The study was conducted jointly at the university of Parakou and the Laboratory “Quality and Safety of Agro-Food Products” of Gembloux Agro-Bio Tech, University of Liège in Belgium, from May 1, 2017, to September 30, 2023. The milk from Borgou and Azawak cow breeds was sampled at Okpara Livestock Farm, located in Kika District (2˚39' - 2˚53'E longitude and 9˚6' - 9˚21'N latitude) of the Commune of Tchaourou, Borgou Department [22] . The milk from Lagunaire cow breed was sampled from the Lagunaire herds kept on natural pasture in the munipality of Savalou (Samiondji) in Benin. The Milk from N’Dama cow was collected from the herd reared on natural pasture in the Municipality of Djougou.

Data on the technological and nutritional properties of milk were collected from 10 liters of fresh milk obtained from 10 cows of each breed reared under identical conditions on natural pasture at the Okpara Livestock Farm. All cows were reared under natural pasture feeding. Each 1-liter sample was immediately chilled and transported to the laboratory, where it was individually analyzed for technological and nutritional properties without pooling.

The technical equipment included a thermometer, micropipettes, standard dairy glassware, standard laboratory glassware, a CRM (Computer Renneting Meter) for determining milk coagulation properties, a centrifuge, plastic bottles of 500 ml, 50 ml, and 10 ml, an analytical balance, a vortex mixer, a desiccator, a water bath, titration devices, a Congo Red dye bottle, a Berthelot 530 rennet bottle, a thermometer, two sachets of concentrated lyophilized lactic starter cultures (DANISCO), 15 burettes, 12 beakers, a pack of pipettes, Kjeldahl glassware, a Kjeldahl apparatus, Kjeldahl catalyst tablets, a digester, a distiller, an acid-base titration setup, a phenolphthalein bottle, sulfuric acid, sodium hydroxide, distilled water, and Mojonnier fat-extraction flasks as specified in ISO 3889 [23] and described by [16] .

Methodologically, the data collected included: milk coagulation time, curd firming time, titratable acidity, pH (hydrogen potential), fresh cheese yield, dry cheese yield, dry matter content of milk, dry matter content of whey, protein content, fat content, total mineral (ash) content, and potassium dichromate content.

Technologically, milk sample pH was measured using a pH meter previously calibrated with buffer solutions at pH 7 and 4 (±50 ml in a small beaker). The characteristics of milk coagulation (MCP) are commonly described using parameters such as rennet coagulation time (RCT), the time required to reach a curd firmness of 20 mm (k20), and the curd firmness measured 30 minutes after the addition of the coagulant (a30) [6] . These parameters (r and k20) were measured in the current study by using computerized renneting meters (Formagraph) as described by [23] . Laboratory cheese yield (fresh and dry) was determined by measuring the quantity of curd obtained after adding rennet to the milk. The potassium dichromate content was determined according to the French standard NF V 04-209 (October 1989), “Determination of the potassium dichromate content of milk: Reference method”.

As for nutritional quality and butter-making potential of milk, dry matter, ash, fat, and protein contents were determined following the standardized procedures recommended by AOAC [24] . Moisture content was determined gravimetrically in accordance with NF V 04-401 (April 2001). Each measurement was performed in triplicate per sample and per breed. Fat content was determined according to NF V 04-214 [25] [26] (December 1985; ISO 1211: 1995), with two replicates per sample and per breed. Total ash content was determined according to NF V 04-208 (October 1989). Protein content was determined according to NF V 04-211 (December 1971), “Determination of total nitrogen content of milk (Kjeldahl method).” The potassium dichromate content was determined following NF V 04-209 (October 1989).

The data collected in the field were coded and entered into a database designed using Excel software and analyzed with SAS software [27] . The PROC GLM procedure of SAS was used for the analysis of variance. The F-test was applied to determine the significance of the breed effect. The Student T-Test was performed for mean comparison.

