Strategies for Enhancing Productivity of Dairy Animals
Way forward in Management for increasing productivity of dairy animals
Sanjay Choudhary1 , Yashpal Singh1 , Ravi Kant1 , Mandeep Singla1 and R S Grewal2 * 1 Department of Livestock Production Management, 2 Directorate of Livestock Farms, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana
Dairy production system is becoming more commercialized and with improvement in animal genetic potential, sound and scientific management of the dairy farm is of prime importance. Mechanized and large operations need special management skills in focussing on calf rearing programs, precision nutrition according to physiological stage, animal comfort and ease of operations. Some of the bottle necks in present scenario are discussed as follows:
Mortality in dairy calf operations
A healthy calf forms the basis for the future replacement of an organised dairy farm. It is said that the best animals are raised, not purchased. Therefore, these calves need to receive individual care and attention immediately after birth. There is a direct link between good calf care, fertility and improved milk production and length of lactation. In India, it is the most neglected management practice in many farms as is reflected with approximately 31% and 52% mortality and lower weight gain in the first 3 weeks of life in cattle and buffalo calves, respectively. Further, calf mortality of neonates is mainly attributed to conditions such as diarrhea and pneumonia associated with poor housing, hygiene, and nutrition. Different management and environmental factors such as colostral feeding, housing, calving assistance, production system, herd size, season, and hygiene of microenvironment were reported to affect significantly calf morbidity and mortality. In dairy calf management, in particular colostrum feeding is a key issue for ensuring calf welfare. The most nutritious food a calf will drink in its entire life is the colostrum. An important antibody, immunoglobulin G (IgG), cannot pass through the placental barrier during pregnancy. So, calves at birth are basically deprived of a functioning immune system. It may take three or four weeks for the new-born calf’s active immune system to establish, so all through that time they need some support. That’s where colostrum for new-born calves is critical to provide passive immunity. Colostrum the “liquid gold” is generally the milk produced by cows up to 4-5 days after calving, contains considerably high levels of protein, fat, minerals, vitamins and various other bioactive components. Unfortunately, restricted suckling systems and artificial rearing of the calves, continue to incur significant loss associated with failure of passive transfer (FPT). As calves are born agammaglobulinemic and so are almost entirely dependent on the absorption of maternal Ig from colostrum after birth. Calves are defined as having FPT, if the calf serum IgG concentration is less than 10mg/mL when sampled between 24 and 48 hours of age. The maternal colostrum is often called “nature’s perfect food”. Therefore, the dairy farmers have to ensure that a calf is provided passive transfer of IgG and look to the five Qs of colostrum management (Quality, quantity, quickness, quite clean and quantifying).
- Quality: It is documented that “good” quality colostrum contains 50 g IgG/liter of colostrum, therefore, to achieve successful passive transfer of immunity, it has been suggested that a calf needs to receive at least 150-200 g of Ig within 2 h of birth.
2. Quantity: The colostrum quantity is defined as litres of colostrum fed to a calf at birth. Therefore, globally, there is a general recommendation of colostrum feeding i.e., at the rate of 10% of the body weight. However, in systems where calves are separated from their mothers immediately after birth, calves should receive 4-6 litres of colostrum during the first 6 hours to achieve the passive transfer of immunity.
3. Quickness: Quickness i.e., time to first colostrum feeding involves two factors:
(a) how quickly the calf is fed, and (b) how quickly the dam is milked. The major factor affecting efficiency of Ig absorption is age of the calf at feeding. The capacity of the calf to absorb IgG (AEA) begins to decline shortly after birth, and this decline is augmented by the introduction of macromolecules into the gastro-intestinal tract. It has been recommended that the ability of calves to absorb immunoglobulin’s decreases from nearly 50% at birth to less than 30% by 6 h and by 2/3 after 12 h and complete closer by 24 hours of birth due to intestinal barrier. So, the efficiency of Ig transfer through the gut epithelium is best within the first 4 hours of birth, but beyond 6 hours, the efficiency of Ig absorption continues to decline with time.
