PROTOCOLS FOR ARTIFICIAL INDUCTION OF LACTATION IN DAIRY CATTLE
Induced lactation can be an alternative for high producing cow with low fertility. Artificial induction of lactation by using hormones can be used as an alternative to normal lactation, further it helps in reducing culling losses in herd and increasing profits. It should only be practiced when the animal is rendered infertile and all efforts to correct reproductive disorders/ abnormality fail. During the course of lactation animals come in to estrus and some of them become pregnant which improves the breeding efficiency besides bringing animal in to milk. The milk produced by this technique is similar in composition to milk produced after normal calving and in most cases fit for human consumption after a week’s time. Economic profit can also be generated from heifers by hormonal lactation induction as compared to rearing of replacement cow.
Hundreds of thousands of high producing dairy cows and buffaloes are culled every year because they fail to become pregnant due to a variety of reproductive problems (e.g. repeat breeding, anoestrus, chronic cervicitis, pyometra, or congenital abnormalities like freemartinism, underdeveloped ovaries or genitalia), anatomical defects (e.g. persistent Mullerian ducts) and hormonal dysfunction (e.g. cystic ovaries). About 27 to 47% dairy cows are culled due to reproductive problems. It is a problem all over the world. Artificial induction of lactation by hormonal treatment/other drugs can reduce the economic losses to the farmers due to infertility/sterility of the high producing dairy cows and buffaloes. Induction of lactation by hormonal treatment of nonbreeding cows has been found to be more profitable than to purchase replacement heifers. This technology can be used as a profitable management tool to help production ability (but suffering from nonresponsive reproductive problems) back into the herd.
Lactation:
It is a combined process of milk secretion and its removal from mammary gland. Milk production is both an endocrine and exocrine function. It has two phases namely- Lactogenesis (initiation of lactation by prolactin, glucocorticoids) and Gatactopoiesis (maintenance of lactation by growth hormone). Other factors affecting milk composition includes breed, genetic variation within breed, health, environment, management practices, and diet of the animal.
Prerequisites for Artificial Induction:
It is a simple and inexpensive method with rapid accomplishing protocols showing high success rates with greater quantity and longevity of milk production. It is acceptable for human consumption as there are no side effects on human health been reported.
Selection Criteria:
Animal should have good genetic merit for milk production, healthy and with good body condition. Repeat breeder or anestrus cow with clinically normal teats and udder is preferred. It can also be used in dry and non-pregnant animals. The treatment is more effective in well fed bovines with an optimum level of protein in diet .
Hormones/Drugs used for Lactation Induction
Hormones play an important role in the development and function of the mammary gland. Several drug combinations are used for induction of lactation. Lobule-alveolar development of the mammary gland is stimulated by combination of estrogen and progesterone . Addition of other hormones (prolactin and glucocorticoids) which work synergistically along with estrogen and progesterone for the onset of galactogenesis, can further enhance milk yield from induced lactation .
Induction Protocol Used:
Protocols used for induction of lactation in cows and buffaloes:
Several different protocols have been used to induce lactation in nonbreeding, infertile non-lactating cows and buffaloes. A few of these protocols are briefly described below which has been practically tried and scientifically documented by veterinary professionals:
Protocol # 1:
Smith et al. (1973) and Smith and Schanbacher (1973; 1974) Daily injections of estrogen plus progesterone @ 0.1 and 0.25 mg kg !1 body weight respectively for seven days. Some cows failed to respond. In cows, in which lactation was successfully induced (= 60% of treated cows), milk yield was relatively high. Important undesirable side-effect of large doses of estrogen included exhibition of abnormal estrous behavior sometimes for as long as 20-50 days after stopping the estrogen injection.
Protocol # 2:
Freitas et al. (2010) protocol was tested on 20 dry Holstein cows that were suffering from reproductive problems and had failed to get pregnant.
