Dependence on the socio-economic system impairs the sustainability of pasture-based animal agriculture.

Livestock systems contribution to environmental change is controversial. Pasture-based systems are considered a sustainable alternative due to their adaptation to the use of local natural resources. However, they have limited productivity per product unit and, in Europe, depend on public economic support. Furthermore, they are heterogeneous in farm structure and resources use, which may determine their sustainability. We use emergy accounting to assess the sustainability of mountain pasture-based cattle systems and analyse the variability among farms. Emergy accounting assesses the sustainability performance of complex systems (i.e., farming systems) and their interaction with other systems (i.e., the environment and the socio-economic system) focusing on the origin, quality and quantity of the energy required for the system to function. Results show that pasture-based systems largely use local natural renewable resources but depend largely on the wider socio-economic system given their reliance on public economic support and purchased animal feeds. This economic dependence turns out in most farms largely using non-renewable resources. Increasing self-produced feeds and grazing on natural pastures can reduce the dependence on the socio-economic system and improve farm sustainability.

Beef cows' performance and metabolic response to short nutritional challenges in different months of lactation.

Lactating cows can react to changes in nutrient availability with a range of behavioural and physiological mechanisms, which may differ among lactation stages. We investigated the effects of short feed restriction and refeeding periods on beef cows' performance and metabolic status in different months of lactation. For this, Parda de Montaña beef cows [n = 31; 626 ± 47.7 kg body weight (BW)] were subjected to short nutritional restriction and refeeding cycles, which were repeated in months 2, 3 and 4 of lactation. Each month, cows were consecutively fed a diet to meet 100% of their energy and protein requirements during a 4-day basal period, 55% during a 4-day restriction period, and again 100% during a 4-day refeeding period. The performance (energy balance, BW, milk yield and composition) and plasma metabolite concentrations (glucose, non-esterified fatty acids (NEFA), ß-hydroxybutyrate (BHB), urea and malondialdehyde) were measured daily. Most of the traits were significantly affected by the interaction between feeding period and lactation month. Feed restriction induced milk yield loss, decreased milk protein and increased milk urea contents to different extents. The plasma NEFA concentrations rose with restriction in months 2, 3 and 4 but BHB and urea concentrations increased only in month 4. Most of these metabolites lowered to basal values during refeeding. These results suggest that beef cows use different adaptation strategies to cope with nutritional challenges as lactation advances, body fat mobilisation predominates in early lactation and protein catabolism prevails at later stages.

Performance and milk fatty acid profile of beef cows with a different energy status with short nutrient restriction and refeeding.

Our study objective was to determine the effect of a short feed restriction (4 d) and subsequent refeeding (4 d) on the performance and metabolism of beef cows with a different nutritional status by particularly focusing on their milk fatty acid (FA) profile, to consider its potential use as biomarker of metabolic status. Thirty-two Parda de Montaña multiparous lactating beef cows were individually fed a diet based on the average cow's net energy (NE) and metabolizable protein requirements. At 58 d in milk (DIM, day 0), cows underwent a 4 d feed restriction (55% requirements, restriction period). Before and after the restriction, diets met 100% of their requirements (basal and refeeding periods). Cow performance, milk yield and composition, and plasma metabolites, were determined on day -2, 1, 3, 5, 6, and 8. Cows were classified into two status clusters according to their pre-challenge performance and energy balance (EB) (Balanced vs. Imbalanced). All traits were statistically analyzed considering the fixed effect of status cluster and feeding period or day, with cow as a random effect. Imbalanced cows were heavier and had a more negative EB (P < 0.001), but similar milk yield, milk composition, and circulating metabolites (except for greater urea) than Balanced cows (P > 0.10). Milk contents of C18:1 cis-9, monounsaturated FA (MUFA), and mobilization FA were greater (P < 0.05), whereas saturated FA (SFA) and de novo FA were lesser in Imbalanced than Balanced cows (P < 0.05). Restriction decreased body weight (BW), milk yield, and milk protein compared to the basal period, but increased milk urea and plasma nonesterified fatty acids (NEFA) (P < 0.001). Milk contents of SFA, de novo, and mixed FA decreased immediately during the restriction, while MUFA, polyunsaturated FA and mobilization FA increased (P < 0.001). Basal milk FA contents were recovered on day 2 of refeeding, and all their changes strongly correlated with differences in EB and NEFA (P < 0.05). The general lack of interactions between status clusters and feeding periods implied that the response mechanisms to diet changes did not differ between cows with a different pre-challenge nutritional status.