4. Quite Clean: As stated earlier, introduction of bacteria into the gut has the capacity to hasten the closing of the gut lining. In addition, data indicate that as bacterial content of the colostrum increases, blood serum IgG decreases at 24 h of life. This negative correlation has directed to the recommendation that colostrum should have a total bacteria count of less than 100,000 cfu/mL and a total coliform count of less than 10,000 cfu/mL.
5. Quantification: Quantification is purely the benchmarking of passive transfer of immunity (PTI) on a given farm. If PTI is not consistently reached on farm, it is more than likely one of the 5 Q’s of colostrum management is not being met and further auditing should be conducted.
1.Housing-
Compared with individual calf housing, housing calves in groups helps develop social and cognitive skills which are important to adapt to changes that occur on dairy farms such as diet changes, pen movements, and other new routines (Costa et al., 2016). However, negative behaviors such as cross sucking and competition/ aggression can also occur in grouped dairy calves when they are separated from their mother immediately after birth.
2. Ventilation, temperature, ammonia, and humidity are all components that can modulate air quality and the prevalence of disease. Appropriate ventilation and low stocking density decrease concentrations of airborne bacteria (Lago et al., 2006). Similarly, keeping the pen/hutch temperature within the thermo-neutral zone and maintaining low levels of ammonia (i.e., > 7 ppm.
3. Regarding bedding, long wheat straw bedding has a higher capability to absorb water compared with other bedding materials and is associated with increasing the ideal nesting condition. Therefore, it is recommended use bedding that allows calves to nest properly and remove soiled bedding and manure from pens and add fresh bedding as needed to keep calf housing clean and dry (Salfer and Broadwater, 2020).
Reducing age at first calving
The cost of raising dairy replacement heifers is one of the largest for the dairy operation (15 to 20% of the total milk production cost). Attainment of puberty and sexual maturity in dairy animals depends on many factors like genetic potentiality, plane of nutrition, growth, body weight, hormones, health and other management conditions. Compared to exotic cattle, puberty in indigenous cattle and buffaloes is delayed (28 to 36 months). This results in delayed age at first calving leading to the low reproductive efficiency, thus lengthening the non-productive life and ultimately results into increase in rearing cost, slower return on capital investment, decrease lifetime production, longer generation interval, slower genetic gain in the herd, and increase in requirement of replacement heifers. Onset of puberty depends on body weight than age.
Following management points may be given due consideration:
1. Scientific calf rearing is a good practice to ensure profitable dairy farming. In well managed dairy herds, calf mortality usually should not exceed five per cent from birth to 30 days of age.
2. Calf should be offered starter feed from day 7 onwards and only milk and starter feed should be offered up to two months. Good quality green fodder should be included after two months of age and corn silage only after four months of age.
3. During growing phase the increase in rate of udder DNA is faster than increase in rate of other body DNA. Any deficiency especially proteins can hamper increase in number of milk secretary cells in udder which will permanently impair the milk production potential of the heifer.
4. In a research done in the university on crossbred heifers it was concluded that TMR containing 15.5%CP and CP:ME of 62.0 g of CP per Mcal of ME should be optimum for rapidly growing heifers than for heifers growing at a standard rate without effecting their normal blood biochemical constituents, liver and kidney function tests. Besides, the CP:ME ratio can be a reliable indicator of energy protein needs of growing heifers
5. Comfortable housing should be provided. The first design criteria to consider should be the orientation of the building. In areas where temperatures remain in excess of 30 degrees for up to 5 hrs a day, East-West orientation is recommended.
6. In many countries, varying results have been obtained after cooling treatments to keep the animals in comfort during hot seasons. Evaporative cooling through fans, foggers (effective in hoy-dry), sprinklers (hot-humid) and splashing of water has become a common practice to improve milk production, feed utilization and improve reproductive efficiency.
High milk producing animals
- Separate animal at least 45 days before expected date of calving and start close-up feed to these animals. Close up feed consists of –ve DCAD balance and with required micronutrients. After calving start fresh feed which has +ve DCAD and more energy, protein and minerals. Maintaining dry matter intake, avoiding overfeeding energy, preventing body condition score (BCS) gain (>4.0 in 0 to 5 scale), optimizing comfort and addressing hoof health. Avoid excessive quantity of lush green fodder which is high in potassium before calving.
