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Comentários e sugestões para:

Relationship between
Nutrition and Reproduction

Giuseppe Campanile
Department di Scienze Zootecniche, Università Federico II - Napoli


Meeting of nutritional requirements is only one of the factors that can influence the reproductive activity of the buffalo cow, which does yet show a lactiferous habit. Nutritional effects on reproductive performances give results that depend on the sanitary conditions in which the buffalo lives and on the breeder’s managerial abilities. The nutrition effects on the reproductive performances are more evident in those countries where buffaloes calve during the most favourable periods for their ovarian cyclic activity and where forage availability depends on climate. In those countries where the calving calendar has to be modified for commercial reasons, dietary errors increase the negative effects determined by the atmospheric conditions.

Continuous modification of nutritional levels, which in many cases is responsible for a cyclic activity break in young subjects and in those in lactation, is a very important factor. Nutritional errors during the dry milk period may worsen reproductive performances affecting, in turn, normal energetic balance, immediately after calving, and mineral equilibrium. Consequently an alteration of the normal endocrine-metabolic state is found, which is necessary for the ready recovery of reproductive activity.

In this present study, the various effects that diet can have on buffaloes as opposed to milk cows is highlighted.

Key words: buffalo, nutrition, reproductive performances



In zootechnics the optimization of production depends on the quick restoration of reproductive activity immediately after calving and/or the anticipation of puberty in subjects destined to the culling. These conditions help to reduce the herd’s unproductive period knocking down production costs within the last decades, have rocketed in industrialized countries. Moreover, the anticipation of puberty shortens the generational interval favours genetic improvement. Various factors influence reproductive activity, in particular pathologies, farm management, climatic conditions, space availability and nutrition. They may play a direct or an indirect role  but they always modify the reproductive characteristics of the zootechnical species. The reactions of the single species to the above mentioned factors are always very evident; and whereas environment has  a greater influence on the photoperiodic species, nutrition plays a very important role in the species with a high productive specialization for which it has become more and more difficult to meet the productive requirements and reduce the energetic gap at the beginning of lactation. Anyway, generally the factors listed above interact and strengthen the negative effects that influence the subject’s productive and reproductive activity.

In the present work we will consider the effects of nutrition on buffalo reproductive activity and their possible interactions with  climatic conditions and farm management; therefore we will illustrate the characteristics that  a correct diet should have in the various reproductive phases paying particular attention to the dairy buffalo diet.


Buffalo Reproductive Characteristics

 The buffalo is a  photoperiodic species. Like sheep, buffaloes have to be considered a "short day" species. They have heats throughout the  year but tend to result more fertile when day light hours decrease. According to Zicarelli (1995) this characteristic is due to their tropical origins. They come from North equatorial areas where the availability of forage coincides with the period in which the dark hours increase. Therefore, it has been supposed, that animals which calve in the most suitable period for survival of the offspring, were selected. It seems that they kept this characteristic even when they were transferred to places where forage is always available (Zicarelli, 1995). In countries like Italy, where market demand requires more calvings in the spring-summer period (not in keeping with this species reproductive activity) the out of season technique is largely applied. Thanks to this buffaloes less sensitive to photoperiodic effects were selected. Where the out of season technique has been applied for long periods there is a lower loss of fertility  (15% vs 30%) compared to the farms where it has been adopted for shorter periods. These results are also due to the renewal of the herd  that is very frequent in those farms that apply the out of  breeding  season technique. It is known that after their 5th calving, buffaloes decrease production during the 270 lactation days. They may have relaxation of the pelvic girdle and a delayed uterine involution, probably due  to an altered mineral exchange. This situation creates an uterine environment unfavourable to conception and it worsens the herd reproductive performances. Moreover the season-dependant  reproduction phenomenon is more frequent in older buffaloes (Zicarelli et al., 1988) that feel the bull effect more and they meet the season aciclia phenomenon more easily. In studies carried out on Mediterranean buffaloes bred in Italy it resulted that melatonin represents the light/dark alternation endocrine sign. The elevation of the melatonin plasma levels, 2 hours after sunset, is much lower in  less photoperiod-sensitive subjects (Di Palo et al., 1993; Parmeggiani and Di Palo, 1994). The high repeatability of this character leads us to  suppose  that it may be a hereditary character, very useful for genetic aims.


Dry Matter  Intake and Feeding Behaviour

            The productive increase registered in some Italian herds or the lack of optimal forage may be the cause of  imbalances between animal intakes and requirements for milk and/or meat production. This situation has negative effects on the subject’s productive and reproductive activity.

