Karan Swiss Research Articles

Polymorphism study of BMP-15 (FecXR) and GDF-9 gene related with twinning in cattle

Natural mutations in prolificacy genes in some species especially sheep has been shown transforming growth factor beta (TGF-β) super family ligands such as growth differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15) and their type I receptor (bone morphogenetic protein receptor, BMPR1B) crucial for ovulation and as well as for increasing litter size. Mutations in any of these genes increased prolificacy in carrier. The present investigation was carried out for identification of fecundity genes in cattle, with comparison of DNA fragment between dams bearing twin and singleton and to see inheritance pattern of these fragments in their twin progenies. The animals belonged to six breeds viz. pure (Sahiwal and Hariana) and three crossbreeds (Karan Swiss, Karan Fires, Holstein Friesian) besides other cross breeds of unknown lineage selected from field. The study involved analysis of genome related to twinning using molecular markers (PCR) on BMP-15 (FecXR) gene and A competitive technique called tetra-primer amplification refractory mutation system-PCR was adapted to type G1 locus mutation GDF-9 fecundity gene. PCR analysis of the FecXR allele of the BMP-15 gene detected the presence of wild-type allele in the dams and their progenies. An allele specific primer used for detection of GDF-9 gene mutation, identified only wild-type and control fragment which revealed the absence of the mutant fragment for this gene locus. The study revealed monomorphic pattern of the two fecundity genes BMP-15 and GDF-9 genes, which has no effect on twinning in cattle.

Economic Loss due to Clinical Mastitis in Crossbred Cows

Experimental data from stock-health registers and history sheets of animals maintained at the institute for a period of 12 years (2000-2011) was used for this study. A total of 1078 lactation records comprising Karan Fries (943) and Karan Swiss cows (135) were classified according to parity viz., I, II, III, IV, V, VI & above. The average days under treatment were maximum in Ist parity (14.28) and minimum in 3rd parity (8.63). The total treatment cost was more (P

Effect of parity, stage of lactation and udder type on milkability of crossbred dairy cows milked in automated Herringbone milking parlour

The aim of the study was to investigate the effect of parity, stage of lactation and udder type on milkability of crossbred dairy cows milked in automated Herringbone milking system. Crossbred cows (218; Karan Fries and Karan Swiss) of different parities, stages of lactation and udder types were milked in 8×2 low-line automated Herringbone milking parlour having automatic cluster removal (ACR) settings for a period of 3 months. The milkablity of cows in automated herringbone milking parlour was based on parameters such as total milk yield, milk yield/session, machineon time, yield first 2 min, and milk flow rates generated automatically in herd management Software during each session of milking. The results showed that milkability of cows was affected significantly based on parity and stage of lactation. The udder types had no effect on milkability except type D (pendulous) udders having least flow rate, which caused increased machine-on time. The overall mean milk flow rates over different intervals during the first two minutes of milking differed significantly in parity and udder types. Similarly, significant differences were observed in the flow rates over different intervals of milking.The milking efficiency benchmarks in terms of cow throughput and milk harvesting efficiency with 2 operators in the milking pit were 69.75±0.57 cows/ h and 305.21±2.75 kg/h, respectively. The operators had idle time during milking in batches of around 4.28 minutes/batch. It can be concluded from the present study that the milkability of crossbred dairy cows was significantly affected by parity, stage of lactation and type of udder in automated Herringbone milking parlour.

Establishment of Natural Levels of Thiocyanate in Milk of Different Breeds of Cow and Murrah Breed of Buffalo

Thiocyanate is a compound of Lactoperoxidase (LP) system in milk which helps naturally to preserve the milk. The malpractices of preserving the milk is done by adding thiocyanate in milk where chilling facilities does not exist. The natural thiocyanate level was determined to identify the externally added thiocyanate in milk of different breeds of cow and buffalo milk. Also, there is no study on the natural levels of thiocyanate in milk of cross breed (Karan Fries and Karan Swiss) and pure breed of cows (Sahiwal and Tharparkar) and Murrah breed of buffalo. The study was conducted on pooled milk samples of different breeds of cow and Murrah breed of Buffalo. The present investigation revealed the thiocyanate content of milk samples of individual crossbred Karan Fries and Karan Swiss cow and pure breeds Sahiwal and Tharparkar cow. The thiocyanate contents in individual milk samples of crossbred cows combined ranged from 6.01-8.92 mg/litre with an average of 7.30 ± 0.13. Similarly, the thiocyanate contents in individual milk samples of pure breeds of cows combined ranged from 6.41-9.68 mg/litre with an average of 7.87 ± 0.17. Likewise, the thiocyanate content in milk of all breeds of cows when combined and was determined and found in the ranged from 6.01-9.68 mg/litre with an average of 7.58 ± 0.27. In case of milk of Murrah buffaloes, the thiocyanate content in individual milk samples varied from 7.56 to 9.77 mg/litre with an average of 8.73 ± 0.19 mg/litre.

