Way forward in Nutrition for Increasing Productivity of Dairy Animals
J S Hundal*, Digvijay Singh, Amit Sharma, Udeybir Chahal and R S Grewal1 Department of Animal Nutrition, 1 Directorate of Livestock Farms College of Veterinary Science, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab
The livestock sector is an integral part of India’s agricultural sector, contributing about 29.35% of total agriculture Gross Valued Added (GVA) alone and about 4.35% of national GVA (National Accounts Statistics, 2020). India ranks as the world’s highest milk-producing country, with 221.06 million tonnes accounting for 24% of global milk production in the years 2020–22, with an annual increase of 5% from the previous year (Basic Animal Husbandry Statistics, 2022). During the last decade (2012–13 vs. 2021–2022), the milk production of India has registered a 67% increase, while there has been only a 6% increase in milch animals (19th vs. 20th livestock census). These facts clearly depict that rising productivity is the major driving force behind the rise in India’s milk production, rather than expansion in herd size. Further, India’s milk demand is expected to increase by up to 400 million tonnes by 2050 with increased income and unprecedential growth in population (IGFRI Vision, 2050). Furthermore, the livestock sector faces a number of complex challenges, such as climatic change, competition for land or other resources for human food production, and rising prices of feed ingredients. Therefore, the production as well as species-specific revision and optimization of nutrient requirements, strategic and target nutrient delivery, precision feeding, nutrient use efficiency, exploring newer feed resources, development of silage inoculants, fibrous crop residue utilization through harnessing gut microbial diversity, environmental sustainability, and food and feed safety will be crucial to boosting animal production intensity for fulfilling future milk demand and ensuring sustainable dairy production.
- Production as well as species-specific revision and optimization of nutrient requirements
In India, milk production from dairy cattle and buffalo has consistently supported the rural economy, contributed to the nation’s development, and sustained the first position in milk production in the world. Over the years, dairy farming has seen significant advancements in genetic selection and breeding programmes. Animal breeding, feeding, and management programmes have equally contributed to improvement. With increased milk production, the nutrient requirements of these animals (cattle and buffalo) change as well. In high-yielding cross-bred dairy animals, exotic blood percentages have increased significantly. Probably the nutrient needs of these animals must differ from those recommended for feeding standards in temperate countries because of differences in genetic makeup, mature body size and growth rate, quality of feeds, climatic conditions, and efficiency of nutrient utilisation. The climatic conditions of temperate regions are entirely different from those of tropical countries; most of the year, from April to September, the Temperature Humidity Index (THI) remained higher than 72, which exerts climate stress on dairy animals. Therefore, a way forward is as follows: a) The nutrient requirements (species and category-wise) for growth, production, and different physiological stages (phase feeding) must be structured under the Indian climate. b) There should be dedicated and planned research on precise nutrient requirements in ICAR institutes and State Agricultural universities. c) Frequent mineral mapping of soil, feed, and fodder for precision feeding as well as the development/re-formulation of area-specific mineral mixtures will be required. d) Nanoscience for target nutrient delivery (minerals, amino acids) e) Mathematical model or equation for better prediction of nutrient utilization
- Calfhood nutrition and reducing the age of first calving (AFC)
Reducing the age of first calving requires careful management of their nutrition and feeding. Age at first calving (AFC; the period that a female calf needs to reach puberty and reproduce for the first time), is an important factor in the cost of rearing replacements in dairy herds. In India, usually AFC in crossbred Holstein, indigenous cattle and buffalo heifers are 23 to 24, 36, and 48 months, respectively. The higher AFC results from a lack of precision nutrient feeding of the calf during different phases and a lack of awareness about scientific calf rearing protocols at the field level. Age at first calving is a prime reproductive trait affecting the herd’s productivity as well as profitability through the direct cost of rearing bovine heifers, including buffaloes, and for its effect on the animal’s future performance. Shorter AFC prolongs the productive life (PL) lactation performance; maintains persistency in lactation; lowers somatic cell score; and shortens the length of the calving interval in cattle and buffalo. However, data on the age of first calving has a direct relationship with body weight and nutritional management. A way forward for calfhood nutrition and reducing the age of first calving (AFC) is as follows: a) Post-pubertal needs of energy, protein, and micronutrients need to be studied precisely for controlling the AFC in cattle and buffaloes. b) Re-establish nutrient requirements for different calfhood stages in the Indian climate. c) Develop feeding modules for different phases of calves (smart feeding). d) Calf rearing programme awareness at the field level, with special reference to buffaloes e) Optimising gut microflora with feed additives to enhance nutrient use efficiency and prevent calf diarrhoea f) Residual feed intake (RFI) as measure of feed efficiency should be integrated into breeding programs