Protocol:
1. Day 1, 8 and 21: Recombinant bovine somatotropin (bSTr, 500 mg) 2. Day 2 to 15: Estradiol benzoate (0.071 mg kg !1 per day subcutaneously) 3. Day 2 to 8: Medroxy progesterone acetate (0.25 mg kg !1 per day, subcutaneously) 4. Day 19: Prostaglandin F2á (0.530mg, subcutaneously) 5. Day 19-21: Isoflupredone acetate (0.05 mg kg !1 ) intramuscularly 6. Massage of teats and udder for 5 minutes daily from Day 17 to 21. Milking carried out from 22nd day of induction. 7. bSTr was injected every two weeks after induction of lactation. 8. Mean milk yield with this protocol was 21.9±2.9 kg day
Protocol # 3:
Collier et al. (1977) the protocol was tested in two experiments. In experiment I, 10 cows were administered estradiol-17â (0.1 mg kg!1 per day) and progesterone (0.25 mg kg !1 per day) for 7 days. On Day 18 to Day 20, dexamethasone (20 mg per day) was administered. After this, animals were divided into two equal groups. Five animals were kept as control whereas the other 5 animals were administered reserpine 5mg per day on Day 13 to Day 16. In experiment II, 9 animals were given injections of estradiol-17â, progesterone and dexamethasone as in experiment I. After Day 7, animals were divided into 2 groups (4 control and 5 treated with reserpine @ 5 mg kg !1 per day on Day 8, 10, 12 & 14). During estradiol-progesterone injections, serum prolactin levels were 30 ng mL !1 . In control cows, serum prolactin levels increased on Day 14 to Day 21 in a variable pattern. During the period of reserpine administration, serum prolactin levels increased. In both experiment I and experiment II, reserpine treated cows had higher peak milk yield and overall higher milk production over a period of 100 days than those of control groups. Peak milk yields of reserpine groups were 10 to 21 kg per day in experiment I whereas in experiment II, the corresponding range was 16 to 24 kg day !1 . Results of the study were consistent with hypothesis that serum prolactin levels may be low in those cows which fail to lactate following the estrogen-progesterone treatment to induce lactation.
Protocol # 4:
Magliaro et al. (2004) tested on 28 parity 1 or greater, non-pregnant healthy Holstein cows
Protocol:
1. Day 1 to7: Estradiol-17â (0.075 mg kg !1 per day) and progesterone (0.25 mg kg !1 per day). 2. Day 18: Milking begun 3. Day 37±20 of milking: Cows randomly divided into Control or bST groups and their milk yield of 70 days compared 4. The average milk yield of bST treated cows (28.4 kg day !1 ) was higher than that of the control cows (24.1 kg day !1 )
Protocol # 5:
Ramgattie et al. (2014) this protocol was tested on 21 dry crossbred cows (Holstein x Jersey or Holstein x Jamaica Hope) and 26 nulliparous heifers aged more than 18 months.
Protocol:
1. Day 1 and Day 10: Prostaglandin F2 á (Inj. Lutalyse ® ) 25 mg IM on day 1 and day 10 2. Day 11 to Day 17: Daily subcutaneous injections of 17â-estradiol (0.1 mg kg !1 ) and progesterone (0.25 mg kg !1 ) for 7 days 3. Day 18: Injection Prostaglandin F2 á (Inj. Lutalyse ® ) 25 mg IM 4. Day 19 to Day 21: Reserpine (5 mg day !1 ) IM and dexamethasone (20 mg day !1 ) IM for 3 days Lactation was successfully induced is 71% of cows and 85% of heifers. Milking was started on Day 23 and continued for 154 days. Mean weekly milk yield was 78.2±5.1 kg. Massage of udder and teats before milking did not increase milk yield.
Protocol # 6:
Successive induction of lactation twice (Dabas and Sud, 1989). Protocol was tested on 5 cross bred heifers aged 32-42 months and 4 multiparous crossbred cows which were dry for 15-60 months Eight of these animals were repeat breeders.
