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Phenotypic relationships between udder and milking characteristics, milk production and California mastitis test in goats
SmallRuminantResearch, 12 (1993) 329-337 © 1993 Elsevier Science Publishers B.V. All rights reserved. 0921-4488/93/$06.00
329
Phenotypic relationships between udder and milking characteristics, milk production and California mastitis test in goats H. Montaldo and F.J. Martinez-Lozano Escuela de Agronomia y Zootecnia, Universidad de Guanajuato, Irapuato, Mdxico (Accepted 12 April 1993)
ABSTRACT Data of crossbreed goats (28 Alpine × criolla; 6 Granadina X criolla; 13 Nubian × criolla) kept on natural pasture at Irapuato, M6xico, and hand-milked once a day, were studied for daily milk production (MP), milking time (MT), California mastitis test score (CMT), udder perimeter (UP), teat perimeter (TP), teat length (TL), udder cleft (UC), udder shape (US), teat shape (TS) and teat end shape (TE). UP, TP, TL and UC were measured before milking. Kids were separated from their mothers for a 24-h period prior to milking. Milking rate (MR) was MP/MT. MP (r= -0.32) and UP (r= -0.33) were correlated with CMT (P< 0.05 ). UP had r=0.81 (P< 0.01 ), and TP had r= 0.45 (P< 0.05 ) with MP. Goats with globular udders had significantly lower values (P< 0.05 ) for CMT, and higher (P< 0.05 ) for MR and MP than goats with non-globularudders. Goats with non-halloon teat shape had sig~nificantlylower (P< 0.05 ) CMT values than those with balloon-shaped teats. Results suggest that goats with globular udders and non-balloon-shapedteats have greater resistance to mastitis. UP and TP had greater correlations with MP than other morphological variables. Key words: Goat; Milk production; California mastitis test; Udder characteristic; Milking characteristic
INTRODUCTION
In goats, udder characteristics, milk production, milking time and rate are traits with adequate genetic variation to allow selection responses (Mavrogenis et al., 1989; Ricordeau, 1981; Wang, 1989). Although mastitis causes significant economic losses in milk goat flocks (Kalogridou-Vassiliadou, 1991; Pijoan and T6rtora, 1986), information concerning correlations with such characteristics in goats appears to be scarce. Knowledge about these relationships can been utilized in the design of breeding programs to improve milkability and udder health and to identify certain morphological and physiological factors related with changes in these Correspondence to: H. Montaldo, Escuela de Agronomia y Zootecnia, Universidad de Guanajuato. A.P. 31 l, Irapuato 36500, M6xico.
330
H. MONTALDOAND F.J. MARTtNEZ-LOZANO
traits (Boettcher et al., 1992; Schutz et al., 1990; Seykora and McDaniel, 1985a; Shook, 1989). This study had the objective of evaluating phenotypic associations between some udder and milking characteristics and mastiffs susceptibility in goats, measured with the California mastitis test (CMT), with the view of evaluating the feasibility of including them in dairy goat selection programs. MATERIALS A N D M E T H O D S
Data utilized in this study were obtained from the goat flock of the Escuela de Agronomia y Zootecnia de la Universidad de Guanajuato in Irapuato, Mexico from crossbreed goats (28 Alpine X crioUa; 6 GranadinaX criolla; 13 Nubianxcriolla), kept on natural pasture and daily supplemented with sorghum grain (200-300 g/head) and lucerne ( 1.5-3.0 kg/head) in the dry season (October until April), and hand-milked once a day. Annual mean temperature was 18 °C and mean precipitation 590 ram. All goats had kidded in May 1989. From July to October, four measurements were made of milk production (MP), milking time (MT), California mastiffs test score (CMT-S) (0, negative; 1, suspicious; 2, slightly positive; 3, positive) (Lerondelle, 1984), maximum udder perimeter (UP), teat perimeter in half part (TP), teat length (TL), and udder cleft (UC). UP, TP, TL and UC were measured before milking. Udder measurements are shown in Fig. 1. Kids were separated from their mothers for a 24-h period prior to
r !
B
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I!
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Fig. 1. Udder measurements: A, udder perimeter; B, udder cleft; C, teat perimeter; D, teat length.
RELATIONSHIPS BETWEEN UDDER AND MILKING CHARACTERISTICS PRODUCTION AND MT
3 31
milking recording. Milking rate (MR) was defined as MP/MT. Also, in July a single visual appraisal of udder shape (US) (globular or non-globular) (LeJaouen, 1981 ), teat shape (TS) (funnel, bottle, cylinder and balloon) (Fig. 2) and teat end shape (TE) (sharp or round) (Fig. 3) was taken. In this study, teat shape levels of funnel, bottle and cylinder were joined in one level (as non-balloon), because no differences between them were found in a preliminary analysis (Montaldo and Martinez-Lozano, 1992). Milking time was measured from the moment when the milker put hands on the udder to begin milking, to the moment when the last drop of milk was released from the goat, utilizing a digital chronometer. One experienced milker milked animals every day. Means of the two teat and four measurements were utilized in the analyses. The mean of CMT-S (CMT) was considered as a quantitative variable. The square root transformation of CMT (SCMT) was
k/ k/ k/ A
B
G
D
Fig. 2. Shape of teat: A, funnel;B, cylinder;C, bottle; D, ballon.
A
B
Fig. 3. Teat end shape: A, sharp; B, round.