- Greenhouse gas emissions, carbon footprints, and the environment
According to estimates, 14.5% of all anthropogenic greenhouse gas (GHG) emissions come from livestock worldwide, including animals, manure, feed production, and land expansion into forested regions. Enteric CH4 is produced by ruminants for roughly 2% to 12% of their total energy consumption, and it accounts for about 6% of all anthropogenic greenhouse gas emissions worldwide. Due to advancements in production efficiency and animal performance, methane emissions per unit of meat and milk have been steadily declining over the past few decades. To reduce an upsurge in atmospheric concentrations of greenhouse gases, CH4 emissions must be lowered both in intensity and in absolute terms. While various solutions have been put out to reduce CH4 , many of them have limited mitigation potential (e.g., yeast, bacterial-directed microbials, saponins, ionophores), are difficult to execute on farms (such as protozoa defaunation), or are still in the early stages of development (such as bacteriocins). There are many strategies that are feasible on farms, like animal breeding for low-CH4 production, increased animal productivity, feed efficiency, and residual feed intake; Nutrition inventions like fats, concentrates, forage quality, and ration balancing; Rumen microbiome and fermentation manipulation through the use of vaccines, chemicals, algae, tannins, etc. A way forward for Greenhouse gas emissions, carbon footprints, and the environment is as follows: a) Initiate a network project on the life cycle assessment of the carbon footprints state wise: Buffalo and cattle (descript & non-descript) and crossbred cows separately to develop policy and recommendations. b) To combine strategies to attain the sizable reduction in CH4 needed: 3-NOP + linseed oil c) Develop and use specific chemical inhibitors of methanogenesis, such as 3-NOP, with consistent effects. d) Breed animals for low CH4 production, high nutrient efficiency, and low residual feed intake. e) Manure management strategies should be prioritised to curb ecological harm. However, for the use of methane inhibitors, regulatory approval, consumer acceptance, and government incentives will be required. To boost the environmental sustainability of ruminant production, high-priority research in the fields of metagenomic and metatranscriptomic analysis to disclose the complexity and functionality of the rumen microbiome should be explored.
- Feeding strategies to curb Nitrogen and Phosphorus excretion in manure
Nutrient over-loading, particularly with respect to nitrogen (N) and phosphorus (P), is very harmful for the environment as these nutrients over-stimulate the primary production of microbes and plant species in water, which changes the ecology of the system and creates a cascade of events that present environmental risks to ecosystems and water quality. Further, under modern intensive livestock rearing, the lack of scientific data at frequent intervals about soil and plant mineral profiles leads to overfeeding of crude protein (N source) and mineral supplementation (P source) at a very high level to raise animals’ productivity, which further aggregates the condition. Further, low nutrient use efficiency leads to higher excretion of nitrogen and phosphorus. A way forward to curb Nitrogen and Phosphorus excretion in manure is as follows: a) Precision feeding of nutrients • Feed to meet the metabolizable protein (rumen degradable plus undegradable: post-ruminally absorbable) and phosphorus requirements precisely (follow feeding standards). • Ration formulation to match the animals’ requirements for essential amino acids leads to a 15% reduction in N excretion. • Phase feeding for similar ages, weights, production, or management groups can reduce excretion of both N and P by 5–10%. • Regular monitoring of the N and P footprints of soil, plants, and feeds helps formulate rations with minimum nutrient excretions. b) Enhance the nutrient use efficiency of animals with the use of enzymes (phytase), specific ingredients, and feed processing technologies. c) Select the feed ingredients carefully, as they will reduce P excretion by up to 50%. For instance, corn gluten or distiller’s grains are inexpensive sources of N and energy but have more than twice the P content of traditional feed grain sources.