The effect of cow breed on the technological quality of milk is given in Table 1 . The results indicate that breed has a significant effect on all measured parameters. Borgou milk exhibited the shortest coagulation time at 1.72 minutes, followed by N’Dama at 2.25 minutes, Azawak at 3.2 minutes, and Lagunaire at 5.4 minutes, demonstrating that Borgou milk coagulates more rapidly, which is advantageous for cheese production (P < 0.001). Curd firming time, as measured by K20, also varied significantly among breeds, with Borgou and Lagunaire showing faster curd firming than Azawak and N’Dama, suggesting that breed influences the rate at which milk solidifies after coagulation begins (P < 0.05). Titratable acidity was slightly lower in Borgou milk compared to the other breeds, indicating a slower acidification process (P < 0.05), while pH values differed as well, with Azawak milk having a higher pH than the other breeds (P < 0.001). Overall, these results highlight that Borgou milk possesses favorable technological properties for dairy processing, whereas Azawak and Lagunaire milk exhibit characteristics that may influence curd formation differently. The findings confirm that breed plays a critical role in determining the coagulation behavior, acidity, and pH of milk, which are key factors for cheese-making and other dairy applications.

SE: Standard error; *: P < 0.05; ***: P < 0.001.

The effect of cow breed on the technological quality of milk is given in Table 2 . The data on the chemical and technological composition of milk show that breed has a significant influence on most parameters. Raw curd yield was highest in Borgou milk at 0.36%, followed by Lagunaire at 0.32%, N’Dama at 0.30%, and lowest in Azawak at 0.24% (P < 0.001), indicating that breed affects the amount of curd obtained immediately after coagulation. Similarly, dry curd yield was significantly higher in Borgou, N’Dama, and Lagunaire (59.73%, 59.2%, and 59.4%, respectively) compared to Azawak (47.65%) (P < 0.001), suggesting that milk from these breeds is more efficient for cheese production. Ash content varied with breed, being higher in Azawak and Lagunaire (0.8% and 0.78%) than in Borgou and N’Dama (0.70%), showing a significant effect of breed on mineral content (P < 0.05). Potassium dichromate content did not differ significantly among breeds (P > 0.05), indicating that this parameter is not breed-dependent. Fat content was highest in Borgou (3.49%) and N’Dama (3.38%), lower in Azawak (2.74%), and lowest in Lagunaire (2.18%) (P < 0.001), reflecting substantial breed variation in milk richness. Whey dry matter content differed significantly among breeds, being lowest in Azawak (11.2%) and highest in Lagunaire (13.08%) (P < 0.001), while milk dry matter content was highest in Lagunaire (8.4%) and Borgou (7.6%), moderate in Azawak (7.73%), and lowest in N’Dama (6.51%) (P < 0.001). Protein content also varied significantly, with the highest levels in Lagunaire (4.11%) and Azawak (3.66%), moderate in N’Dama (3.34%), and lowest in Borgou (3.15%) (P < 0.001). Overall, these results indicate that breed plays a critical role in determining milk composition and cheese-making potential, with Borgou, N’Dama, and Lagunaire generally exhibiting more favorable technological and compositional characteristics compared to Azawak.

NS: P > 0.05; *: P < 0.05; ***: P < 0.001.

Table 3 presents the correlations between the parameters of cheese-making, butter-making, and technological properties of milk from Borgou cows (below the diagonal) and Azawak cows (above the diagonal).

In Borgou cows, the milk coagulation time was positively and strongly correlated with the curd firming time, titratable acidity, milk pH, and total nitrogen content (0.80 ≤ r ≤ 0.96; P < 0.001), indicating that samples that coagulate more slowly tend to have higher acidity and protein content. However, coagulation time was negatively and weakly associated with fat content, whey dry matter, and fresh curd yield (−0.67 ≤ r ≤ −0.52; P < 0.05). Conversely, the curd firming time was positively and weakly correlated with titratable acidity, pH, and total nitrogen content (0.63 ≤ r ≤ 0.69; P < 0.05), but negatively and weakly correlated with fat content (r = −0.47; P < 0.05).