332
H. MONTALDOAND F.J. MART[NEZ-LOZANO
also analyzed (Harvey, 1982; Gill, 1978). In order to estimate correlation between left and right half CMT values, separate means were also obtained. A linear statistical model including breed group and parity (first and > 2nd ) was utilized to analyze all quantitative variables. As breed group was not significant (P> 0.05), a model containing parity only was utilized in order to obtain residuals to estimate correlation coefficients between the variables. Also, possible non-linear relationships between CMT and other quantitative variables were evaluated with second order polynomial regression models utilizing same residuals. Effects of US, TS and TE were tested by including subclass effect formed by combinations of US, TS and TE in the model together with parity. Linear contrasts for udder shape, teat shape, teat end shape and interaction effects were performed. Individual subclass means were also compared by least significant difference method. When TE effect and their interactions were not significant (P> 0.05 ), they were dropped from the model in order to clarify results and improve the test of other effects. All statistical analyses were performed utilizing General Linear Models Procedure of Statistical Analysis System (SAS, 1985 ). RESULTS
Significant positive correlation coefficients were found between udder perimeter and milking time (P<0.01), udder perimeter and teat perimeter (P< 0.05 ), udder perimeter and daily milk production (P< 0.01 ), udder perimeter and milking rate (P<0.01), teat perimeter and milking rate (P< 0.05 ), teat perimeter and milk production (P< 0.01 ), milking time and milk production (P< 0.01 ), and milk production and milking rate (P< 0.01 ) (Table 1). Also, significant negative correlation coefficients were found between CMT and udder perimeter (P<0.05), CMT and milk production (P< 0.05 ), udder cleft and milk production (P< 0.05 ), and milking time and TABLE1 Phenotypic correlation coefficients between variables studied in goats Variable
UP
UC
TL
TP
MT
MP
MR
CMT Udder perimeter ( U P ) Udder cleft (UC) Teat length (TL) Teat perimeter (TP) Milking time (MT) Milk production ( M P ) Milking rate (MR)
-0.33* -
0.06 -0.21 -
0.02 -0.07 -0.23 -
-0.24 0.30* -0.05 0.28 -
-0.08 0.52" -0.19 0.04 0.37* -
-0.32* 0.81"* -0.31" 0.22 0.45** 0.64" -
-0.22 0.39" -0.10 0.16 -0.06 -0.34* 0.40"
**P
RELATIONSHIPS BETWEEN UDDER AND MILKING CHARACTERISTICS PRODUCTION AND MT
333
TABLE 2 L e a s t - s q u a r e s m e a n s a n d significance for factors affecting California m a s t i t i s test, milking rate a n d u d d e r m e a s u r e m e n t s in goats Factor
U d d e r s h a p e + teat s h a p e Globular+non-balloon Non-globular+non-balloon Non-globular+balloon First parity >- 2 n d parity Contrast udder shape ~ C o n t r a s t teat s h a p e 2
Variable n
CMT
SCMT
25 11 11 14 23
0.33 a 0.52" 1.00 b 0.44 0.88 -0.43* - 0.58**
0.23 ~ 0.31 a 0.79 b 0.23 a 0.64 b -0.32* - 0.52**
TL (cm)
12.2 a 13.0 ~b 13.9 b 12.2 a 13.8 b
-1.3" NS
TP (cm)
UC (cm)
MR (g/s)
21.4 21.3 21.6 22.5 21.1 NS NS
25.5 ab 27.1 a 23.8 b 28.1 a 22.8 b NS 2.5*
16.1 a 12.0 b 12.1 b 12.2 14.6 4.1"* NS
W i t h i n c o l u m n s values with different superscripts are significantly different ( P < 0.05 ); **P < 0.01; * P < 0 . 0 5 ; NS, P > 0.05. 1Globular vs. non-globular. 2Non-balloon vs. balloon. C M T = C a l i f o r n i a m a s t i t i s test; S C M T = s q u a r e root o f C M T ( u n t r a n s f o r m e d ) ; T L = t e a t length; T P = teat perimeter; U C = u d d e r cleft; M R = m i k i n g rate. TABLE3 L e a s t - s q u a r e s m e a n s a n d significance for factors affecting m i l k production, m i l k i n g t i m e a n d u d d e r p e r i m e t e r in goats Factor
U d d e r s h a p e + teat s h a p e + teat e n d s h a p e Globular + non-balloon + sharp Globular + non-balloon + round Non-globular + n o n - b a l l o o n + s h a r p Non-globular + non-balloon + round N o n - g l o b u l a r + balloon + s h a r p N o n - g l o b u l a r + balloon + r o u n d First parity > 2 n d parity Contrast udder shape I C o n t r a s t teat s h a p e 2 C o n t r a s t teat e n d s h a p e 3
n
20 5 9 2 5 6 14 33
Variable UP (cm)
MT (s)
MP (g)
45.6 a
65.3ab 53.3a 64.2ab 50.1 ab 85.9 b 58.5 ~b 57.0 68.8 NS NS 17.8*
1010 ~ 885~ 713 bc 384 c 990 ab 646 b~ 584" 959 b 264* NS 266*
4 4 . 4 ab
40. lbC 30.7 d 41.6 a~ 37.1 ~ 37. I a 42.7 b 7.6** NS 5.0*
W i t h i n c o l u m n s v a l u e s with different superscripts are significantly different ( P < 0.05); **P< 0.01; * P < 0.05; N S P > 0.05. t G l o b u l a r vs. non-globular; 2non-baUoon vs. balloon; 3sharp vs. round. U P = u d d e r perimeter; M T = m i l k i n g time; M P = milk p r o d u c t i o n .
