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Intensive Sheep Meat Production Systems: The Use of Beef Fat or Sugar Cane Molasses as Energy Sources and Performance of Hair Sheep Lambs Fed Total Mixed Rations
Written By
Arnoldo González-Reyna, José Fernando Vázquez-Armijo, Rosendo Alberto Alcaraz-Romero, Francisco Javier Trejo-Meza, Samuel Tabe-Roldán, Javier Hernández-Meléndez, Froylán Andrés Lucero-Magaña, Nazario Pescador-Salas and Yuridia Bautista-Martínez
Submitted: 04 July 2024Reviewed: 28 January 2025Published: 30 April 2025
Energy is an important component in total mixed rations (TMR) for ruminants, most commonly sugars (as sugarcane molasses, SCM) and animal fats (rendered beef fat, RBF) are often included in finishing lambs. The effects of feeding TMR with RBF, SCM or control were determined on lamb performance. Lambs (103) were divided into three groups by sex and fed the three rations; rations were iso-proteinaceous and iso-energetic. Lambs were allotted by sex, breed and weight, and lambs were weighed every 14 days. Data was analyzed using a general linear model for average daily gain (ADG), feed intake (FI), feed conversion (FC) and scrotal circumference (SC) to determine the effects of sex, ration, breed, nandrolone and their interactions. Sex affected ADG (P<0.05), ram lambs gained more (159.8 g) than ewe lambs (119.1 g); the lambs fed RBF gained more (150.0 g) than control (138.8 g) or SCM (129.4 g) rations. Lambs fed SCM consumed more (P<0.05) than the lambs fed RBF or control rations. Main factors studied, sex, TMR and nandrolone affected (P<0.05) FC. The interactions sex*ration, sex*nandrolone and ration*nandrolone were significant (P<0.05) for ADG, whereas sex*breed, sex*ration, sex*nandrolone and ration*nandrolone were significant (P<0.05) for FI and sex*ration and ration*nandrolone were significant (P<0.05) for FC. Lambs fed RBF gained more weight than lambs fed the other rations, ram lambs also gained more weight than the ewe lambs and also lambs treated with nandrolone gained more weight than the non-treated lambs.
Instituto Tecnológico Nacional de México, Unidad Tlaxcala, Tlaxcala, Mexico
Javier Hernández-Meléndez
Universidad Autónoma de Tamaulipas, Mexico
Froylán Andrés Lucero-Magaña
Universidad Autónoma de Tamaulipas, Mexico
Nazario Pescador-Salas
Universidad Autónoma del Estado de México, Mexico
Yuridia Bautista-Martínez
Universidad Autónoma de Tamaulipas, Mexico
*Address all correspondence to: aglezr1952@gmail.com
1. Introduction
Reliable, sustainable, and profitable sheep meat production is of world-wide concern, it is even of greater concern in developing and underdeveloped countries; the adoption of global trading and marketing policies for agricultural products have contributed to magnify the situation, and in addition, grazing and forage conservation strategies must also be developed in parallel.
In addition, ruminants, mainly cattle, have been blamed for current global pollution (mostly methane); however, it should be born in mind that approximately 90% of all animal products and services is provided by only four of the 111 species of the Bovidae family, namely cattle, sheep, goats, and buffaloes [1]. Thus, precautions should be taken, when drawing conclusions from this situation.
Livestock production systems in Mexico are currently facing a similar critical situation, systems with low productivity and terminal efficiency [2, 3], marketing deficiencies [4], with production not being in sufficient amounts to meet the national demand [5].
Despite the situation, the sheep industry appears to be operating under conditions similar to those of poultry, beef or pork producers; however, productivity [2, 3, 6] and prices, as well as marketing [4], are better, which in addition to an increasingly greater demand for sheep meat, this resulting into a more profitable industry for the producers.
Mexico has traditionally been a sheep producer [2, 7], although at levels that the national consumption from the last 12 years has imposed an importation quota of over 60% [5]; with a sheep population of almost 6 millions, current production and productivity are low.
Currently producers are being forced to search for strategies to become more profitable and sustainable, with high production costs and the lack of national production and support programs [2, 3, 5, 8], still being problems to solve.
Sheep types in Mexico include wool breeds (Merino, Rambouillet, Suffolk, Dorset, Texel, Ile de France, among other breeds), Creole wool sheep, Spanish in origin (in Chiapas, Oaxaca and Central Mexico, [9]), hair sheep, of African origin (Pelibuey, PB, Blackbelly, BB, Saint Croix, SC), and some modern hybrid breeds, as Dorper and Katahdin. Production traits of the above breeds have also been described [2, 10, 11, 12, 13].
There has been a shift in the sheep population, where hair sheep has grown at the expense of wool breeds, the magnitude of this shift has not been determined [8]. This phenomenon is taking place in tropical regions of Mexico not known for its sheep production, such as the northeast and the gulf coast; where hair sheep has been raised since the early 1960s [3, 12, 14].
Production systems have employed different feeding strategies for hair sheep, one of them is the consideration of the main nutrients, such as the use of roughage [15, 16] and the type of energy and protein sources [17, 18, 19].
Surplus energy in TMR for ruminants can be supplied from several sources, including plant (SCM) and animal sources (RBF); both SCM and RBF are readily available in México, its use is economically feasible, since México is self-sufficient in sugar cane production, and it is a prominent beef producer, which allows for sufficient amounts of RBF, which is not usually used for human consumption [8].
Information on the use of non-conventional energy sources, as RBF as feed for ruminants, is not readily available. In addition, consideration should be given to the quality and source of the other TMR components available, where protein and energy quality affect animal performance [20, 21] and human consumption [22, 23, 24].
This study was undertaken to determine the effects of including RBF or SCM as energy sources on performance of PB, BB, and SC lambs, fed TMR low in roughage.
The study was conducted simultaneously on a private farm, “Ganadera Mirasol” and the Posta Zootécnica (La Posta), research station of the Universidad Autónoma de Tamaulipas, both sites are nearby each other, located at the municipality of Güémez, in Tamaulipas state, Mexico. Both sites are located very close to 24°03′ of latitude north and 98°59′ of longitude west, and the climate is semiarid, subhumid, classified as (A)c(w), with rains in the summer and light rain and strong north winds in the winter, with an annual mean temperature of 23°C and rainfall of 800 mm [8].
2.2 Feed components and experimental rations
The experimental rations (Table 1) were prepared with whole sorghum grain, soybean meal, a commercial concentrate (15% of crude protein, CP), ground buffel grass (Cenchrus ciliaris) hay, RBF, SCM, and a commercial mineral complex.