            In buffaloes, as in other domestic ruminants, the dry matter intake (DMI) depends on different factors related to the chemical composition of the diet, to the organoleptic characteristics, to the storage conditions of the food, to the presence of chemical contaminations, to the animal’s physiological condition, to its age, sex and reproductive specialization and, finally, to its productive levels.

            The content in the cellular walls (ADF, NDF, ADL), and the energetic and proteic density  of the diet may influence the ingestion of DM. The increase of fibrous fractions (Mudgal, 1988) and of proteic concentration (Campanile et al., 1997b) determines a lower DMI, while the increase of the energetic density of the diet (Mudgal, 1988) has a contrary effect. This last affirmation is true in developing  countries but in Italy, where diets are composed of energetic concentrations ranging between 0.88 MFU and 0.94 MFU per DM Kg, a further increase could determine effects that contradict the results reported by Indian researchers. This effect could enlarge if  the raising of the energetic level is obtained with  highly fermentable feed. An energetic or proteic excess, in fact, increases glycemia which exerts a negative feed-back on the appetite through endocrine-metabolic changes.

            The ingestion of DM, referred to the metabolic weight (W0.75), increases according to the age of the subject. Voluntary intake ranged between 1.6% and 2.2% of live weight have been noticed in  growing subjects (Ranjhan , 1992); Tabaria and Sharma (1980) have observed  that in  heifers weighing 220 - 240 kg LW, voluntary ingestion ranged from 56 to 76g/kg W0.75. Italian authors (Moniello et al. 1992) have recorded intake of DM equal to 109g/kg W0.75 in Mediterranean race castrated males bred in Italy (live weight equal to about 360 kg). Mudgal (1988) carried out  a study on  Murrah buffaloes from which it results that they intake about 68g/kg W0.75 in dry period and  137 g/kgW0.75 during lactation. In Mediterranean buffaloes the DMI ranges from 112 to 137g/kg W0.75 (Verna et al. 1992/1994), showing  fluctuations  between 102 and 164g/kg P0.75 according to the open period, to the productive level and to  the dietary characteristics (Campanile et al., 1997a). In the last two months of lactation there is a lower  DMI ( 93- 104 g/kg W0.75)  (Campanile et al., 1996). In all the experiments mentioned above the intake resulted conditioned negatively by the content in the cellular walls (ADF, NDF, ADL) and positively by milk production. In recent studies concerning buffalo feeding behaviour during lactation, it has resulted that the  DM average intake, reduced by the dose required for maintenance, is equal to 275g per Kg of equivalent corrected milk (Campanile  et al., 1977b). 


Influence of  Nutrient Lack/Excess on Fertility

a) Energy

            The energetic requirement for maintenance depends on the physiologic conditions of the subject. According to Arora et al.(1978) in calves with live weight equal to 70 kg  the  energetic requirement for maintenance is equal to 186 kcal of ME (metabolizable energy) /kg W0.75 and it reaches 197 and 206 kcal ME/kg  in heifers weighing 135 and 200 kg that grow 450g/die. According to experiments carried out on Mediterranean heifers with a starting weight of about 260 kg, the mean daily intake of 8500 kcal of  NEl (net energy for lactation) allowed  a daily gain ranging from 636 to 742 g. It resulted higher in the subjects whose diet was rationed according to the Unifeed technique with a  14 % proteic concentration on dry matter (Borghese et al., 1997). We have reported analogous results in our experiments (date not published); it has resulted that the daily gain depends on the age and body conditions of the subject at the beginning  of the experiment. Because of the compensatory growth phenomenon the highest increases occurred in the older and underweight heifers.

             According to Mudgal and Kurar (1978) at the beginning of lactation the subjects’ requirements for maintenance result equal to 188.85 kcal of ME/kg W0.75 and more than 37% of those required in mid lactation (119.57 kcal ME/ kg W0.75; Sivaiah And Mudgal, 1978). In the dry-period, buffalo needs range from 100 to 147 kcal ME/kg W0.75. I think that the energetic maintenance requirements for buffalo during the different physiological phases  may be similar to those reported by French authors for dairy cows  (70 kcal NEl/ kg W0.75) and that the productive requirements, referring to standard milk/kg (4% fat content), are quite similar to those reported for dairy cows. To verify this, we have reported in the table the results obtained in experiment carried out on Mediterranean buffaloes (Verna et al., 1992/1994). Reading the data in the table it is clear that subtracting or adding  the body weight loss or energetic dose accumulation to produce a kg of milk about 750 kcal of NEl are necessary.

