Productive and Economic Responses in Grazing Dairy Cows to Grain Supplementation on Family Farms in the South of Brazil

Black oat grown with common vetch improves the chemical composition and degradability rate of forage

This study aimed to evaluate the effect of cultivating a combination of common vetch (Vicia sativa L.) with black oats (Avena strigosa Schreb.) on the chemical composition of forage and the grazing behavior of heifers. To accomplish this, two paddocks 2500m2 each from a Voisin Rational Grazing management system were divided into three blocks each and then into thirds (278m²) characterizing a randomized block design. Three different forage compositions were distributed into these thirds: oats grown alone, vetch grown alone, and oats grown with vetch. Forage samples were collected after 65 days through the square method. Right after collection, three groups of four heifers each grazed the plots for two hours in a 3x3 double Latin Square design for behavioral observation, grazing simulation through the hand-plucking method, and biting rate determination. Forage samples collected either by hand-plucking or the square method, were analyzed for chemical composition and “in vitro” degradability.  Statistical analyses were performed using the R package lme4. Data were evaluated with linear mixed-effects models. The inclusion of common vetch significantly increased forage production and oat protein content, but decreased the fiber content, which promoted better “in vitro” degradability. Grazing frequency was higher in pasture where oats were grown with vetch, but the biting rate was similar in all the three forage compositions evaluated. Forage collected by the square method did not differ from forage consumed by the heifers, probably meaning low herbage selectivity by heifers.  Furthermore, no interaction of investigated variables occurred between forage compositions and the method of collection. The inclusion of common vetch with black oats increased forage chemical composition, “in vitro” degradability, and forage production, thus having positive effects on the time cows spent grazing.

Effect of recovery period of mixture pasture on cattle behaviour, pasture biomass production and pasture nutritional value

Pasture management that considers pasture growth dynamics remains an open question. Conceptually, such management must allow for grazing only after the recuperation of the pasture between two separate timely grazing periods when pasture reaches optimum recovery, as per the first law of Voisin's rational grazing system. The optimum recovery period not only implies a pasture with better nutritional value and higher biomass yield but one that also reduces the production of enteric methane (CH4) to improve the grazing efficiency of cattle. Therefore, this study aimed to evaluate three different recovery periods (RP) of mixed grasses on the grazing behaviour of heifers, as well as herbage selectivity, herbage yield and nutritional value, in vitro degradability and CH4 production. Based on these criteria, three pasture RPs of 24 (RP24), 35 (RP3) and 46 (RP46) days were evaluated in six blocks using a randomized block design. At each predetermined RP, samples of the pasture were taken before the animals were allowed to graze. Right after collecting the pasture samples, heifers accessed the pasture during 4 h consecutively for grazing simulation and behavioural observations. We also measured the bite rate of each animal. The pasture growing for 24 days had the highest biomass production, best nutritional value, best efficiency of in vitro CH4 relative emission (ml) per DM degraded (g) and bite rate of the three RPs. Heifers all selected their herbage, irrespective of RP, but with different nutritional value and higher in vitro degradability. However, this did not change the production of in vitro CH4. Considering the growth conditions of the area where the study was performed, we recommend the shorter RP24 as the most suitable during the summer season. The study's findings support the idea of management intervention to increase the quality of grazing systems.

Comparative Grain Chemical Composition, Ruminal Degradation In Vivo, and Intestinal Digestibility In Vitro of Vicia Sativa L. Varieties Grown on the Tibetan Plateau

Simple Summary

Common vetch (Vicia sativa L.) grain is an important source of protein in rations for ruminants, but little information is available on the protein value of common vetch grains, both in terms of chemical composition and protein degradability, and regarding variation between intra-species and year. The objective of this study was to evaluate grain chemical composition, ruminal protein degradability in vivo, and intestinal protein digestibility in vitro of four common vetch varieties over two cropping years on the Tibetan Plateau. This study was also conducted to establish correlations of grain chemical composition with ruminal degradability parameters of grain protein and with intestinal digestibility of grain protein. Results of this study demonstrated that grain quality characteristics varied significantly among varieties and years. The relationship between grain chemical composition and intestinally absorbable digestible protein (IADP) was best described by a linear regression equation, and coefficients of determination remained very high (R² = 0.891). Overall, the results indicated that in terms of effective crude protein degradability and IADP of grain, common vetch varieties Lanjian No. 2 and Lanjian No. 3 have the greatest potential among varieties examined for supplementing ruminant diets when grown on the Tibetan Plateau.

