Abstract: Total of 4926 records were obtained over the first 5 lactations of Egyptian buffalo. Records were used to estimate the effect of first-lactation performance on subsequent lactations. Buffalos were divided into 4 sets based on its first-lactation milk yield; (1) Buffalos that had non-lactation milk yield at 1st lactation and culled (G100), (2) that had milk yield at 1st lactation and culled (G110), (3) that had non-lactation milk yield at 1st lactation and retained in the herd (G101) and (4) that had milk yield at 1st lactation and retained in the herd (G111). At the 1st-lactation, better significant reproductive efficiency (days open and calving interval) was obtained for the group 100, compared with the culled group 110 and the retained ones (G101 and G111). Culled buffalos (G110) had insignificant differences for reproductive traits, but had a significantly lower total milk production than group 111. The differences between the 2 groups (101 and 111) were significant for total milk yield and lactation period up to 4th lactation and up to 3rd lactation for 305 day milk yield, however, the differences of days open and calving interval were insignificant over all lactations. The group 101 was significantly higher than the group 111 for milk yield/day of milking and non-significant difference was obtained for milk yield/day of productive life. The buffalos that had non-lactation milk yield with high reproductive efficiency at 1st-lactation should have a special management conditions to be able to retain in the herd and maintaining acceptable milk yield for subsequent lactations.
INTRODUCTION
Buffalos form the principal dairy animal in the developing countries and mainstay of some specific dairy industry contributing high percent of the total milk production. Egyptian buffalo is contributing by about 70% of total country milk production (Fooda et al., 2010). Buffalo is an important animal in the agricultural economy because of its resistance to disease, ability to convert poor quality roughage to meat and milk, its powerful draft capacity and better adapted to local climatic conditions (Kumar et al., 2014). Therefore, buffalos should be the target group of any proposed integrated rural development program in developing countries (Soliman, 2013).
However, the effective production of buffalo farms is a result of a system of factors influencing the herd’s reproduction and productivity. Generally, buffalo productivity in Egypt is about 210-280 days/lactation, an average of 7 lactations and milk yielding of 1600 kg and the average age at the 1st calving is about 34-41 months (Soliman and Bassiony, 2011; Ibrahim, 2012). However, due to weak expression of oestrus and the variability in its length large number of buffaloes are not bred at all, which contributes substantially to the overall figure for days open and calving interval. On the other hand, high percentage of buffaloes are producing very low milk yield during first lactation. Therefore, higher culling probabilities were observed for lowest buffaloes first-lactation milk yield (Peeva and Ilieva, 2007; Galeazzi et al., 2010) and the relative part of first-lactation culled with reproductive disorders is largest (Peeva and Ilieva, 2007). Moreover, the low longevity of buffaloes decreases to a great extent the farm’s profit. Accordingly, the 1st lactation yield provides most efficient measure to assess the inherent capacity of an individual and indicates the breeding value of a dairy cow accurately (Yadav et al., 2002).
However, the ability of the female to remain in the herd is an economically relevant trait because it is positively correlated with milk production (Vollema and Groen, 1998). Peeva and Ilieva (2007) showed that low milk yield is the 2nd cause of culling, after reproductive problems for Murrah buffaloes reared in Bulgaria. Moreover, studies show that the economic and genetic losses most often are due to reproductive disturbances (Zicarelli, 2000; Peeva and Ilieva, 2007). Hence, when a valuable young buffalo is culled, it is not only her future milk production which is lost, but also her genetic potential as the source of replacement heifers. Therefore, not only milk production but also the reproduction during 1st-lactation should be considered before making breeding management decisions (i.e., culling or keeping the animal in the herd for an additional interval).
The objective of this study is to investigate the effect of first lactation productive performance on Egyptian buffalo longevity.