Climatic effects on occurrence of clinical mastitis in different breeds of cows and buffaloes

The study was conducted to find out the effect of different seasons on incidence of mastitis throughout the year in Indigenous cows, crossbred cows and Murrah buffaloes. Lactation records pertaining to the 12 year period were collected and incidence of mastitis was plotted against the climograph of the Karnal zone, Haryana, India. The hot humid climate was found to adversely affect the incidence of mastitis in all the breeds of cows and Murrah buffaloes. The incidence was significantly affected by the season (p<0.01) in all the breeds, however incidence was lowest in Murrah buffaloes in comparison to cows. Further incidence was more in Sahiwal and Tharparkar cows (p<0.01) than the crossbred Karan Swiss and Karan Fries cows. The increase in temperature humidity index resulted in increased incidence of mastitis in cows (p<0.01) but Murrah buffaloes were less affected.

Comparative evaluation of raw and roasted soybean in lactating crossbred cows

An experiment was conducted to evaluate the effect of roasting whole soybean in the local level on their chemical composition, nitrogen fractions, in situ degradability, and feeding performance in crossbred (Karan Swiss and Karan Fries) dairy cows. Twelve lactating crossbred cattle (369.08 ± 17.53 kg body weight) were randomly divided into two groups on the basis of milk yield (10.18 kg/day) and day of calving (89 days) in a randomized block design. Cows were fed green maize fodder and concentrate mixtures with 1 kg raw soybean as fed basis (7.6% of total diet) in the control group, where as roasted soybean replaced raw soybean in the treatment group to make both diets isonitrogenous and isocaloric. The roughage to concentrate ratio was around 55:45 in both diets. The cows were housed in individual byres and fed experimental diet for 90 days. The total dry matter intake per animal in both groups was similar. The digestibility of dry matter, organic matter, crude protein, ether extract, and neutral detergent fiber was comparable in both groups. The average milk production and fat-corrected milk yield per day was similar during the trial. Milk fat, milk protein, and solids not fat content remained unaffected and similar in both groups. All the animals maintained their body weight in both groups. Thus, rumen bypassing of protein fractions at the present method of bypassing did not have the desired level of beneficial effect in medium producing crossbred cows.

Nutritional evaluation of transgenic cottonseed in the ration of lactating dairy cows

The effects of feeding transgenic (Bt) whole cottonseed (WCS) were studied in lactating cows. Twenty multiparous crossbred cows (Karan Swiss x Karan Fries) in early lactation were given a concentrate mixture containing 40% crushed delinted non-transgenic (non-Bt) WCS, 2 kg wheat straw and green fodder ad lib for a 15-day adaptation period. Thereafter, the cows were divided in two similar groups of 10 each on the basis of milk yield, body weight (BW) and date of calving. The non-Bt control group continued on same ration, while for the Bt group the non-Bt WCS was replaced by transgenic WCS, in a feeding trial of four weeks. The diets provided a minimum of 2 kg cottonseed/cow/d. Mean DMI/100 kg BW and milk yield of non-Bt and Bt groups was 3.48 and 3.45 kg and 11.4 and 12.0 kg/d, respectively. Intake of nutrients, digestibility, milk production and body condition score (BCS) did not differ between the groups (P > 0.05), but BW gain was higher (P < 0.05) in the Bt group than the non-Bt group, probably as a result of hoof problem in two cows of non-Bt group, which when compared excluding two animals from each group did not differ significantly (P > 0.05). Transgenic protein (Cry1C) was not detected in the weekly milk samples or in blood plasma at the end of the experiment, showing that delinted WCS containing Cry1C protein can safely be fed to lactating cows.