334
H. MONTALDO AND F.J. MART~NEZ-LOZANO
milking rate (P< 0.05 ) (Table 1 ). The unadjusted correlation coefficient between left and right CMT values was 0.79 (P<0.01). Quadratic effects of quantitative variables were found to be not significant (P> 0.05 ) on CMT. Most variables were significantly influenced (P< 0.05 ) by the effect of udder shape, teat shape or both (Tables 2 and 3). Effect of teat end shape significantly influenced (P< 0.05 ) udder perimeter, milking time and milk production (Table 3). Breed group and interaction effects between US, TS and TE were not significant (P> 0.05 ). Goats with globular udders exhibited significantly lower (P< 0.05 ) values for CMT, SCMT, teat length and were significantly greater (P< 0.05 ) for milking rate, udder perimeter and milk production than goats with non-globular udders (Tables 2 and 3). Goats with nonballoon-shaped teats show significantly lower (P<0.05) values for CMT, SCMT and significantly greater (P< 0.05 ) for udder cleft than goats with balloon-shaped teats (Table 2). Goats with sharp teat ends had significantly greater (P< 0.05 ) values for udder perimeter, milking time and milk production than goats with round-shaped teat ends (Table 3 ). First parity goats exhibited significantly lower values (P< 0.05) for SCMT, teat length, udder perimeter and milk production and were significantly greater (P< 0.05 ) for udder cleft than goats of greater parity. DISCUSSION
In dairy cattle as well, negative phenotypic correlation coefficients have been found between somatic cell counts and milk production (Boettcher et al., 1992; Seykora and McDaniel, 1985a,b; Schutz et al., 1990). This relationship however, does not indicate that high producing goats had more resistance to mastitis because this negative relationship could be caused by reduced production of goats with mastitis. In bovines, several studies have shown positive genetic relationships between milk production and somatic cell counts (Boettcher et al., 1992; Seykora and McDaniel, 1985a). The correlation between left and right udder halves CMT values (0.79) was lower than that obtained by Lerondelle (1984) of 0.89 in goats free of infection, but the value indicated a good assessment of degree of udder infection utilizing CMT in goats. Correlation between udder perimeter and milk production (0.81 ) was similar to that found by Gall (1980), Mavrogenis et al. ( 1989 ) and Montaldo et al. (1988), but was superior to the value of 0.21 reported by MeUado et al. ( 1991 ). Other variables, correlated significantly with milk production were teat perimeter (0.45), udder cleft ( - 0.31 ), milking time (0.64) and milking rate (0.40). Thus, prediction of milk production from external measures of the udder can been based on udder and teat perimeter in agreement with resuits of Montaldo et al. (1988 ). This could explain the nearly identical correlation coefficients of udder perimeter with CMT and milk production with
RELATIONSHIPS BETWEEN UDDER AND MILKING CHARACTERISTICS PRODUCTION AND MT
335
CMT. Milking time increased and udder cleft decreased with greater production as expected. Milking rate increased in high producing goats, the same trend was observed by LeJaouen (1981 ) for goats with machine milking. Negative correlation between milking time and milking rate ( - 0 . 3 4 ) is explained by a known decrease in rate of milk release from peak level near the start of milking (LeJaouen, 1981 ). Averages for CMT scores and milking time (Tables 2 and 3), were lower than those obtained by Lu et al. ( 1991 ) for Alpine goats with machine milking and daily production level from 2.5 to 3.4 kg. In this study, CMT values were from 0.33 to 1.00 vs. 0.48 to 1.80, and milking times were from 53 to 86 s vs. 85 to 139. Milking rate was very similar with 12.0 to 16.1 g/s in this study vs. 13.3 to 16.2 g/s in the study o f L u et al. ( 1991 ). Globular udders and non-balloon teats were related to lower CMT values, while non-globular udders and balloon teats had high CMT values. Also, globular udders were shown to have a greater milking rate, indicating that this type of udders is preferable to non-globular udders for manual milking as well as for machine milking, despite recommendations to the contrary (LeJaouen, 1981 ). Sharp teat end shapes showed higher levels of milk production, udder perimeter and milking time but did not influence CMT, SCMT and milking rate. Studies to establish genetic correlations between milk production and mastitis resistance in goats and to investigate the genetic basis of the relationships encountered in this work need to be done. ACKNOWLEDGEMENTS We thank Dr. Christian Gall for helpful comments, and Ing. H6ctor Jim6nez for his assistance in reviewing the manuscript. Data analysis was supported by grant Dl12-904180 of the Consejo Nacional de Ciencia y Tecnologia.
REFERENCES Boettcher, P.J., Hansen, L.B., Van Raden, P.M. and Ernst, C.A., 1992. Genetic evaluation of Holstein bulls for somaticcellsin milk of daughters. J. Dairy Sci., 75:1127-1137. Gall, C., 1980. Relationshipsbetweenbody conformationand productionin dairygoats.J. Dairy. Sci., 63: 1768-1781. Gill, J.L., 1978. Design and analysis of experiment in the animal and medical sciences. The Iowa State UniversityPress, Ames, IA. Vol. 1, pp. 409. Harvey, W.R., 1982. Least-Squaresanalysisof discrete data. J. Anita. Sci., 54: 1067-1071. Kalogridou-Vassiliadou,D., 1991. Mastitis-relatedpathogens in goat milk. SmallRumin. Res., 4: 203-212. LcJaouen, J.C., 1981. Milkingand the technologyof milk and milk products. In: C. Gall (ed.). Goat Production.AcademicPress, London, UK, pp. 345-377.
