Effect of functional traits on subsequent reproduction performance of Murrah buffaloes in India

ABSTRACT

A study was conducted on calving records of Murrah buffaloes to study the influence of various functional traits on subsequent reproductive performance. The effects of calving abnormalities, uterine health problems, female fertility problems and udder health problem on calving to first service (CFS), service period (SP), dry period (DP) and calving interval (CI) were studied by the least-squares method using the SAS package. The increase in CFS, SP, DP and CI was 27.07%, 18.71%, 96.74% and 6.70%, respectively. Subsequently, the average milk yield per day of calving interval was found to be reduced (from 4.91 to 2.10 kg/day) in these animals in comparison with the normal calvers. A highly significant increase in average CFS, SP, DP and CI was found among animals susceptible to metritis (16.93%, 73.88%, 53.92% and 20.04%, respectively). The decrease in average milk yield per day of calving interval (MY/CI) was 18.55% in comparison with the animals not affected by metritis. The average MY/CI was observed to be 16.47% lower in the anoestrus-affected animals in comparison with normal animals. The increase in average SP, DP and CI associated with repeat breeding cases was 162.63%, 87.58% and 50.15%, respectively. The increase in average DP and CI due to incidence of mastitis was 10.48% and 4.26%, respectively. The increase in average dry period associated with the incidence of mastitis during early stage of lactation (1–60 days) was 13.63%. The incidence of mastitis during early stage of lactation significantly reduced the average MY/CI by 5.50 and 14.20%, respectively.

KEYWORDS:

• Murrah buffaloes
• functional traits
• abnormal calving
• uterine health problems
• anoestrus
• repeat breeding
• fertility problems
• reproduction traits

1. Introduction

Buffalo is considered as the major dairy animal and backbone of Indian dairy production. It is now well established that buffalo represents a unique dairy animal in terms of feed conversion ability with low-grade course feeds, ability to sustain under adverse climatic conditions and resistance to many diseases of cattle. Buffalo's milk is superior to cow milk in fat content and total solids, giving more economic returns to farmers. Murrah is one of the superior breeds of Indian buffaloes, which constitutes around 65% of Indian buffaloes of well-defined breeds. Murrah buffaloes are being used for various buffalo improvement programmes inside and outside the country.

The economics of any dairy enterprise is influenced by the production, reproduction and health status of livestock. Various udder and reproductive disorders are causing huge economic losses in terms of discarded milk, production loss, treatment cost, reduced consumer's preference, increased service period (SP) and calving interval (CI). Among the reproductive problems, abnormal calving and utero-vaginal disorders are observed during the peri-partum period. The abnormal calvings such as abortion, premature birth, still birth and dystocia lead to reduced birth rate of live calves and hence reduced availability of replacement herd. Utero-vaginal disorders such as retention of foetal membranes (RFM), uterine and vaginal prolapse and metritis are also responsible for increased days open, dry period and services per conception. Incidence of other problems such as poor health, anoestrus, cystic ovaries and repeat breeding is also increased following abnormal calvings and utero-vaginal disorders. Among the lactation disorders, mastitis is the most important livestock disease affecting a variety of livestock species including cattle and buffaloes with major economic losses and trade impact around the globe.

Selection pressure on production traits increases milk yield in dairy animals but it also leads to an increased incidence of disease and reduced fertility. Better herd management can reduce the occurrence of disease and fertility problems but this may increase the cost of production. Therefore, a combination of better management and genetic selection for health traits is an effective long-term solution. The term ‘functional traits’ is used for those characters of an animal that increases efficiency not by higher output of product but by reduced costs of input (Groen 1996). Fertility, calving ease, morbidity, mortality, disposal pattern, udder and uterine disorders, etc. are some of the important functional indicator traits, which are associated with resultant higher culling rates, reduction in longevity of buffaloes, increased veterinary costs, losses due to lower production and discarded milk.