MATERIALS AND METHODS
The data were collected from Stations: El-Nattafe El-Gidid, El-Nattafe El-Kadim and Mahalet Mousa, located in Kafr El-Sheikh Governorate, belonging to Animal Production Research Institute, Ministry of Agriculture, Dokki and Cairo, Egypt. During the period from 1972-2001 were used in this study. Abnormal records of buffalos affected by diseases (such as mastitis and udder troubles) or reproductive disorders were excluded. Animals were kept loose under semi-open sheds all the year. They were grazed on Egyptian clover berseem (Trifolium alexandrinum) during December to May. During the rest of the year, the animals were fed limited amount of clover hay when available, buffalo cows producing more than 10 kg a day and those are pregnant in the last 2 months of pregnancy were supplement with extra concentrate ration. Buffalos are milked twice a day by hand and/or machine milking.
Records were obtained on productive and reproductive performance over the first 5 lactations of Egyptian Buffalos. Total of 4926 records of buffalos was divided into 4 sets according to its first-lactation milk yield. Group 100 comprised 184 records of buffalos that had non-lactation milk yield at 1st lactation and culled, while group 110 had 202 records of buffalos that had milk yield at 1st lactation and culled, with no subsequent lactation records. Group 101 had 1564 records of buffalos that had non-lactation milk yield at 1st lactation and retained in the herd, while group 111 had 2976 records of buffalos that had milk yield at 1st lactation and retained in the herd.
The traits studied were, Total Milk Yield (TMY), 305-d milk yield (305-MY), Lactation Period (LP), Dry Period (DP), Days Open (DO) and Calving Interval (CI). Lifetime traits throughout first five lactations were, number of lactations, lifetime total milk yield, lifetime 305-d milk yield, lifetime lactation period, milk yield per day of milking, milk yield per day of productive life and milk yield per day of life.
Statistical analysis: Statistical analysis was performed by the least squares method using the GLM procedure of the SAS computational program (SAS., 2008) according to the following model:
where, Yijkm is the observation taken on the animal, μ is the overall mean, Li is the fixed effect of difference between produced and non-produced milk in first-lactation, YRj is the fixed effect of jth year of calving, Sk is the fixed effect of kth season of calving and eijkm is the random residual error. The results are significant at p<0.05.
RESULTS AND DISCUSSION
The basic traits of milk production in the monitored set of buffalos are presented in Table 1. In the 1st lactation the animals produced 1055.02 kg of TMY and 1002.93 kg of 305-MY. An increase in production in the 2nd lactation was 36.9% for TMY and 36.5% for 305-MY. In the 3rd and 4th lactation a slight increases in total milk production were achieved (9.8 and 4.2%, respectively). The present value of TMY is more close to those reported by Abd El-Raoof (1995), Mourad et al. (2005) and Fooda et al. (2010) on Egyptian buffalo.
The obtained data (Table 1) reveal that the Lactation Period (LP) and dry period (DP) were found to be decreased by lactations. The obtained present (LP) is in the range of some buffalo farms given by Fooda et al. (2010), Soliman and Bassiony (2011) and Ibrahim (2012) on Egyptian buffalo. Herein the lengths of Days Open (DO) and Calving Interval (CI) were decreased by lactations and were found to be from 224.28-141.46 days and from 541.06-457.97 days, respectively.
In the 1st-lactation, culled buffalos (group 110) had slightly but significantly (p<0.05) lower production than those retained in the herd (group 111), expressed as TMY and 305-MY (Table 2). The differences in production between the 2 groups could be attributed to the effect of significant shorter LP in the culled buffalos than in retained ones.
| Table 1: | Least squares Mean±SD of some productive and reproductive traits of the Egyptian buffalo in different lactations |
| a-dMean with the same letter in each row are not significantly different at≤0.05, TMY: Total milk yield, 305-MY: 305 day milk yield, LP: Lactation period, DP: Dry period, DO: Days open, CI: Calving interval | |
| Table 2: | No. of animal and least squares Means±SD of some productive and reproductive traits of the retained and culled groups of Egyptian buffalo in the 1st-lactation |
| a-cMean in the same column with different superscripts for each treat are significantly different at p<0.05, TMY: Total milk yield, 305-MY: 305 day milk yield, LP: Lactation period, DP: Dry period, DO: Days open, CI: Calving interval | |
| Table 3: | No. of animals and least squares Mean±SD of some productive and reproductive traits of Egyptian buffalo in different lactations classified based on 1st lactation production |
| a-cMean in the same column with different superscripts for each treat are significantly different at p<0.05, TMY: Total milk yield, 305-MY: 305 day milk yield, LP: Lactation period, DP: Dry period, DO: Days open, CI: Calving interval | |
Partially, there were no significant differences were obtained in the DP and reproduction traits (DO and CI) between the two groups (110 and 111) (Table 2). There were significant differences between the groups 100 and 101 for DP and DO, while, no significant difference was detected for CI.