Rations
Rendered beef fat, 87.5% DM
Sugar cane molasses, 86.2% DM
Control, 86.2% DM
Ingredients
%
CP (%)
ME (kcal/kg)
%
CP (%)
ME (kcal/kg)
%
CP (%)
ME (kcal/kg)
Concentrate
40
6.0
1.3
40
6.0
1.3
35
5.25
1.13
Sorghum grain, ground
34
3.06
1.11
31
2.79
1.0
43
3.87
1.39
Soybean meal
10
4.7
0.30
10
4.7
0.3
10
4.7
0.30
Ground hay
8
0.48
0.15
8
0.48
015
8
0.48
0.15
Rendered beef fat
4
—
0.18
—
—
—
—
—
—
Sugar cane molasses
—
—
—
7
.032
0.18
—
—
—
Mineral mix
4
0.48
0.10
4
.048
0.10
4
0.48
0.10
Totals
100
14.72
3.14
100
14.77
3.03
100
14.78
3.07
Table 1.
Characteristics and fractional composition of the experimental rations, the average dry matter of rations was 87.1%.
Three rations were used, the RBF, the SCM, and the control (C), and the rations were prepared to contain approximately equal amounts of CP, 14.7% (14.72–14.78%, [25]) and metabolizable energy, 3.08 kcal/kg (3.03–3.14) of feed, as offered. Dry matter in the three diets varied less than 4%, whereas the crude protein content varied less than 5%; analyses were conducted on a weekly basis. The fatty acid profile and content of the RGF are presented in Table 2, whereas the carbohydrate composition for the SCM is presented in Table 3.
Thereafter, the lambs were given the same treatment every 28 d, except for the vaccination. One half of the lambs of each sex and on each pen were treated IM with 40 mg of nandrolone decanoate with ADE complex (ND-ADE); treatment was repeated every 28 days.
Rendered beef fat (RBF) fatty acid (FA’s) composition as estimated for the study and compared to results of other publications, expressed as percent of total fatty acids.
These values were obtained and modified from several references, some of which include the following, [26, 27, 28, 29, 30, 31, 32, 33].
Nutritional composition (components expressed/100 g of molasses) of sugar cane molasses (SCM) as estimated and as used in this study.
These values were obtained and modified from several references, some of which include the following [34, 35, 36, 37, 38, 39].
Empty cells indicate that values were not determined for this study.
2.3 Lamb management and care
A total of 103 lambs were used in the study, 52 ewe lambs and 51 ram lambs of ages three to four months and weights of 19.7 (± 0.72) kg and of 17.9 (± 0.48) kg, respectively.
The lambs were 28 SC, 34 PB, and 41 BB; the lambs for the three rations were 37, 32, and 34, respectively, for the BF, SCM, and the C rations, and were allotted according to sex (S), breed (B), and weight to the different rations (R) and treatment (T). The lambs were identified individually and placed on pens, according to the experimental protocol, freshwater and feed were offered daily, at the start of the adaptation period (14 d), the lambs were treated with vitamins ADE and B complex, a calcium-phosphorus complex, treated for internal parasites and vaccinated against enterotoxemia.
2.4 Experimental procedure
The lambs were started on dry feed (pre-weaning concentrate, 18% CP) within two weeks of age, and immediately after weaning, lambs were fed a whole, starter ration; at the start of the study, the lambs were fed the experimental rations during a 14-d adaptation period. Lambs were placed on 12 pens, according to S, R, and T with ND-ADE; each pen represented one ration, same sex, and the three breeds. Table 4 shows the distribution and number of lambs for each pen and group.
Rations and treatments
N
Sex
Males
Females
Rendered beef fat
19
9
10
Rendered beef fat + nandrolone decanoate
18
9
9
Sugar cane molasses
16
7
9
Sugar cane molasses + nandrolone decanoate
16
9
7
Control
17
8
9
Control + nandrolone decanoate
17
9
8
Breeds
Saint Croix
28
15
13
Pelibuey
34
17
17
Blackbelly
41
20
21
Table 4.
Distribution and number of observations for each of the lamb groups, according to ration, sex, treatment, and breed; lambs of both sexes were kept on separate pens.
Briefly, three rations were tested, each ration was represented in 4 pens, and one pen of each sex, treated with ND-ADE, lambs of two other pens of both sexes remained as non-treated controls. All pens were provided with fresh feed and water daily, and feed offered was weighed daily, whereas feed refused was weighed only every three days.
Data collected included biweekly body weights, feed offered and refused, and final weights, and raw data was used to calculate average daily gain (ADG), feed intake per day (kg/day, FI), and feed conversion (kg feed/kg gained, FC); FI and FC were calculated on a per group and pen basis, data for FI and FC was corrected for dry matter of each ration (Table 1). Scrotal measurements (SM) were also taken at the end of the trial for all ram lambs.
2.5 Statistical analysis
Least square means (LSM) and standard errors (SE) for body weight, ADG, FI, FC, and SM were calculated. Feed conversion was estimated on a per group basis, and thus, care must be taken when using this information. Data was analyzed using a GLM procedure [40], the initial weight of the lambs was used as covariable, since it did not significantly affect either variable, it was not further considered in the analysis.
The effects of S, T, R, and B on ADG, FI, and FC were determined using the equation:
Where: Yijklm = is the lamb’s daily gain in g/day, μ = is the overall mean for daily gain in g/day, Si = is the effect of the ith sex, Rj = is the effect of the jth ration, Tk = is the effect of the kth treatment, Bl = is the effect of the lth breed, (SB)ij = is the effect of the interaction of the ith sex with the lth breed, (SR)ij = is the effect of the interaction of the ith sex with the jth ration, (ST)ik = is the effect of the interaction of the ith sex with the kth treatment, (RT)jk = is the effect of the interaction of the jth ration with the kth treatment, (RB)jl = is the effect of the interaction of the jth ration with the lth breed, (TB)kl = is the effect of the interaction of the kth treatment with the lth breed, and ε ijklm = is the random error.
The effects of S, T, R, and B on SM were determined using the initial weight of the ram lambs as covariable, the two factor interactions in the GLM procedure were not significant, they were not further considered in the analysis, and a model with the following equation was used:
Yijklm=μ+Rj+Tk+Bl+εijklmE2
Where: Yijklm = is the lamb’s SM in cm, μ = is the overall mean for SM in cm, Rj = is the effect of the jth ration, Tk = is the effect of the kth treatment, Bl = is the effect of the lth breed, and ε ijklm = is the random error.