2. Materials and methods

The data on 1585 reproduction records of Murrah buffaloes maintained at National Dairy Research Institute, Karnal, Haryana (India), and spread over a period of 18 years (calved from 1993 to 2010) were used for the present investigation. The data were analysed using the SAS package (enterprise guide 5.1) to study the effect of various peri-parturient production and reproduction problems on the incidence of subsequent reproductive performance. The reproductive problems considered in the present investigation were abnormal calving (abortion, stillbirth, premature birth and dystocia), uterine health problems (RFM, Metritis and pyometra) and fertility problems (anoestrus and repeat breeding). The data were further analysed based on the type of anoestrus (true anoestrus and anoestrus due to persistent corpus luteum-PCL). The influence of various udder health problems was also considered in the study. The incidence of udder disorders especially mastitis varies significantly in different stages of lactation, thus the data were classified accordingly to early (1–60 days), mid (61–180 days) and late (above 180 days) lactation. The category variables 1 and 2 were assigned to the affected and non-affected buffaloes. The subsequent reproduction performance traits considered in the study were calving to first service (CFS), SP, dry period (DP) and CI. Milk yield per day of calving interval (MY/CI) was also considered to evaluate the production and reproduction efficiency. The following least-squares model was used for the analysis:

where Y_ij is the reproduction performance of the jth buffalo that suffered from a particular health problem, μ the population mean d_i  the effect of the ith category of health problem (i = 1 for affected, i = 2 for non-affected) and e_ij the random error associated with Y_ij NID (0,σ²)

3. Results

The data on all lactation records on Murrah buffaloes including those suffering from calving abnormalities, uterine health problems, fertility problems and udder health problems were analysed by least-squares analysis of variance (ANOVA) to examine the effect of these disorders on reproduction performance of buffaloes.

3.1. Effect of abnormal calvings

Least-squares ANOVA of subsequent reproduction performance traits in relation to various types of calving abnormalities has been presented in Table 1. The influence of overall calving abnormalities and abortion were highly significant (p < .01) for CFS, DP and MY/CI. Significant variation in SP and CI was observed between two groups of animals (affected vs. not affected). Premature birth caused significant variation in SP and CI. Still birth was found to be a highly significant (p < .01) source of variation on DP and MY/CI. The least-squares means of CFS, SP, DP, CI and MY/CI in association with various calving abnormalities are presented in Tables 2 and 3.

Table 1. Least-squares ANOVA of reproduction performance traits in relation to calving abnormalities and uterine health problems.

Source of variation	df	Mean sum of squares
		CFS	SP	DP	CI	MY/CI
Effect of overall calving abnormalities
Overall	1	54,414.8**	73,568.4*	1,670,083.5**	70,172.3*	557.42**
Error		3171.5	12,943.3	13,098.4	13,671.0	3.95
Effect of abortion
Abortion	1	71,855.2**	41,158.5	1,983,537.7**	39,454.7	573.58**
Error		3160.5	12,963.2	12,890.1	13,691.4	3.94
Effect of premature birth
Premature birth	1	3.0	77,488.9*	10,293.0	66,102.0*	5.42
Error		3205.9	12,940.8	14,201.2	13,673.7	4.31
Effect of still birth
Still birth	1	3.7	272.4	85,092.9**	160.4	62.59**
Error		3205.9	12,988.4	14,151.5	13,717.5	4.28
Effect of dystocia
Dystocia	1	285.1	26,182.6	22,962.7	27,877.2	10.19
Error		3205.7	12,972.4	14,192.8	13,699.1	4.31
Effect of overall uterine health problems
Overall	1	22,739.5**	1,808,313.1**	1,395,547.4**	1,565,642.1**	283.10**
Error		3191.5	11,875.1	13,280.8	12,678.7	4.13
Effect of RFM
RFM	1	1863.6	3952.7	1,22,486.1**	2181.9	59.58**
Error		3204.7	12,986.1	14,126.7	13,716.1	4.28
Effect of endometritis
Endometritis	1	6312.3	22,677.5	1,42,559.1**	36,110.1	55.31**
Error		3201.9	12,974.6	14,113.3	13,693.6	4.28
Effect of metritis
Metritis	1	78,439.4**	3,122,164.5**	1,973,451.1**	2,668,365.0**	320.25**
Error		3156.3	11,066.0	12,896.8	11,946.9	4.11
Effect of pyometra
Pyometra	1	45,728.5**	1,95,021.8**	1,50,932.7**	1,46,385.0**	23.14*
Error		3177.0	12,868.5	14,107.8	13,620.4	4.30
Error DF		1583	1624	1503	1503	1503

Notes: *Significant (p < .05).