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Lcrondelle, C., 1984. Ddnombrement ceUulaircdans le laitdc demi-mamelles de chbvrc (Cell counts in milk of goat half udders). Colloquc sur les Maladies dc la Ch~vrc, Ed. INRA. Niort, France. Oct. 9-I l, pp. 225-232. Lu, C.D., Potchoiba, M.J. and Loctz, E.R., 1991. Influenceofvaccum level,pulsationratioand rate on milking performance and udder health in dairy goats.Small Rumin. Res., 5: I-8. Mavrogcnis, A.P., Papachistoforou, C., Lysandridcs, P. and Roushias, A., 1989. Environmental and genetic effectson udder characteristicsand milk production in Damascus goats. Small Rumin. Res., 2: 333-343. McUado, M., Footc, R.H. and Borrego, E., 199 I. Lactationalperformance, prolifcacy and relationshipto partityand body weitght in crossbreed native goats in northern Mexico. Small Rumin. Rcs., 6: 167-174. Montaldo, H., Ochoa, M. and Ldpez, J.J.,1988. Relacioncs fcnotlpicasentre el ticmpo dc ordcfiomanual, flujodc Icche,produccidn dc Icchc y conformacidn dc la ubre cn cabras nativas y mestizas en Mdxico (Phenotypic relationshipsbetween milking time, milk fux, milk production and udder conformation in native and cross-bredgoats in Mexico). Cong. Intcram. Prod. Caprina. Torredn, Mdxico. Oct. 11-14, pp. AI-A3. Montaldo, H. and Martinez-Lozano, F.J., 1992. Phenotypic relationshipsof udder characteristics,milk production, milking time and rate with Californiamastitistestin goats. Proc. of the V InternationalConference on Goats, N e w Delhi, India. March 2-6, pp. 24-34. Pijoan, P. and Tdrtora, J., 1986. Principalcs cnfcrmedades dc los ovinos y caprinos. (Main diseasesof sheep and goats) Pijoan y Tdrtora eds, U.N.A.M., Mdxico D.F., pp. 405. Ricordeau, G., 1981. Genetics: Breeding plans. In: C. Gall (cd.). Goat Production. Academic Press, London, UK, pp. I I 1-169. SAS, 1985. SAS user'sguide: statistics-version5th edition.StatisticalAnalysis System Institute. Cary, NC, pp. 584. Schutz, M.M., Hansen, L.B., Stcucrnagel,G.R., Rencau, J.R. and Kuck, A.L., 1990. Genetic parameters for somatic cells,protein and fat in milk of Holsteins.J. Dairy Sci.,73: 494-502. Scykora, A.J. and McDaniel, B.T., 1985a. Udder and teat morphology relatedto mastitisresistance: A review. J. Dairy Sci.,68: 2087-2093. Scykora, A.J. and McDanicl, B.T., 1985b. Heritabilityof teattraitsand theirrelationshipswith milk yield,somatic cellcount, and percent two-minute milk. J. Dairy Sci.,68: 2670-2683. Shook, G.E., 1989. Selectionfor diseaseresistance.J. Dairy Sci.,72: 1349-1362. Wang, P.Q. 1989. Udder characteristicsin Toggcnburg dairy goats.Small Rumin. Rcs., 2:181190.
RESUMEN Montaldo, H. and Martinez-Lozano, F.J., 1993. Rclaciones fenotipicas entre caracteristicas de la ubrc y de ordcfio, produccidn de leche y prucba de mastitis de California cn cabras. Small Rumin. Res., 12: 329-337.
Se estudiaron datos dc cabras mestizas (28 Alpina X criolla;6 Granadina × criolla;13 Nubia×crioUa) cxplotadas en pastoreo y ordcfiadas manualmentc una vcz al dla cn Irapuato, M~xico cn cuanto a produccidn diariadc lechc (PL), ticmpo de ordefio (TO), valor dc la prucba dc California (CMT), pcrlmetro de la ubre (PU), pcrimctro de los pezoncs (PP), longitud dc los pczoncs (LP) alturade la ubrc al piso (AU), forma de la ubrc (FU), forma dcl pczdn (FP) y forma dcl cxtrcmo del pez6n (FE). PU, PP, LP y A U fueron medidas antes del ordcfio.Los cabritos fucron scparados dc sus madres por un pcriodo dc 24 h antes dc la mcdicidn de la producci6n dc Ivche.El flujodc leche (FL) se defini6 como PL/TO. C M T estuvo correlacion-
RELATIONSHIPS BETWEEN UDDER AND MILKING CHARACTERISTICS PRODUCTION AND MT
337
ada con PL (r= - 0 . 3 2 ) y con PU ( R = - 0 . 3 3 ) (P<0.05). PL tuvo r=0.81 ( P < 0.01 ) con PU y r = 0.45 ( P < 0.05) con PP. Cabras con ubres globulares tuvieron valores significativamente menores ( P < 0.05) para CMT y mayores para P L y FL que cabras con ubres no globulares. Cabras con pezones de forma diferente a la de globo tuvieron valores significativamente menores de CMT ( P < 0.05) que aquellas con pezones en forma de globo. Los resultados sugieren que cabras con ubres globulares y pezones con forma diferente a la de globo tienen mayor resistencia a la mastitis. PU y PP mostraron correlaciones mas altas con PL que otras variables morfol6gicas. RESUME Montaldo, H. and Martinez-Lozano, F.J., 1993. Relations phdnotypiqucs entre caract6ristiques du mamelle et de traite, production de lait et dpreuve de mammite de California dans la ch~vre. Small Rumin. Res., 12: 329-337.
Donnds dc chevres croissdes (28 Alpinc×criolla; 6 Granadinc×criolla; 13 Nubicnnc×criolla) cxploitdcs en paturagc cn Irapuato, Mcxiquc, et avcc un traitc/tla main par jour on 6td estudidcssur Icsvariablesproductionjoumalierc du lait(PL), temps dc traitc(TT), valcur du dprcuve dc mammite dc California (CMT), perimctrc du mamcllc (PM), pcrimctrc du trayon (PT), longeur du trayon (LT), hauteur du mamcllc au sol (HS), conformation du mamcllc (CM), conformation du trayon (CT) ct conformation du extreme du trayon (CE). PM, PT, L T et H S on ete mesurdcs avant le traite.Lcs chevreau on dtd separdes de leur m~res 24-h avant renrcgistremcnt du production du lait.Lc taux d'cmision (TE) on dtd dcfinicc o m m c PL/TT. C M T ayant correlationsavcc P L (r= -0.32) ct avcc P M (r= -0.33) (P<0.05). PL ayant r=0.81 (P<0.01) avec P M et r=0.45 (P<0.05) avcc PT. Ch~vres avcc mamcllcs globulcuscs ayant valeurs significativementinferieurespour C M T (P< 0.05 ) quc chcvres avec mamcllcs non-globulcuscs. Chcvrcs avcc trayons non-globe ayant valucurs significativcmcntinfcricures quc ch~vrcs avcc trayons globe. Lcs rcsultdcs indiqucnt quc chbvrcs avcc mamcllcs globulcuses et trayons non-globe on dt6 plus resistantesa la mammitc. P M ct P T ayant correlations plus elevdes avec P L quc outres variablesmorphologiqucs.