The initial data analysis was carried out using the initial weight of lambs as a covariable, since it did not significantly affect ADG, FI, or FC, it was not further considered in the discussion. Furthermore, a GLM procedure was also run for SM, in which case, the interactions were not significant, and thus, these results were not described or discussed further. Overall results are described for the effects of the main factors S, R, T, and B on ADG, FI, FC (Tables 5–7) and their interactions (Figures 1–3), and the effects of the main factors S, R, T, and B on SM (Table 8).
Main factors
N
Mean
SE mean
Sex (p = 0.0001)
Ram lambs
51
159.8a
4.0
Ewe lambs
52
119.1b
4.0
Ration (p = 0.028)
Rendered beef fat
37
150.1a
4.0
Sugar cane molasses
32
129.4bc
5.0
Control
34
138.8ac
5.0
Treatment (p = 0.129)
Without nandrolone decanoate
52
134.8a
4.0
With nandrolone decanoate
51
144.1a
4.0
Breed (p = 0.163)
Saint Croix
28
145.6a
5.0
Pelibuey
34
140.0a
5.0
Blackbelly
41
132.7a
4.0
Table 5.
Least square means for average daily gain (g/day) for lambs of hair sheep breeds fed whole rations and the effects of the factors studied.
Means with unequal superscript within each factor are different (P < 0.05).
Main factors
N
Mean
SE mean
Sex (p = 0.185)
Ram lambs
51
0.90a
0.02
Ewe lambs
52
0.88a
0.01
Ration (p = 0.0001)
Rendered beef fat
37
0.84a
0.01
Sugar cane molasses
32
0.96b
0.03
Control
34
0.86b
0.01
Treatment (p = 0.519)
Without nandrolone decanoate
52
0.88a
0.02
With nandrolone decanoate
51
0.89a
0.02
Breed (p = 0.385)
Saint Croix
28
0.90a
0.03
Pelibuey
34
0.89a
0.02
Blackbelly
41
0.88a
0.02
Table 6.
Least square means for feed intake (kg/day), on a dry matter basis, for lambs of hair sheep breeds, fed whole rations, and the effects of the factors studied.
Means with unequal superscript within factors are statistically different (P < 0.05).
Main factors
N
Mean
SE mean
Sex (p = 0.0001)
Ram lambs
51
5.81a
0.19
Ewe lambs
52
6.71b
0.59
Ration (p = 0.0001)
Rendered beef fat
37
5.94a
0.41
Sugar cane molasses
32
8.58b
0.44
Control
34
6.61a
0.45
Treatment (p = 0.0459)
With nandrolone decanoate
52
6.58a
0.34
Without nandrolone decanoate
51
7.45b
0.36
Breed (p = 0.1366)
Saint Croix
28
6.51ª
0.47
Pelibuey
34
6.92ª
0.44
Blackbelly
41
7.60a
0.39
Table 7.
Least square means for feed conversion (feed consumed/kg gained), on a dry matter basis, in lambs of hair sheep breeds fed whole rations and the effects studied.
Means with unequal superscripts within each factor are different (P < 0.05).
Figure 1.
Least square means for the double interactions between BxS (1a), RxS (1b), TxS (1c), RxB (1d), TxR (1e) and TxB (1f) for means for average daily gain (g/day) in lambs of hair sheep breeds.
Figure 2.
Least square means for the double interactions between BxS (2a), RxS (2b), TxS (2c), RxB (2d), TxR (2e) and TxB (2f) for means for feed intake (kg/day), on a dry matter basis, in lambs of hair sheep breeds.
Figure 3.
Least square means for the double interactions between BxS (3a), RxS (3b), TxS (3c), RxB (3d), TxR (3e) and TxB (3f) for means for feed conversion (feed consumed/kg gained), in lambs of hair sheep breeds.
Least square means for scrotal measurements (cm) in lambs of hair sheep breeds fed whole rations and the effects of the factors studied.
Means within a factor with unequal superscript are different (P < 0.05).
As stated previously, the aim of the study was to determine the effects of energy source on lamb performance, as part of the process of evaluating individual performance of purebred lambs of hair sheep breeds, under tropical conditions.
Previous reports on the use of varying amounts of protein and energy for finishing lambs have indicated effects on lamb performance and meat quality [25, 41]. In addition, protein also has direct effects on lamb performance, including ADG, FI, and FC [17, 42, 43]; the use of rations high in energy and protein also results in improved performance in finishing lambs of hair sheep breeds [43, 44].
Information on the use of animal fats as energy sources is not abundant or is not readily available, but there is some evidence that the type of energy in the ration is as important [22, 45].
The LSM and SE for the effects of S, R, T, and B on ADG are presented in Table 5. Significant effects of S (P = 0.0001) and R (P < 0.05) on ADG were observed, whereas T and B did not affect ADG. Ram lambs (159.8 g) gained almost 35% more than the ewe lambs (119.1 g), ADG was greater for the lambs fed the BF ration (150.1 g), and then the lambs fed the SCM (129.4 g) or the lambs fed the C (138.8 g) rations.
Although the T lambs gained more (144.1 g) than the no treated lambs (134.8 g), the difference was not significant; similarly, B did not significantly affect the ADG, and the SC lambs gained more (145.6 g) than the PB (140.0 g) or the BB (132.7 g) lambs (Table 5). For ADG, the interactions S*R (P < 0.006), S*T (P < 0.05), and R*T (P < 0.05) were significant (Figure 1).
Ram lambs of the three breeds gained more (ADG varied from 155 g to 166 g) than the ewe lambs (ADG varied from 103 g to 134 g); similarly, ram lambs fed the three rations (ADG varied from 156.3 g to 161.1 g) gained more than the ewe lambs (ADG varied from 97 g to 144 g), and the same was observed for the S*T interaction (ADG varied from 157 g to 161 g for ram lambs and from 108 g to 132 g for ewe lambs).
For the R*T interaction, lambs fed the SCM and the C rations and treated with ND-ADE gained more (137.2 g and 150.4 g) than the non-treated lambs (121.1 g and 127.3 g); T did not affect ADG in the lambs fed the BF ration (145 g vs. 155 g, T and non-treated, respectively). Even though the R*B interaction was not significant, the ADG varied from 122.5 g for the BB lambs fed the SCM ration to 158.5 g for the SC lambs fed the RBF ration. In the T*B interaction, all lambs treated with ND-ADE gained more (ADG varied from 139.3 g to 149.3 g) than the non-treated lambs (ADG varied from 125.7 g to 141.9 g).