**Significant (p < .01).

Table 2. Least-squares means of reproduction performance traits (CFS and SP) in relation to various calving abnormalities and uterine health problems in Murrah buffaloes (affected vs. non-affected).

Effect	Status	CFS (days)			SP (days)
		No.	Mean	SE	N	Mean	SE
Calving abnormality	Non-affected	1487	89.83^a	1.46	1533	154.78^a	2.91
	Affected	98	114.15^b	5.69	93	183.74^b	11.80
Abortion	Non-affected	1513	89.86^a	1.45	1558	155.38	2.88
	Affected	72	122.19^b	6.63	68	180.51	13.81
Premature birth	Non-affected	1582	91.33	1.42	1623	156.14	2.82
	Affected	3	90.33	32.69	3	317.00	65.68
Still birth	Non-affected	1565	91.33	1.43	1606	156.39	2.84
	Affected	20	90.90	12.66	20	160.10	25.48
Dystocia	Non-affected	1577	91.36	1.43	1618	156.15	2.83
	Affected	8	85.38	20.02	8	213.50	40.27
Uterine health problems	Non-affected	813	87.64^a	1.98	845	124.37^a	3.75
	Affected	772	95.22^b	2.03	781	191.12^b	3.90
RFM	Non-affected	1398	90.93	1.51	1441	155.87	3.00
	Affected	187	94.29	4.14	185	160.78	8.38
Endometritis	Non-affected	1354	92.15	1.54	1398	154.92	3.05
	Affected	231	86.50	3.72	228	165.68	7.54
Metritis	Non-affected	991	85.88^a	1.78	1023	122.79^a	3.29
	Affected	594	100.42^b	2.31	603	213.51^b	4.28
Pyometra	Non-affected	1532	90.33^a	1.44	1571	154.38^a	2.86
	Affected	53	120.21^b	7.74	55	214.96^b	15.30

Note: Means with different superscript differ significantly in each effect.

Table 3. Least-squares means of various reproduction traits (DP, CI and MY/CI) in relation to calving abnormalities and uterine health problems in Murrah buffaloes (affected vs. non-affected).

Effect	Status	No.	DP (days)		CI (days)		MY/CI (kg/day)
			Mean	SE	Mean	SE	Mean	SE
Calving abnormality	Non-affected	1431	159.25^a	3.02	465.81^a	3.09	4.91^a	0.05
	Affected	74	313.31^b	13.30	496.99^b	13.41	2.10^b	0.23
Abortion	Non-affected	1455	160.10^a	2.97	466.41	3.07	4.89^a	0.05
	Affected	50	362.66^b	16.06	494.44	16.23	1.48^b	0.28
Premature birth	Non-affected	1502	166.70	3.07	467.08^a	3.01	4.78	0.05
	Affected	3	225.33	68.80	615.67^b	67.51	3.43	1.20
Still birth	Non-affected	1486	165.97^a	3.08	467.34	3.03	4.80^a	0.05
	Affected	19	233.32^b	27.29	470.26	26.87	2.92^b	0.49
Dystocia	Non-affected	1497	166.53	3.08	467.06	3.02	4.78	0.05
	Affected	8	220.25	42.12	526.25	41.38	3.65	0.73
Uterine health problems	Non-affected	786	137.75^a	4.11	436.57^a	4.01	5.19^a	0.07
	Affected	719	198.68^b	4.30	501.05^b	4.19	4.32^b	0.08
RFM	Non-affected	1341	163.67^a	3.24	466.95	3.20	4.85^a	0.06
	Affected	164	192.62^b	9.28	470.78	9.06	4.21^b	0.16
Endometritis	Non-affected	1291	162.86^a	3.30	465.38	3.25	4.85^a	0.06
	Affected	214	190.72^b	8.12	479.38	7.98	4.31^b	0.14
Metritis	Non-affected	953	139.31^a	3.67	435.35^a	3.54	5.12^a	0.07
	Affected	552	214.42^b	4.83	522.59^b	4.64	4.17^b	0.09
Pyometra	Non-affected	1455	164.96^a	3.11	465.55^a	3.06	4.80^a	0.05
	Affected	50	220.84^b	16.80	520.58^b	16.50	4.11^b	0.29

