RESUMEN

BACKGROUND: Oversupply of dietary copper (Cu) is common among UK dairy herds, but studies on the long-term outcomes of this oversupply are scarce. METHODS: A longitudinal study was undertaken to determine the long-term implications when 80 Holstein‒Friesian heifers with a mean (±standard error) age of 4.1 ± 0.1 months and a mean liveweight of 137 ± 2.4 kg were fed a recommended (R; 16 mg/kg dry matter [DM]) or high (H; 32 mg/kg DM) dietary Cu concentration until 6 weeks prior to calving. RESULTS: Hepatic Cu concentrations in both treatment groups were elevated into the ranges used to diagnose chronic Cu toxicity in cattle at 6.9 months of age (798 ± 46.4 mg/kg DM for H vs. 643 ± 35.4 mg/kg DM for R), with associated evidence of liver damage. Hepatic Cu concentrations then returned to normality but remained higher (p < 0.001) for heifers fed H than for those fed R and were associated with a reduced (p = 0.044) conception rate to first and second services (73.7 ± 8.05% for H vs. 91.2 ± 7.68% for R). LIMITATION: This retrospective analysis identified pre-study liver damage, which may have affected results. CONCLUSIONS: Supplying Cu in excess of requirements resulted in liver damage and reduced conception rates.

Asunto(s)

Alimentación Animal , Cobre , Fertilidad , Hígado , Animales , Bovinos , Cobre/análisis , Femenino , Hígado/efectos de los fármacos , Fertilidad/efectos de los fármacos , Estudios Longitudinales , Alimentación Animal/análisis , Embarazo , Dieta/veterinaria , Industria Lechera

RESUMEN

The apparent absorption of copper (Cu) in ruminants is low, with between 0.01 and 0.07 g/g absorbed from sources such as copper oxide (CuO) under typical feeding conditions, resulting in high levels of excretion. Improving the bioavailability of Cu could reduce the supplemental amount required to maintain Cu status and reduce excretion, particularly in the presence of dietary antagonists such as sulfur (S) and molybdenum (Mo). The objective of our study was to determine the Cu status of cows when fed nanoparticle CuO coated with Lys compared with conventional CuO when fed without or in combination with antagonists to Cu absorption (S and Mo) in the diet of dairy cows. Fifty-six multiparous Holstein-Friesian cows that were 48 d ± 17.4 (mean ± SD) post calving and yielding 40.6 ± 6.9 kg milk/d were used in a 2 × 2 factorial design. The 4 treatment groups were; CuO (O-), CuO with added antagonists (O+), nano CuO with a lysine coating (N-), and nano CuO with a Lys coating with added antagonists (N+), fed for 16 wks. We formulated the diets to contain approximately 17 mg Cu/kg dry matter (DM) and diets with antagonists contained an additional 1 g S/kg DM and 6 mg Mo/kg DM, with Lys added to O- and O+ to provide the same daily supply as N- and N+. Blood samples were collected at wk 0, 2, 4, 6, 10 and 16, and liver biopsy samples at wk 0 and 16. We found no effect of dietary treatment on DM intake, milk yield, live weight or body condition score, with mean values of 23.3 kg/d, 40.1 kg/d, 646 kg and 2.68, but milk SCC was higher in cows fed conventional compared with non CuO, or with added antagonist. We also found no effect of treatment on blood activity of gamma glutamyl transferase, superoxide dismutase or ceruloplasmin, hematology profile, or plasma Cu and iron concentration. We found that plasma Mo concentration was increased from 0.36 µmol/L in cows fed O- or N- to 0.80 µmol/L in those receiving O+ or N+. Additional dietary antagonists also decreased the concentration of Cu in the liver of cows fed conventional CuO (C+) over the study period by 1.3 mg/kg DM/d, but in cows fed dietary antagonists and nano CuO coated with Lys (N+), liver Cu concentration was increased by 1.1 mg/kg DM/d. Our study is the first to demonstrate that reducing the particle size of CuO into the nano scale with a lysine coating improves the bioavailability of CuO in the presence of dietary antagonists in dairy cattle, and we did not observe any negative effects on performance or health.

