needs. However, the energy and protein allowances were not always consistent with the theoretical requirements considering all 3 nutritional systems. Energy and protein INRA recommendations showed, on average, +0.90 and +0.27 greater DI than actual intakes, respectively, for IH and HOL stallions, whereas the theoretical requirements were much closer to allowances for the IHDH stallions (DI close to 0). The 1989 NRC energy and protein recommendations, respectively, were +0.67 and +0.87 greater than intake for IH, +0.28 and +0.43 greater for HOL, and only +0.06 and +0.17 greater for IHDH stallions. The 2007 NRC energy and protein recommendations, respectively, were +0.70 and +0.52 greater for IH, +0.33 and +0.17 greater for HOL, and +0.52 and +0.49 greater for IHDH than actual intakes. Therefore, all systems overestimated the requirements of the stallion, particularly in lighter breeds. Further studies to validate requirements for breeding stallions of different sizes are recommended.
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Alimentación Animal/análisis , Cruzamiento , Dieta/veterinaria , Proteínas en la Dieta/metabolismo , Metabolismo Energético/fisiología , Caballos/fisiología , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Peso Corporal/fisiología , Caballos/genética , Masculino , Condicionamiento Físico Animal , ReproducciónRESUMEN
The effects of low-protein (LP) diets and rumen-protected CLA on DMI, ADG, carcass traits, and health status of double-muscled Piemontese young bulls were investigated. Forty-eight bull calves (BW = 237 ± 24 kg) were divided in 4 groups and housed in 12 fully slatted pens. Bulls were fed 2 diets differing in CP density [high-protein (HP) diet: CP = 145 g/kg of DM; LP diet: CP = 108 g/kg of DM] and top-dressed with 80 g/d of rumen-protected CLA or 65 g/d of hydrogenated soybean oil. Orts were collected weekly and feed intake was estimated on a pen basis, with 3 replicated pens for each treatment. Each bull was weighed monthly and examined for alterations of the locomotion system by using the locomotion score as an index of lameness and by counting the number of swollen joints. Carcass quality traits were measured at slaughter, after a feeding period of 332 d. Compared with HP, LP reduced ADG only during the first 4 mo of the trial (1.30 vs. 1.53 kg/d, P = 0.003). However, because of compensatory growth, over the whole trial, no significant effects attributable to CP or to additive were found on final BW (668 kg), ADG (1.19 kg/d), DMI (8.50 or 86 g/d per kg of BW(0.75)), dressing percentage (67.3%), carcass conformation (5.2 points), and carcass fat covering (1.87 points). Feed efficiency was affected by a CP × additive interaction (P = 0.030), with CLA improving feed efficiency when added to the LP diets, whereas feed efficiency was reduced with the HP diets. The addition of both LP and CLA reduced the number of bulls presenting swollen joints (P = 0.001), and LP improved the locomotion score (P = 0.021) compared with HP. It was concluded that 10.8 g/kg of CP density in the diet is sufficient for double-muscled Piemontese bulls. The reduction in CP density from 145 to 108 g/kg of DM, in addition to reducing the feeding cost, allows a strong reduction in N consumption without negative consequences on growth performance and carcass traits.
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Bovinos/crecimiento & desarrollo , Dieta/veterinaria , Ácidos Linoleicos Conjugados/farmacología , Carne/normas , Deficiencia de Proteína/fisiopatología , Alimentación Animal , Animales , Encuestas sobre Dietas , Proteínas en la Dieta/farmacología , Masculino , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/crecimiento & desarrolloRESUMEN
Ageing, like all physiological effects, has a multifactorial origin and is linked to the progressive reduction in the function of some organs and systems. Feeding can play an important role in the control of the ageing process by the improvement of quality of life and the prevention of some pathologies associated with age (renal diseases, obesity, rheumatism, dental pathologies, cardiovascular disorders). Clinical nutrition of old dogs allows us to clarify the animals' nutritional requirements, the required balance of nutrients, the quality of ingredients and dietetic function of some substances. Twenty commercial dry foods formulated for old dogs were analysed. A wide variability of chemical composition was observed among the samples. Very different values were found for size and hardness of kibbles (parameters correlated with the incidence of some dental diseases). Good availability of foods with different nutritional characteristics could be useful to the needs of geriatric dogs. Similarly, a balanced home-made ration could satisfy the specific requirements of old dogs and gratify their owners. In conclusion, a diet for ageing dogs should be "personalized", considering both the nutritional and extra-nutritional factors, which contribute to guarantee optimal well-being and health.