Note: Means with different superscript differ significantly in each effect.

Significantly higher values of CFS, SP, DP and CI were observed in the animals affected with any of the calving abnormalities in comparison to the non-affected group. The increase in CFS, SP, DP and CI was 27.07%, 18.71%, 96.74% and 6.70%, respectively. Subsequently, the average MY/CI was found to be reduced (from 4.91 to 2.10 kg/day) in these animals in comparison with the normal calvers. Significantly longer DP in association with abnormal births in Murrah buffaloes were reported (Tomar & Verma 1984).

3.2. Effect of uterine health problems

The least-squares ANOVA (mean sum of squares) of reproduction performance traits in relation to various uterine health problems are presented in Table 1. The influence of overall uterine health problems, metritis and pyometra on CFS, SP, DP, CI and MY/CI was highly significant (p < .01). RFM and endometritis showed highly significant (p < .01) effect on average DP and MY/CI.

The least-squares means of CFS, SP, DP, CI and MY/CI in association with various uterine health problems are presented in Tables 2 and 3. The overall uterine health problems resulted in a significant increase in average CFS, SP, DP and CI in Murrah buffaloes. The average MY/CI was significantly lower among animals suffering from uterine health problems in comparison with normal.

3.3. Effect of fertility problems

The least-squares ANOVA (mean sum of squares) of reproduction performance traits in relation to various fertility problems are presented in Table 4. The effect of incidence of overall fertility problems was found to be highly significant for CFS, SP, DP, CI and MY/CI. The influences of overall anoestrus, true anoestrus and anoestrus PCL were found to be significant on CFS, SP, DP, CI and MY/CI. The variations in SP, DP, CI and MY/CI were significantly different between animals affected and non-affected with repeat breeding. However, the average CFS was not significantly different in repeat breeder cases.

Table 4. Least-squares ANOVA of reproduction performance traits in relation to various fertility-related problems.

Source of variation	df	Mean sum of squares
		CFS	SP	DP	CI	MY/CI
Effect of overall fertility problems
Overall	1	466,224.4**	6,044,372.3**	1,943,757.4**	4,896,833.3**	225.21**
Error		2911.4	9266.7	12,916.5	10,468.2	4.17
Effect of anoestrus
Anoestrus	1	565,516.9**	4,550,394.8**	1,550,253.9**	3,502,641.8**	222.02**
Error		2848.6	10,186.6	13,178.0	11,393.3	4.17
Effect of true anoestrus
True anoestrus	1	482,614.1**	3,517,940.5**	1,025,779.4**	2,896,112.4**	91.12**
Error		2901.0	10,822.3	13,526.5	11,795.8	4.26
Effect of anoestrus PCL
Anoestrus PCL	1	311,190.2**	2,846,764.6**	1,106,484.2**	2,162,974.0**	143.77**
Error		3009.3	11,235.6	13,472.9	12,282.3	4.22
Effect of repeat breeding
Repeat breeding	1	2125.5	4,905,551.2**	1,676,189.7**	4,469,218.0**	47.31**
Error		3204.5	9967.9	13,094.3	10,751.9	4.29
Effect of prolapse
Prolapse	1	3620.8	15,559.7	1488.5	10,219.3	0.29
Error		3203.6	12,979.0	14,207.1	13,710.8	4.32
Effect of cystic ovary
Cystic ovary	1	142,299.4**	435,638.1**	158,170.0**	274,738.1**	6.23
Error		3116.0	12,720.3	14,103.0	13,535.3	4.31
Effect of gestational heat
Gestational heat	1	27.61	14,222.1	3815.6	814.1	2.74
Error		3205.85	12,979.8	14,205.5	13,717.0	4.32
Effect of ovulation abnormalities
Ovulation abnormalities	1	54,389.4**	371,829.4**	79,233.0*	249,809.0**	2.89
Error		3171.5	12,759.6	14,155.4	13,551.8	4.32
Error DF		1583	1624	1503	1503	1503