RESUMEN

During the transition period three weeks before and after calving the dairy cow is at greater risk of developing disease, to the detriment of welfare and production. An understanding of the reasons why and how farmers and their advisors engage in efforts to control metabolic disease during the transition period is required if these diseases are to be more successfully controlled. The study reported here, based on interview research, investigates the opinions and behaviours of farm advisors on transition cow management and nutrition, their experiences of working with their respective farm clients, and interactions with other farm advisors to help manage transition cow health and productivity. Semi-structured interviews were conducted with 12 veterinary advisors and 12 non-veterinary advisors (nutritionists, feed company representatives and independent consultants) in England. A key theme emerging from this qualitative data was a perceived lack of focussed transition management advice provided by advisors. Reasons for suboptimal or lack of appropriate advice included: time pressures for advisors to visit as many farms as possible; avoiding the investigation of areas of potential improvement, for fear of not meeting transition health and performance targets; financial disincentives for nutritionists, as the sales commission attributed to transition cow feeding was small relative to the main milking herd; and a lack of confidence in the subject. Other aspects included the responsibility of providing transition advice which was perceived to be high-risk, a lack of cooperation between veterinarians and nutritionists, and the perceived varying competencies of nutritionists. The findings demonstrate the importance of the varied influences of 'people factors' on transition cow health such as the nature of the advisor-farmer relationship, advisor-farmer communication and herd-level advisor collaboration on transition cow health and management.

Asunto(s)

Industria Lechera , Veterinarios , Bienestar del Animal , Animales , Bovinos , Agricultores , Granjas , Femenino , Humanos

RESUMEN

During the transition from the dry period to lactation the dairy cow undergoes a period of physiological, metabolic and immunological change, and is at greater risk of developing disease, to the detriment of health, welfare and production. Many studies have been undertaken to determine appropriate management strategies to improve health and welfare during the transition period, however the incidence of disease, particularly metabolic disease, in this period remains high. To date, a lack of research attention has been paid to the social factors which may affect the management of transition dairy cows. An understanding of farmer and advisor attitudes and behaviour, and the challenges they face in managing transition cows, may help to direct farmers towards more effective disease prevention and control. It is also possible that transition cow morbidity may be due to complex interactions that are difficult to manage, despite efforts to implement best practice. This review paper provides a brief overview of some of the management factors that may influence herd health during the transition period. It then investigates how social influences may relate to the uptake of transition management practices by exploring the use of qualitative interviews investigating farmer and stakeholder attitudes and behaviour in relation to cattle health and welfare, before focussing more specifically on farmer behaviour. Additionally, this paper explores farm advisor behaviour, and how that has been shown to influence farmer adherence to advice, which has particular relevance to transition cow management. It then suggests potential research strategies to investigate the human influences affecting the scale of the problem that may provide solutions to tackle the challenge of improving dairy cow health and welfare.

Asunto(s)

Enfermedades de los Bovinos/prevención & control , Industria Lechera , Periodo Posparto , Animales , Bovinos , Industria Lechera/métodos , Agricultores , Femenino , Humanos , Lactancia/fisiología