Diet with high or less energy  (A/B) and/or protein content (a/b):
experimental dates (Verna et al., 1992/1993/1994)







Milk (kg)





ECM (kg)





MFU intake/day





kg W0.75





Weight  variation (g/day)










These data are confirmed  by Mudgal and Kurar (1978) who refer analogous values for the production of equivalent corrected milk (ECM); the requirements estimated by Sivaiah  and Mudgal in the same year are quite different. They  propose 600 kcal of NEl.

The evaluation of the energetic density (MFU/DM) is very important in a diet. It varies according to the shorter buffalo calving period, responsible for the variable inter-calving interval throughout the year.

Since there are herds with very highly productive subjects, the energetic density of the diets is more and more similar  to that used for dairy cows also because the lactation period is shorter in buffaloes than in cows (270 days vs 305 days). This means that for the same quantity of energy produced during a lactation, the daily energetic requirements are higher for buffaloes.

A buffalo that produces 2000 kg of milk containing 8.5 % fat and 4.5% protein (data  concerning buffaloes registered in  the Italian Herd Book) is equal to a Frisian cow that produces 3635 kg of milk containing 3.5% fat and 3.1% protein in 305 days. Using  the same energetic equivalent  obtained with  formulas elaborated for cows (INRA, 1988) and buffaloes (Di Palo, 1992) we notice that buffaloes  require, during the 270 lactation days, 3032 MFU (( kg ECM x 0.44 MFU) + (5.75 MFU (maintenance dose for loose housed) x 270 days)) and, therefore, 11.23 MFU (1 MFU = 1700 kcal NEl) a day; cows require 3233 MFU because the maintenance requirements are estimated for 305 days and the daily needs are equal to 10.6 MFU. Since in both species the DMI  amounts to a little more than 14 Kg a day, we deduce that buffalo diets should have a higher energetic density (0.802 MFU vs 0.757 MFU). This difference increases with the increase of the herd’s productive level  and  it will be very evident at the beginning of lactation. Owing to these considerations,  in herds producing an average of over 2000 Kg and during the months in which the greater part of the calvings occur, we recommend the administration of  diets containing  energetic concentrations higher than 0.9 MFU/DM. In this way there wont be  a strong mobilization of body reserves that would determine a great weight loss with consequences on the subject’s productive and reproductive activity. It is known that a negative energetic balance causes a reduction of IFG1s and of insulinaemia (Gluckman et al., 1987; Lucy et al., 1992) which is a critical condition for development (Adashi et al., 1985, Hammond et al., 1988) and follicular growth (Lucy et al., 1992). The existence of  insulin receptors in  hypothalamus median eminence suggests a modulating action of the pancreatic hormone on the GnRH hypothalamic output (Butler et al., 1989). This regulation could depend on the greater quantity of energy (glucose) that insulin could guarantee to the hypothalamic cells that determine GnRH incretion. Insulin is hormone that regulates the metabolic activities of the various tissues by favouring the energetic influx required for cell functionality. The lower quantity of hypophysial LH in underfed subjects  associated with high levels of GnRH (Dunn and Moss, 1992) is proof that underfeeding has effects mainly of the hypophisial level. I'Anson et al. (1990) have reported that the administration of pentobarbital, a non specific neural inhibitor, increases the number of LH pulses in underfed subjects. According to Lucy (1992) there are negative correlations between the E2:P4 ratio in the follicular liquid and IFG1 (lower when there is an energetic deficiency) that could affect for follicular growth and development in diets with energetic deficiencies probably because the LH ovarian receptors decrease (Roche and Diskin, 1995). According to Adams et al. (1996) the elevation of GH in underfed sheep is necessary to keep IGF1 levels with in physiologic limits but it does not have effects on the hypophysial gonadotropins concentration and follicular growth.

The increase of GH levels in nutritionally restricted ewes reduces ovarian stimulation by gonadotropins (Suttie et al., 1991); the aim of all this is to favour the subject’s survival through the reduction of metabolic demand (Adams et al., 1996).

The exogenous administration of GH as r-BSt in buffaloes improves the superovulatory response increasing the number of subjects responsive to treatment with p-FSH but it reduces the number of embryos recovered for positive flushing (Zicarelli et al., 1994). In studies carried out on sheep Davis et al. (1990) noticed that the administration of bGH does not increase the ovulation rate. In bovine heifers, on the other hand, the small follicles increase (Gong et al., 1991).

