Insights Into The Effect of Shelter Modification On Key Biochemical Aspects vis-a-vis the Performance of Sahiwal Zebu Cows Reared in Hot Arid Ambience

This study was undertaken to evaluate the effect of shelter modifications in the form of floor alteration and heat stress amelioration aids on the biochemical aspects and productive performance of Sahiwal zebu cows. 24 healthy Sahiwal cows in their second or third parity were randomly assigned to four groups (G1, G2, G3, and G4) having 6 cows each and were studied for duration of 150 days from June to November. G1 acted as control without any shelter modification, while G2 cows were housed in stalls with rubber mat covered floors, G3 cows were provided with cooling fans along with water sprinkling twice a day, and G4 cows were housed in stalls combining rubber mat floors with cooling fans and water sprinkling twice a day. This study revealed a significant (p<0.05) effect of shelter modification on milk yield, though no significant effect on milk composition was found. Among blood biochemical parameters, serum cholesterol and cortisol levels registered a significant (p<0.05) effect of shelter modification. The use of heat amelioration aids with, and without rubber mat floors positively influenced the productive and biochemical aspects of Sahiwal cows. Such strategies can be utilized to reduce stress on animals and help in maintaining their production.

OVARIAN STATUS OF NON-GRAVID SLAUGHTERED ZEBU COWS IN ZARIA: RELATIONSHIP WITH AGE, SEASON AND CARCASS WEIGHT

OF 3,900 non-gravid zebu ovaries examined at 3 Zaria slaughter houses, 2,652 (68%) were active, Ovarian activity was highest during the rainy season and anestrus highest during the dry season (P < 0.01). Anestrus non-gravid cows and empty cows with active ovaries had the lowest (135+41 kg) and the highest (170 +43 kg) carcass weight respectively. Aged anestrus empty COWS had the lowest carcass weight (127+28 kg) and mature empty cows with active ovaries had the highest (180 +47 kg). The incidence of anestrus increased with age. The magnitude of slaughtering of young and mature empty cows with active ovaries was discussed and it was recommended that rectal examination be done before culling animals in order to reduce this major source of loss of reproductively active cows.

ASSESSMENT OF RECTAL PALPATION AS A TECHNIQUE FOR THE DETECTION OF CORPORA LUTEA AND ESTIMATION OF THE STAGE OF PREGNANCY IN ZEBU COWS

Twenty eight multiparous Bunaji cows were used to evaluate rectal palpation as a technique for identifying the presence or absence of corpora lutea (CL) and estimating the stage of pregnancy in Zebu cows. Overall correlations (85.7%) between rec tal p alpa­tion findings and progesterone (P4) levels were more than non-correlations (14.3%). Correlations between CL diagnosis or lack of CL and progesterone levels were 78.8% and 88.4% respectively. Estimation of the stage of pregnancy by rectal palpation corre­lated with the stages based on calving dates in 77.1, 55.6 and 60.9% of the cases during the first, second and third trimesters of pregnancy, respectively. In general, rectal palpation was a reliable method of detecting CL and estimating the stage of pregnancy in the Zebu cows.

INFLUENCE OF BREWERS DRIED GRAINS ON THE RUMINAL VOLATILE FATTY ACIDS (VFA)PRODUCTION AND MILK CONSTITUENTS IN ZEBU COWS

Four lactating White Fulani (Zebu) cows fitted with permanent rumen cannular were fed four. diets: (A) Acha hay (Digitaria exilis Stapf, (B) 50% acha hay plus 50% brewers dried grains (BDG), (C) 75% BDG plus 25% hay and (D) 100% BDG in a 4 x 4 latin square design. Analysis of rumen total Volatile Fatty acids (VFAS), individual VFAs, ammonia-N and pH as well as some milk constituents were carried out simultaneously. Mean ruminal pH and total VFA (MM/100ml) were 7.1,6.2; 6.5, 8.0; 5.8, 14.9 and 5.8, 13.1 for A, B, C, and D respectively. The corresponding acetate to propionate (A/P) ratios were 4.97, 4.40, 3.20 and 3.40. The molar percent values of butyrate yielded by A and B were similar and less (P<0.05) than the value for C or D. Ruminal ammonia-N (mg/100ml) ranged from 5.7 for A to 6.8 for D. Total VFA, NH3-N and pH of the rumen fluid were affected by time of feeding (P<0.05). The correlations between ruminal pH and acetate (r = 0.98), pH and total VFA (r = -0.90), and acetate and propionate (r = -0.75) were significanct(P <0.05). Cows on treatment A (acha hay) yielded higher percent milk fat (P<0.05) and lower percent milk protein than those on B, C, or D. Treatment effects on milk pH and percentages of lactose, solids-not-fat (SNF) and ash were not significant. The observed depression in milk fat of cows on treatments B, C and D in comparison with cows on treatment A wasrelated to a decrease in rumen acetate and an increase in propionate. It was observed that the fermentation of BDG yielded acetate within limits required for efficient milk production.