Similarly, titratable acidity showed positive and weak correlations with milk pH and total nitrogen content (r = 0.50; 0.70; P < 0.05). In addition, total ash content was positively and strongly associated with milk dry matter (r = 0.92; P < 0.001) and weakly but positively correlated with potassium dichromate content (r = 0.61; P < 0.05). The potassium dichromate content was also weakly and positively correlated with milk dry matter (r = 0.69; P < 0.05).

The fat content was positively and strongly correlated with milk dry matter, fresh curd yield, and dry curd yield (0.84 ≤ r ≤ 0.89; P < 0.001), but negatively and strongly correlated with pH and total nitrogen content (r = −0.84; −0.76; P < 0.001). Similarly, the whey dry matter was positively and strongly correlated with fresh and dry curd yields (r = 0.79; 0.74; P < 0.001), but negatively and strongly correlated with pH and total nitrogen content (r = −0.77; −0.75; P < 0.001).

Moreover, pH was positively and strongly associated with total nitrogen content (r = 0.95; P < 0.001), but negatively and strongly correlated with fresh curd yield (r = −0.76; P < 0.001) and weakly with dry curd yield (r = −0.68; P < 0.05). In turn, the total nitrogen content was negatively and strongly correlated with fresh and dry curd yields (r = −0.83; −0.77; P < 0.001). Furthermore, the fresh curd yield was positively and very strongly correlated with the dry curd yield (r = 0.99; P < 0.001), confirming the consistency between these two cheese yield indicators.

In Azawak cows, the milk coagulation time was positively and strongly correlated with curd firming time, total ash, titratable acidity, pH, and total nitrogen content (0.65 ≤ r ≤ 0.85; P < 0.001), indicating that longer coagulation is associated with higher acidity, protein, and mineral content. Conversely, it was negatively and strongly associated with fat content (r = −0.63; P < 0.001), and negatively and weakly related to fresh and dry curd yields (r = −0.69; P < 0.05). Additionally, the potassium dichromate content was weakly and positively correlated with whey dry matter, fresh curd yield, and dry curd yield (0.43 ≤ r ≤ 0.44; P < 0.05).

Legend: R: Coagulation time; K20: Curd firming time; TA: Titratable acidity; Ash: Total ash content; PDC: Potassium dichromate Content; Fat: Fat content; WDM: Whey dry matter; MDM: Milk dry matter; PH: Hydrogen potential; CP: Crude Protein; FCY: Fresh curd yield; DCY: Dry curd yield; NS: Not significant; *: P < 0.05; ***: P < 0.001.

Table 4 shows the correlations between Physicochemical and Technological Parameters of N’Dama Milk (below the diagonal) and Lagunaire Milk (above the diagonal).

In N’Dama cow milk, coagulation time (R) showed a strong positive correlation with curd firming time (K20, r = 0.80; P < 0.001) and titratable acidity (AT, r = 0.78; P < 0.001), indicating that milk samples that coagulate more slowly also require longer firming times and have higher acidity. R was also highly and positively associated with pH (r = 0.96; P < 0.001) and total nitrogen (MAT, r = 0.77; P < 0.001), suggesting that milk with higher pH and protein content tends to coagulate more slowly.

Total ash (CT) correlated positively with total potassium dichromate (TDP, r = 0.61; P < 0.05) and whey dry matter (MSL, r = 0.91; P < 0.001), revealing that mineral-rich milk contributes to higher solid fractions. A strong association was also observed between CT and milk dry matter (MS2, r = 0.92; P < 0.001), as well as between CT and total nitrogen (MAT, r = 0.93; P < 0.001), confirming that mineral content is tightly linked to overall milk solids and protein.

Fat content (MG) displayed negative correlations with coagulation time (R, r = −0.67; P < 0.05), pH (r = −0.84; P < 0.001), and total nitrogen (MAT, r = −0.76; P < 0.001), suggesting that fattier milk tends to have lower pH, lower protein content, and faster coagulation. MG was, however, strongly positively correlated with curd yield—both fresh (RDMFF, r = 0.89; P < 0.001) and dry (RDMFS, r = 0.84; P < 0.001)—indicating that higher fat levels enhance cheese-making performance.