Sastry (1989) reported that in buffaloes the  loss of body weight  during the first 4-5 months of lactation results inversely correlated to the mating period  and to the number of services necessary for conception. Negative correlations between the daily milk yield average  and the mating period length were reported by Zafar (1985); weight gain during the insemination period (mostly regarding the less productive subjects) improves fertility (Kaikini et al., 1981). As proof of a negative energetic balance, Eltohamy et al. (1994) noticed that subjects affected with ovarian hypoactivity had low levels of glucose and cholesterol. Here it must be underlined that  the lowering of the glycemic levels occurs only when there are high energetic deficiencies but it may be registered more easily when there are proteic deficiencies due to lack of carboxylic neogluco markers. Only 10-15% of haematic glucose comes from food, the remaining part comes from neoglucogenesis (Otchere et al., 1974).

In buffaloes aged between 6 and 10 years glucose haematic levels have resulted higher in pregnant subjects on the basis of the not-rebreeding index. Besides negative correlations with the number of services for conceptions have been reported  (El-Belely et al., 1994). The relation between this metabolite and milk production makes one think that in the more productive subjects the negative energetic balance modifies normal reproductive activity. In the Mediterranean buffalo the energetic deficit retards ovulation by about 6 hours (Campanile et al., 1991a); this may depend on a slower LH response IGF1 mediated. Studies carried out in Brazil demonstrate that increasing the number of head /hectare the percentage of calvings throughout a year decreases (Baruselli, 1993). In a study carried out on Murrah buffaloes, Arora and Kaur (1982) reported a great reduction in the conception rate in underfed subjects (66.6% vs 16.6 %) compared to those whose diet satisfied productive requirements.

            The beginning of lactation is generally characterized by loss of body weight because of the imbalance that occurs between ingested energy and the energy utilized for milk production; the organism remedies to this gap through fat mobilization that is higher than the energetic deficiency increase. The loss of body weight (more than 10% of live weight) in the first two months of lactation increases post-partum anestrous in the dairy cow. The ovarian cyclic activity will start again when the subject recovers its body weight which coincides with the elevation of insulinaemia and with the flexion of the lactation curve. To obviate this phenomenon, at the beginning of lactation the energetic density of the diet should be increased changing the F:C (forage:concentrates) ratio. If this is obtained increasing the  starch dose a sub clinic metabolic acidosis condition occurs in buffalo cow. It increases the endometritis rate, the calving-conception interval and the number of empty subjects (Campanile et al., 1991c). In p-FSH superovulated buffaloes, increasing of the energetic concentration with a high starch dose reduces the number of embryos recovered for flushing (Di Palo et al., 1994). Therefore one needs to increase the diet energetic density with high quality forage (grazing stage of ryegrass hay silage) instead of hay and/or with rumen protected fats.

            In  dairy cows the use of calcium soaps retards the ovarian cyclic activity (Sklan et al., 1991) and increases the number of follicles with a diameter greater than 15 mm responsible for the increase of circulating oestrogens and embryo mortality. (Lucy et al., 1991). Dietary rumen protected fats stimulates milk production with the increase of  mobilization of body reserves; as proof, the levels  of circulating NEFA result increased  (Sklan an coll., 1994). This phenomenon has been registered also in buffaloes that have received cryo-crystallized fatty acids from  the beginning of lactation (Di Palo et al., 1997). Studies in progress demonstrate that in Mediterranean buffaloes the increase of diet  energetic density  using protected fats, reduces the calving-conception interval from 48 to 38 days (Zicarelli, 1997). The same situation occurs in beef cows. Hightshoe et al. (1994) report that supplementing the diet with calcium soaps does not have an effect on the cycle and on reproductive activity resumption; it favours  follicular growth, and P4 and LH haematic levels during the luteinic phase, increases the linolenic acid that augments the PGF2 s and, thus, cyclic activity starts again and the pregnancy rate increases.