Overall results indicated that ADG was affected by S (P = 0.0001) and R (P < 0.05), whereas T or B did not affect ADG (Table 5); ram lambs showed greater ADG values than the ewe lambs; similarly, lambs fed the C and the RBF rations showed greater ADG. Treatment with ND did not significantly affect ADG; however, the T lambs showed greater ADG than the non-treated lambs; a similar situation was observed on the lambs of the three breeds used, and SC lambs showed greater ADG, followed by the PB and the BB lambs. Considering the conditions under which the study was conducted, the results for ADG showed some degree of variability, which suggests a wide genetic base and the potential for genetic selection in hair sheep, in comparison with results of others; Hosseini et al. [43] reported values for ADG varying from 197 to 218 g/d, whereas Ríos-Rincón et al. [24] reported values varying from 253 to 291 g/d. Variation is expected to be greater, perhaps due to varying environmental conditions, including variability in genotype, management, and feedstuffs; as reviewed by Muñoz-Osorio et al. [46], whom have reported ADG values ranging from 45 to 306 g.
The effects of S on ADG found in this study were as expected, and ram lambs gained more than the ewe lambs and as has also been reported by others, for purebred and crossbred lambs [47, 48]. The ADG values found here fall within the limits reported in the literature for hair sheep, Velázquez [49] reported smaller gains for PB and BB lambs, in comparison with those reported here; greater values for ADG have been reported for males of the SC breed [50]. Values for ADG of 67 to 286 g have been reported for males of the PB, BB, and SC breeds, under performance testing conditions [51]. Values for ADG are usually greater than those found here when crossbred lambs are fed under feedlot conditions [47, 52, 53].
The type of R and the source of fat also affects the ADG. In this study, lambs fed the BF, and the C ration gained more that the lambs fed the SCM ration, results that are in agreement with those found by others [15, 22]. On the other hand, crossbred lambs gained more weight when fed BF or chicken fat rations [45]. Diet composition directly affects lamb performance, where energy seems to play a major role [24, 43], in relation to crude protein provided that minimum protein requirements are provided [54].
The interactions for ADG (Figure 1) tested in this study were S*B, S*R, S*T, R*T, R*B, and T*B. The S*B interaction was not significant; however, ram lambs in the three breeds showed greater ADG values than the ewe lambs. The S*R interaction was significant (P < 0.006), and the ram lambs in the three rations and the ewe lambs on the RBF ration showed greater ADG than ewe lambs on the SCM and C rations. The S*T interaction was significant (P < 0.05), ram lambs gained more than the ewe lambs, T and non-treated ram lambs showed similar ADG, whereas T ewe lambs gained more weight than the non-treated ewe lambs. The ADG values found here indicate greater gains for the T lambs; however, the differences were not significant; this finding is in agreement with the results of others, in the way that treatment with growth promoters does not always result in better performance [44, 55]. It is generally accepted that growth promoters and feed additives induce a better health status in the treated animals [56]. Reports on the forementioned interactions for lambs of hair sheep are not readily available; however, in a report by Partida et al. [57] significant interactions were determined for B and S, for ADG, FI, and FC.
Least square means and SE for the effects of S, R, T, and B on FI are presented in Table 6, there were no significant effects of S, T, or B on FI; on the other hand, R had a significant effect (P = 0.0001) on FI, and the lambs fed the SCM ration consumed more feed (0.96 kg) than the lambs fed the BF ration (0.84 kg) or the C ration (0.96 kg). Individual LSM for the several factors studied ranged from 0.85 kg to 0.97 kg (Table 6).
The FI interactions for S*B (P = 0.002), S*R (P0.007), S*T (P = 0.0001), and R*T (P = 0.006) were significant, while those for R*B and T*B were not significant (Figure 2). There were apparently important tendencies within the S*B, S*R, S*T, R*T, and R*B, which suggested a possible significant biological effect (Figure 2). BB ewe lambs consumed more feed (0.85 kg) than the rest of the S*B interaction groups and less than the PB (0.92 kg) or the SC (0.90 kg) ewe lambs. Both ram and ewe lambs fed the SCM ration consumed more feed (0.99 and 0.93 kg) than the rest of the S*R interaction groups. Non-treated ram lambs (0.98 kg) and treated ewe lambs (0.93 kg) consumed more feed than the other two groups (0.86 and 0.84 kg, Figure 2).
Treated and non-treated lambs fed the SCM ration consumed more feed (0.98 and 0.93 kg) than the other groups (0.83 and 0.88 kg). Lambs fed the RBF and C rations consumed more than the lambs fed the SCM ration; somehow, there was more variation within the R*B interaction, than in any other interaction. The LSM varied from 0.88 to 0.91 kg (Figure 2). The differences found in the study for FI of the RBF and the SCM groups perhaps were due to the type of energy of the diets.
Several factors affect FI, including, ration components are important, and it is generally accepted that FI increases with increased protein and decreases with increased energy levels (Ahmed, 2003, cited by [58]); on the other hand, the energy level plays a more important role on feed efficiency [24, 59]. Furthermore, not only the energy level in the diet is important [21, 22, 60], but also the energy source [22, 58]. Besides, FI is also affected by protein levels, but also by the type and quality of protein [23, 54, 61].
Of the factors analyzed, only energy affected FI, lambs on the SCM ration consumed more feed than lambs on the RBF or C rations. There were no effects of S, T, or B on FI (Table 6). The differences due to S, B, and T were small and unexpected, finding not in agreement with others [47, 62, 63].
The fact that FI was lower in the lambs consuming the RBF, as explained by the results of the statistical analysis and can be further explained by individual lamb differences, influenced by sex, smell, taste, and satiety; no information regarding these effects was found in the literature.
The type of energy in the ration affected FI, a finding that agrees with previous reports [22, 45, 64], usually FI depends more on the type of ration and its protein and energy levels [19, 24, 45, 59], than on other factors. Other studies have shown that high energy levels in the ration result in better FI indexes, thus resulting in better FC rates, in lambs of hair sheep breeds [17, 24, 57, 63]. On the other hand, S did not affect FI, usually rams consume more feed than ewe lambs [47, 65].
The differences due to B found in this study for FI were not significant, finding that is not surprising, for comparisons within breeds of hair sheep; since, these results are consistent with results of others [9, 51].
Results which are also common for wool sheep [47, 50, 52] or when lambs of wool and hair sheep crosses are used [53, 57].
However, Iriarte et al. [65], reported significant effects of live weight, S, B, and season of year, on FI when comparing lambs of different breeds. Based on results reported here and the results of others, it seems likely to suggest that the type of energy in the ration is equally important as the total amount, and probably, the same principle applies for protein content, a fact that has also been shown by others [22, 24, 54].