RESUMEN

The aims of the study were to determine the long-term effects of dietary supplementation with microalgae (SCIM) on milk and blood fatty acid (FA) composition and reproductive hormones in early lactation dairy cows. Sixty Holstein-Friesian dairy cows (30 per treatment) were unsupplemented (Control) or supplemented with 100 g of SCIM (Schizochytrium limacinum sp.) per cow per day from 25 ± 0.5 d post-partum for 98 d. Intake and milk yield were recorded daily, with milk samples collected at weeks 0, 1, 2, 4, 8 and 14, and blood samples collected from 12 representative pairs per treatment at weeks 0, 2, 4, 8, and 14 for subsequent analysis of FA, ß-hydroxybutyrate, non-esterified fatty acids and glucose. At 33 ± 0.9 d postpartum the oestrus cycle of 24 cows (12 per treatment) were synchronized and plasma 13,14-dihydro-15-keto PGF2α (PGFM) concentrations determined following an oxytocin challenge. Data were analysed by repeated measures analysis of variance. There was no effect of treatment on dry matter intake, milk yield or milk fat content, with mean values across treatments of 22.1 and 40.6, and 37.2 g/kg respectively. Milk fat concentration of C22:6 n-3 increased rapidly in cows receiving SCIM, reaching a maximum of 0.38 g/100 g FA by week 14. Similarly, blood concentration of C22:6 n-3 increased to 1.6 g/100 g FA by week 14 in cows fed SCIM. There was no effect of treatment on plasma metabolites, but plasma glucose was lower in cows fed SCIM compared to the Control at week 2, and higher in week 8. There was no effect of treatment on peak plasma PGFM concentration or area under the curve. It is concluded that feeding SCIM rapidly increases blood and milk concentrations of C22:6 n-3 which are maintained over time, but does not improve plasma PGFM in dairy cows.

Asunto(s)

Suplementos Dietéticos , Dinoprost/análogos & derivados , Ácidos Docosahexaenoicos/análisis , Microalgas , Leche/química , Animales , Bovinos/sangre , Bovinos/metabolismo , Dinoprost/sangre , Ácidos Docosahexaenoicos/sangre , Ácidos Grasos/análisis , Ácidos Grasos/sangre , Femenino , Lactancia , Microalgas/química

RESUMEN

Several factors influence whether dairy cattle prefer to be indoors or at pasture, including weather conditions and milk yield, but it is unclear how motivated cows are for access to pasture. One way to measure motivation is to require the animal to work (e.g., walk different distances) for access to a resource. This study investigated whether pasture access located 60, 140, or 260m from the indoor housing would affect the proportion of time dairy cows spent at pasture. Thirty-two Holstein-Friesian dairy cows were used during the study, which took place in the United Kingdom from May to July 2010. The experiment consisted of four 18-d experimental periods, with 8 cows in each period, which were further divided into 2 groups of 4 cows. Following a training period, the cows were randomly allocated to distances of 60, 140, or 260m to pasture over three 4-d measurement periods. A video camera was used to record time spent indoors and outdoors 24h/d, and manual behavior observations (0700 to 2200h) took place 6 times during each period to record how the cows spent their time in each location. The video data showed that cows spent, on average, 57.8% (±3.44) of their time outside (either at pasture or on the track). One-sample t-tests revealed that this value was different from 0% (t=16.80), 50% (t=2.26), and 100% (t=-12.28). Analysis of the percentage time spent outside revealed that distance did not influence nighttime pasture use (2100 to 0430h; F2,8=0.16; 81.0% vs. 81.0% vs. 76.7%, for 60m vs. 140m vs. 260m, respectively). In contrast, during the day (0700 to 2100h; from behavior observations), time spent at pasture declined as distance increased; that is, cows spent more time at pasture when they had to walk 60m (F2,80=10.09) than when they had to walk 140 or 260m (45.3% vs. 27.4% vs. 21.2%, respectively). Time spent at pasture decreased on rainy days (y=-1.0672x + 59.646, R(2)=0.09, n=48d), but the indoor temperature-humidity index (THI), the outdoor THI, and body condition score did not influence time spent outside. Under the climatic conditions of the current study in the United Kingdom, cows had a partial preference for pasture, which was influenced by distance to pasture during daytime but not at night. This shows that dairy cows were more motivated to access pasture at night compared with during the day.