Lactating cows can undergo periods with a negative energy balance due to feed shortages, which trigger metabolic adaptations to support cow maintenance and milk yield. We explored beef cows' response to a short feed restriction (4 d, 55% of their energy and protein requirements) and subsequent refeeding (4 d, 100% of their energy and protein requirements) in the second month of lactation. We analyzed the effect on their performance and metabolism by placing special emphasis on milk production and milk fatty acid composition in two beef cow groups with a different nutritional status before the challenge. When cows faced a food restriction, both groups had similar changes in productive and metabolic traits. These changes are similar to those occurring in restricted dairy cows, but of lesser magnitude due to the lower milk yield and associated metabolic load of beef cows. The milk fatty acid profile, rarely analyzed in beef cows, proved to be an accurate indicator of their metabolic status.

Sainfoin in the Dams' Diet as a Source of Proanthocyanidins: Effect on the Growth, Carcass and Meat Quality of Their Suckling Lambs.

Sainfoin (Onobrychis viciifolia) is a forage legume with a medium content of proanthocyanidins (PAC), which may affect animal performance and product quality. The objective of the present study was to assess the effect of PAC from sainfoin fed to dams, using polyethylene glycol (PEG) as a blocking agent, on the performance and carcass and meat quality of their suckling male lambs. After lambing, twenty lactating dams were fed fresh sainfoin ad libitum plus 200 g per day of barley; ten were orally dosed with water (Sainfoin), and ten were dosed orally with a water dilution of 100 g PEG (Sainfoin + PEG). Their lambs (4.1 ± 0.64 kg at birth) suckled ad libitum until they reached the target slaughter weight of 10-12 kg. The presence of PAC in the dams' diet did not affect the growth, blood metabolites and carcass weight and fatness of the suckling lambs but decreased the lightness of caudal fat (p < 0.05) and increased the weight of the digestive compartments (p < 0.05). Regarding the meat characteristics, PAC only decreased polyphenols content (p < 0.05). In conclusion, the presence of PAC in the dams' diet had not significant effects on the performance and product quality of their suckling lambs.

Long-term effects of early maternal undernutrition on the growth, physiological profiles, carcass and meat quality of male beef offspring.

The effects of maternal undernutrition in early gestation on growth, metabolic and endocrine profiles, carcass and meat quality of male offspring in cattle were assessed. Twenty-one Parda de Montaña and 14 Pirenaica cows received a CONTROL (100% nutrition requirements) or a SUBNUT (65%) diet from day 0 to 82 of gestation and thereafter were fed to requirements until calf weaning at 4 months of age. The performance and physiological profiles of male offspring during an 8-month fattening period were analyzed. Bulls were slaughtered at 12 months of age, and their carcasses and meat color, tenderness and intramuscular fatty acid profile were evaluated. Maternal undernutrition increased plasma NEFAs and impaired the growth of Pirenaica bulls, resulting in lower weights at slaughter and fatter carcasses with impaired meat tenderness. Irrespective of the breed, maternal undernutrition affected meat color and increased the meat content of some healthy fatty acids. In summary, early maternal undernutrition affected the fetal programming of beef male offspring with persistent consequences at slaughter.

The Inclusion of Pea in Concentrates Had Minor Effects on the Meat Quality of Light Lambs.

The use of pea (Pisum sativum) has been recommended to replace soybean meal in the diet of ruminants, but it may affect meat quality. The aim of this study was to evaluate the effect of the proportion of pea (0%, 10%, 20% and 30%) in fattening concentrates fed to light lambs for 41 days on carcass colour and on the meat quality. Pea inclusion affected neither the colour of the lamb carcasses nor affected most of the parameters of the meat quality. However, the inclusion of pea affected the cholesterol content, and the 20%pea concentrate yielded meat with greater cholesterol contents than the 30%pea concentrate did (p < 0.05). The inclusion of pea had minor effects on individual FAs but affected the total saturated fatty acids (p < 0.01) and the thrombogenicity index (p < 0.05). A greater total saturated fatty acid content was recorded for the 20%pea concentrate than for the rest of the concentrates, and a greater thrombogenicity index was recorded for the 20% concentrate than for the 10%pea concentrate. The results indicated the viability of the inclusion of pea in the fattening concentrate of light lambs without impairing meat quality, with the 30%pea concentrate being the most suitable to reduce the soya-dependency.

Field Pea can be Included in Fattening Concentrate without Deleterious Effects on the Digestibility and Performance of Lambs.

The inclusion of different proportions of field pea (0%, 10%, 20% and 30%) for partially replacing soybean in the fattening concentrate of lambs was studied for its impact on apparent digestibility and performance during fattening. In the in vivo digestibility trial, 12 lambs (33 kg body weight) were placed in metabolic crates for two periods and received restricted amounts of concentrate and straw. The performance trial involved 54 lambs (13.4 kg body weight) that received concentrate plus straw ad libitum from weaning to slaughter. The intake of crude protein was higher in the 0% pea group than in the other groups (p < 0.05). The inclusion of field pea did not affect the digestibility, N retained or blood metabolites. In the performance trial, most traits were not affected, although a cubic effect of field pea inclusion on hot carcass weight and dressing percentage was observed (p < 0.05). The inclusion of field pea did not affect total protein, urea or ß-hydroxybutyrate concentrations but it affected creatinine and cholesterol concentrations (p < 0.05). In conclusion, field pea can constitute up to 30% of the fattening concentrate of lambs without deleterious effects on the digestibility and performance during fattening, and with minor effects on carcass characteristics.