            Energetic deficiencies during puerperium accentuate the phenomenon of follicle atresia that develops in the following cycles (Wright et al., 1992). The effects of energetic deficiency may be determinant in the precalving period; it seems that underfeeding effects weigh mainly on the preantral follicles (Britt, 1991) that need about 110 days to pass from the primordial to the preovulatory phase (Lussier et al., 1987). Experiments carried out by Kruip et al. (1995) quite agree with this hypothesis. Perry et al. (1991) and Selk et al. (1988) think that the ingestion  of a lower amount of nutrients in the last quarter of gestation  influences the following reproductive activity in the post-partum period. Optimum body conditions at calving time, valued through BCS, positively influence reproductive efficiency through a quick restarting of the ovarian cycle and an improvement of fertility. A quick activation of hypophosys and higher levels of LH have been observed as proof of an efficient GnRh hypothalamic release (Wright et al., 1990). Low energetic levels  in the pre-calving period cause a decrease of the GnRH hypothalamic release and of the  LH pulsatile release (Proknor et al., 1986); these effects should be mediated by insulin and by IGF1s (Lucy et al., 1992). It has been observed that in sheep too, underfeeding could cause a lower secretion of LH and an increase of GH (Foster, 1989) that, facilitating lipolysis would preserve body proteins during loss of weight (Hart et al., 1995; Waghorn et al., 1987). In buffaloes an optimal BCS at calving time ( 3.5 points; 1 to 5 scale) improves  reproductive efficiency (Hegazy et al., 1994; Baruselli et al., 1997) due to a shortening of the calving/conception period and to a diminution in the number of the services/conception. Baruselli et al. (1997) have noticed a worsening of fertility in subjects that were very fat at calving time. They agree with Dhilon et al. (1994) that have noticed in these subjects a quick restarting of ovarian activity, a retarded conception and an increase in the number of services required for conception. This should demonstrate that the excessive fat accumulation could influence the uterine environment. As well as buffaloes, dairy cows that are very fat at calving time present a greater incidence of retained foetal membranes and uterine atony that  retard lochia expulsion. According to Hegazy et al. (1994) the effects of underfeeding in the pre-calving period decrease, in buffaloes, the effects of high energetic levels at the beginning of lactation. These last studies could explain Zicarelli’s hypothesis (1994) according to which this species’ season-dependent reproduction activity, connected with a negative photoperiod, is the consequence of the adaptation of this animal, over centuries, to the  availability of forage  required to satisfy its requirements and survival. In Brazil, in  the Southern tropical and subequatorial areas, buffalo dry period occurs when there is the greatest availability of forage; in the tropical and subtropical areas of  Asia and Africa, forage is mostly available during the last phase of gestation.


b) Proteins

            In buffaloes, the urea levels in blood and milk reached a higher level when a low-protein diet was given for a fairly long period of time. Decreasing occurs when the dietary proteic concentrations from high become low, i.e. when there is an acute stimulus (Campanile et al., 1996a). Smith (1969) reports that in ruminants that live in tropical areas, nitrogen  deficiencies decrease the urea kidney clearance,  increase ruminal return and  decrease haematic levels. Therefore there would be better urea recycling in the digestive trait and better ruminal bacteria proteic synthesis (Houpt, 1970).

            With the same ECM value the lower quantity of proteins produced with buffalo  milk compared to the cow (31 g vs 27.1 g) allows buffaloes to use  low proteic forages (Zicarelli, 1994). This could explain the adaptation of this species in South American countries where there is forage with low proteins:energy (P:E)  ratio (Zicarelli, 1994). Anyhow, we must underline that buffaloes react to proteic deficiencies better than dairy cattle (Bertoni et al., 1993).

            In Italy the diets used in buffalo breeding contain high proteic concentrations (between 14.5 and 16.5% CP/DM) and small quantities of fermentable carbohydrates (between 26 and 30 % of NSC). This does not lead to deleterious effects on the productive activities of the subjects. On the basis of our experience, with the above mentioned diets the NH3  levels  have resulted lower than those reported by Jordan et al. (1983) in cattle; in these buffaloes an increase of the urea levels in blood and milk and probably a greater elimination of the metabolite through urine occurred. The intake of more proteins increases the metabolic activity of the hepatic microsomes and this favours the transformation into urea of the alimentary derivation ammonia  (Visek, 1984).

            Feeding buffaloes with 6 different energy:proteins ratios Kurar and Mudgal (1980) have shown that the maintenance requirements of DCP (digestible crude protein) are equal to 3.2g/kg W0.75  a day and 166.34g DCP/100g of milk produced proteins. Analogous values were previously observed in Indian Murrah buffaloes (Sivaiah and Mudgal, 1978/1985).  The results obtained in a study carried out to value the effects of the energy:proteins ratio on milk characteristics  and on blood and milk urea levels  are the following: 2.53 g of CP/kg W0.75 and 2.7 g of CP x g of protein produced with milk (Campanile et al., 1996a). According to Rai and Aggarwal (1991) proteic concentrations ranged between 11% and 14% should be administered to buffaloes during the lactation period. It has been noticed that the proteic concentration used in Mediterranean buffaloes  could be lower than 12 % (Verna et al., 1992/1994). The proteic concentration depends on the herd’s milk yield level and on the days in milk. This changes throughout the year because of the concentration of calvings both in seasonal  herds and in the out of seasonal ones. Proteic concentrations 9% lower blood and milk urea levels  and increase the milk freezing point, especially if combined to a high level of fermentable energy (Campanile et al., 1996a). Therefore in order to obtain a balanced diet it is very important to value the proteins:energy ratio. In buffaloes this ratio may be higher; in buffaloes the administration of  high proteic concentrations have less deleterious effects than on dairy cows. Buffaloes use the nitrogen intake with the diet better than cattle even when there is a lack of carbohydrates (Langer, 1969) because the  buffalo intraruminal environment is more favourable to  the  growth of microrganisms that use NPN (non proteic nitrogen).

