EFFECT OF TWO METHODS OF SUCKLING ON THE YIELD OF MILK AND THE PERFORMANCE OF CALVES

Methods of milking influence the milk yield of a cow to a great extent. To obtain a high milk yield throughout a lactation, milking should be done quickly, quietly, cleanly and completely. Complete milking is very important and the calf could be introduced after milking to ensure that each quarter is completely milked. In Zebu crossbred cows suckling to stimulate milking seems particularly beneficial.'

were completely milked leaving the fourth t o the calf (3Q).The quarter t o be unmilked in 3Q was rotated weekly among the four quarters during each month for the two experiniental periods.In both treatments, calves were allowed to suckle all four quarters after milking.Before milking, suckling was used only as a stimulus for milk let-down as judged by the engorgement of teats.A simple change-over design was used to test the two treatments.
Two groups of experimental calves were kept in two separate pens, except at milking.In addition to the feeding of milk (through suckling only), concentrates (15% crude protein), Brachiaria brizantha (12.5% crude protein) and water for drinking were provided ad libitum.Proximate analysis of grass was determined according t o A.O.A.C. (1975).
The cows were milked twice daily by hand.After milking in the morning cows were allowed t o graze on natural pasture until they were milked in the afternoon and then kept in a small enclosure for the night without feed.

First preliminary investigation
Different stages afid timing of the existing once a day milking practices of the farm, as recorded with all the animals t o be included in the experiment are given in Table 1.Time of suckling required to stimulate milk let-down judged from the engorgement of teats was less before than after the first milking (Table 1, item 1 vs 5).As would be expected, the duration of milking until the quarter was empty was greater at first thac at the second milking (item 3 vs 7).The entire milking operation took 13.08 + 2.17 min.
(range 5.71 to 24.24 min) which tended to be greater than the normally accepted duration of the effect of oxytocin.

Third preliminary investigation
The results are presented in Table 3.There was an average of 40.13 k 10.54%' increase in the milk yield due t o twice a day milkjng as compared to once a day milking.Increasing the frequency of milking from twice a day to three and four times a day has also increased the milk yield of cows by 10-25% and 5-15%, respectively.'This tendency is in agreement with the present findings.The ad libitum intake of grass and concentrates by calves is presented in Table 5.The consumption of grass and concentrates by the calves OK' two treatments were approximately similar although they were offered ad libitum.Total DM intake from grass and concentrates was satisfactory, being 2.71 to 2.93% live vveight, where DM intake from grass accounted for 2.25 t o 2.41% live weight.On a fresh basis, the ad libitum intake of grass was about 5.5 kg/head/day.a Grass and concentrates were offered ad libitum and each value is a mean of 8 observa-'tions (4 weekly observations per experimental period x 2 experimental periods).Intake measured on a group basis and divided by 4 t o obtain per head intake.

Four quarters milked
Three quarters milked Suckling Effects on Calves and' Yield of Milk Data o n calf performance and milk yield are presented in Table 6.
The method of milking and suckling had no significant effect (p > .05) on any of the calf performance and milk yield data. Milking all four quarters (4Q) compared with the leaving of one quarter for the calf (3Q) tended to give a higher amount of milk in the bucket, but a reverse tendency in the intake of milk by the calf was noted as normally expected.Consequently the total amount of milk drawn was almost the same (3.68 vs 3.67 kg/cow/d) in the above two treatments.Although the intake of milk by calves was insufficient in 4Q and 3Q (3.39 and 3.65% live weight, respectively) the average daily gain (ADG) of calves was quite satisfactory by local standards.This may have been at least due partly to the adequate intake of grass and concentrates by the calves.
In both treatments the calves were allowed to suckle before each of the two milkings at a milking sessio~l in order t o stimulate milk let-down and were allowed ad libitum suckling only after two milkings were completed.If forages and concentrates of satisfactory quality are not available in required quantities, additional milk will have t o be offered t o the calves for satisfactory growth if the methods of suckling as done in this study are t o be adopted.
All the cows were free of mastitis, which may have been partly due t o suckliflnce a lower incidence of mastitis due t o suckling has been reported.The practice of suckling has also increased the total milk yield of cows.Considering the existing milking practices of the dairy herd, the practice of suckling is recommended t o be continued.Twice a day instead of once a day milking, however, be adopted and calves kept back from dams at grazing while offering the calves ad libztum good quality forages and concentrates in the pens.a Each value is a mean of 32 observations (4 cowlcalf palrs x 2 experimental periods x 4 weekly intervals per experimental period based on records kept daily) i k n e of the differences were significant (P> .05).

~athirana 1.2.. Second preliminary investigation
Data on the effect of suckling prestimulus on milk yield'are given in Table2.Without a suckling prestimulus the milk yield was only 4.49% that of the cows which were suckled befpre milking.The necessity for the presence of the calf for proper milk let--down in indigenous cows is thus confirmed.

Table 2 .
Effect of suckling on the amount of milk let-dew# . .sucklingEffects

Table 3 .
Effect of milking frequency on milk yield a hlran values of 6 days3.2.Experin~ent,al Phase;Proximate composition of forage (Brachiaria brizantha) offered is presented in Table4.The protein content of forage was acceptable (12.51%) by local standards and the dry matter (DM) content was as expected (20.32 5 2.69%)

Table 4 .
Proximate Composition of Brachiaria brizanthaa ~x ~i r i m e n t a l Chemical composition (%) o n DM basis period D.M. % Crude E. E. C. F. Ash N.F.E.protein a Grass offered was sampled once every 3 days , dry matter determined in triplicate and samples pooled within the two experimental periods for proximate analysis.. ..Table 5. Intake of Brachiaria brizantha And concentrates by calves on a DM ..basisaDry matter 'Grass ConcentratesTotal .

Table 6 .
Data on calf performance and milk yielda