- Newer feed resources for mitigating feed crises
There is a shortage of green fodder, dry fodder, and concentrate mixture in India of about 35%, 11%, and 28%, respectively, when calculated on the basis of the adult cattle unit system. Issues like narrowing agricultural land, less availability of quality seeds, and improved varieties lead to low fodder production. The scenario is precarious in several emerging nations, where ongoing feed deficits and expanding animal numbers are widespread, making the challenge an endless problem. The conventional feed resources used for the preparation of concentrate mixtures compete with food for humanity, which results in a demand-supply gap. The lack of information on risk analysis of newer feed resources for their safe use in animal feed, sensible utilisation of feed resources, and the absence of fodder or feed security policy further aggregate the conditions. A way forward to mitigate feed and fodder crises is as follows: a) Estimate resource demand based on the actual feeding system to achieve the actual deficiency or surplus, not on the basis of Adult cattle units. b) Develop high-quality fodder varieties, quality seeds, draught-resistant types, a package of practises for improved yield, quality, and plant protection, fodder banks, and the popularisation of fodder conservation strategies. c) Develop feeding guidelines for food wastes (the recycling of ‘misplaced nutrients’) and the target-oriented use of emerging or underused feed resources like agro-industrial by-products, algae, fermented feeds, processed animal proteins, fruit and vegetable wastes, etc. after assessing their nutrient profile, quality, and inclusion level in animal feed. d) An in-depth risk analysis that investigates animal well-being, human health, food safety (deleterious effects), and the surroundings to assure their secure use in the animal food chain. e) Fermented incorporation of unconventional ingredients by reducing anti-nutrients, toxin, and fibre f) Implementation of the fodder security policy as food security g) Resource-based, region-specific feeding modules
- Development of silage inoculants
Maize silage is prepared by most commercial dairy farmers because of its high energy content and the non-availability of green fodder throughout the year. Silage feeding as compared to green fodder feeding has reported significant improvements in the production efficiency of milk and the growth performance of the animals. The maize silage business has grown significantly in the last few years. If we look at the potential of the silage market in India, the cattle and buffalo population is 302 million (20th Census), and if the average silage consumed per day is 10 kg, a tentatively calculated silage industry is about 1400 billion rupees. During ensiling, fermentation occurs under anaerobic conditions due to the native bacteria of plants. However, inadequate epiphytic bacterial populations (<1,00,000 CFU/g > fresh biomass) result in higher dry matter losses (10–20%), prolonged fermentation, and lowquality silage with lower aerobic stability. Sometimes the chances of clostridial fermentation and mycotoxin issues may necessitate the use of silage inoculants. Silage inoculant (LAB) application has been utilised to improve silage quality, nutritive value, and aerobic stability. However, most of the silage inoculants available on the market are developed in temperate climates and are more suitable for their crops; therefore, there is a need to develop inoculant cultures that are collected from regional silage and conduct experimental trials to assess their effect on quality characteristics and nutrient utilisation. A way forward for better silage quality is as follows: a) Develop silage inoculants for hot climates. b) Isolation of epiphytic Lactic acid bacterial strains that should be crop-specific, costeffective, and can withstand with climate and regional variations c) Follow monumental practices with respect to stage of harvesting, pack density, silo design, and aerobic stability during the feed-out phase.
- Fibrous crop residue utilization through harnessing gut microbial diversity
In India, about 683 million tonnes of crop residues are generated annually; however, their sustainable utilisation is a big challenge. Among various options, crop residue can also be used as animal feed. Lower fibre digestibility is a major challenge for maximising crop residue utilisation in animal rations without any negative effect on production performance. Crop residues are rich sources of fibre, such as wheat straw (77% neutral detergent fibre; NDF), but the digestibility of NDF (20–40%) is lower than green fodder. Further, microbes
can be explored for efficient utilisation of crop residues in ruminants; however, the limited understanding of rumen fermentation and nutrient utilisation by rumen microbes due to low information about diversity, composition, and function of the rumen ecosystem, Metabolic pathways utilised by rumen microbes for the utilisation of feed, and Functional relationships between different microbial communities of the rumen hinder the way. A way forward for better utilization of fibrous crop residue through harnessing gut microbial diversity is as follows: a) Enhance nutrient use efficiency through the deconstruction of lignocellulosic biomass by the rumen metagenomic approach. b) Identification of the rumen microbiome to develop effective enzymes that have the potential to enhance the digestion of crop residue c) Bio-manufacturing of Rumen-specific fibre-degrading enzymes using SSF technology d) Animal scientists, plant breeders, and biotechnologists collaborate for the development of low lignin, high sugar content, and low silica crops or fodder. e) Maximise the use of crop residues for animal bedding and animal rations specifically for buffalo meat production. f) Large-scale DNA sequencing from the rumen ecosystem for better understanding of the microbial community, their function, and interrelationships to improve rumen fermentation, digestibility, and nutrient utilisation efficiency.