            In our study we have noticed that the proteic concentration increase (up to 15% DM) at the beginning of lactation stimulates the productive activity of the buffaloes without affecting the increase of fat mobilization. NEFA values were lower higher than those registered in animals that ingested  DM with lower levels of CP. It is known that in cattle a higher proteic concentration increases milk production because the increase of absorbable proteins quickens fat mobilization (Orskov et al., 1997; Rulquin, 1992). Post-ruminal casein infusion determines an increase of the palmitate percentage (König et al., 1984). It seems that  high proteic concentrations  stimulate GH (Oldham et al., 1978-1982) responsible for the decreased responsivity of the adipose tissue to insulin, and of a greater sensibility to the adrenergic stimulus at the end of gestation  and at the beginning of lactation. These stimulus might be mediated by gastroenteric hormones that can modulate sympathetic nervous system activity (Choung and Chamberlain, 1992).  In confirmation Cadòrnige and Lopez Diaz (1995) noticed a greater fat mobilization in cattle that had a higher BCS and fed with diets containing a higher dose of UIP; they also noticed that their adipose tissue was more sensible to epinephrine  administrations.

            The proteic surplus characterized by unbalances between degradable and undegradable fractions determines, in dairy cattle, an increase of ammonia in blood and in the female genital trait. This situation is unfavourable to  the survival of spermatozoa and embryos (Jordan et al., 1983). Moreover the elevation of ureic nitrogen  in the local (reproductive) or systemic apparatus reduces the ovarian receptors LH linkage and, therefore, it would be responsible for the lower production of progesterone in the post ovulation days and of the lowering of the conception rate. It is known that this ovarian steroid is fundamental for  embryo progression in the uterine tube, for the production of uterine milk that represents the only nourishment of the embryo before implantation and, finally, for pregnancy maintenance. Hypoluteinism, characterized by a lower progesterone secretion in the first phases of gestation, causes early embryo mortality.  It seems that the unfavourable action of ammonia on reproductive activity is insulin-mediated (Visek, 1984) for its known effects at hypothalamic level. It has been hypothesized that ammonia acts on the central nervous system through the increase of glutamate and depletion of -ketoglutarate interrupting the ATP synthesis (Visek, 1984).

            A diet with a proteinic content 50% higher than required, has led in Mediterranean  buffaloes to an increase of heats followed by an appropriate luteinic phase and  a prolongation of the inter-oestrus interval (Campanile et al., 1991a).In this species anaestrous is favoured by lack of CP and energy (Salama et al., 1982). Analogous results have been noticed in the beef cattle with a lack of energy and protein (Randel, 1990). Proteinic and/or energetic underfeeding determines a decrease of ruminal microbial activity and, therefore, of the whole VFA content. The organism answers through  an increase of GH and a decrease of insulin, allowing the mobilization  of the muscular proteins used for neoglucogenesis and, therefore, for glycemia homeostasis. Even in this case the reduction of insulin activity could interfere with buffalo reproductive activity.

            It has been demonstrated that land fertilization with 300 kg of nitrogen/Ha/year in tropical areas increases the conception rate in cows and buffaloes especially with the addition of 3.5kg of molasses a day (Orr et al., 1994). Land fertilization with nitrogen increases the forage yield per hectare and increases the quantity of soluble nitrogen, that is used better by ruminal microflora in presence of highly fermentable carbohydrates.

            Experiments in progress demonstrate that diets containing over 15% CP/DM and variable doses of degradable proteins administered to buffaloes did not influence the intercalving interval and ureic and ammonia concentrations  in the vaginal mucus that have resulted lower than those reported by Jordan et al.(1983) for dairy cattle. Carroll et al. (1988) did not notice differences as to the urea concentrations in the vaginal mucus of cattle  fed very  high  proteinic diet and this whether they had conceived or not. Thus they hypothesized  that the surplus of nitrogen in the vaginal mucus found in other studies was probably due to other causes, i.e. contamination phenomena due to faeces, urine and bacterial infections. The elevation of the ammonia blood levels may reduce the immunoresponsiveness of the animals (Targowski, 1983/1984).