Abstract

Four varieties of common vetch, three improved varieties and one local variety, were evaluated for grain chemical composition, rumen protein degradability, and intestinal protein digestibility over two cropping years on the Tibetan Plateau. This study also examined correlations of grain chemical composition with rumen degradability parameters of grain protein and with intestinal digestibility of grain protein. Results of this study showed that grain quality attributes varied (p < 0.05) among varieties and cropping years. Significant intra-species variation was observed for concentrations (g/kg dry matter) of crude protein (CP; range = 347–374), ether extract (range = 15.8–19.6), neutral detergent fiber (aNDF; range = 201–237), acid detergent fiber (range = 58.2–71.6), ash (range = 27.6–31.0), effective CP degradability (EDCP; range = 732–801 g/kg CP), and intestinally absorbable digestible protein (IADP; range = 136–208 g/kg CP). The relationship between grain chemical composition and IADP was best described by the linear regression equation IADP = –0.828CP + 8.80ash + 0.635aNDF + 70.2 (R² = 0.891), indicating that chemical analysis offers a quick and reliable method for IADP of common vetch grain. In terms of EDCP and IADP of grain, common vetch varieties, Lanjian No.2 and Lanjian No. 3, have the greatest potential among varieties tested for supplementing ruminant diets when grown on the Tibetan Plateau.

Blood metabolite concentration, milk yield, resumption of ovarian activity and conception in grazing dual purpose cows supplemented with concentrate during the post-partum period

Cattle grazing on natural pasture face seasonal variation in pasture availability and nutritive value. Improving the nutrition of cows by providing supplementary feeds during periods of pasture or nutrient deficit is necessary for improved productivity. This study was conducted to determine the effect of feed supplementation during the post-partum period on the metabolic status and reproductive performance of 40 grazing Sanga and Friesian × Sanga cows. Twenty out of a total of 40 cows (10 Sanga and 10 Friesian × Sanga cows) were supplemented with 2.5 kg of concentrate per day for 16 weeks after calving. Parameters measured include daily milk yield, concentration of blood metabolites, resumption of ovarian activity and conception. Supplemented cows had higher partial milk yield than their non-supplemented counterparts (2.07 vs. 1.60 kg/day; P < 0.001). Sanga cows had lower milk yield than the Friesian × Sanga crossbreds (1.61 vs. 2.05 kg/day; P < 0.01). Supplemented cows had higher mean total protein (86.7 vs. 81.3 g/L; P = 0.007) and globulin (53.0 vs. 47.7; P = 0.014) concentrations than non-supplemented cows. Sanga cows had higher glucose (P = 0.027), total protein (P < 0.001) and globulin (P < 0.001) but lower triglyceride (P = 0.003) and progesterone (P = 0.023) concentrations than Friesian × Sanga cows. Supplemented cows had less proportion not cycling (20 vs. 55%; P = 0.022) and less days open (95.8 vs. 106 days; P = 0.032) than non-supplemented cows. The Friesian × Sanga cows had higher progesterone concentrations at first progesterone rise (3.34 vs. 1.32 ng/mL; P = 0.032) and shorter interval from calving to conception (96.7 vs. 106 days; P = 0.042). The results from this study indicate the beneficial effects of feed supplementation in terms of increased milk yield, better metabolic status and reproductive performance.

Brazilian Citizens: Expectations Regarding Dairy Cattle Welfare and Awareness of Contentious Practices

Simple Summary

Animal welfare is an important issue for citizens in North America and Europe, but much less is known about how citizens from emergent countries, such as Brazil, view this topic. Our aim was to explore attitudes of urban Brazilian citizens about dairy production and, in particular, how they view four routine husbandry practices: early cow-calf separation; zero-grazing; culling of the newborn male calf; and dehorning without pain mitigation. Through in-depth interviews and a questionnaire using open-ended questions, we can conclude that animal welfare was a major issue for our participants, especially in terms of its perceived relation with milk quality. Although participants were initially unaware about any of the four management practices, they were all viewed as contentious and not supported. This study provides some insights that farmers and others working in the Brazilian dairy supply chain should take into consideration, particularly in terms of social sustainability.

Abstract

The primary aim of this study was to explore attitudes of urban Brazilian citizens about dairy production. A secondary aim was to determine their knowledge and attitudes about four potentially contentious routine dairy cattle management practices: early cow-calf separation; zero-grazing; culling of newborn male calves; and dehorning without pain mitigation. To address the first aim 40 participants were interviewed using open-ended semi-structured questions designed to probe their views and attitudes about dairy production in Brazil, and 300 participants answered a questionnaire that included an open-ended question about the welfare of dairy cattle. Primary concerns reported by the participants centered on milk quality, which included the rejection of any chemical additives, but also animal welfare, environmental and social issues. The interviewees rarely mentioned animal welfare directly but, when probed, expressed several concerns related to this topic. In particular, participants commented on factors that they perceived to influence milk quality, such as good animal health, feeding, clean facilities, and the need to avoid or reduce the use of drugs, hormones and pesticides, the avoidance of pain, frustration and suffering, and the ability of the animals to perform natural behaviors. To address our second aim, participants were asked questions about the four routine management practices. Although they self-reported being largely unaware of these practices, the majority of the participants rejected these practices outright. These data provide insight that animal welfare may be an important issue for members of the public. Failure to consider this information may increase the risk that certain dairy production practices may not be socially sustainable once lay citizens become aware of them.