Asunto(s)

Conducta Animal/fisiología , Bovinos/fisiología , Conducta Alimentaria/fisiología , Motivación/fisiología , Animales , Industria Lechera , Femenino , Herbivoria , Vivienda para Animales , Lactancia/fisiología , Embarazo , Lluvia , Temperatura , Factores de Tiempo , Reino Unido , Tiempo (Meteorología)

RESUMEN

Conjugated linoleic acids (CLA) have been demonstrated to be a potent inhibitor of milk fat synthesis in ruminants, but effects on carcass composition and organ weight are unknown. Our objectives in this experiment were to determine the dose response of ruminally protected CLA on the performance, organ weight, and fatty acid (FA) composition of early lactation dairy ewes. Twenty-four multiparous dairy ewes were fed a basal diet for 10 wk that was supplemented with a lipid-encapsulated CLA at 1 of 3 levels: no CLA (control, CON), low CLA (L-CLA), or high CLA (H-CLA) to supply 0, 1.5, or 3.8 g/d, respectively, of both trans-10, cis-12 and cis-9, trans-11 CLA. Dry matter intake was not affected (P > 0.05) by dietary treatment. Ewes fed H-CLA had a 13% higher milk yield compared with those receiving either CON or L-CLA. Compared with CON, milk fat yield (g/d) was 14 and 24% lower in ewes fed L-CLA or H-CLA, respectively. Supplementing ewes with CLA did not affect carcass or organ weights, carcass composition, or organ FA content. Compared with ewes receiving the CON diet, CLA supplementation had little effect on the FA composition of the Longissimus dorsi, although cis-9, trans-11 and trans-10, cis-12 CLA were increased in ewes receiving H-CLA. The current findings are consistent with the view that the energy spared by the CLA reduction in milk fat content was mainly partitioned to milk yield and there was no evidence of organ hypertrophy or liver steatosis.

Asunto(s)

Distribución de la Grasa Corporal/veterinaria , Dieta/veterinaria , Grasas de la Dieta/análisis , Lactancia , Ácidos Linoleicos Conjugados/administración & dosificación , Leche/química , Oveja Doméstica/crecimiento & desarrollo , Tejido Adiposo/química , Tejido Adiposo/crecimiento & desarrollo , Animales , Peso Corporal , Industria Lechera/métodos , Grasas de la Dieta/administración & dosificación , Ácidos Grasos/análisis , Femenino , Corazón/crecimiento & desarrollo , Isomerismo , Ácidos Linoleicos Conjugados/química , Ácidos Linoleicos Conjugados/metabolismo , Pulmón/química , Pulmón/crecimiento & desarrollo , Glándulas Mamarias Animales/crecimiento & desarrollo , Leche/metabolismo , Músculo Esquelético/química , Músculo Esquelético/crecimiento & desarrollo , Miocardio/química , Tamaño de los Órganos , Factores de Tiempo

RESUMEN

The objectives of the study were to determine whether supplementation of pregnant ewes with long-chain (n-3) fatty acids present in fish oil, in combination with dietary vitamin E, would alter neonatal behavior in sheep. Twin- (n=36) and triplet- (n=12) bearing ewes were allocated at d 103 of gestation to 1 of 4 dietary treatments containing 1 of 2 fat sources [Megalac, a calcium soap of palm fatty acid distillate or a fish oil mixture, high in 20:5(n-3) and 22:6(n-3)] and 1 of 2 dietary vitamin E concentrations (50 or 500 mg/kg) in a 2 x 2 factorial design. Feeding fish oil increased gestation length by 2 d and increased the proportion of 22:6(n-3) within neonatal plasma by 5.1-fold and brain by 10%, whereas brain 20:5(n-3) was increased 5-fold. Supranutritional dietary vitamin E concentrations decreased the latency of lambs to stand in ewes fed fish oil but not Megalac, whereas latency to suckle was decreased from 43 to 34 min by fish oil supplementation. Supplementation with fish oil also substantially decreased the secretion rate (mL/h) of colostrum and the yield (g/h) of fat and protein. We conclude that supplementation of ewes with fish oil decreases the latency to suckle, increases gestation length and the 22:6(n-3):20:4(n-6) ratio in the neonatal brain, and may improve lamb survival rate. However, further work is required to determine how to mitigate the negative effects of fish oil on colostrum production.