Protocol:
1. Day 1 to 7: Estradiol -17 â (0.1 mg kg !1 per day) and Progesterone (0.25 mg kg !1 per day) Each day, calculated doses of estradiol and progesterone were divided into two equal portions and injected subcutaneously in the morning and evening. 2. Day 9 to 12: Two mg of reserpine twice a day subcutaneously 3. Day 10 onward: Hand milking twice a day 4. Induction of lactation was successful in all 9 animals and they produced milk for periods varying from 258-476 days and were then dried off for 2-4 months. 5. After a minimum dry period of 2 months, all animals were injected estradiol valerate (0.1 mg kg!1 per day) and hydroxyl progesterone caproate (0.25 mg kg !1 per day) on day 1 to 3 and 2 mg twice daily of reserpine on day 8 to 11 Re-induction of lactation was successful in all 9 animals and in 2nd induced lactation they produced milk for 228 to 426 days. Milk yield of animals ranged from 4.1 to 9.6 kg day !1 during first induced lactation and 3.9 to 9.2 kg day !1 in 2nd induced lactation.
Protocol # 7:
Buffalo protocol (Singh et al., 2002) Protocol tested on 4 repeat breeding multiparous buffaloes and two heifers of Murrah breed.
Protocol:
1. Day 1 to 7: Estradiol-17 â (0.1 mg kg !1 ) and progesterone (0.1 mg kg !1 ) dissolved in absolute alcohol and administered subcutaneously in the neck during and evening. 2. Udder stimulation (massage) started on Day 8 and continued till the udder was full of secretion 3. Day 23 to 24: milking started. In the beginning, 4 treated buffaloes yielded a greenish yellow secretion whereas 2 buffaloes produced normal looking white milk even on the first day of milking. The buffaloes produced 3.7, 3.8, 8.0, 6.5, 6.7 and 7.5 kg milk day !1 at peak lactation. Milk composition changed to normal over a period of 7-14 days. There was a significant decrease in levels of plasma growth hormone after start of lactation. Per rectal examination indicated changes in reproductive organs due to treatment with the hormones. Out of the 6 buffaloes induced into lactation, 3 became pregnant. This study indicated that induction of lactation could also prove useful in correcting reproductive disorders.
Endocrinological and therapeutic basis of induction of lactation in cows and buffaloes:
In artificial induction of lactation by hormones and drugs, we try to create conditions which resemble the mammary gland development during pregnancy and particularly at the time of parturition. During the last few days of pregnancy, levels of prolactin, estrogens and cortisol increase tremendously. Different hormones (e.g. estrogen, progesterone, prolactin placental lactogen, insulin and glucocorticoids) act synergistically to induce lactation (Jewell, 2002). Functions of these hormones and other drugs are briefly described below :
Estrogen and progesterone:
Estrogen stimulates development and growth of mammary gland ducts. Estrogen and progesterone in combination stimulate development of lobule-alveolar tissue (milk producing tissue) of the mammary gland. Estrogen additionally helps in initiation of lactation in two ways. Firstly, it causes release of prolactin from the anterior pituitary gland into the blood. Secondly, it causes an increase in prolactin receptors in mammary cells (Tucker, 2000; Jewell, 2002).
Glucocorticoids ( e .g. co r tiso l and dexamethasone):
Glucocorticoids cause alveolar cell differentiation of the mammary gland. They compete with the progesterone for binding sites on the mammary epithelial cells. Injecting glucocorticoidsto dry cows which have already been treated with estrogen and progesterone (and thus have a developed mammary gland) helps in the induction of lactation. An increased level of glucocorticoid as a result of dexamethasone injection, would displace progesterone from the receptors on mammary cells, thus reducing the inhibitory action of progesterone on the synthesis of prolactin receptors .
Prolactin:
Prolactin is released from anterior pituitary gland. Its main function is lactogenesis and not galactopoiesis. Stimulation of udder and teats (e.g. by massage) at the time of milking causes release of prolactin. Prolactin is not required for milk production after lactation has been established.
Bovine somatotropin (bSTr, growth hormone):
bSTr is used to increase milk production. Magliaro et al. (2004) evaluated the efficiency of bSTr in the increase in milk production in dairy cows artificially induced into lactation with estrogen and progesterone and observed that bSTr treated cows produced 21.9% more milk when compared to induced cows that did not receive bSTr. Growth hormone increases milk production by partitioning of available nutrients away from body tissues and towards milk synthesis.