Performance Evaluation of Karan Fries and Karan Swiss Cattle under Closed Breeding System

The 490 and 380 performance records of Karan Fries and Karan Swiss cows developed through crossbreeding followed by inter-se mating were evaluated for production, reproduction performance and disposal rate. Duration of study (1982-92) was grouped into five periods (1982-83; 1984-85; 1986-87; 1988-89; 1990-92) and each year was divided into four seasons (Winter: Dec.- Jan.; Spring: Feb.-March; Summer: April-June; Rainy: July-Sept.; Autumn: Oct.-Nov). Data were also classified according to sire and level of inbreeding. The least squares means of FLY (first lactation yield -305 days), FLL (first lactation length), FSP (first service period), FDP (first dry period), FCI (first calving interval ), MY/FLL (milk yield per day of first lactation length), MY/FCI (milk yield per day of first calving interval), EBV (expected breeding value) and EBE (expected breeding efficiency) were 3,173±82 kg, 346±11 days, 143±11 days, 75±6 days, 423±11 days, 10.6±0.2 kg, 8.9±0.2 kg, 3,380±26 kg, and 88.2±1.3% respectively in Karan Fries. Corresponding estimates in Karan Swiss cows were 2,616±82 kg, 328±8 days, 148±12 days, 103±9 days, 435±13 days, 8.9±0.2 kg, 7.2±0.3 kg, 2,924±38 kg and 86.0±3.8% respectively. The effect of sire was significant on FLY, MY/FLL, MY/FCI and EBV in both the herd (p<0.01). The 10 and 15% sires showed superiority (FLY) over herd average of 11 and 7% in Karan Fries and 32 and 21% in Karan Swiss cattle respectively. Inbreeding has adversely and significantly (p<0.05) affected the FLY, MY/FLL, MY/FCI and survivability of Karan Fries females; FDP and disposal through culling of Karan Swiss heifers. The Karan Fries heifers with inbreeding above 12.5% performed 16% lower FLY to herd average. The effect of season of calving was significant on FLL, FSP and FCI (p<0.05) in Karan Fries. Summer calvers (361±12) were have higher lactation length and autumn calvers (329±14) had minimum. Period of calving significantly influenced the FSP, FCI, MY/FLL and MY/FCI in Karan Fries and FLY, MY/FLL and MY/FCI in Karan Swiss. Production efficiency traits in Karan Fries herd witnessed higher yield in the last two periods whereas, Karan Swiss heifers showed fluctuating performance. The findings suggested judicious use of available genetic variability, keeping of inbreeding under safer level and managemental interventions for the consistent improvement of both herds. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 1 : 1-6)

Disposal Pattern and Its Impact on Milk Production and Herd Size in Karan Fries and Karan Swiss Cows

Data on 958 Karan Fries (KF) and 780 Karan Swiss (KS) cows, born during 1974 to 1992 at National Dairy Research Institute, Karnal were evaluated for causes of culling and their impact on milk performance and herd strength. Causes of culling were classified as voluntary culling (low milk yield) and involuntary culling (other than milk yield). The milk yield of cows was evaluated inretrospectively by estimating expected breeding value (EBV) on the basis of first lactation yield (FLY) and all available lactation yield (ALY). The culling rate of KF cows over the years varied from 10.89 (1988) to 33.92% (1991) with an overall average of 20.96% and in KS from 19.91 (1984) to 33.74% (1989) with an overall average of 25.01%. Reproductive disorders, teat and udder problems, low milk production, health and locomotive disorders were the major reasons of culling accounted respectively for 5.56, 4.97, 4.61, 3.18 and 2.24% of herd strength in KF cows. The corresponding causes of culling were 6.20, 6.26, 7.69, 1.49 and 2.67% of herd strength in KS cows. The involuntary culling of cows accounted for 82.4% in K F and 76.1% in KS cows of total culling. The average annual disposal rate in KF and KS was 26 and 30% whereas annual replacement rate was 24 and 26% respectively. The EBV of involuntary culled cows on the basis of FLY and ALY was 3,111 and 3,515 kg in KF; and 2,669 and 2,940 kg in KS cows respectively. The EBV of selected cows on the basis of FLY and ALY was 3,242 and 3,549 kg in KF and 2,893 and 3,245 kg in KS cows respectively. The average breeding value of involuntary culled cows was not significantly different from selected cows in both the herds. The high rate of involuntary culling of potential cows might be major factor responsible for declined performance and size in these herds. The results indicated that higher genetic gain (2.14% of herd average in KF and 3.49% of herd average in KS) could be obtained by restricting the involuntary culling (50% of total culling) through improved management practices and increasing replacement rate.