            In the current situation the numerous contradictions present in international literature do not allow us to exclude the possibility that proteinic surpluses may have deleterious effects only or most of all in farms where the sanitary conditions and management are not optimum.

            In a study carried out on buffaloes with a higher productive level (> 30 kg of ECM/die) Infascelli et al. (1977) noticed that the increase of the undegradable protein concentration,  obtained with supplementation of Aspergillus oryzae, determined  a greater milk production, higher blood urea levels and  loss of fertility (Infascelli, personal communication). The authors do not exclude that this might depend on the different fertility rate of the bulls used in the different groups. The milk production increase following the better use of  undegradable protein doses  in cows causes a  fat mobilization  increase and a negative energetic balance that would negatively influence  the reproductive phenomena.  The UIP surplus in subjects , whose energy requirements are marginally  satisfied, or in the primiparae fed sufficient energy, determine a decrease of calving rate (Ferguson and Chalupa, 1989). In this case we can hypothesize that the -OHB surplus, due to the NEFA utilization, could not be used for the lesser disponibility of ossalacetiic the following sub -clinical ketosis as is well known has a negative influence on reproductive performances.

 c) Minerals and Vitamins

            The Ca and P amounts for buffalo maintenance requirement are those recommended by the INRA French authors  (1988) for dairy cows. As regards production, in consideration of the higher quantity of these elements contained in milk and of their digestive use, Zicarelli (1990) recommends 6 - 6.5 g of calcium and 2.2 - 2.5 g of phosphorus for each litre of milk. Similar requirements are proposed by Proto (1993). In the diet of lactation groups the Ca:P ratio to use will be 2:1.  It is very important to satisfy the requirements of Ca and P during the dry period;  in buffaloes this physiological phase lasts at least 120 days and small deficiencies protracted for such a long time may worsen. It has been reported many times that a diet with excess of calcium and/or lack of phosphorus or a Ca:P ratio close to the unit plays an important role in determining vaginal and/or uterine prolapse (Zicarelli et al., 1982; Campanile et al., 1989). In particular, high Ca:P ratio in the diet induce an alteration of the normal Ca:Mg ratio at the haematic level followed by an alteration of the uterine-vaginal fibre muscular excitability, atony of the organ and prolapse (Campanile et al., 1989). Supplementation with hyperphosphoric salts (at least during the last phase of gestation)  to obtain  the ratios of the two microelements near to one, stimulates the parathyroid activity (Campanile et al., 1995) useful to bone re-arrangement immediately after calving.

            According to Patak (1989) calcium supplementation in the last gestation phase reduces the time necessary for placenta expulsion and increases the haematic levels of this mineral immediately after calving. It is possible to suppose that - in this case -  calcium administration before calving had positive effects because the subjects received food containing a high amount of phosphorous or because at the beginning of lactation they produced such a small quantity of milk that the organism did not require to use bone calcium.

            In buffaloes subjected to A.I. an increase of the heats with an appropriate luteinic phase and a reduction of double ovulations in the subjects that received a quantity of phosphorous exceeding requirements of 60% has been recorded (Campanile et al., 1991a). Dunn et al. (1992) noticed  that integrating the pasture cow’s diet with phosphorous before and after calving reduces the calving  oestrus interval and the effects strengthen if combined with a higher protein administration.

            Selenium supplementation becomes particularly important, especially if carried out during the dry period,  because it reduces, in buffaloes as well as in cows, placenta retentions and favours a ready recovery of the reproductive activity immediately after calving,  because of uterine phlogosis reduction (Smith et al., 1995). In cows this microelement added to vit. E activates the immunity system (Harrison et al., 1984). In buffaloes, diet integration with 4200 mg of vit. E + 4.2 mg of Se or with a AD3 vitamin complex during the dry period and after calving reduces the calving-1st heat interval (Ezzo, 1995). In confirmation of this datum Hurley and Doane (1989) report that the alimentary supplementation with -carotene or vit. A increases the pregnancy rate, reduces the calving conception-interval  and the number of services required for conception in cow. The presence of -carotene and of vit. A in cow luteinic cells (Chew et al., 1984) and follicular liquid (Schweigert and Zucker, 1988), leads  us to suppose that these two vitamins play a very important role in the functionality of these organs. On this regard - in a trial carried out on cow -  Schweigert and Zucker (1988) found  a high correlation between estradiol-17 and vit. A in fluid from healthy follicle compared with atresic or small follicles.