Characterisation of smallholding dairy farms in southern Brazil

Smallholder dairy farmers that are responsible for 90% of the milk produced in Santa Catarina State, in southern Brazil, transitioned in recent decades from milk production for self-consumption to commercial dairying. The objective of this study was to identify groups sharing common characteristics, potentials and limitations and compare their main management practices, milk production and milk quality. We collected data from 124 farms distributed in 24 municipalities, using semi-structured interviews, inspection of the housing and milking environment, and live observations during one complete milking. Multivariate analyses revealed three groups of farmers: ‘Semi-Intensive’ (n = 51), ‘Pasture-Based’ (n = 50), and ‘Extensive’ (n = 23). Group differences included land and herd size (both larger in Semi-Intensive, P < 0.002); feeding management of dairy cows (e.g. greater use of pasture improvement techniques in Extensive and Pasture-Based, and more efficient rotational grazing management in Pasture-Based, P < 0.04); use of external inputs (e.g. lower use of concentrate and silage in Pasture-Based, P < 0.001); milking infrastructure and hygiene practices (better in Semi-Intensive, P < 0.04), and milk productivity (greater in Semi-Intensive, P < 0.001). The Extensive group conserves several features of the subsistence, traditional mode of milk production, and makes inefficient use of costly feeding practices, which threatens its sustainability. The two other groups of farms took different, almost opposite directions to deal with the limitations in farm area: the Semi-Intensive group have adopted an entrepreneurial farming style and the Pasture-Based, a more agroecological path. These results highlight the need to develop specific strategies and policies to help these different types of producers to coexist in the dairy production chain.

Grazing management: setting the table, designing the menu and influencing the diner

Pastoral livestock-production systems are under increasing environmental, social and consumer pressures to reduce environmental impacts and to enhance biodiversity and animal welfare. At the same time, farmers face the challenge of managing grazing, which is intimately linked with profitability. Recent advances in understanding grazing patterns and nutritional ecology may help alleviate such pressures. For instance, by managing grazing to (1) manipulate links between ingestive–digestive decisions and temporal patterns of nutrient excretion, (2) provide phytochemically diverse diets at appropriate temporal (the menu) and spatial (the table) scales and (3) influence the behaviour of animals (the diners) on the basis of their specific ‘personalities’ and needs, to overcome or enhance animal differences, thereby enhancing their and farm productivity and welfare, as well as our health. Under pastoral systems, synergies between animals’ and farmers’ grazing decisions have the potential to offer greater benefits to the animal, the environment and the farm than does simple and parsimonious grazing management based on a single component of the system. In the present review, we look at grazing and its management through an alternate lens, drawing ideas and hypotheses to stimulate thinking, dialogue and discussions that we anticipate will evolve into innovative research programs and grazing strategies. To do so, we combined experimental and observational studies from a wide range of disciplines with simulation-modelling exercises. We envisage a more holistic approach to manage grazing based on recent advances in the understanding of the nutritional ecology of grazing animals, and propose management practices that may enable pastoral livestock-production systems to evolve continually as complex creative systems.

Modelling preference and diet selection patterns by grazing ruminants: a development in a mechanistic model of a grazing dairy cow, MINDY

The work presented here represents additions to the mechanistic and dynamic model of a grazing dairy cow (MINDY). The additions include a module representing preference and selection, based on two theories, namely, post-ingestive feedback and discomfort. The model was evaluated by assessing its ability to simulate patterns of preference and selection in response to a variety of feeding management. The improvements detailed here enable a realistic simulation of patterns of food selection by grazing ruminants, based on a range of feeding situations from different studies with cattle and sheep. These simulations indicate that the concepts encoded in MINDY capture several of the underlying biological mechanisms that drive preferences and selective behaviour. Thus, simulations using MINDY allow prediction of daily and diurnal patterns of selection based on preference, derived from some post-ingestive feedbacks and total discomfort. Estimates of herbage intake and parallel measurements of ingestive behaviour, rumen function and metabolism in grazing ruminants pose experimental and technical difficulties, and matching these processes to animal preference and selective behaviour is a greater challenge. As a consequence, advances in knowledge of foraging behaviour and dietary choice are slow and costly. On completion of more thorough testing, MINDY can be used as a tool for exploratory mechanistic research, to design and organise experimental programs to address a range of factors that control intake and its ecology, helping advance knowledge faster and at a low cost.

Synthesis: foraging decisions link plants, herbivores and human beings

Herbivores make decisions about where to forage and what combinations and sequences of foods to eat, integrating influences that span generations, with choices manifest daily within a lifetime. These influences begin in utero and early in life; they emerge daily from interactions among internal needs and contexts unique to biophysical and social environments; and they link the cells of plants with the palates of herbivores and humans. This synthesis summarises papers in the special issue of Animal Production Science that explore emerging understanding of these dynamics, and suggests implications for future research that can help people manage livestock for the benefit of landscapes and people by addressing (1) how primary and secondary compounds in plants interact physiologically with cells and organs in animals to influence food selection, (2) temporal and spatial patterns of foraging behaviours that emerge from these interactions in the form of meal dynamics across landscapes, (3) ways humans can manage foraging behaviours and the dynamics of meals for ecological, economic and social benefits, and (4) models of foraging behaviour that integrate the aforementioned influences.