2. Prevent subclinical milk fever: Reduce the risk of subclinical milk fever (low blood calcium) during the first week of lactation. Low blood calcium (less than 8.0 milligrams decilitre) correlates with the following Ketosis, higher somatic cell count, delayed uterine involution, metritis, depressed feed intake and reduced milk yield. Negative DACD before calving and sufficient calcium and other mineral post calving is key to reduce chances of milk fever. Feed minimum 3000 IU Vit E per day before calving and 1000 IU to fresh animal for one month post calving to boost immunity.
3. Optimize feed intake immediately after calving: Round the clock availability of clean drinkable water, allow access to fresh total mixed ration, provide 10 to 20 kg of green fodder and keep the feed bunks clean and fresh. Provide 2 feet of linear bunk , space/ cow, do not let feed bunks go empty, push feed up at least six times/day, remove old feed daily and feed a balanced diet
4. Optimize cow comfort: To optimize cow comfort in the fresh cow group: Use a stocking rate at 70 to 80 per cent of capacity; keep cows in a fresh cow group for 14 to 21 days. Provide 30 to 36 inches of bunk space per cow, Reduce social stress (especially for first calf heifers), Prevent cows from separating from the normal herd mates. Invest in cow cooling for dry and lactating cows. Trim feet at least an average of 1.5 times/year, treat all cows with sore feet, provide secure footing in all walkways, supply adequate airflow for proper ventilation (heat abatement) and avoid drafts and storm penetration in the winter
5. Evaluate BCS: The target BCS at calving is 3.0-3.25. You should avoid having cows reach a BCS greater than 4. A lower BCS at calving allows for 0.5 to 1.0 units of BCS within herd variation. This provides a safety margin to avoid overweight cows that: have a higher risk for ketosis and fatty liver and letter are often more difficult to breed back.
Reproductive efficiency post calving
Better reproductive management facilities are decisive in enhancing the efficiency,
sustainability and profitability of the dairy farm. It includes proper heat detection, calving at right intervals, timed artificial insemination, efficient service and normal parturition. Therefore, it is evident that following the correct management practices would definitely help in the growth of the dairy farm. Best management practices are: Efficient Utilisation of heat detection aids along with night-time observations, appropriate nutrient supply for reproduction, effective breeding stock identification, and artificial insemination must be done at appropriate time of estrus. Records must be maintained of individual animals regarding their reproductive parameters, sufficient feeding of lactating cows to rebreed, to prevent infertility problems. Periodic checking of the herds and artificial Insemination must be conducted properly. Appropriate treatment of problems related to anoestrous, infertility and repeat breeding, implementation of mating plans.
Energy and reproduction
As the milk production per animal is increasing, there is tendency for reproductive performance to decrease. In early lactation when animal is producing maximum milk, the reproduction suffers. For each additional decreased of extent of negative energy balance of estimated energy balance by 5.20 MJ of NE2 /d, the first estrus post partum was detected a day later. Negative energy balance result in decrease in size of CL and decrease in progesterone within CL as compared with cows on a high plane of nutrition. Post partum ovarian activity starters earlier in cows with an improved energy status.
Protein and reproduction:
The first service conception rate was lower (31% Vs 43%) and plasma urea higher (18.5 mg% Vs 13 mg%) in animals fed high protein diet. The most likely mechanisms by which high protein diets affect reproduction and depress fertility involves alterations of uterine environment. The high protein diets elevate urea nitrogen in plasma and the bovine reproductive tract. Feeding excess protein (19.3%) of DM) to dairy cows impaired fertility by increasing days open and services preconception as compared to lower percent of dietary protein (12.7% of DM) For optimum post partum reproductive performance the animal should be moderately conditioned at calving and the days of negative energy balance should be minimized.