Effects of immunocastration performed at two live weights on the growth physiology, temperament and testicular development of feral beef bulls.

The aim of this study was to examine the effect of administering an anti-gonadotropin-releasing hormone vaccine (Improvac® , developed for pigs) on the performance, temperament, testicular development, and hormone and metabolite profiles of feral bulls (Bos taurus) vaccinated at two different live weights (LW). In all, 16 Serrana de Teruel animals were involved in this 2 x 2 factorial design using the factors LW (LIGHT vs. HEAVY) and vaccine treatment (control, C vs. vaccinated, VA). All animals received the same diet (ad libitum concentrate plus straw) over a 164-day fattening period. Temperament was assessed using chute and flight speed tests. Testicular diameter and subcutaneous fat thickness were recorded. Testosterone, IGF-1, urea, NEFA, and creatinine profiles were analyzed. Bull weight gain was reduced in VA compared to C animals, regardless of the initial LW. The vaccine did not affect the temperament tests, subcutaneous fat thickness or NEFA and creatinine concentrations and had minor effects on linear body measures. The vaccine inhibited testicular growth, reduced plasma testosterone to residual levels, and increased urea concentrations. LIGHT-C animals exhibited increased mean plasma IGF-1 concentrations compared to LIGHT-VA animals. In conclusion, vaccination reduced bull growth and sexual development irrespective of LW at immunization.

Effects of Developmental Programming Caused by Maternal Nutrient Intake on Postnatal Performance of Beef Heifers and Their Calves.

In this study, we evaluated the effects of maternal subnutrition in early pregnancy on the growth and reproductive performance of female offspring during their rearing, first gestation, and lactation. We inseminated 21 Parda and 15 Pirenaica multiparous cows and assigned them to a CONTROL (100% of nutrition requirements) or SUBNUT (65%) diet until day 82 of gestation. Cows were fed 100% requirements afterward. During the rearing of female offspring, growth, physiological profiles and ovarian follicular dynamic were studied. At 16 months old, heifers were inseminated. After first calving, dam-calf weights were recorded during lactation. Heifers born from CONTROL cows were heavier at weaning (four months old) than heifers born from SUBNUT cows, but this difference disappeared at the end of rearing and during the first gestation and lactation periods. All heifers reached puberty at a similar age and live weight. During rearing, SUBNUT heifers had higher concentrations of non-esterified fatty acids, urea, and cholesterol and a lower antral follicle count than CONTROL, but no difference was found in their fertility rate. After heifer first calving, dam-calf weights were similar among groups. In conclusion, maternal undernutrition reduced offspring postnatal gains at weaning, compromising metabolic status and follicle population during rearing but did not impair performance in the first gestation and lactation periods of beef heifers.

Long-Term Effects of Maternal Subnutrition in Early Pregnancy on Cow-Calf Performance, Immunological and Physiological Profiles during the Next Lactation.

This study aimed to evaluate the effects of undernutrition during the first third of gestation on cow-calf performance, immunological and physiological profiles during the next lactation in two cattle breeds. Fifty-three Parda de Montaña (PA) and 32 Pirenaica (PI) cows were inseminated, assigned to one of two diets (CONTROL or SUBNUT; 100% or 65% of their requirements) until day 82 of gestation, and fed 100% of the requirements during gestation and next lactation. Cow and calf performance were assessed during lactation. Colostrum and cow-calf plasma samples were analyzed to assess the passive transfer of immunoglobulins and to characterize energy metabolism. At calving, SUBNUT cows had a lower body condition score, which impaired most of the cow-calf parameters. All cows had considerable weight losses during lactation except for SUBNUT-PI cows. Colostrum immunoglobulin G (IgG) concentration was lower in SUBNUT-PI cows, and milk fat content was higher in SUBNUT cows. SUBNUT calves had lower values of body measurements at weaning, and calves born from SUBNUT-PI dams had lower milk intake and the lowest average daily gain (ADG), which was reflected in their lower plasma insulin-like growth factor-1 (IGF-1) concentration. In conclusion, undernutrition in early gestation in suckler cows had long-term effects on offspring postnatal growth, this physiological evidence being more severe in Pirenaica cow-calf pairs.

Effects of maternal subnutrition during early pregnancy on cow hematological profiles and offspring physiology and vitality in two beef breeds.