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Alimentación Animal/normas , Fenómenos Fisiológicos Nutricionales de los Animales , Perros/fisiología , Necesidades Nutricionales , Envejecimiento/fisiología , AnimalesRESUMEN
The traceability of Asiago mountain cheese was established by analyzing samples of herbaceous species, milk, and cheese of mountain origin using the head-space solid-phase microextraction sampling procedure coupled with gas chromatography-mass spectrometry. As preliminary work had highlighted the characteristic presence of sesquiterpenes in Asiago mountain cheese, these species were considered effective markers of mountain origin. Systematic qualitative analysis, carried out using a carboxen/polydimethylsiloxane fiber, revealed several sesquiterpenes in mountain herbage and milk, in particular beta-caryophyllene and alpha-humulene, in Asiago mountain cheese, confirming sesquiterpenes as markers of cheese produced from animals grazing on mountain pastures. Analysis was performed on 19 samples of herbage, 8 of milk, and 8 of cheese, collected in summer from 4 mountain farms on the Asiago plateau. For quantitative analysis of caryophyllene in cheese, polydimethylsiloxane fiber sampling, coupled with the standard addition method to eliminate matrix effect, was preferred. The amount of beta-caryophyllene found ranged from 21 to 65 microg/kg.
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Queso/análisis , Queso/clasificación , Altitud , Animales , Cromatografía de Gases y Espectrometría de Masas/economía , Cromatografía de Gases y Espectrometría de Masas/métodos , Geografía , Leche/química , Sesquiterpenos Monocíclicos , Sesquiterpenos Policíclicos , Sesquiterpenos/análisisRESUMEN
Dry matter degradability (DMD), gas production (GP), functional specific gravity (FSG), volume of gas associated (GA), water-holding capacity (WHC), and sedimentation measurements of orchard-grass (OG) and alfalfa (AA) hays (ground through a 8-mm screen) were studied before and after in vitro incubation with ruminal fluid for 2, 4, 8, 24, 48, and 72 h. The DMD was higher for AA than for OG (P < .001), but GP did not differ. The FSG of unfermented OG and AA was .59 and .73, respectively (P < .01). During fermentation, the FSG of OG increased more than did that of AA (from .93 to 1.39 for OG and from .97 to 1.27 for AA after 2 and 72 h, respectively), and GA decreased more rapidly (from .94 to -.04 mL/g DM and from .74 to .15 mL/g DM, respectively). The DMD was positively correlated with FSG (r = .83; P < .001) and, therefore, negatively with GA (r = -.72; P < .01). The WHC increased similarly in the two forages with fermentation time. Unfermented and fermented samples were incubated in sedimentation columns filled with distilled water for 19, 37, 75, 150, and 300 s. After 300 s of sedimentation time, the unfermented AA and OG samples tended to float (91.1 and 72.7% of DM, respectively). In contrast, fermented samples tended to sediment (90.7 and 90.9% of DM, respectively). There were only small effects of forage species and fermentation time on sedimentation tendency. Correlations between sedimentation measurements and DMD and FSG were not significant, with the only exception of DM recovered in the lower section of sedimentation columns after 75 s, which was particularly correlated with DMD (P < .01) and FSG (P < .05). The results suggest that degradation rate of fibrous particles is related to changes in FSG and GA and, therefore, could influence ruminal transit. However, FSG was unable to predict accurately the sedimentation behavior of samples.
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Alimentación Animal , Bovinos/fisiología , Digestión , Medicago sativa/química , Poaceae/química , Rumen/fisiología , Animales , Femenino , Fermentación , Tránsito Gastrointestinal/fisiología , Técnicas In Vitro , Medicago sativa/metabolismo , Tamaño de la Partícula , Poaceae/metabolismo , Gravedad Específica , Agua/metabolismoRESUMEN
Four primiparous Holstein cows were gradually introduced, according to a Latin square design, to four diets obtained from the factorial combination of two forage to concentrate ratios (70:30 and 50:50) and two concentrations of monensin sodium (0 and 300 mg/d per cow). Addition of monensin tended to depress feed intake and milk fat content without affecting milk production and without interactions with forage to concentrate ratios. Ruminal propionate percentage was increased more by the addition of monensin to the low forage diet than by the addition of monensin to the high forage diet. Serum urea and concentrations of nonesterified fatty acids tended to decrease when monensin was added to the high forage diet but did not change when monensin was added to the low forage diet. The results suggested that monensin had moderate positive effects on efficiency of milk production and might have an antiketogenic effect with high forage diets.