- Food and Feed Safety: Regulatory control
A food safety and regulatory body like FSSAI needs to be established for the enforcement of standards and to ensure the quality of animal feed and feed additives. Food safety regulations should recommend a maximum permissible limit (MPL) for harmful substances such as pesticides, antibiotics, heavy metals, and mycotoxins in animal feed; their presence could pose risks to animal as well as human health. Regulatory bodies establish guidelines and protocols to prevent the introduction and spread of diseases through animal feed, protecting both animal and human populations from potential outbreaks. Animal feed often contains various additives, such as vitamins, minerals, and feed additives, to enhance animal nutrition and performance. Regulatory bodies establish guidelines for the use of these additives, ensuring their safety, appropriate dosage, and compliance with labelling requirements. Furthermore, it improves feed and food security and reduces feed storage losses. In actuality, feed is a crucial link in the food chain, and it is recognised that every person has a stake in keeping it safe. Many countries lack adequate awareness to ensure feed safety among all stakeholders across the entire value chain. In India, quality control is regulated by a state body, the Bureau of Indian Standards (BIS), established under the BIS Act, 1986. In the event of a food safety issue or product recall related to animal feed, a regulatory body plays a vital role in traceability and recall management. They help track the source of the problem, initiate necessary recalls, and implement corrective measures to prevent future occurrences.
A way forward for Feed Safety and regulatory control is as follows:
- a) Regulatory control to enforce standards, ensure quality and safety of animal feed, feed additives and fodder including silage b) Generate more data on variability and prevalence in feed and fodder samples for Aflatoxins, heavy metal, pesticides and antibiotic residues c) Development of simple and rapid screening methods for laboratories to manage large number of samples. d) Developing biosensors for detecting contaminants in animal feed and products e) Assessment of undetected or emerging hazards from newer feedstuffs viz. biofuel by-products, insects, aquatic plants and marine products, which may be used as feed materials f) Hazard Analysis and Critical Control Points (HACCP) protocols need to be established for the feed industry to guarantee compliance with good manufacturing practice.
9.Assessment of Aflatoxin B1 levels in feed raw materials: region-wise and season-wise
The feeding of farm animals with aflatoxin-contaminated feed results in increased susceptibility to infectious diseases, weight loss, poor production, and compromised reproduction. Therefore, the control of aflatoxins in animal feed is important, but the regulatory bodies and the feed industry have not been able to reach a consensus regarding the aflatoxin B1 level in feed. Moreover, there is a higher permissible toxin limit (up to 50 ppb) in some feed ingredients instead of the proposed 20 ppb (proposed) in the finished feed. Further, there is limited data generated by different institutes on the aflatoxin level of feed ingredients, making it hard to arrive at decisions. A way forward for the assessment of Aflatoxin B1 levels in feed raw materials is as follows: a) An All-India Coordinated Research Project on Assessment of Aflatoxin should be initiated under the aegis of the ICAR. The responsibility of generating data on the aflatoxin B1 content of various compound feed raw materials needs to be taken up by various institutes, region-wise and season-wise, by following a common protocol. b) The data thus generated should be used to set an Aflatoxin B1 limit in feed raw materials, and it further reinforces regulatory agencies’ stance on Aflatoxin B1 in cattle feed. In conclusion, the production as well as species-specific revision and optimization of nutrient requirements, strategic and target nutrient delivery, precision feeding, nutrient use efficiency, development silage inoculants, fibrous crop residue utilization through harnessing gut microbial diversity, environmental sustainability, and food and feed safety will be essential to increasing animal production intensity in order to meet future milk demand and ensure sustainable dairy production. Furthermore, the resource-constrained ecosystem should be sustained through effective, goal-oriented use and the recycling of nutrients to support animal feeding and a healthy environment.