329
Phenotypic relationships between udder and milking characteristics, milk production and California mastitis test in goats H. Montaldo and F.J. Martinez-Lozano Escuela de Agronomia y Zootecnia, Universidad de Guanajuato, Irapuato, Mdxico (Accepted 12 April 1993)
ABSTRACT Data of crossbreed goats (28 Alpine × criolla; 6 Granadina X criolla; 13 Nubian × criolla) kept on natural pasture at Irapuato, M6xico, and hand-milked once a day, were studied for daily milk production (MP), milking time (MT), California mastitis test score (CMT), udder perimeter (UP), teat perimeter (TP), teat length (TL), udder cleft (UC), udder shape (US), teat shape (TS) and teat end shape (TE). UP, TP, TL and UC were measured before milking. Kids were separated from their mothers for a 24-h period prior to milking. Milking rate (MR) was MP/MT. MP (r= -0.32) and UP (r= -0.33) were correlated with CMT (P< 0.05 ). UP had r=0.81 (P< 0.01 ), and TP had r= 0.45 (P< 0.05 ) with MP. Goats with globular udders had significantly lower values (P< 0.05 ) for CMT, and higher (P< 0.05 ) for MR and MP than goats with non-globularudders. Goats with non-halloon teat shape had sig~nificantlylower (P< 0.05 ) CMT values than those with balloon-shaped teats. Results suggest that goats with globular udders and non-balloon-shapedteats have greater resistance to mastitis. UP and TP had greater correlations with MP than other morphological variables. Key words: Goat; Milk production; California mastitis test; Udder characteristic; Milking characteristic
INTRODUCTION
In goats, udder characteristics, milk production, milking time and rate are traits with adequate genetic variation to allow selection responses (Mavrogenis et al., 1989; Ricordeau, 1981; Wang, 1989). Although mastitis causes significant economic losses in milk goat flocks (Kalogridou-Vassiliadou, 1991; Pijoan and T6rtora, 1986), information concerning correlations with such characteristics in goats appears to be scarce. Knowledge about these relationships can been utilized in the design of breeding programs to improve milkability and udder health and to identify certain morphological and physiological factors related with changes in these Correspondence to: H. Montaldo, Escuela de Agronomia y Zootecnia, Universidad de Guanajuato. A.P. 31 l, Irapuato 36500, M6xico.
330
H. MONTALDOAND F.J. MARTtNEZ-LOZANO
traits (Boettcher et al., 1992; Schutz et al., 1990; Seykora and McDaniel, 1985a; Shook, 1989). This study had the objective of evaluating phenotypic associations between some udder and milking characteristics and mastiffs susceptibility in goats, measured with the California mastitis test (CMT), with the view of evaluating the feasibility of including them in dairy goat selection programs. MATERIALS A N D M E T H O D S
Data utilized in this study were obtained from the goat flock of the Escuela de Agronomia y Zootecnia de la Universidad de Guanajuato in Irapuato, Mexico from crossbreed goats (28 Alpine X crioUa; 6 GranadinaX criolla; 13 Nubianxcriolla), kept on natural pasture and daily supplemented with sorghum grain (200-300 g/head) and lucerne ( 1.5-3.0 kg/head) in the dry season (October until April), and hand-milked once a day. Annual mean temperature was 18 °C and mean precipitation 590 ram. All goats had kidded in May 1989. From July to October, four measurements were made of milk production (MP), milking time (MT), California mastiffs test score (CMT-S) (0, negative; 1, suspicious; 2, slightly positive; 3, positive) (Lerondelle, 1984), maximum udder perimeter (UP), teat perimeter in half part (TP), teat length (TL), and udder cleft (UC). UP, TP, TL and UC were measured before milking. Udder measurements are shown in Fig. 1. Kids were separated from their mothers for a 24-h period prior to
r !
B
!!
I!
! !
!
Fig. 1. Udder measurements: A, udder perimeter; B, udder cleft; C, teat perimeter; D, teat length.
RELATIONSHIPS BETWEEN UDDER AND MILKING CHARACTERISTICS PRODUCTION AND MT
3 31
milking recording. Milking rate (MR) was defined as MP/MT. Also, in July a single visual appraisal of udder shape (US) (globular or non-globular) (LeJaouen, 1981 ), teat shape (TS) (funnel, bottle, cylinder and balloon) (Fig. 2) and teat end shape (TE) (sharp or round) (Fig. 3) was taken. In this study, teat shape levels of funnel, bottle and cylinder were joined in one level (as non-balloon), because no differences between them were found in a preliminary analysis (Montaldo and Martinez-Lozano, 1992). Milking time was measured from the moment when the milker put hands on the udder to begin milking, to the moment when the last drop of milk was released from the goat, utilizing a digital chronometer. One experienced milker milked animals every day. Means of the two teat and four measurements were utilized in the analyses. The mean of CMT-S (CMT) was considered as a quantitative variable. The square root transformation of CMT (SCMT) was
k/ k/ k/ A
B
G
D
Fig. 2. Shape of teat: A, funnel;B, cylinder;C, bottle; D, ballon.
A
B
Fig. 3. Teat end shape: A, sharp; B, round.