Notes: *Significant (p < .05).

**Significant (p < .01).

The least-squares means of CFS, SP, DP, CI and MY/CI in association with incidence of various fertility problems are presented in Tables 5 and 6. The incidence of various fertility problems like anoestrus (both true anoestrus and anoestrus PCL) was associated with significantly higher CFS, SP, DP and CI. The increase in average CFS, SP, DP and CI associated with anoestrus was 51.58%, 94.35%, 47.56% and 23.84%, respectively. The average MY/CI was also observed to be 16.47% lower in the affected animals in comparison with normal animals. The increase in average SP, DP and CI associated with repeat breeding cases was 162.63%, 87.58% and 50.15%, respectively.

Table 5. Least-squares means of reproduction performance traits (CFS and SP) in relation to various fertility-related problems in Murrah buffaloes (affected vs. non-affected).

Effect	Status	CFS (days)			SP (days)
		No.	Mean	SE	N	Mean	SE
Fertility problems	Non-affected	1015	78.48^a	1.69	1042	110.79^a	2.98
	Affected	570	114.22^b	2.26	584	237.87^b	3.98
Anoestrus	Non-affected	1071	78.24^a	1.63	1100	119.85^a	3.04
	Affected	514	118.60^b	2.35	526	232.93^b	4.40
True anoestrus	Non-affected	1271	82.66^a	1.51	1305	133.36^a	2.88
	Affected	314	126.44^b	3.04	321	250.22^b	5.81
Anoestrus PCL	Non-affected	1261	84.23^a	1.54	1297	135.36^a	2.94
	Affected	324	118.97^b	3.05	329	239.51^b	5.84
Repeat breeding	Non-affected	1488	91.63	1.47	1529	142.60^a	2.55
	Affected	97	86.79	5.75	97	374.51^b	10.14
Prolapse	Non-affected	1564	91.50	1.43	1605	156.08	2.84
	Affected	21	78.29	12.35	21	183.48	24.86
Cystic ovary	Non-affected	1570	90.40^a	1.41	1612	154.91^a	2.81
	Affected	15	188.27^b	14.41	14	332.07^b	30.14
Gestational heat	Non-affected	1552	91.35	1.44	1597	156.03	2.85
	Affected	33	90.42	9.86	29	178.38	21.16
Ovulation abnormalities	Non-affected	1568	90.72^a	1.42	1610	154.92^a	2.82
	Affected	17	147.59^b	13.66	16	308.13^b	28.24

Note: Means with different superscripts differ significantly in each effect.

Table 6. Least-squares means of various reproduction traits (DP, CI and MY/CI) in relation to fertility-related problems in Murrah buffaloes (affected vs. non-affected).