Role of prostaglandins (e.g. PGF2á ):
For artificial induction of lactation PGF2á is used to induce luteolysis which brings all treated cows and buffaloes in a uniform phase of the estrous cycle. This uniformity may eliminate variations among animals related to differences in concentrations of estrogen, progesterone, glucocorticoids and prolactin at the time of initiation of lactation. In addition, removing the progesterone source (corpus luteum) by PGF2á may allow induced cows to be more responsive to reserpine and dexamethasone treatment following the initial estrogen and progesterone treatment. It also allows glucocorticoids to displace progesterone from binding sites in mammary tissue, thereby removing the progesterone block to lactogenesis. Thus, use of PGF2á to induce luteolysis offers the opportunity to initiate a lactation induction protocol during very different stages of the estrous cycle; estrus and metestrus when progesterone is low and estrogen is elevated, or diestrus when progesterone is the dominant steroid hormone.
Thyroid and parathyroid hormones:
Thyroid hormone is an iodine containing hormone that increases the basic metabolic rate of the animal. Owing to loss of iodine in the milk, during lactation, the mammary gland is in a euthyroid state while the rest of the body is hypothyroid . During lactation, parathyroid hormone isresponsible for removal of calcium from the bones and adding it to the blood for milk synthesis.
Insulin:
In cattle, insulin is involved in mechanisms partitioning nutrients away from synthesis of milk and towards body tissues. Thus, higher the insulin consideration, the lower the milk yield .
Reserpine:
Reserpine (an alkaloid obtained fromthe roots of Rauwolfia serpentina) is used to stimulate release of prolactin and its use decreases the variation in milk production amongst animals as well as it shows an increase in the induction of lactation rate .
Milk Yield and Quality:
When induced heifers (responders) were compared with natural lactation the differences in milk compositions (fat, protein and lactose) were slight and non-significant .There was no effect of the artificial inductions of lactation protocols on milk composition and somatic cell count (SCC) (P>0.05) (Freitas et al., 2010). Milk production of induced cows has been variable, ranging from 63 to 106% from the best previous lactation (Magliaro et al., 2004). The milk yield was significantly (P<0.05) greater in pre-synchronized heifers with PGF2α (.25 mg) I/m as compared to non-synchornized heifers (Mohan et al., 2009). Uniform development of follicles following luteolysis coupled with metoclopramide therapy may be the reason for increased yield in pre-synchronized animals .
General considerations for artificial induction of lactation:
Artificial induction of lactation in cows or buffaloes should be taken as a last resort. One should exhaust all recommended procedures before considering induction of lactation Not all animals are suitable for artificial induction of lactation. Only cows and buffaloes with well-developed healthy teat and udder are suitable for induction of lactation. Treatment of cows and buffaloes suffering sub-clinical mastitis may flare up signs of acute clinical mastitis. For good results, artificial induction of lactation should be attempted only in those cows and buffaloes which have been good producers in the previous lactation. In cyclic cows and buffaloes, hormonal treatment should be started preferably 7 to 10 days after the animal is detected in heat. For good results, a thorough and frequent massage of udder is essential. In additional, one should start frequent milk as soon as secretion commences. Massage of udder and frequent milk will stimulate the hypophysis (pituitary gland) to secrete the hormones which promote mammary gland development, synthesis of milk and milk secretion . Owing to excretion of hormones in the milk, the milk of treated animal should not be put for human consumption for about 30 days from the start of the hormonal therapy. Treated animals requires separate special housing as they may show signs of heat If successive induction of lactation is considered, a dry period of at least 50 days should be targeted between two artificially induced lactation Cows and buffaloes with artificially induced lactation generally produce 60 to 70% of normal milk yield that they had yielded in the previous lactation after calving.
Source- Dr Manoj kr.Jha,Dairy Consultant,NewDelhi.
Reference-On request.