332
H. MONTALDOAND F.J. MART[NEZ-LOZANO
also analyzed (Harvey, 1982; Gill, 1978). In order to estimate correlation between left and right half CMT values, separate means were also obtained. A linear statistical model including breed group and parity (first and > 2nd ) was utilized to analyze all quantitative variables. As breed group was not significant (P> 0.05), a model containing parity only was utilized in order to obtain residuals to estimate correlation coefficients between the variables. Also, possible non-linear relationships between CMT and other quantitative variables were evaluated with second order polynomial regression models utilizing same residuals. Effects of US, TS and TE were tested by including subclass effect formed by combinations of US, TS and TE in the model together with parity. Linear contrasts for udder shape, teat shape, teat end shape and interaction effects were performed. Individual subclass means were also compared by least significant difference method. When TE effect and their interactions were not significant (P> 0.05 ), they were dropped from the model in order to clarify results and improve the test of other effects. All statistical analyses were performed utilizing General Linear Models Procedure of Statistical Analysis System (SAS, 1985 ). RESULTS
Significant positive correlation coefficients were found between udder perimeter and milking time (P<0.01), udder perimeter and teat perimeter (P< 0.05 ), udder perimeter and daily milk production (P< 0.01 ), udder perimeter and milking rate (P<0.01), teat perimeter and milking rate (P< 0.05 ), teat perimeter and milk production (P< 0.01 ), milking time and milk production (P< 0.01 ), and milk production and milking rate (P< 0.01 ) (Table 1). Also, significant negative correlation coefficients were found between CMT and udder perimeter (P<0.05), CMT and milk production (P< 0.05 ), udder cleft and milk production (P< 0.05 ), and milking time and TABLE1 Phenotypic correlation coefficients between variables studied in goats Variable
UP
UC
TL
TP
MT
MP
MR
CMT Udder perimeter ( U P ) Udder cleft (UC) Teat length (TL) Teat perimeter (TP) Milking time (MT) Milk production ( M P ) Milking rate (MR)
-0.33* -
0.06 -0.21 -
0.02 -0.07 -0.23 -
-0.24 0.30* -0.05 0.28 -
-0.08 0.52" -0.19 0.04 0.37* -
-0.32* 0.81"* -0.31" 0.22 0.45** 0.64" -
-0.22 0.39" -0.10 0.16 -0.06 -0.34* 0.40"
**P
RELATIONSHIPS BETWEEN UDDER AND MILKING CHARACTERISTICS PRODUCTION AND MT
333
TABLE 2 L e a s t - s q u a r e s m e a n s a n d significance for factors affecting California m a s t i t i s test, milking rate a n d u d d e r m e a s u r e m e n t s in goats Factor
U d d e r s h a p e + teat s h a p e Globular+non-balloon Non-globular+non-balloon Non-globular+balloon First parity >- 2 n d parity Contrast udder shape ~ C o n t r a s t teat s h a p e 2
Variable n
CMT
SCMT
25 11 11 14 23
0.33 a 0.52" 1.00 b 0.44 0.88 -0.43* - 0.58**
0.23 ~ 0.31 a 0.79 b 0.23 a 0.64 b -0.32* - 0.52**
TL (cm)
12.2 a 13.0 ~b 13.9 b 12.2 a 13.8 b
-1.3" NS
TP (cm)
UC (cm)
MR (g/s)
21.4 21.3 21.6 22.5 21.1 NS NS
25.5 ab 27.1 a 23.8 b 28.1 a 22.8 b NS 2.5*
16.1 a 12.0 b 12.1 b 12.2 14.6 4.1"* NS
W i t h i n c o l u m n s values with different superscripts are significantly different ( P < 0.05 ); **P < 0.01; * P < 0 . 0 5 ; NS, P > 0.05. 1Globular vs. non-globular. 2Non-balloon vs. balloon. C M T = C a l i f o r n i a m a s t i t i s test; S C M T = s q u a r e root o f C M T ( u n t r a n s f o r m e d ) ; T L = t e a t length; T P = teat perimeter; U C = u d d e r cleft; M R = m i k i n g rate. TABLE3 L e a s t - s q u a r e s m e a n s a n d significance for factors affecting m i l k production, m i l k i n g t i m e a n d u d d e r p e r i m e t e r in goats Factor
U d d e r s h a p e + teat s h a p e + teat e n d s h a p e Globular + non-balloon + sharp Globular + non-balloon + round Non-globular + n o n - b a l l o o n + s h a r p Non-globular + non-balloon + round N o n - g l o b u l a r + balloon + s h a r p N o n - g l o b u l a r + balloon + r o u n d First parity > 2 n d parity Contrast udder shape I C o n t r a s t teat s h a p e 2 C o n t r a s t teat e n d s h a p e 3
n
20 5 9 2 5 6 14 33
Variable UP (cm)
MT (s)
MP (g)
45.6 a
65.3ab 53.3a 64.2ab 50.1 ab 85.9 b 58.5 ~b 57.0 68.8 NS NS 17.8*
1010 ~ 885~ 713 bc 384 c 990 ab 646 b~ 584" 959 b 264* NS 266*
4 4 . 4 ab
40. lbC 30.7 d 41.6 a~ 37.1 ~ 37. I a 42.7 b 7.6** NS 5.0*
W i t h i n c o l u m n s v a l u e s with different superscripts are significantly different ( P < 0.05); **P< 0.01; * P < 0.05; N S P > 0.05. t G l o b u l a r vs. non-globular; 2non-baUoon vs. balloon; 3sharp vs. round. U P = u d d e r perimeter; M T = m i l k i n g time; M P = milk p r o d u c t i o n .