Effect	Status	No.	DP		CI		MY/CI
			Mean	SE	Mean	SE	Mean	SE
Fertility problems	Non-affected	973	140.25^a	3.64	425.28^a	3.27	5.06^a	0.07
	Affected	532	215.37^b	4.92	544.46^b	4.43	4.25^b	0.09
Anoestrus	Non-affected	1028	144.99^a	3.58	434.62^a	3.32	5.04^a	0.06
	Affected	477	213.95^b	5.26	538.24^b	4.89	4.21^b	0.09
True anoestrus	Non-affected	1206	153.84^a	3.35	445.60^a	3.12	4.90^a	0.06
	Affected	299	219.26^b	6.73	555.51^b	6.28	4.28^b	0.12
Anoestrus PCL	Non-affected	1212	153.51^a	3.33	448.83^a	3.18	4.93^a	0.06
	Affected	293	221.97^b	6.78	544.67^b	6.49	4.14^b	0.12
Repeat breeding	Non-affected	1412	158.26^a	3.04	453.51^a	2.75	4.82^a	0.05
	Affected	93	296.86^b	11.87	680.96^b	10.81	4.07^b	0.22
Prolapse	Non-affected	1487	166.93	3.09	467.08	3.03	4.77	0.05
	Affected	18	157.78	28.09	490.42	26.86	4.90	0.49
Cystic ovary	Non-affected	1493	165.90^a	3.07	466.17^a	3.01	4.78	0.05
	Affected	12	281.17^b	34.28	618.08^b	33.58	4.06	0.60
Gestational heat	Non-affected	1479	167.03	3.10	467.28	3.04	4.78	0.05
	Affected	26	154.81	23.37	472.92	22.97	4.45	0.41
Ovulation abnormalities	Non-affected	1493	166.17^a	3.08	466.22^a	3.01	4.78	0.05
	Affected	12	247.75^b	34.35	611.08^b	33.61	4.29	0.60

Note: Means with different superscripts differ significantly in each effect.

The influences of various miscellaneous fertility problems on reproduction performance traits were also analysed. The effect of ovarian disorders such as cystic ovary and ovulation abnormalities was found to be highly significant on CFS, SP, DP and CI. The animals affected with adhesion of reproductive organs were ultimately culled from the herd and subsequent records on reproduction performance of those were not available. The incidence of cystic ovary and ovulation abnormalities were associated with a significantly higher CFS, SP, DP and CI in Murrah buffaloes. The increase in average CFS, SP, DP and CI associated with the incidence of cystic ovary cases was 108.26%, 114.36%, 69.48% and 32.59%, respectively (Sharma 2010).

3.4. Effect of udder health problems

The least-squares ANOVA (mean sum of squares) of reproduction performance traits in relation to various udder health problems are depicted in Table 7. The overall udder health problems and mastitis were significantly affecting the average DP, CI and MY/CI in Murrah buffaloes. The incidence of mastitis during early stage of lactation and short lactation cases was significantly influencing DP and MY/CI. The mastitis during late stage of lactation and average CI also revealed significant association.

Table 7. Least-squares ANOVA of reproduction performance traits in relation to various udder health and short lactation problems.

Source of variation	df	Mean sum of squares
		CFS	SP	DP	CI	MY/CI
Effect of overall udder health problems
Overall	1	6734.47	46,353.78	72,825.1*	112,380.7**	17.32*
Error		3118.27	12,946.37	12,034.0	13,522.4	3.98
Effect of clinical mastitis
Clinical mastitis	1	5805.09	36,261.96	70,456.1*	100,631.5**	19.63*
Error		3118.88	12,952.79	12,035.6	13,530.4	3.97
Effect of lactation stage I mastitis
Stage one mastitis	1	8266.72	18,184.64	64,894.1*	2347.9	70.08**
Error		3117.26	12,964.29	12,039.3	13,596.9	3.94
Effect of lactation stage II mastitis
Stage two mastitis	1	1118.27	11,810.24	13,291.1	24,719.6	0.26
Error		3121.95	12,968.35	12,074.2	13,581.8	3.99
Effect of lactation stage III mastitis
Stage three mastitis	1	4003.82	146,126.79	635.7	1,45,840.1**	4.19
Error		3120.06	12,882.90	12,082.8	13,499.8	3.98
Effect of blood in milk
Blood in milk	1	2082.03	99.85	27,955.8	15,717.3	6.06
Error		3121.32	12,975.79	12,064.3	13,587.8	3.98
Effect of teat block
Teat block	1	3413.41	1300.52	631.9	440.3	0.07
Error		3120.44	12,975.03	12,082.8	13,598.2	3.99
Effect of teat/udder wound
Teat/udder wound	1	1528.13	1000.87	7880.3	4719.5	2.41
Error		3121.68	12,975.22	12,077.9	13,595.3	3.99
Effect of short lactation
Short lactation	1	1557.28	162.29	4,164,666.0**	4248.3	1345.72**
Error		3121.66	12,975.75	9267.3	13,595.6	3.08
Error DF		1524	1572	1478	1478	1478