Moreover, total nitrogen (MAT) was highly positively correlated with pH (r = 0.95; P < 0.001) and curd yields (RDMFF, r = 0.84; P < 0.001; RDMFS, r = 0.89; P < 0.001), reinforcing the close link between milk protein and cheese yield. Overall, in the N’Dama breed, milk composition traits such as fat, protein, and dry matter are key determinants of curd formation and yield, while pH and acidity play a decisive role in coagulation kinetics.

In the Lagunaire breed, coagulation time (R) was strongly and positively correlated with curd firming time (K20, r = 0.85; P < 0.001), titratable acidity (AT, r = 0.71; P < 0.001), and pH (r = 0.86; P < 0.001), showing that slower-coagulating milk also tends to have higher acidity and firmer curd formation. R was moderately related to total nitrogen (MAT, r = 0.66; P < 0.001) and negatively related to curd yields (RDMFF, r = −0.69; P < 0.05; RDMFS, r = −0.69; P < 0.05), suggesting that prolonged coagulation reduces cheese yield.

Legend: R: Coagulation time; K20: Curd firming time; TA: Titratable acidity; Ash: Total ash content; PDC: Potassium dichromate Content; Fat: Fat content; WDM: Whey dry matter; MDM: Milk dry matter; PH: Hydrogen potential; CP: Crude Protein; FCY: Fresh curd yield; DCY: Dry curd yield; NS: Not significant; *: P < 0.05; ***: P < 0.001.

Curd firming time (K20) correlated positively with R (r = 0.85; P < 0.001) but showed weak or non-significant associations with most compositional traits, indicating limited influence on milk’s chemical composition. Total ash (CT) was positively correlated with potassium dichromate (TDP, r = 0.43; P < 0.05) and with curd yields (RDMFF, r = 0.87; P < 0.001; RDMFS, r = 0.91; P < 0.001), emphasizing the role of mineral content in cheese formation.

Fat content (MG) showed a strong negative correlation with pH (r = −0.90; P < 0.001) and total nitrogen (MAT, r = −0.90; P < 0.001), while being positively correlated with curd yield (RDMFF, r = 0.84; P < 0.001). Similarly, whey dry matter (MSL) was strongly correlated with milk dry matter (MS2, r = −0.40; P < 0.05) and with protein and curd yield parameters, highlighting their interdependence.

Total nitrogen (MAT) exhibited a high positive correlation with pH (r = 0.81; P < 0.001) and curd yields (RDMFF, r = 0.84; P < 0.001; RDMFS, r = 0.89; P < 0.001), confirming that higher protein levels enhance curd formation. The strong correlation between fresh and dry curd yields (RDMFF–RDMFS, r = 0.99; P < 0.001) further supports the consistency of the Lagunaire milk’s technological performance.

In summary, Lagunaire milk showed strong interrelations among fat, protein, and cheese yield, while ash and acidity appeared to modulate coagulation time and curd firmness. These relationships highlight the integrated influence of compositional and physicochemical traits on the technological behavior of milk from this breed.

The results of this study demonstrate that the breed of dairy cattle exerts a significant influence on the rennet coagulation properties, curd firmness, and overall technological potential of milk. The significant differences observed among Borgou, N’Dama, Azawak, and Lagunaire breeds confirm that genetic and physiological factors associated with breed composition affect milk coagulation behavior and curd formation dynamics. The shorter rennet coagulation time (RCT) recorded for Borgou milk (1.72 min) suggests a higher aptitude for cheese-making compared with the other breeds. This rapid coagulation may be attributed to differences in casein micelle structure, κ-casein content, and calcium ion concentration, which are known to accelerate rennet-induced gelation [6] [10] . Similar findings were reported by [8] , who observed breed-dependent variations in milk coagulation linked to both genetic background and environmental adaptation. The slower coagulation time observed in Azawak and Lagunaire cows indicates a lower enzymatic reactivity of their milk, which could result in weaker curd formation and reduced cheese yield.