Mortality Patterns in Dairy Animals under Organized Herd Management Conditions at Karnal India

Mortality patterns of two Zebu cattle breeds, Sahiwal and Tharparkar, and two crossbred strains, Karan Swiss and Karan Fries, maintained at the National Dairy Research Institute, Karnal were studied. Nine-year (1989--90 to 1997--98) data on mortality were analysed for year, season, age and cause effects on mortality rate. The overall mortality was 14.17%. The mortality in Sahiwal, Tharparkar, Karan Swiss and Karan Fries averaged 14.35%, 7.21%, 17.12% and 13.46%, respectively. The breed mortality rate did not vary significantly between years, seasons, age categories and causes of disease. However, the trends indicated appreciable difference in mortality rates. The mortality was highest in the year 1994--95 (19.53%) and lowest in 1991--92 (8.56%). There was very little variation in seasonal mortality rate and mortality rate averaged 4.53%, 4.81% and 4.84% in hot-dry (March-June), hot-humid (July-October) and cold (November-February) seasons, respectively. The mortality up to 2 months of age accounted for a major share (50-60% or higher) in different breed groups. Digestive problems followed by respiratory disorders together accounted for 70-80% of total deaths.

Performance evaluation, conservation and improvement of Sahiwal cattle in India

SummaryThe Sahiwal cattle, one of the best dairy breeds of Zebu cattle in India and Pakistan, originate from the Montgomery district of Pakistan and is distributed on farmer herds in certain pockets of the bordering districts of Punjab and Rajsthan in India. The animals of this breed are also available in Kenya and are used for crossing with local East African Zebu types to improve milk production. Sahiwal cattle have deep body, loose skin, short legs, stumpy horns and a broad head with pale red to dark brown body colour. The average body weight in adult females and males is around 350 and 500 kg, respectively. The animals of this breed are maintained on various State and Central Government farms, privately owned farms, charitable trusts and a small proportion of animals are also available with the farmers. More than 1 200 breedable females are available at various farms in the country. The average lactation milk yield of Sahiwal cattle on organized farms ranges between 1 500 to 2 500 kg. However, in well-managed herds, the highest lactation milk production in certain cows is more than 4 500 kg. The overall weighted average milk yield, age at first calving, lactation length and calving interval based on the performance at various herds is around 1 900 kg, 36 months, 315 days and 420 days, respectively. The fat and Solid Non Fat (SNF) percent ranges from 4.6 to 5.2 percent and 8.9 to 9.3 percent, respectively. Quite a large proportion of pure-bred Sahiwal cattle maintained on organized breeding farms has been used for the production of cross-bred cattle. As a result, different cross-bred strains of dairy cattle viz Karan Swiss, Karan Fries and Frieswal have evolved at the National Dairy Research Institute, Karnal and Military Dairy Farms. The breed has also been utilized for the production of synthetic strains like Jamaica Hope (JH), Australian Milking Zebu (AMZ) and Australian Friesian Sahiwal (AFS) in other countries. Currently, efforts are being made to characterize, evaluate and conserve the breed in field conditions. More than 0.10 million doses of frozen semen of this breed are cryopreserved at various semen banks in the country. The frozen semen is being utilized for strengthening and genetically improving the existing herds of the breed through progeny testing programmes of sires associating various herds of Sahiwal in the country.

Sperm chromosome analysis of Karan Swiss and Karan Fries crossbred bulls

Abstract Zona-free hamster eggs were penetrated by Karan Swiss and Karan Fries crossbred bull spermatozoa capacitated using calcium ionophore A23187. Zona-free hamster egg penetration percentage varied between 59 and 83 among 11 crossbred bulls. Penetrated eggs were cultured in TC 199 medium with 10% fetal calf serum. Podophyllotoxin and vinblastine were used to interrupt karyogamy and tubulin polymerization, respectively. Gradual fixation air drying method was modified for the preparation of slides. Hamster cattle metaphase yield was 28 ± 5.2%. The analysis of 105 crossbred cattle sperm metaphases indicated that 51 contained a Y-chromosome and 54 had an X-chromosome. The incidence of aneuploidy was 14.28%.