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Bovinos/crecimiento & desarrollo , Bovinos/metabolismo , Coccidiostáticos/farmacología , Dieta/veterinaria , Lactancia/efectos de los fármacos , Leche/metabolismo , Monensina/farmacología , Ácido Acético/análisis , Análisis de Varianza , Alimentación Animal/normas , Animales , Peso Corporal/efectos de los fármacos , Peso Corporal/fisiología , Bovinos/fisiología , Dieta/normas , Metabolismo Energético/fisiología , Ácidos Grasos no Esterificados/sangre , Ácidos Grasos Volátiles/metabolismo , Femenino , Productos Pesqueros/normas , Medicago sativa/normas , Leche/química , Propionatos/análisis , Rumen/química , Rumen/metabolismo , Glycine max/normas , Urea/sangre , Zea mays/normasRESUMEN
Thirty-six Alpine goats (10 primiparous and 26 multiparous) were used to study the milk yield response induced by recombinant bST administered in a sustained-delivery vehicle. Eighteen goats were injected with recombinant bST at 4-wk intervals from about 7 wk postpartum for 12 wk. Patterns of milk yield were highly affected by injection of recombinant bST. Milk yield of treated goats increased from day of injection, peaked between d 3 to 5 after treatment, and then decreased progressively. This pattern of response was well fitted by a curve containing two exponential terms: Yi = A x [exp(-k1di - exp(-k2di)], where Yi = daily relative response of treated goats to recombinant bST, computed as a deviation of least squares means of milk yield at day i (i = 0,..., 26) of the treatment interval from least squares means of milk yield at d 27 of the treatment interval; A = constant; k1 and k2 = response rate parameters; and di = day from treatment (i = 0,..., 27). Administration of recombinant bST also improved persistency of lactation, and the overall milk yield response to exogenous hormone was 300 g/d (13.9%) higher than the yield of untreated goats. This response was due to both the short-term response immediately after injection (53%) and the medium-term effect on lactation persistency.
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Cabras/fisiología , Hormona del Crecimiento/farmacología , Lactancia/efectos de los fármacos , Animales , Bovinos , Preparaciones de Acción Retardada , Femenino , Hormona del Crecimiento/administración & dosificación , Inyecciones Subcutáneas , Cinética , Proteínas Recombinantes/farmacologíaRESUMEN
Cows from 25 dairy herds were scored for body condition at 3-mo intervals for over 2 yr to study the pattern of changes during lactation and the effects of parity and milk yield capability of cows on changes in body reserves. Data were recorded for 1395 Holstein cows grouped into three parity classes and five classes of mature equivalent milk yield. The analysis model accounted for nearly 70% of the variation in body condition score. Body reserves decreased during early lactation until about 100 DIM and were restored during mid and late lactation. The pattern of change in body condition score varied among lactations and dairy merit of cows. Depletion and subsequent recovery of body reserves were less intense for primiparous cows than for multiparous cows. Loss of body condition scores was higher and more prolonged for cows of higher dairy merit. The minimum body condition score occurred at 3 mo after calving for the worst yielding cows and at 4 mo after calving for the best yielding cows; the highest yielding cows had twice the loss in body condition as the lowest yielding cows. General equations are presented as a proposed guideline to examine changes in body condition score of Holstein cows of different parities and dairy merit.
Asunto(s)
Composición Corporal , Bovinos/fisiología , Lactancia , Paridad , Tejido Adiposo , Animales , Femenino , Análisis de RegresiónRESUMEN
The rate and extent of degradation of forage feed fractions contained in alfalfa and Italian ryegrass hays were determined. Nylon bags filled with 4 g of each forage were suspended in the rumen of two cannulated cows immediately before feeding and incubated for 10 different times (0, 2, 4, 8, 12, 24, 48, 72, 120, and 168 h). The alfalfa hay, which had lower NDF, showed a lower extent, but a higher rate, of NDF degradation than the Italian ryegrass (41.1 vs. 59.8% and 4.64 vs. 2.91%/h, respectively). Alfalfa cell walls were degraded more rapidly than Italian ryegrass even though their lignin content was higher. The hemicellulose fermentation of alfalfa showed a longer lag time (13 h) and an undegradable fraction nearly twice that for Italian ryegrass (63.3 vs. 37.1%). Cellulose from alfalfa was degraded at a higher rate than NDF or ADF, indicating that cellulose may be the primary site of hydrolysis of the cell wall in the rumen. Calculations based on in situ degradability indicate that alfalfa can have a higher inclusion than Italian ryegrass in diets for dairy cows because of lower NDF and greater availability of cell contents.