Heat stress
The environmental conditions driving heat stress are presented using the unit less temperature-humidity index (THI), a calculated index that incorporates the effects of environmental temperature with relative humidity. THI <71 as a thermal comfort zone (assuming the THI does not drop below the thermoneutral conditions of dairy cows, which induces cold stress), 72 to 79 as mild heat stress, 80 to 90 as moderate heat stress, and >90 as severe heat stress. Dash et al. on the basis of THI identified three different zones as non heat stress zone (NHSZ), heat stress zone (HSZ) and critical heat stress zone (CHSZ). The months from October to March were included under NHSZ with THI values 56.71-73.21 and months from April to September were incorporated under HSZ with THI values 75.39-81.60 while the months of May and June were identified as the CHSZ within the HSZ with THI values 80.27-81.60. However, the categorical THI values can only act as a rough indicator for the effects of heat stress on production measures, in lieu of knowing the animal’s internal body temperature. Wind speed has also been shown to affect environmental temperatures and should be included in THI calculations when possible. Clearly, with nutritional corrections and management practices, the effect of heat stress on dairy animals can be alleviated. Therefore, in order to prevent the effects of heat stress, the modification of the surrounding environment is the key management practices to be followed in the dairy herd. Primary methods for altering the environment can be classified into two categories; first is the provision of shade and the other is evaporative cooling strategies with water. Theoretically, ideal type of animal shelters should maintain micro environment temperature between 15 to 25o C and humidity level around 10-12 mm Hg. The long axis of the shed should be in east-west direction. This east-west orientation helps to keep the shelter shaded for most of the day. Open type of shed is preferred in hot dry and hot humid climate. Various cooling options for dairy cows exist based on the principles of convection, conduction, radiation, and evaporation. Though the evaporative cooling strategies are costly, but they are more useful to alleviate the heat stress in animals. Evaporative cooling systems use the energy from the air to evaporate water and evaporation of water into warm air reduces the air temperature. The milk production and reproductive performances of dairy cattle were improved using an evaporative cooling system. Fogging systems use very fine droplets of water and these water droplets are immediately dispersed into the air stream and quickly evaporate, thus cooling the surrounding air. Misting systems generate larger droplets than fogging systems, but cool the air by the same principle. The sprinklers are different from foggers and misters. The sprinklers do not cool the air rather than the large droplet arising from them wet the hair coat and skin of the cows and buffaloes and then water evaporates to cool the hair and skin. This system is a very effective in combination with air movement. The mechanical air cooling is possible by using the evaporative cooling pad and fan system which are very useful in reducing the rectal temperature and respiratory rate in cows and buffaloes. Sprinkler-system water use can range from 215 L/cow per day to 454.2 L/cow per day, quantities that may become economically and environmentally unsustainable in the near future. However, long-term strategies have to be evolved for adaptation to climate change. Differences in thermal tolerance exist between livestock species provide tools to select thermo tolerant animals using genetic tools. The identification of heat-tolerant animals within highproducing breeds will be useful only if these animals are able to maintain high productivity and survivability when exposed to heat stress conditions. Cattle with shorter hair, hair of greater diameter and lighter coat color are more adapted to hot environments than those with longer hair coats and darker colors The DMI of crossbreds during heat stress is reduced. The effect of heat stress on DMI is more severe for high milk producing animals. The body heat production of cow producing 18.5 kg milk per day and 31.6 kg milk per day was 27.3 per cent and 48.5 per cent higher as compared to dry cows of similar body weight (Purwanto et al, 1990). The DMI is reduced by 0.85 kg per day for every 1o C increase in temperature. Cooling of cows by showers, sprinklers and fans etc. helps in maintaining the DMI and milk production during summer. Increasing the CP % by 2 percentage units in diet is helpful in maintain the milk production during heat stress. Feeding of buffers is very important during summers as cows are more prone to rumen acidosis during heat stress. A modern dairy cow is quite a different animal from the low producing subsisting on crop residues native animals. The nutritional needs of such animals pose a challenge to both the farmer and a nutritionist. A well balanced ration in all the major and minor nutrients is powerful tool for increasing the growth, production and reproduction.
Record keeping
In India, to be successful in dairy farming record keeping plays a vital role. The major element cannot be disregarded is record keeping. Conventionally records were maintained in registers but now-a-days even computers can be used for the same. The absence of records creates problems for the owners to schedule future management programmes, which would impair the production levels further resulting in severe losses. Hence, it is most important to maintain records in a dairy farm. Types of dairy farm records: Animal Identification Record, Breeding Record, Feeding Record, Milk Production Record, Animal Health and Treatment Record, Deworming and Vaccination Record, Young-stock Record and Financial Record.