Mimosine degradation in calves fed a sole diet of Leucaena leucocephala in India.

Five Karan Swiss crossbred (Sahiwal x Brown Swiss) calves were abruptly switched over from a diet of concentrate and maize fodder to ad libitum air dried Leucaena leucocephala leaves plus twigs. After 17 days on the L. leucocephala diet, 3 of the calves were supplemented with copper sulphate (10 mg/kg DM L. leucocephala) for 12 days. Thereafter all the calves were taken off the L. leucocephala diet and returned to the pre-experimental concentrate and maize fodder diet. While on the L. leucocephala diet, the average DM intake/d of L. leucocephala declined to 497 g within 3 weeks and all calves lost weight. This weight loss was reversed in the 3 calves that received copper sulphate, and all calves gained weight when they resumed the concentrate and maize fodder diet. The toxic effects of L. leucocephala feeding for 24 days were characterised by poor growth, emaciation, alopecia, loss of hair from the tail switch, ear and eye lesions, ulceration of the mouth region, drooling viscid saliva and vomiting of thick green saliva in one of the calves. Mean levels of 3,4 dihydroxypyridone (DHP) (mg/100 ml) were 30.35 +/- 13.52 and 55.57 +/- 13.77 on days 2 and 4 respectively in rumen liquor and up to 136.01 +/- 80.18 in urine. The mean ratios of mimosine: DHP of 3.14, 0.12 and 0.04 in feed, faeces and urine respectively revealed extensive degradation of mimosine to DHP in the calves fed the L. leucocephala diet and it was concluded the calves were unable to tolerate a diet consisting solely of L. leucocephala.

Influence of gestation on blood plasma concentrations of oestrone and oestrone sulphate in Karan Swiss cows and murrah buffaloes

Single blood samples from 106 pregnant and seven non-pregnant Karan Swiss cows and 104 pregnant and nine non-pregnant Murrah buffaloes were measured for oestrone and oestrone sulphate hormones by radioimmunoassay. Mean plasma oestrone level was below detection limit (< 2·5 pg/ml) in non-pregnant and 1 month pregnant cows and buffaloes. In cows the mean oestrone level fluctuated narrowly between 10·25 and 26·65 pg/ml between the second and eighth months of pregnancy, followed by a steep rise in the ninth and especially in the tenth month (151·24 pg/ml). In buffaloes mean oestrone concentrations were lower and fluctuated between 14·81 and 23·56 pg/ml during the second to ninth months of pregnancy, rising sharply in the tenth month to a peak of 47·37 pg/ml. Mean oestrone sulphate levels were below detection limit (< 16 pg/ml) during non-pregnancy, first and second months of pregnancy in cows, increasing sharply thereafter to a peak of 6401·38 pg/ml in the tenth month of pregnancy. In buffaloes, low mean levels of oestrone sulphate were recorded in the non-pregnant and up to the fourth month of pregnancy with the levels rising sharply thereafter to a peak of 6559·82 pg/ml in the tenth month. The hormone levels were not significantly different in the two species ( P > 0·01). The possibility of using oestrone sulphate measurement as a test of pregnancy confirmation has been indicated for both species.

Influence of gestation on jugular plasma thyroxine levels in Murrah buffalo and Karan Swiss cows

Plasma samples from 106 pregnant Karan Swiss (Brown Swiss x Sahiwal) cows and 108 Murrah buffalo were tested for thyroxine (T(4)) levels to determine the relationship between the hormonal changes and advancing pregnancy in the two species. All samples were collected within 2 months (January and February) to avoid seasonal interference on T(4) levels. In pregnant cows, the concentration of T(4) increased sharply during the first trimester, reaching a peak at the third month of gestation followed by a gradual decline until the last month of pregnancy. In pregnant buffalo, peripheral plasma T(4) levels fluctuated slightly throughout pregnancy without exhibiting a specific trend. Statistical analysis revealed that the magnitude of T(4) levels was significantly lower in buffalo (P < 0.01) than in the cows throughout pregnancy and that the hormonal patterns of the two species were significantly different (P < 0.05) during gestation. It was hypothesized from this study that T(4) requirements for the fetal buffalo calf may be lower than that for the fetal cattle calf since the buffalo gestation period is a month longer and the metabolic rate lower vis-a-vis the cow.