The curd firming time (k20) and curd firmness (a30) also varied significantly among breeds, highlighting the differential capacity of milk to form and consolidate the gel structure. Borgou and Lagunaire milk exhibited faster firming and higher curd firmness, consistent with the pattern of shorter RCT, whereas Azawak and N’Dama milk showed longer firming times. This variability aligns with the findings of [7] , who emphasized that milk from different breeds can exhibit distinct rheological behaviors during coagulation due to compositional differences, notably in fat and protein fractions.

The observed effects of cow breed and the average values of rennet coagulation time, curd firmness, and butter-making potential of milk from the four indigenous cattle breeds of Benin are consistent with those reported by [16] and colleagues in their study on the cheesemaking, butter-making, and nutritional quality of milk from Borgou and Azawak cows raised on natural pastures. In their findings, the average coagulation time of Azawak milk was around 24.5 minutes, compared to 18.3 minutes for Borgou milk [16] . According to these authors, the firming time of coagulated milk averaged 11.2 minutes for Azawak cows and 8.4 minutes for Borgou cows [16] . The titratable acidity was about 0.23 g lactic acid/100mL for Azawak milk and 0.22 g/100mL for Borgou milk [16] . According to these authors [16] , milk pH was close between breeds (6.68 for Borgou and 6.65 for Azawak).

In terms of milk composition, the higher fat and dry matter contents in Borgou and N’Dama milk suggest better cheese-making efficiency, as these parameters directly influence curd yield and texture. The positive correlation observed between fat content and curd yields in all breeds corroborates the results of [10] , who demonstrated that higher lipid content enhances the retention of solids during curd formation. Conversely, the negative correlation between pH and fat content indicates that more acidic milk tends to have reduced fat levels, which may affect curd consistency.

The observed differences in titratable acidity and pH among breeds further reflect differences in microbial activity, buffering capacity, and casein micelle stability. The slightly higher pH in Azawak milk could explain its delayed coagulation, as high pH values generally reduce the rate of κ-casein hydrolysis by chymosin and hinder casein aggregation [6] . In contrast, the moderate acidity and optimal pH of Borgou milk favor faster rennet action and stronger curd formation. Similar relationships between pH and coagulation dynamics have been documented by [2] and [8] , emphasizing the delicate balance between milk composition and enzymatic coagulation processes.

Furthermore, milk with higher dry matter content, particularly in N’Dama and Borgou cows, supports better butter texture due to the presence of solid components that contribute to plasticity and spreadability. This aligns with observations in both African and European dairy systems, where dry matter has been identified as a key determinant of butter consistency and sensory properties [13] [14] [18] .

In the Northern Benin, [16] found that the total ash and dichromate contents were similar between the Azawak and Borgou cow breeds. According these authors, Borgou milk showed a higher average fat content (4.8%) compared with Azawak milk (4.1%), and a greater whey dry matter content (6.2% vs. 5.6%) [16] . In contrast, from their study, Azawak milk had a higher protein concentration (3.7%) than Borgou milk (3.15%). Despite this, the average fresh cheese yield was greater in Borgou milk (16.4%) compared with Azawak milk (14.8%), and the dry cheese yield followed the same trend [16] .

The present findings on the significant influence of local cow breeds on the processing properties of milk is also in agreement with previous reports that identified breed as a major source of variation in milk coagulation parameters [28] - [32] . The significantly shorter rennet coagulation time (RCT) observed in Borgou milk (1.72 min) compared to N’Dama (2.25 min), Azawak (3.2 min), and Lagunaire (5.4 min) suggests a superior coagulation aptitude of Borgou milk, which is advantageous for cheese production. Similar trends were reported by [33] , who noted breed-dependent differences in RCT, with local or dual-purpose breeds generally showing faster coagulation than specialized dairy breeds such as Holstein-Friesian.