            In buffaloes as in sheeps - "white milk species"- -carotene turns into vit. A  immediately after assimilation (Zicarelli et al., 1986). It follows that the corpus luteum does not appear yellow as usual. Many experiences demonstrate that the administration of  about 400.000 U.I. of vit. A and 10.000 of vit. D3 some months before bull entry and during the dry period improves the herd conception rate. During winter time buffalo diet vitamin integration becomes necessary where low temperatures and, probably, the lower activation of vit. D at cutaneous level cause hair fall and a lower resistance to ectoparasitic infestations.

 Nutrition and Puberty

            In buffalo heifers the beginning of the ovarian cyclic activity depends on live weight; in fact it has been observed that buffaloes have normal oestrus cycles when they reach 2/3 of their adult body weight (Campanile et al., 1991b; Esposito et al., 1992). Nutrition plays an important role on the beginning of the reproductive activity. In the Mediterranean buffalo (Campanile et al., 1991b; Esposito et al., 1992) there is a puberal retard when in the months preceding puberty insufficient energetic levels are adopted.  In the trials carried out  till now we have noticed that subjects having a daily body weight gain (BWG)  > 500g reach puberty about 50 days before those with  lower BWG; this occurs if high energetic levels are not followed by low ones. Positive effects occur, instead, when low nutritive levels are followed by high ones. Afidi et al. (1979) noticed that reproductive activity did not benefit by a 20% and 35%  increase of diets that  guaranteed a BWG mean increase of about 450 g in about 15-month-old subjects. According to El Nouty (1971) an earlier of puberty and  conception age  occurs in subjects fed rationally  since weaning. In a study carried out on  25 Murrah heifers, Prased et al. (1995)  noticed that protein and phosphorous excesses (30% and 150% more than requirements, respectively) delay first heat and conception age, and increase the number of services required per conception. Results in progress demonstrate that Mediterranean heifers that received 1 kg of CP a day had a lower conception rate compared to those that received 800 kg of CP a day. Even in this case conception occurred when the animal’s live weight was included between 370 and 380 kg ( about 2/3 of adult body weight). In many trials (Kamonpatana et al., 1988; Mc Cool et al., 1988; Borghese et al., 1997) it has been reported that in buffaloes, aside from race, the beginning of puberty occurs at different ages but generally it occurs when they weigh more than 300 kg, i.e. 2/3 of the adult live weight. It may be hypothesized that a modification of the GH and insulin ratio at haematic level occurs. This condition favours LH pulsate secretion and, therefore, the beginning of puberty.

 Final Considerations

The nutrition effects on reproductive performances are more evident in those countries where buffalo cow during the most favourable periods for their ovarian cyclic activity and where, thanks to the climate, forage availability  changes throughout the year.

In Italy the rationalization  of buffalo breeding and the necessity to modify calving calendars in order to satisfy market demand, leads to the reproduction of this animal in a period known to be unfavourable to its reproductive activity. The atmospheric conditions (number of day light hours, rainfall, cold winds, thermal excursion, etc.) in this case worsen the reproductive performances. Nutritive errors, i.e. unbalances between the various nutritive principles during the phase preceding sexual promiscuity, may have negative effects on the reproductive performances. This situation occurs more frequently when there is irrational pasture and when green forage is administered. Forage essences have a variable chemical composition that modifies the nutritional intake, especially  during the positive photoperiod months (spring) that in Italy correspond to the months in which sexual promiscuity starts again. The continuous modification of nutritional levels is responsible, in many cases, of the cyclic activity break in young subjects and in those in lactation.

 Hygiene and food quality, an aspect which breeders often disregard, have great importance. Badly preserved or overripe forage oblige  technicians to increase concentrate portions; the effects on fertility are deleterious. Moreover, there are the effects of the toxic substances produced by fungi that colonize food especially poor silages quality.

Considering the results reported herein, and the many conflicting opinions it appears clear that meeting of nutritional requirements is only one of the factors that can influence the reproductive phenomena of a species like the buffalo that does not yet a lactiferous habit. Stimulating production by means of a rich diet gives results that depend on the sanitary conditions in which the buffalo lives and on the breeder’s managerial abilities. An effective collaboration between breeders and technicians is the only way to maximize the productive activity of the subjects in order to increase the profits through the reduction of fixed costs.


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