334
H. MONTALDO AND F.J. MART~NEZ-LOZANO
milking rate (P< 0.05 ) (Table 1 ). The unadjusted correlation coefficient between left and right CMT values was 0.79 (P<0.01). Quadratic effects of quantitative variables were found to be not significant (P> 0.05 ) on CMT. Most variables were significantly influenced (P< 0.05 ) by the effect of udder shape, teat shape or both (Tables 2 and 3). Effect of teat end shape significantly influenced (P< 0.05 ) udder perimeter, milking time and milk production (Table 3). Breed group and interaction effects between US, TS and TE were not significant (P> 0.05 ). Goats with globular udders exhibited significantly lower (P< 0.05 ) values for CMT, SCMT, teat length and were significantly greater (P< 0.05 ) for milking rate, udder perimeter and milk production than goats with non-globular udders (Tables 2 and 3). Goats with nonballoon-shaped teats show significantly lower (P<0.05) values for CMT, SCMT and significantly greater (P< 0.05 ) for udder cleft than goats with balloon-shaped teats (Table 2). Goats with sharp teat ends had significantly greater (P< 0.05 ) values for udder perimeter, milking time and milk production than goats with round-shaped teat ends (Table 3 ). First parity goats exhibited significantly lower values (P< 0.05) for SCMT, teat length, udder perimeter and milk production and were significantly greater (P< 0.05 ) for udder cleft than goats of greater parity. DISCUSSION
In dairy cattle as well, negative phenotypic correlation coefficients have been found between somatic cell counts and milk production (Boettcher et al., 1992; Seykora and McDaniel, 1985a,b; Schutz et al., 1990). This relationship however, does not indicate that high producing goats had more resistance to mastitis because this negative relationship could be caused by reduced production of goats with mastitis. In bovines, several studies have shown positive genetic relationships between milk production and somatic cell counts (Boettcher et al., 1992; Seykora and McDaniel, 1985a). The correlation between left and right udder halves CMT values (0.79) was lower than that obtained by Lerondelle (1984) of 0.89 in goats free of infection, but the value indicated a good assessment of degree of udder infection utilizing CMT in goats. Correlation between udder perimeter and milk production (0.81 ) was similar to that found by Gall (1980), Mavrogenis et al. ( 1989 ) and Montaldo et al. (1988), but was superior to the value of 0.21 reported by MeUado et al. ( 1991 ). Other variables, correlated significantly with milk production were teat perimeter (0.45), udder cleft ( - 0.31 ), milking time (0.64) and milking rate (0.40). Thus, prediction of milk production from external measures of the udder can been based on udder and teat perimeter in agreement with resuits of Montaldo et al. (1988 ). This could explain the nearly identical correlation coefficients of udder perimeter with CMT and milk production with
RELATIONSHIPS BETWEEN UDDER AND MILKING CHARACTERISTICS PRODUCTION AND MT
335
CMT. Milking time increased and udder cleft decreased with greater production as expected. Milking rate increased in high producing goats, the same trend was observed by LeJaouen (1981 ) for goats with machine milking. Negative correlation between milking time and milking rate ( - 0 . 3 4 ) is explained by a known decrease in rate of milk release from peak level near the start of milking (LeJaouen, 1981 ). Averages for CMT scores and milking time (Tables 2 and 3), were lower than those obtained by Lu et al. ( 1991 ) for Alpine goats with machine milking and daily production level from 2.5 to 3.4 kg. In this study, CMT values were from 0.33 to 1.00 vs. 0.48 to 1.80, and milking times were from 53 to 86 s vs. 85 to 139. Milking rate was very similar with 12.0 to 16.1 g/s in this study vs. 13.3 to 16.2 g/s in the study o f L u et al. ( 1991 ). Globular udders and non-balloon teats were related to lower CMT values, while non-globular udders and balloon teats had high CMT values. Also, globular udders were shown to have a greater milking rate, indicating that this type of udders is preferable to non-globular udders for manual milking as well as for machine milking, despite recommendations to the contrary (LeJaouen, 1981 ). Sharp teat end shapes showed higher levels of milk production, udder perimeter and milking time but did not influence CMT, SCMT and milking rate. Studies to establish genetic correlations between milk production and mastitis resistance in goats and to investigate the genetic basis of the relationships encountered in this work need to be done. ACKNOWLEDGEMENTS We thank Dr. Christian Gall for helpful comments, and Ing. H6ctor Jim6nez for his assistance in reviewing the manuscript. Data analysis was supported by grant Dl12-904180 of the Consejo Nacional de Ciencia y Tecnologia.
REFERENCES Boettcher, P.J., Hansen, L.B., Van Raden, P.M. and Ernst, C.A., 1992. Genetic evaluation of Holstein bulls for somaticcellsin milk of daughters. J. Dairy Sci., 75:1127-1137. Gall, C., 1980. Relationshipsbetweenbody conformationand productionin dairygoats.J. Dairy. Sci., 63: 1768-1781. Gill, J.L., 1978. Design and analysis of experiment in the animal and medical sciences. The Iowa State UniversityPress, Ames, IA. Vol. 1, pp. 409. Harvey, W.R., 1982. Least-Squaresanalysisof discrete data. J. Anita. Sci., 54: 1067-1071. Kalogridou-Vassiliadou,D., 1991. Mastitis-relatedpathogens in goat milk. SmallRumin. Res., 4: 203-212. LcJaouen, J.C., 1981. Milkingand the technologyof milk and milk products. In: C. Gall (ed.). Goat Production.AcademicPress, London, UK, pp. 345-377.