*Significant (p < .05).

**Significant (p < .01).

The least-squares means of CFS, SP, DP, CI and MY/CI in association with incidence of various udder health problems are presented in Tables 8 and 9. The increase in average DP and CI associated with the incidence of overall udder health problems was 10.35% and 4.37%, respectively. The MY/CI was also significantly lower in the affected group. The increase in average DP and CI due to incidence of mastitis was 10.48% and 4.26%, respectively. The increase in average DP associated with the incidence mastitis during early stage of lactation was 13.63% in Murrah buffaloes. The incidence of overall mastitis and mastitis during early stage of lactation significantly reduced the average MY/CI by 5.50% and 14.20%, respectively.

Table 8. Least-squares means of reproduction performance traits (CFS and SP) in relation to various udder health and short lactation problems in Murrah buffaloes (affected vs. non-affected).

Effect	Status	CFS			SP
		N	Mean	SE	N	Mean	SE
Udder health problems	Unaffected	1133	89.19	1.66	1176	153.14	3.32
	Affected	393	94.00	2.82	398	165.63	5.70
Clinical mastitis	Unaffected	1167	89.35	1.63	1209	153.66	3.27
	Affected	359	93.95	2.95	365	165.03	5.96
Stage one mastitis	Unaffected	1361	89.62	1.51	1406	157.47	3.04
	Affected	165	97.12	4.35	168	146.46	8.78
Stage two mastitis	Unaffected	1385	90.16	1.50	1429	155.42	3.01
	Affected	141	93.11	4.71	145	164.90	9.46
Stage three mastitis	Unaffected	1411	89.97	1.49	1458	153.58^a	2.97
	Affected	115	96.10	5.21	116	190.46^b	10.54
Blood in milk	Unaffected	1504	90.57	1.44	1552	156.33	2.89
	Affected	22	80.77	11.91	22	154.18	24.29
Teat block	Unaffected	1488	90.192	1.45	1535	156.15	2.91
	Affected	38	99.79	9.06	39	162.00	18.24
Teat/udder wound	Unaffected	1498	90.29	1.44	1547	156.19	2.90
	Affected	28	97.75	10.56	27	162.33	21.92
Short lactation	Unaffected	1460	90.216	1.46	1504	156.23	2.94
	Affected	66	95.18	6.88	70	157.79	13.61

Note: Means with different superscripts differ significantly in each effect.

Table 9. Least-squares means of various reproduction traits (DP, CI and MY/CI) in relation to various udder health and short lactation problems in Murrah buffaloes (affected vs. non-affected).