This experiment evaluated the effects of subnutrition during early gestation on hematology in cows (Bos Taurus) and on hematological, metabolic, endocrine, and vitality parameters in their calves. Parda de Montaña and Pirenaica dams were inseminated and assigned to either a control (CONTROL, 100% requirements) or a nutrient-restricted group (SUBNUT, 65%) during the first third of gestation. Dam blood samples were collected on days 20 and 253 of gestation, and calf samples were obtained during the first days of life. Pirenaica dams presented higher red series parameters than Parda de Montaña dams, both in the first and the last months of gestation. During early pregnancy, granulocyte numbers and mean corpuscular hemoglobin were lower in Pirenaica-SUBNUT than in Pirenaica-CONTROL cows. Calves from the SUBNUT cows did not show a physiological reduction in red series values in early life, suggesting later maturation of the hematopoietic system. Poor maternal nutrition affected calf endocrine parameters. Newborns from dystocic parturitions showed lower NEFA concentrations and weaker vitality responses. In conclusion, maternal nutrition had short-term effects on cow hematology, Pirenaica cows showing a higher susceptibility to undernutrition; and a long-term effect on their offspring endocrinology, SUBNUT newborns showing lower levels of IGF-1 and higher levels of cortisol.

Is meat quality of forage-fed steers comparable to the meat quality of conventional beef from concentrate-fed bulls?

BACKGROUND: Replacing concentrates with forages in the diet of finishing cattle to satisfy societal demands and for economic reasons is a target for beef farmers, but this change may affect meat acceptance. In the Mediterranean area, young bulls are usually finished on concentrates (Conventional beef). Alternatively, steers can be finished on grass with supplements (G-supp); however, if carcasses are too lean, meat quality may be negatively affected. To increase fat deposition, grazing steers were finished on a total mixed ration composed of alfalfa hay and corn (TMR). Thus the objective of the study was to compare the quality of Longissimus muscle of the three systems. RESULTS: Conventional beef had low yellowness and similar lightness and redness values compared with the beef from the forage-based systems, which differed slightly. The meat of the G-supp and TMR steers had higher conjugated linoleic acid (CLA) and total n-3 polyunsaturated fatty acid (PUFA) contents and lower n-6/n-3 PUFA ratio (more appropriate from a human health point of view) but was tougher than the Conventional beef. CONCLUSION: The Conventional beef was better accepted by consumers than the beef from both forage-based systems because it was the most tender. Thus tenderness of meat from forage-fed steers should be improved to ensure consumer acceptance. © 2017 Society of Chemical Industry.

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.

Evaluation of "Pampa-Corte" simulation model in different beef cattle fattening systems in Spain / Desempenho do modelo "Pampa-Corte" em diferentes sistemas de terminação de bovinos na Espanha

The Pampa-Corte model was developed to simulate the growth of beef cattle in grazing systems in a dynamic and mechanistic way. It was validated under Brazilian conditions. This paper aims to verify the performance of the model in conventional and alternative beef cattle finishing systems in Spain. An experimental dataset of 21 Parda de Montaña calves of similar age and weight at weaning was used to evaluate the model. They were slaughtered individually on reaching 450kg liveweight. The model considered genetic group maturity rather than breed, in order to adjust growth parameters, once Parda de Montaña breed is not contemplated by AFRC (1993). Parameters from late maturing group were initially used considering adult animal size of Parda de Montaña animals; however, the best fit was with values from the early maturing group. The model predicted accurately animal growth in grazing and conventional finishing systems in Spain, although estimates were less precise when changes in animal management involved physiologic modifications.

O modelo Pampa Corte foi desenvolvido para simular de forma dinâmica e mecanistica o crescimento de bovinos de corte em sistemas de pastejo, sendo validado nas condições de produção brasileiras. Este trabalho tem como finalidade demonstrar a performance do modelo em situações de engorda tradicionais e alternativos de bovinos de corte na Espanha. Com essa finalidade, foram utilizados dados de 21 animais inteiros da raça Parda de Montanha com similar idade e peso de desmame e que foram abatidos individualmente quando atingiram o peso vivo de 450kg. O modelo considera grupos genéticos no ajuste de seus parâmetros conforme AFRC (1993), entretanto, a raça Parda de Montanha não é contemplada em suas tabelas. Devido ao seu tamanho adulto, inicialmente, foram considerados os parâmetros referentes ao grupo tardio de maturidade, entretanto, os melhores ajustes ocorreram ao serem utilizados os parâmetros de animais de maturidade precoce. O modelo prediz satisfatoriamente o crescimento e terminação dos animais nos sistemas convencionais e alternativos de produção. No entanto, essas predições são menos precisas quando envolve a troca de sistema de pastoreio para confinamento total.