Asunto(s)

Conducta Animal/efectos de los fármacos , Grasas Insaturadas en la Dieta/administración & dosificación , Grasas Insaturadas en la Dieta/farmacología , Suplementos Dietéticos , Efectos Tardíos de la Exposición Prenatal , Animales , Animales Recién Nacidos , Encéfalo/metabolismo , Calostro/efectos de los fármacos , Calostro/metabolismo , Grasas Insaturadas en la Dieta/metabolismo , Femenino , Periodo Posparto/fisiología , Embarazo , Ovinos , Vitamina E/farmacología

RESUMEN

The present study investigated the effect of maternal vitamin E and fatty acid supplementation on lamb antioxidant status. Forty-eight ewes were fed one of four concentrate diets supplemented with a basal (50 mg/kg) or supranutritional (500 mg/kg) level of vitamin E plus a source of either saturated fat (Megalac; Volac Ltd, Royston, Hertfordshire, UK) or long-chain PUFA (fish oil) from 6 weeks prepartum until 4 weeks postpartum. Blood samples were taken from ewes and lambs at intervals throughout the experiment and, at parturition, muscle, brain and blood samples were obtained from twelve lambs (three per treatment). Colostrum and milk samples were obtained at 12 h and 21 d after parturition, respectively. Supranutritional vitamin E supplementation of the ewe significantly increased concentrations of vitamin E in neonatal lamb tissues although plasma concentrations were undetectable. A significant increase in lamb birth weight resulted from increasing the dietary vitamin E supply to the ewe. Furthermore, maternal plasma, colostrum and milk vitamin E concentrations were increased by vitamin E supplementation, as were lamb plasma concentrations at 14 d of age. Neonatal vitamin E status was not significantly affected by fat source although plasma vitamin E concentrations in both ewes and suckling lambs were reduced by fish oil supplementation of the ewe. Fish oil supplementation reduced vitamin E concentrations in colostrum and milk and the activity of glutathione peroxidase in suckling lambs. The data suggest that the vitamin E status of the neonatal and suckling lamb may be manipulated by vitamin E supplementation of the ewe during pregnancy and lactation.

Asunto(s)

Fenómenos Fisiológicos Nutricionales de los Animales , Animales Lactantes/metabolismo , Suplementos Dietéticos , Intercambio Materno-Fetal , Ovinos/metabolismo , Vitamina E/administración & dosificación , Animales , Peso Corporal , Calostro/química , Grasas de la Dieta/administración & dosificación , Eritrocitos/enzimología , Ácidos Grasos/administración & dosificación , Femenino , Glutatión Peroxidasa/análisis , Glándulas Mamarias Animales/metabolismo , Leche/química , Placenta/metabolismo , Embarazo , Vitamina E/análisis , Vitamina E/sangre

RESUMEN

The effect on lamb muscle of five dietary supplements high in polyunsaturated fatty acids (PUFA) was measured. The supplements were linseed oil, fish oil, protected lipid (high in linoleic acid (C18:2 n-6) and α-linolenic acid (C18:3 n-3)), fish oil/marine algae (1:1), and protected lipid/marine algae (1:1). Eicosapentaenoic acid (C20:5 n-3) and docosahexaenoic acid (C22:6 n-3) were found in the highest amounts in the meat from lambs fed diets containing algae. Meat from lambs fed protected lipid had the highest levels of C18:2 n-6 and C18:3 n-3, due to the effectiveness of the protection system. In grilled meat from these animals, volatile compounds derived from n-3 fatty acids were highest in the meat from the lambs fed the fish oil/algae diet, whereas compounds derived from n-6 fatty acids were highest in the meat from the lambs fed the protected lipid diet.