Effect	Status	No.	DP		CI		MY/CI
			Mean	SE	Mean	SE	Mean	SE
Udder health problems	Non-affected	1112	156.88^a	3.29	461.64^a	3.49	4.92^a	0.06
	Affected	368	173.11^b	5.72	481.80^b	6.06	4.67^b	0.10
Clinical mastitis	Non-affected	1144	157.18^a	3.24	462.19^a	3.44	4.92^a	0.06
	Affected	336	173.65^b	5.98	481.87^b	6.35	4.65^b	0.11
Stage one mastitis	Non-affected	1325	158.65^a	3.01	467.09	3.20	4.93^a	0.05
	Affected	155	180.28^b	8.81	462.97	9.37	4.23^b	0.16
Stage two mastitis	Non-affected	1343	159.96	3.00	465.35	3.18	4.86	0.05
	Affected	137	170.30	9.39	479.45	9.96	4.90	0.17
Stage three mastitis	Non-affected	1374	161.10	2.96	463.90^a	3.13	4.84	0.05
	Affected	106	158.56	10.68	502.40^b	11.29	5.05	0.19
Blood in milk	Non-affected	1460	160.41	2.87	466.28	3.05	4.87	0.05
	Affected	20	198.05	24.56	494.50	26.07	4.33	0.44
Teat block	Non-affected	1444	161.02	2.89	466.57	3.07	4.86	0.05
	Affected	36	156.78	18.32	470.11	19.44	4.90	0.33
Teat/udder wound	Non-affected	1455	160.61	2.88	466.42	3.06	4.86	0.05
	Affected	25	178.52	21.98	480.28	23.32	4.56	0.39
Short lactation	Non-affected	1416	149.65^a	2.56	467.02	3.10	5.05^a	0.05
	Affected	64	410.44^b	12.03	458.69	14.58	0.22^b	0.23

Note: Means with different superscripts differ significantly in each effect.

4. Discussion

The effect of abortion on reproduction traits revealed the increases in CFS, SP and DP as 35.98%, 16.17% and 126.52%, respectively. The incidence of abortions was also associated with 69.73% reduction in average MY/CI in Murrah buffaloes. However, the increase in CI associated with abortions was not significant in Murrah buffaloes. The severely affected animals severely affected due to abortions and subsequent complications might get removed from the herd and the performance record in subsequent calving might not be available. Furthermore, the aborted animals generally yield a shorter lactation and thus production stress will not be there during the next reproduction cycle. The CI itself being the sum of SP and gestation length, which is generally associated with a low coefficient of variation, also contributed to the non-significant differences in average CI of aborted and normal animals. Other factors contributing to this dilution effect might be the longer CI associated with uterine health problems and fertility problems which were treated normal as per the calving health status.

Most of the reports (Tomar 1979; Tomar & Verma 1984; Mukherjee 1989; Khan et al. 2009) also revealed significantly longer average SP and DP in aborted cattle and buffaloes. Contrary to the present results, significant increase in average CI of aborted animals in comparison with normal calvers was also reported (Khan et al. 2009).

The increase in average CFS and SP in buffaloes affected with RFM was found to be not significant as per the results of the present investigation. Similar influence of RFM on average SP of Murrah buffaloes was earlier reported (Pal 2003). However, longer SP in cows which were affected with RFM are also available (Pandit et al. 1982; Balasundaram 2008).

A highly significant increase in average CFS, SP, DP and CI was found among animals susceptible to metritis. The increase in average CFS, SP, DP and CI associated with metritis was 16.93%, 73.88%, 53.92% and 20.04%, respectively. The decrease in average MY/CI was 18.55% in comparison with animals resistant to metritis. Incidence of pyometra was also associated with significant reduction in MY/CI (14.38%) and highly significant increase in CFS (33.08%), SP (39.24%), DP (33.87%) and CI (11.82%) in Murrah buffaloes. Majority of reports (Erb et al. 1985; Balasundaram 2008; Khan et al. 2009) also showed a significant increase in average SP in cattle and buffaloes affected with metritis. However, some authors (Mukherjee 1989; Pal 2003) failed to observe any significant influence of metritis on SP of dairy animals.

The results of the present investigation also revealed that variation in average CFS and SP in buffaloes affected with overall udder health problems and mastitis were not significantly different from normal animals. The average SP of buffaloes affected with udder health problems were around 12 days longer than normal animals. However, reports of significantly shorter SP in Murrah buffaloes affected with various udder disorders are available (Pal 2003).

From the results of the present investigation it was concluded that the incidence of various udder and reproductive problems was adversely affecting the subsequent production and reproduction performance in Murrah buffaloes. The significant reduction in production and reproduction performance revealed the need of better management practices for those affected buffaloes to alleviate the adverse effect.

Disclosure statement

No potential conflict of interest was reported by the authors.