The interactions for FI studied (Figure 2) were significant for S*B (P = 0.002), S*R (P = 0.007), S*T (P = 0.0001), and R*T (P = 0.006); whereas R*B and T*B were not. Within the S*B interaction, the BB ram lambs and the PB ewe lambs consumed more feed than the rest of the S*B combinations; which suggests that even though the S*B interaction was significant, the variation and lack of effects on the other groups are perhaps due to the lack of effects of S and B (Figure 2). In the S*R interaction, both ram and ewe lambs fed the SCM ration consumed more feed than the other groups, perhaps, a carryover effect from R. Although the S*T interaction was significant, the main effect of T was not significant on FI; in the interaction, non-treated ram lambs and T ewe lambs consumed more feed than the other. It was expected that treated lambs of both sexes would have shown smaller FI values, had the effect of T been more influential. Interestingly enough, within the interactions R*T and R*B, the lambs fed the SCM ration, showed greater values for FI, regardless of T and B, also suggesting a carryover effect of R on FI and ADG. Interactions of S, B, and type of birth have also been reported to affect ADG, FI, and FC [46].
Least square means for FC varied from 5.1 to 8.6 kg, for lamb groups (Table 7). There were significant effects of S (P = 0.0001), R (P < 0.0001), and T (P < 0.05). While the B effects were not significant (Table 7). Ewe lambs consumed more feed per kg of body weight gain (8.2 kg) than ram lambs (5.8 kg), lambs fed the SCM ration consumed more feed (8.5 kg) than the lambs fed the RBF (5.9 kg) or C (6.6 kg) rations.
Likewise, non-treated lambs (7.5 kg) required more feed per kg of body weight gain than the T lambs (6.6 kg). B did not affect FC, and LSM varied from 6.5 kg for the SC lambs to 7.6 kg, for the BB lambs. Significant interactions for FC were observed for S*R (P = 0.0004) and R*T (P = 0.009), and the S*B, the S*T, the R*B, and the T*B interactions were not significant (Figure 3).
It was observed that ram lambs required less feed (5.75 to 6.0 kg) than the ewe lambs (7.4 to 9.2 kg); similarly, the ewe lambs fed the SCM ration required more feed (10.8 kg) per kg of body weight gain than the rest of the groups within the S*R interaction. For the S*T interaction, the T ewe lambs (Figure 3) consumed significantly (P = 0.0001) more feed than the other combinations; a similar situation was observed within the R*T and the R*B interactions, namely only the non-treated lambs fed the SCM ration and the BB lambs fed the SCM ration consumed more feed than the other groups (Figure 3).
Values for FI were affected by S, R, and T, whereas B did not affect it; as expected, rams and T lambs showed better FC values, and the lambs fed the SCM ration showed the greater values for FC, indicating a poorer performance (Table 7). Although there were differences in FC, due to B, these differences were not statistically significant. In this study, overall, FC ranged from 5.8 to 8.6 kg, values that fall within the ranges reported for hair sheep breeds (6.6 to 8.3 kg, [57]). These ranges could be wider depending on experimental conditions, and values of 4.0 to 12.2 kg have also been reported [15, 18, 44, 45, 63]. On the other hand, lower ranges have been reported for wool breeds, like FC values of 4.1 to 6.7 kg [50, 52, 53, 57, 63], under feedlot conditions.
Values for FC in lambs of hair sheep breeds are generally higher in comparison with values for lambs of wool breeds, as mentioned previously; but lower ranges (4.1 to 5.0 kg) for FC have been reported when crossbred lambs have been used [53, 56, 57]. As discussed previously, B has significant effects on lamb performance, FC ranges of 4.0 to 8.1 kg have been reported for sheep breeds from different far east countries [58, 60, 61], and even wider ranges for FC have been reported (9.1–25.4 kg) for breeds in Arab countries [59, 66]. In brief, the ranges previously reported and those reported here suggest the potential of hair sheep and other sheep breeds from developing countries for better lamb performance under feedlot settings, and to compete with good quality mutton and lamb meat production in global markets.
The S of lambs had a significant effect on FC, ram lambs performed better than the ewe lambs, finding that has been previously reported for both, hair [47, 57] and wool sheep [57, 62]. The source of energy had also a significant effect on FC, and lambs fed the RBF ration performed better than the lambs fed the SCM ration, with the lambs fed the C ration being intermediate. Ortíz [45] reported that lambs fed rations with beef or chicken fat performed better than lambs with no fat on the ration, and other reports have indicated that not only the type of energy in the ration is important [22], but also, the total energy of the diet [15, 43, 58].
The fact that FC was lower in the lambs consuming the RBF, as explained by the results of the statistical analysis and can be further explained by individual lamb differences, influenced by sex, taste, and satiety; no information regarding these effects was found in the literature.
The T lambs showed lower FC values than the non-treated lambs, suggesting a better performance; previous reports have indicated no effects of some anabolic agents or feed additives used [67], in hair sheep, whereas others have reported beneficial effects [44, 56]. Generally feed additives, growth promoters, and anabolic agents have at times beneficial effects, such as health improvement, when no direct effects on lamb performance were observed.
The B of lamb did not affect FC, the SC lambs showed lower FC values than the PB or BB lambs, and differences were not significant. Others reports indicated breed differences, when ram lambs have been performance-tested up to 50–60 kg of live weight [51], in this study, the lambs were finished at 30–32 kg, which may have masked other possible effects. B had effects on FC, in particular when wool breeds [53, 57] or crosses of wool and hair sheep breeds [53, 56, 57] have been used. Interactions S*B, S*T, R*B, and T*B were not significant, while the interactions S*R (P = 0.0004) and R*T (P = 0.009) were significant (Figure 3). Ram lambs performed better that the ewe lambs, regardless of breed, and for the S*R interaction, except for the ewe lambs fed the SCM ration, which showed significantly lower FC values. Within the S*T interaction, only the T ewe lambs showed greater values for FC, likewise, the non-treated lambs fed the SCM ration showed greater values for FC. For the R*B interaction, all lambs fed the BF ration performed better than the lambs fed the SCM or C rations.
There were no effects on the use of ND-ADE as anabolic agent on SM, nor effects of B or R Table 8. None of the factors studied affected testicular size in males (Table 8). Other reports for hair sheep indicate smaller testicular values (19–26 cm) for adult PB rams [68], whereas Iriarte et al. [65] reported greater values (32–35 cm), for yearling and adult rams of the PB, BB, and SC rams; the testicular size in this study varied from 26 to 27 cm.