A conceptual model for inter se mating of cows in India

Results of crossbreeding experiments for milk production revealed that in an inter se-mated population of Karan Swiss cows, 305-days first lactation milk output of F 1, F 2 and F 3 progenies was 2690 ± 40, 2159 ± 55 and 2018 ± 43 kg, respectively. In F 2 and F 3 progeny milk yield registered a decline of 19·73 and 24·98%, respectively. First lactation milk output of 23% of F 2 and 33% of F 3 progeny was less than the herd average of their Zebu parental stock. With a view to improving the productivity of low producing inter se-mated cows a model was constructed.

Retained placenta and plasma prostaglandin F profile after induced parturition in Karan Swiss cattle.

Abstract Fifteen Karan Swiss (Brown Swiss x Sahiwal) cows were assigned to one of three groups: group A calved spontaneously, groups B and C were induced to calve nearly one month prior to expected term by administration of dexamethasone alone, and dexamethasone along with stilboestrol dipropionate, respectively. The object of the experiment was to investigate and compare the prostaglandin F profile in cows peripartum and relate the changes (if any) to the expulsion of placenta. All induced cows retained their placentas. The periparturient prostaglandin F profile was similar among all groups and indicated a sharp rise in prostaglandin F levels at calving, which declined gradually to basal levels by day 18 post partum . No relationship could be established between the prostaglandin F pattern peripartum and placental retention among induced animals.

Concentrations of plasma hormones in relation to placental retention in Karan Swiss cows during and after induction of parturition with dexamethasone and stilboestrol dipropionate

ABSTRACTFive Karan Swiss cows were allowed to calve spontaneously and served as controls (Group A), while another 10 were induced to calve about 1 month prior to expected term using either 25 mg dexamethasone alone (Group B) or 25 mg dexamethasone in combination with 25 mg stilboestrol dipropionate (Group C). Blood samples were collected prior to, and for 50 days following, parturition for subsequent hormone analysis, and observations were made on the occurrence of retained placentae.Parturition was successfully induced in all treated cows within 72 h of drug administration. Placental membranes were retained for 24 h in all treated animals and were manually removed in the farm veterinary clinic. No incidence of placental retention occurred in control cows.Mean plasma oestradiol-17β in control cows showed a gradual rise from days 30 to 5 pre partum, followed by a sharp increase to peak value 1 day before calving. The rise in mean oestradiol-17β levels in the 2 days before parturition in controls was significantly greater than that recorded for the treated animals. A precipitous drop in plasma oestradiol-17β level occurred following parturition in all groups, with the levels staying low for the rest of the sampling period. Drug administration to animals in groups B and C resulted in a rapid and significant drop in plasma progesterone concentrations to a level similar to that for control animals at parturition. Subsequently, the plasma progesterone remained low in all treatment groups. Mean plasma cortisol levels showed a significant but transient increase at calving in control cows, but were suppressed for at least 48 h following drug administration in treated cows before exhibiting a rebound phenomenon to reach high values after calving.It is concluded that for normal placental expulsion, oestradiol-17β levels are more critical than progesterone, and that the rise in oestradiol-17β and fall in progesterone levels pre partum must be gradual.

Induction of parturition in cattle

ABSTRACTTen crossbred (Karan Swiss) cows were induced to calve about 1 month prior to expected term using either 25 mg dexamethasone alone (Group B) or 25 mg dexamethasone in combination with 25 mg vetoestrol (Group C). Another five animals served as controls (Group A). The average time interval from injection to calving was not significantly influenced by the two treatments used, and was 52·2 ± 4·07 h and 49·0 ± 1·55 h for groups B and C respectively. The mean gestation lengths for animals in groups A, B and C were 283·60 ± 2·77, 255·20 ± 1·93 and 255·20 ± 2·3 days respectively. The calves born from cows induced to calve early were significantly lighter at birth compared to controls (P &lt; 0·05). The average live-weight gain over the first 12 weeks among calves was not significantly influenced by treatment averaging 2·58 ± 0·07, 2·81 ± 0·16 and 2·20 ± 0·16 kg/week for groups A, B and C respectively. Foetal membranes had not been voided by 24 h in the animals induced to calve early and hence required manual intervention. The length of the service period, number of services per conception and the milk yield of the cows induced to calve was not significantly different from their previous records (P &gt; 0·05).