Generally, it is pronounced that better significant reproductive efficiency was obtained for the buffalos had non-lactation milk yield at 1st-lactation and culled (group 100), compared with the lactated and culled group 110 and the retained ones (groups 101 and 111), likewise, the same trend was observed between the groups 101 and 111 in this aspect.
However, Table 2 and 3 showed that 59.5% of the non-lactated buffalos at first lactation retained in the herd and considered 24.7% of the 2nd lactation animals, while, 27.8% of the animals culled after the first-lactation. In this aspect, Peeva and Ilieva (2007) and Galeazzi et al. (2010) concluded that higher culling probabilities were observed for lowest buffaloes 1st-lactation milk yield. Generally, the Bulgaria buffalo culling percentage was also high at 1st and 2nd lactations (Ilieva and Peeva 2007).
Over the 2nd, 3rd and 4th lactations, the differences between the two groups (101 and 111) in TMY and LP traits were statistically significant (p<0.05) (Table 3, Fig. 1), however, the differences were non-significant at the 5th lactation. Likewise, non-significant differences were detected for the 305-MY starting from the 4th lactation. Clearly, it is observed that the milk yield and the lactation period of the non-lactated buffalos at 1st-lactation (group 101) were increased by advancing in lactations. However, despite the significant differences of TMY and 305-MY, the differences among the two groups (101 and 111) through lactations were only few grams (Table 3). Otherwise, the differences between the two groups (101 and 111) in DO and CI were small and statistically insignificant over all lactations seasons.
| Fig. 1(a-b): | Least squares means of (a) Total milk yield and (b) 305 day milk yield of two groups of Egyptian buffalo in different lactations classified based on 1st lactation production |
| Table 4: | Least squares Mean±SD of some productive efficiency traits and longevity of the retained and culled groups of Egyptian buffalo |
| a-cMean in the same row with different superscripts are significantly different at p<0.05 | |
Culled buffalos (group 110) had higher values of some productive efficiency traits (milk yield/day of productive life and milk yield/day of life) than the buffalos retained in the herd (groups 101 and 111) (Table 4), however, these findings are due to the significant differences in the number of lactations.
Furthermore, the group 101 was significantly higher (p<0.05) than the group 111 for milk yield/day of milking, moreover, non-significant difference was obtained for milk yield/day of productive life between the two groups. Consequently, the non-lactated buffalos at first-lactation (group 101) showed higher daily milk yield during the subsequent lactations, but because of the significant shorter lactation period and the missing first-lactation milk yield the lifetime TMY and 305-MY were significantly lower. In this aspect, the majority of studies were showing that the longer the lactation the more persistent its characteristics (Chaudhary et al., 2000; Elmaghraby, 2009; Penchev et al., 2011). In addition, Metry et al. (1994) concluded that short lactation period and the consequent low yearly milk yield drastically reduce the usefulness of buffalo as dairy animal in Egypt.
CONCLUSION
The present study showed that in regardless of the milk production, the reproductive efficiency of first-lactation culled buffalos was better than the retained ones. Moreover, a high percentage of the non-lactated buffalos at 1st-lactation was able to retained in the herd for subsequent lactations. Therefore, that higher proportion of buffalos that culled after the 1st-lactation could be influenced by poor design and management of health, feeding and nutrition requirements. Thus, buffalos with high reproductive efficiency at 1st-lactation should have a special management conditions to be able to maintain acceptable milk yield and hence improve overall herd profitability.
ACKNOWLEDGMENT
My greatest thanks to the Anim. Prod. Res. Institute, Ministry of Agri., Dokki, Cairo, Egypt for making available these data sets for statistical analysis.