The following conclusions can be drawn from the experimental data presented in this study:
In short, the main conclusions of this study are summarized as follows, R affected ADG, FI, and FC, whereas S affected ADG and FC, and T affected only FC,
ADG was affected by sex and ration, ram lambs gained more weight than ewe lambs, and lambs that consumed the RBF ration in relation to the lambs consuming the SCM ration; lambs treated with nandrolone decanoate gained more than non-treated lambs, and lambs of the three breeds gained differently; in the latter two cases, different were not significant,
The ration affected FI, the lambs fed with the SCM ration consumed more feed than RBF lambs, sex, treatment nor breed affected significantly FI and were no numerical differences detected,
FC was affected by sex ration and treatment, ram lambs and lambs fed RBF and treated with nandrolone decanoate significantly consumed less feed, whereas lambs of the three breeds showed only numerical differences,
Factors studied did not significantly affected scrotal size, and the numerical differences were very small.
The authors deeply acknowledge financial and infrastructure support provided by the Universidad Autónoma de Tamaulipas, the assistance of graduate students, the support of Ganadera Mirasol for the animals and infrastructure provided, and to Franco A. González Q. for the preparation of tables and figures.
All authors made significant contributions to carry out the research, data collection and analysis, and preparation of the final draft. Furthermore, all authors agree to its publication on its current version and have stated no conflict of interest in conducting this study or publishing its results.
References
1.McDowell RE. A Partnership for Humans and Animals. Raleigh, NC, US: Kinnic Publishers; 1991
2.González RA. Los sistemas de producción de ovinos en México: Estado actual y perspectivas. In: Memorias III Foro de Análisis de los Recursos Genéticos: Ganadería Ovina, Caprina, Porcina, Avícola, Equina y de Lidia. D. F., México: México; 1998. pp. 205-219
3.González-Reyna GA, Vázquez Armijo JF, González-Reyna A. Epoca de empadre e introducción del morueco en ovejas de Pelo: Efectos sobre el comportamiento del estro, la tasa de gestación y la prolificidad. Saarbrucken, Germany: Editorial Académica Española; 2011. p. 49
4.Sagarnaga VM, Suárez DH, Salas JGM. Factores económicos que afectan al sistema productivo ovino. In: V Curso Bases de la Cría Ovina. Chapingo, México: Universidad Autónoma Chapingo; 2000. pp. 165-177
5.SIAP-SAGARPA. Producción e importación de carne en México; 2013. Available from: http://sagarpa.gob.mx/Dgg/CNAovi.html
6.Ferrer AA, Lucero MFA, González RA. Estadísticas de comportamiento productivo y reproductivo de ovejas F1 Katahdin, Pelibuey y Blackbelly en trópico húmedo. In: Memorias II Taller Sistemas de Producción Ovina del Noreste y Golfo de México. México: Cd. Victoria; 2002. pp. 13-16
7.Urrutia MJ. Sistemas de producción ovina en el norte de México. In: Memorias Curso de Actualización de Ovinos, INIFAP, UNAM, UAEM. México: Toluca; 1994. pp. 24-34
8.INEGI. Anuario Estadístico del Estado de Tamaulipas. México: Instituto Nacional de Estadística, Geografía e Informática; 2016. p. 365
9.Castro GH, Perezgrovas GR, Pliego CB. Bases de datos y su utilización en evaluaciones genéticas: Caso de estudio de los ovinos del sur de México. In: Memorias I Taller Ovinos de Pelo del Golfo y Noreste de México. México: Cd. Victoria; 2000. pp. 114-134
10.Campo MG, Sánchez GG, Pliego CB, Castro GH. Comparación de la productividad de hembras Pelibuey de las tres variedades de color del ovino Pelibuey. In: Memorias V Congreso Iberoamericano de Razas Autóctonas y Criollas. Cuba: La Habana; 2000. pp. 223-224
11.González RA. Evaluaciones de comportamiento reproductivo en ovinos de Pelo en las regiones tropicales de México. In: Memorias V Curso Bases de la cría ovina. México: Chapingo; 2000. pp. 102-123
12.González-Reyna A, Martínez-González JC, Hernández-Meléndez J, Lucero-Magaña FA, Castillo-Rodríguez SP, Vázquez-Armijo JF, et al. Reproducción de ovinos de pelo en regiones tropicales de México, Revisión. Ciencia Agropecuaria. 2020;31:182-199. Available from: http://www.revistacienciaagropecuaria.ac.pa/index.php/ciencia-agropecuaria/article/view/309
13.Schoeman SJ, Burger R. Performance of Dorper sheep under an accelerated lambing system. Small Ruminant Research. 1992;9(3):265-281. DOI: 10.1016/0921-4488(92)90156-X
14.Galina MA, Morales R, Silva E, López B. Reproductive performance of Pelibuey and Blackbelly sheep under tropical management systems in Mexico. Small Ruminant Research. 1996;22(1):31-37. DOI: 10.1016/0921-4488(95)00878-0
15.Arciga CS, Gómez VA, Huerta BM. Comportamiento de borregos de Pelo alimentados con diferentes proporciones de rastrojo de maíz y grano de sorgo. In: Memorias IV Congreso Nacional de Producción Ovina. México: San Cristóbal Las Casas; 1991. pp. 19-21
16.Sánchez del RC, Hernández CN, Orozco RJ. Fuentes de fibra en la engorda de corderos con dietas a base de grano. In: IX Congreso Nacional de Producción Ovina. México: Querétaro; 1997. pp. 195-199
17.Kawas JR, Guimaraes W, Shelton MJ, Lu CD. Effect of varying concentrations of energy and protein in pelleted diets of Santa Ines and Morada Nova hair sheep on intake, digestion and growth. In: Proceedings Hair Sheep Research Symposium. Virgin Islands: Saint Croix; 1991. pp. 236-242
18.de la Partida PJA, Martínez RL. Comportamiento de borregos Pelibuey alimentados con dos niveles de energía en cuatro periodos de crecimiento. Técnica Pecuaria México. 1992;30(1):1-11. Available from: https://cienciaspecuarias.inifap.gob.mx/index.php/Pecuarias/article/view/3599