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Lcrondelle, C., 1984. Ddnombrement ceUulaircdans le laitdc demi-mamelles de chbvrc (Cell counts in milk of goat half udders). Colloquc sur les Maladies dc la Ch~vrc, Ed. INRA. Niort, France. Oct. 9-I l, pp. 225-232. Lu, C.D., Potchoiba, M.J. and Loctz, E.R., 1991. Influenceofvaccum level,pulsationratioand rate on milking performance and udder health in dairy goats.Small Rumin. Res., 5: I-8. Mavrogcnis, A.P., Papachistoforou, C., Lysandridcs, P. and Roushias, A., 1989. Environmental and genetic effectson udder characteristicsand milk production in Damascus goats. Small Rumin. Res., 2: 333-343. McUado, M., Footc, R.H. and Borrego, E., 199 I. Lactationalperformance, prolifcacy and relationshipto partityand body weitght in crossbreed native goats in northern Mexico. Small Rumin. Rcs., 6: 167-174. Montaldo, H., Ochoa, M. and Ldpez, J.J.,1988. Relacioncs fcnotlpicasentre el ticmpo dc ordcfiomanual, flujodc Icche,produccidn dc Icchc y conformacidn dc la ubre cn cabras nativas y mestizas en Mdxico (Phenotypic relationshipsbetween milking time, milk fux, milk production and udder conformation in native and cross-bredgoats in Mexico). Cong. Intcram. Prod. Caprina. Torredn, Mdxico. Oct. 11-14, pp. AI-A3. Montaldo, H. and Martinez-Lozano, F.J., 1992. Phenotypic relationshipsof udder characteristics,milk production, milking time and rate with Californiamastitistestin goats. Proc. of the V InternationalConference on Goats, N e w Delhi, India. March 2-6, pp. 24-34. Pijoan, P. and Tdrtora, J., 1986. Principalcs cnfcrmedades dc los ovinos y caprinos. (Main diseasesof sheep and goats) Pijoan y Tdrtora eds, U.N.A.M., Mdxico D.F., pp. 405. Ricordeau, G., 1981. Genetics: Breeding plans. In: C. Gall (cd.). Goat Production. Academic Press, London, UK, pp. I I 1-169. SAS, 1985. SAS user'sguide: statistics-version5th edition.StatisticalAnalysis System Institute. Cary, NC, pp. 584. Schutz, M.M., Hansen, L.B., Stcucrnagel,G.R., Rencau, J.R. and Kuck, A.L., 1990. Genetic parameters for somatic cells,protein and fat in milk of Holsteins.J. Dairy Sci.,73: 494-502. Scykora, A.J. and McDaniel, B.T., 1985a. Udder and teat morphology relatedto mastitisresistance: A review. J. Dairy Sci.,68: 2087-2093. Scykora, A.J. and McDanicl, B.T., 1985b. Heritabilityof teattraitsand theirrelationshipswith milk yield,somatic cellcount, and percent two-minute milk. J. Dairy Sci.,68: 2670-2683. Shook, G.E., 1989. Selectionfor diseaseresistance.J. Dairy Sci.,72: 1349-1362. Wang, P.Q. 1989. Udder characteristicsin Toggcnburg dairy goats.Small Rumin. Rcs., 2:181190.
RESUMEN Montaldo, H. and Martinez-Lozano, F.J., 1993. Rclaciones fenotipicas entre caracteristicas de la ubrc y de ordcfio, produccidn de leche y prucba de mastitis de California cn cabras. Small Rumin. Res., 12: 329-337.
Se estudiaron datos dc cabras mestizas (28 Alpina X criolla;6 Granadina × criolla;13 Nubia×crioUa) cxplotadas en pastoreo y ordcfiadas manualmentc una vcz al dla cn Irapuato, M~xico cn cuanto a produccidn diariadc lechc (PL), ticmpo de ordefio (TO), valor dc la prucba dc California (CMT), pcrlmetro de la ubre (PU), pcrimctro de los pezoncs (PP), longitud dc los pczoncs (LP) alturade la ubrc al piso (AU), forma de la ubrc (FU), forma dcl pczdn (FP) y forma dcl cxtrcmo del pez6n (FE). PU, PP, LP y A U fueron medidas antes del ordcfio.Los cabritos fucron scparados dc sus madres por un pcriodo dc 24 h antes dc la mcdicidn de la producci6n dc Ivche.El flujodc leche (FL) se defini6 como PL/TO. C M T estuvo correlacion-
RELATIONSHIPS BETWEEN UDDER AND MILKING CHARACTERISTICS PRODUCTION AND MT
337
ada con PL (r= - 0 . 3 2 ) y con PU ( R = - 0 . 3 3 ) (P<0.05). PL tuvo r=0.81 ( P < 0.01 ) con PU y r = 0.45 ( P < 0.05) con PP. Cabras con ubres globulares tuvieron valores significativamente menores ( P < 0.05) para CMT y mayores para P L y FL que cabras con ubres no globulares. Cabras con pezones de forma diferente a la de globo tuvieron valores significativamente menores de CMT ( P < 0.05) que aquellas con pezones en forma de globo. Los resultados sugieren que cabras con ubres globulares y pezones con forma diferente a la de globo tienen mayor resistencia a la mastitis. PU y PP mostraron correlaciones mas altas con PL que otras variables morfol6gicas. RESUME Montaldo, H. and Martinez-Lozano, F.J., 1993. Relations phdnotypiqucs entre caract6ristiques du mamelle et de traite, production de lait et dpreuve de mammite de California dans la ch~vre. Small Rumin. Res., 12: 329-337.
Donnds dc chevres croissdes (28 Alpinc×criolla; 6 Granadinc×criolla; 13 Nubicnnc×criolla) cxploitdcs en paturagc cn Irapuato, Mcxiquc, et avcc un traitc/tla main par jour on 6td estudidcssur Icsvariablesproductionjoumalierc du lait(PL), temps dc traitc(TT), valcur du dprcuve dc mammite dc California (CMT), perimctrc du mamcllc (PM), pcrimctrc du trayon (PT), longeur du trayon (LT), hauteur du mamcllc au sol (HS), conformation du mamcllc (CM), conformation du trayon (CT) ct conformation du extreme du trayon (CE). PM, PT, L T et H S on ete mesurdcs avant le traite.Lcs chevreau on dtd separdes de leur m~res 24-h avant renrcgistremcnt du production du lait.Lc taux d'cmision (TE) on dtd dcfinicc o m m c PL/TT. C M T ayant correlationsavcc P L (r= -0.32) ct avcc P M (r= -0.33) (P<0.05). PL ayant r=0.81 (P<0.01) avec P M et r=0.45 (P<0.05) avcc PT. Ch~vres avcc mamcllcs globulcuscs ayant valeurs significativementinferieurespour C M T (P< 0.05 ) quc chcvres avec mamcllcs non-globulcuscs. Chcvrcs avcc trayons non-globe ayant valucurs significativcmcntinfcricures quc ch~vrcs avcc trayons globe. Lcs rcsultdcs indiqucnt quc chbvrcs avcc mamcllcs globulcuses et trayons non-globe on dt6 plus resistantesa la mammitc. P M ct P T ayant correlations plus elevdes avec P L quc outres variablesmorphologiqucs.