Differences in curd firming time (K20) among breeds further support the influence of genotype on casein micelle behavior during gel formation. The faster curd firming observed in Borgou and Lagunaire milk indicates a more efficient network formation after enzymatic coagulation, comparable to the higher curd firmness reported for Rendena milk relative to Holstein milk by Mariani et al. (2002). Such differences may be attributed to genetic variations in milk protein fractions, particularly κ-casein and β-lactoglobulin, which are known to affect coagulation kinetics [30] - [34] .

The lower titratable acidity and slightly higher pH observed in Azawak milk suggest slower acid development, which may be linked to lower buffering capacity or different microbial activity during storage. Similar pH variations among breeds were described by [32] , emphasizing the role of breed in determining the physicochemical balance of milk. These parameters are crucial for cheesemaking, as acidification directly influences rennet action, curd firmness, and moisture retention in the final product.

Overall, the results confirm that breed significantly affects milk coagulation behavior, acidity, and pH—factors essential for optimizing traditional dairy processes such as Wagashi cheese production. The superior technological potential of Borgou milk highlights its importance for artisanal cheese and butter production in northern Benin. Conversely, although Azawak milk exhibited higher pH values, its longer coagulation time and lower curd firmness may limit its suitability for certain dairy applications. These findings are consistent with earlier studies indicating that indigenous breeds often possess milk better adapted to traditional processing conditions than exotic or crossbred types [33] .

However, milk quality can also be affected by region through seasonal variations in diet, while diet is a direct factor influencing milk’s nutritional and chemical composition [35] [36] . For instance, summer milk from grazing pastures is often richer in protein, lactose, and antioxidants compared to winter milk from dry forage, a difference influenced by the regional availability of feeds [35] . The region’s climate and feed availability directly impact the cows’ diet, which in turn alters the milk’s fat, protein, and micronutrient content. In the current study, the difference in the agroecological areas of rearing of the different cow breeds under analysis may influences the milk quality [35] .

Correlational analyses reinforce these interpretations. In Borgou milk, rennet coagulation time correlated strongly and positively with curd firming time, acidity, and total nitrogen, while showing a negative relationship with fat and curd yield. These patterns suggest that slower coagulation is associated with higher protein concentration but lower fat retention, a trend also described by [6] . Conversely, in Azawak milk, strong positive correlations between coagulation time, acidity, ash, and total nitrogen indicate that the breed’s milk composition favors slower, mineral-influenced coagulation, possibly due to micellar calcium variability.

In N’Dama and Lagunaire milk, correlations between protein content (total nitrogen) and curd yield were highly significant, confirming the pivotal role of casein concentration in determining cheese yield. The positive association between ash content and milk dry matter in these breeds highlights the contribution of mineral components (notably calcium and phosphorus) to curd structure formation. The negative correlations of fat and protein with pH observed across breeds further support the idea that milk acidity is a key determinant of technological performance, influencing both coagulation speed and curd compactness [7] .

Collectively, these findings underscore that Borgou milk exhibits the most favorable technological profile among the studied breeds, combining rapid coagulation, good curd firmness, and adequate fat and protein contents conducive to high cheese yield. Azawak milk, characterized by longer coagulation time and higher pH, presents less favorable properties for cheese-making but may have advantages in other dairy products requiring slower acidification. N’Dama and Lagunaire milk, although variable, show intermediate technological traits influenced by compositional and mineral balance.

The observed breed effects have important implications for dairy value chains in Benin and similar agroecological zones. Selecting and promoting breeds such as Borgou for cheese-making could enhance local dairy productivity and processing efficiency. Moreover, improving the nutritional management of less favorable breeds as Azawak and optimizing processing conditions (such as pH adjustment or calcium supplementation) could help standardize milk technological quality, as suggested by [6] [10] .

Similar relationships were observed by [16] . Indeed, from their study, milk coagulation time was positively associated with firming time, acidity, pH, and total nitrogen content, while it showed a negative association with fat content, whey dry matter, and cheese yield [16] .