19.Pelcastre CA, Ocaña CE, Sánchez del RC. Engorda de corderos con dietas a base de grano y diferentes fuentes de proteína. In: Memorias IX Congreso Nacional de Producción Ovina. México: Querétaro; 1997. pp. 191-194
20.Aiking H. Future protein supply. Trends in Food Science and Technology. 2011;22(2-3):112-120. DOI: 10.1016/j.tifs.2010.04.005
21.Arulnathan N, Chellapandian M. Effect of dietary energy level on growth performance of fattening ram lambs. Indian Journal of Pure and Applied Biosciences. 2020;8(2):351-353. DOI: 10.18782/2582-2845.8053
22.Jaborek JR, Zerby HN, Wick MP, Fluharty FL, Moeller SJ. Effect of energy source and level, animal age, and sex on the flavor profile of sheep meat. Translational Animal Science. 2020;4(2):1140-1147. DOI: 10.1093/tas/txaa081
23.Pencharz PB, Elango R, Wolfe RR. Recent developments in understanding protein needs-how much and what kind should we eat? Applied Physiology Nutrition and Metabolism. 2016;41:577-580. DOI: 10.1139/apnm-2015-0549
24.Ríos-Rincón FG, Estrada-Angulo A, Plascencia A, López-Soto MA, Castro-Pérez BI, Portillo-Loera JJ, et al. Influence of protein and energy level in finishing diets for hair lambs: Growth performance, dietary energetics and carcass characteristics. Asian-Australasian Journal of Animal Science. 2014;27(1):55-61. DOI: 10.5713/ajas.2013-13307
25.National Research Council (NRC). Nutrient Requirements of Small Ruminants: Sheep, Goats, Cervids and New World Camelids. Washington: National Academy Press; 2007
26.Armstrong EF, Allen J. A neglected chapter in chemistry: The fats. Journal of the Society of Chemical Industry. 1924;I3:207-218t
27.Banks A, Hilditch TP. The glyceride structure of beef tallows. Biochemical Journal. 1931;25:1168-1182
28.Hilditch TP, Longenecker HE. A further study of the component acids of ox depot fat with special reference to the minor constituents. Biochemical Journal. 1937;31:1805-1819
29.Cabezas MT, Hentges JF Jr, Moore JE, Olsen JA. Effect of diet on the fatty acid composition of body fat in steers. Journal of Animal Science. 1965;24(1):57-61. DOI: 10.2527/jas1965.24157x
30.Montoya C, García JF, Barahona R. Contenido de ácidos grasos en carne de bovinos cebados en diferentes sistemas de producción en el trópico colombiano. Vitae Revista de la Facultad de Ciencias Farmceúticas y Alimenticias. 2016;22(3):205-214. DOI: 10.17533/udea.vitae.v22n3a05
31.Aminullah M, Satsuga H, Kemala T. Study of different extraction methods on finger print and fatty acid of raw beef fat using fourier transform infrared and gas chromatography-mass spectrometry. De Gruyter Open Chemistry. 2018;16:1099-1105. DOI: 10.1515/chem-2018-0109
32.Alm M. Animal fats. Lipid Library AOCS. The European Fat Processors and Renderers Association; 2012. p. 18. Available from: https://www.aocs.org/resource/animal-fats/ [Accessed: December 15, 2024]
33.Zhang F, Li L, Meng X, Liu J, Cui X, Ma Q, et al. Feeding strategy to use beef tallow and modify farm puffer fatty acid composition. Animals. 2023;13:3037, 20 p. DOI: 10.3390/ani13193037
34.Cleasby TG. The Feeding Value of Molasses. Proceedings, South African Sugar Technology Association. Mount Edgecomb: Rep. of South Africa; 1963. pp. 113-117
35.Curtin LV. Molasses–general considerations. In: Molasses in Animal Nutrition. Ambler, PA, US: National Feeds Ingredients Association; 1983. p. 11
36.Jamir L, Kumar V, Kaur J, Kumar S, Singh H. Composition, valorization and therapeutical potential of molasses: A critical review. Environmental and Technology Reviews. 2021;10(1):131-142. DOI: 10.1080/21622515.2021.1892203
37.Mohd KSA, Ainy MN, Faridah A, Jamaludin N-S, Mahmud N-K. The proximate composition and metabolite profiling of sugar cane (Saccharum officinarum) molasses. Malaysian Applied Biology. 2022;51(2):63-68. DOI: 10.55230/mabjournal.v51i2.2259
38.Mordenti AL, Giaretta E, Campidonico L, Parazza P, Formigoni A. A review regarding the use of molasses in animal nutrition. Animals. 2021;11:115. DOI: 10.3390/ani11010115
39.Palmonari A, Cavallini D, Sniffen CJ, Fernandez L, Holder P, Faglioli L, et al. Short communication: Characterization of molasses chemical composition. Journal of Dairy Science. 2020;103:6244-+249. DOI: 10.3168/jds.2019-17644
40.Cody RP. An Introduction to SAS®. University ed. Cary, NC, US: SAS Institute, Inc; 2015
41.Beauchemin KA, Rode LM, Sewalt VJH. Fibrolytic enzymes increase fiber digestibility and growth rate of steers fed dry forages. Canadian Journal of Animal Science. 1995;75(4):641-644. DOI: 10.4141/cjas95-096
42.Cruz SR, Cornelio CM. Concentración energética y proteínica del alimento sobre el comportamiento de borregos de Pelo en crecimiento. In: Memorias Reunión Nacional de Investigación Pecuaria. Chihuahua, México: Universidad Autónoma Chihuahua; 1992. p. 177
43.Hosseini SM, Akbary SM, Mahery-Sis N, Aghsaghali AM. Effect of different energy levels of diet on feed efficiency, growth rate and carcass characteristics of fattening Bahmaei lambs. Journal of Animal and Veterinary Advances. 2008;7(12):1551-1554. Available from: https://medwelljournals.com/abstract/?doi=javaa.2008.1551.1554
44.Rincón-Carruyo X, Moreno-Scott F, Rosero O. Efecto de los agentes anabólicos en ovinos tropicales alimentados con dos niveles de energía y proteína. Revista de la Facultad de Agronomía, La Universidad del Zulia. 1995;12(2):257-267. Available from: https://produccioncientificaluz.org/index.php/agronomia/article/view/26024/26650
45.Ortíz de la RB. Alimentación de Ovinos F1 Dorper-Pelibuey con grasa Animal en zona Tropical; 2002. Available from: www.unam.congrciva.mx/pan04
46.Muñoz-Osorio GA, Aguilar-Caballero AJ, Sarmiento-Franco LA, Wurzinger M, Cámara-Sarmiento R. Technologies and strategies for improving hair lamb fattening systems in tropical regions: A revision. Ecosistemas y Recursos Agropecuarios. 2016;3(8):267-277. Available from: www.ujat.mx/era
47.Bores QRF, Velásquez MPA, Heredia AM. Evaluation of terminal breeds in comercial breeding schemes with f1 hair sheep. Técnica Pecuaria México. 2002;40(1):71-79. Available from: https://cienciaspecuarias.inifap.gob.mx/index.php/Pecuarias/article/view/1313
48.Duarte VF, Pelcastre OA. Efecto de la suplementación predestete a corderos en condiciones tropicales. Livestock Research for Rural Development. 2000;12(3):1-9. Available from: http://www.cipav.org.co/lrrd/12/3/duar123a.htm
49.Velázquez MPA. Cruzamiento de ovinos de razas tropicales con razas de clima templado. In: Proceed. Curso de Actualización en Ovinos, Toluca, Edo. de Mex., México, marzo. 1994. pp. 164-172
50.McClure KE, Parker CF, Parrett NA. Feedlot performance and carcass characteristics of hair, wool and hair crossbred lambs fed high energy diets. In: Proceedings Hair Sheep Research Symposium. Virgin Islands: Saint Croix; 1991. pp. 252-256
51.González RA, Duarte OA, Iriarte VE. Utilización de la ganancia de peso como índice de selección en corderos de Pelo sometidos a prueba de comportamiento individual. In: I Taller sobre Ovinos de Pelo del Golfo y Noreste de México. México: Cd. Victoria; 2000. pp. 336-342
52.Moore BL, Berg PT, Haugen R, Limesand WD, Redmer A, Grazul-Bilska A. Evaluation of Katahdin and Wiltshire Horn (Hair Sheep Breeds): Their Effectiveness in Low Input Management Schemes. Fargo, ND, US: NDSU, ARS; 2001. Available from: http://www.ag.ndsu.nodak.edu/hettinge/livestock/2001sheep/moore
53.Vázquez SET, Partida de la PJA, Rubio LMS, Méndez MD. Comportamiento productivo y características de la canal en corderos provenientes de la cruza de ovejas Katahdin con machos de razas cárnicas especializadas. Revista Mexicana de Ciencias Pecuarias. 2011;2(3): 247-258. Available from: https://cienciaspecuarias.inifap.gob.mx/index.php/Pecuarias/article/view/1439
54.Haddad SG, Nasr RE, Muwalla MM. Optimum dietary crude protein level for finishing Awassi lambs. Small Ruminant Research. 2001;39(1):41-46. DOI: 10.1016/S0921-4488(00)00172-3
55.Saleem AM, Singer AM. Growth performance and digestión of growing lambs fed diets supplemented with glicerol. Animal. 2018;12(5):959-963. DOI: 10.1017/S1751731117001793
56.Rivera-Villegas A, Estrada-Angulo A, Castro-Pérez BI, Urías-Estrada JD, Ríos-Rincón FG, Rodríguez-Cordero D, et al. Comparative evaluation of supplemental zilpaterol hydrochloride sources on growth performance, dietary energetics and carcass characteristics of finishing lambs. Asian-Australasian Journal of Animal Science. 2019;32(2):209-216. DOI: 10.5713/ajas.18.0152
57.Partida de la PJA, Braña VD, Martínez RL. Desempeño productivo y propiedades de la canal en ovinos Pelibuey y sus cruzas con Suffolk o Dorset. Técnica Pecuaria México. 2009;47(3):313-322. Available from: https://cienciaspecuarias.inifap.gob.mx/index.php/Pecuarias/article/view/1467
58.Dabiri N. Effects of different energy and protein levels at fixed slaughter weight on performance and carcass characteristics of Arabi fattening lambs. Journal of Fisheries and Livestock Production. 2016;4(4):1-4. DOI: 10.4172/2332-2608.1000201
59.Kioumarsi H, Korshidi J, Zahedifar M, Seidavi AR, Mirhosseine SZ, Taherzadeh AR. The effect of dietary energy and protein level on performance, efficiency and carcass characteristics of Taleshi lambs. Asian Journal of Animal and Veterinary Advances. 2008;3(5):307-313. DOI: 10.3923/ajava.2008.307.313
60.Sayed A-BN. Effect of different dietary energy levels on the performance and nutrient digestibility of lambs. Veterinary World. 2009;2(11):418-420
61.Akhtar M, Ali M, Hayat Z, Yaqoob M, Sarwar M. Effect of varying levels of dietary ruminal undegradable protein on feed consumption and growth performance of growing Kajli lambs. International Journal of Agriculture and Biology. 2016;18(5):969-974. DOI: 10.17957/IJAB/15.0196
62.Ayala OJ, Rangel SR. Comportamiento productivo de dos genotipos ovinos alimentados con una dieta alta en concentrado. In: Memorias IX Congreso Nacional de Producción Ovina. México: Querétaro; 1997. pp. 249-252
63.de la Partida PJA, Martínez RL. Crecimiento de ovinos Pelibuey y sus cruzas con Suffolk o Dorset en estabulación, en clima templado. In: Memorias IV Congreso Nacional de Producción Ovina. México: San Cristóbal Las Casas; 1991. pp. 125-126
64.Wildeus S, Fugle JR. Effects of supplementation on growth and carcass characteristics of hair sheep lambs grazing native tropical pasture. In: Proceedings Hair Sheep Research Symposium. Virgin Islands: Saint Croix; 1991. pp. 243-251
65.Iriarte VE, Molina CSE, Briones EF, González RA. Características del ciclo reproductivo anual en moruecos de las razas Pelibuey, Blackbelly y Saint Croix. In: Memorias Ciclo de Conferencias sobre Evaluación, Comercialización y Mejoramiento Genético. México: Tuxtla Gutiérrez; 2000. pp. 191-195
66.Muftau MA, Malami BS, Maigandi SA, Gwandu HA. Performance and digestibility by Uda rams fed concentrate diets containing graded levels of camel’s foot pod meal (CFPM). Nigerian Journal of Animal Production. 2019;46(5):163-171. DOI: 10.51791/njap.v46i5.270
67.Martínez GJC, Villarreal VE, Salinas ZN, González RA. Aditivos en dietas integrales para corderos de razas de Pelo en estabulación. In: Memorias II Taller Sistemas de Producción Ovina del Noreste y Golfo de México. México: Cd. Victoria; 2002. pp. 29-31
68.Rojas RO. Diferentes tipos de empadre y manejo del semental en ovinos. In: Memorias I Simposio de Ovinos de Pelo en Tamaulipas. México: Cd. Victoria; 1997. pp. 25-33
Written By
Arnoldo González-Reyna, José Fernando Vázquez-Armijo, Rosendo Alberto Alcaraz-Romero, Francisco Javier Trejo-Meza, Samuel Tabe-Roldán, Javier Hernández-Meléndez, Froylán Andrés Lucero-Magaña, Nazario Pescador-Salas and Yuridia Bautista-Martínez
Submitted: 04 July 2024Reviewed: 28 January 2025Published: 30 April 2025
Open access peer-reviewed chapter