Maize seed germination inhibition test for pregnancy diagnosis in Zebu cows

Pregnancy diagnosis is an important part of good management and helps to maximizereproductive performance. Over time, different methods for detection of pregnancy in cows and other female domestic animals have been developed which include observation, physical examination, chemical tests and electronic instruments. Seed germination inhibition technique was carried out to detect pregnancy in Zebu cows. The urine samples collected from four pregnant cows, four non pregnant cows, four bulls and water (control) were subjected to seed germination test using maize seeds. Urine was collected between 5 and 7 am. Pregnant cows were confirmed by rectal palpation. The pH of the urine samples was determined before and after dilution and consequently, the urea concentration was also analyzed in the laboratory. The urine was diluted at the ratio of 1:4 with distilled water. Control test was also carried out with the addition of water only to the maize seeds. In each sterile Petri dish fifteen maize seeds were taken on the filter paper and 15mL of diluted urine was added. The seed germination inhibition percentages were observed after five days while shoot length growth inhibition was also observed after five days. Germination inhibition percentage of pregnant cows (64.16%) was significantly (P<0.05) higher compared to nonpregnant cows (34.18%), bull urine and water control. Shoot length of seeds germinated with distilled water had the highest value (4.38cm), seeds germinated with bull urine and non pregnant cow urine showed similarities while seeds germinated with pregnant cow urine had the least value (1.37cm) across the observations for shoot length growth inhibition. The result on pH showed clear differences in the pH of urine from pregnant (8.11- 8.25), non pregnant cows (6.05-7.04) and bull urine (6.35-7.34). The pH of the urine samples for nonpregnant cow and bull urine samples were similar to that of the control. Urea concentration of pregnant cow urine (11.06 mg/dL) was higher than that observed in bull urine 4.56 mg/dL and non pregnant cow urine 1.39 mg/dL. The study was able to validate that at 60% and above inhibition there is an indication of pregnancy while inhibition less than 60% shows the cow is non pregnant. Increased mean germination inhibition percentage and reduced shoot length in pregnant cow urine were indicative of pregnancy state.

Additive and non-additive effects for mature weight in beef cattle

Selection has emphasized animal growth, leading to an increase in their mature size affecting in some cases the pregnancy of the cows and the efficiency of the systems. Usually, crossbreeding improve productivity because of the genetic effects that the cows exploit, but the impact on mature weight (MW) has not been studied. The present study aimed at estimating MW and genetic parameters associated with the MW in crosses between two British breeds: Hereford (H/H) and Angus (A/A), a Continental: Salers (S/S), and a Zebu: Nelore (N/N). MW was analyzed at 4; 4.5; 5; 5.5 and 6 years of age using a repeated-measure sire model. For parameters estimation, an additive – dominant model was used including the fixed effects of breed group, contemporary group, and age as covariate linear and quadratic, with the linear regression fitted by breed group. Permanent environmental and sire were included as random effects. According to the results, it is expected to observe heterosis between H/H and N/N, however, the structure of the data may not be enough for estimate accurately the genetic parameters in this trait. The A/H, N/H, S/H, S/SH and H/NH cows were heavier than the H/H cows. All the breed groups continue gaining weight until six years of age. The results revealed that British crossbred animals are heavier than H/H at the first crossing but not in the following. Crossbred cows with proportions of 0.5 and greater for the Continental breed are heavier than H/H cows. Crosses between British and Zebu cows have higher mature weight than H/H at the first crossing and in backcrosses toward the British in all ages.

Dynamique de l’involution utérine et de la croissance folliculaire pendant l’anoestrus postpartum chez le zébu peulh d’Afrique

Les perspectives d’une remise en reproduction après vêlage, prennent en compte la durée de l’anoestrus postpartum. Cette durée dépendrait du délai d’involution utérine et du fonctionnement de l’axe gonado-hypothalamo-hypophysaire. L’objectif de cette étude a été d’apprécier les caractéristiques de l’anoestrus postpartum, notamment l’involution utérine complète et la reprise de l’activité ovarienne après la parturition chez la vache zébu Peuhl. Elle a concerné dix femelles (n = 10) d’âge et de poids moyens compris respectivement dans les intervalles [4 – 13] ans et [190 – 250] kg. Elles ont été examinées à partir deJ7 jusqu’à J100 postpartum, au moyen d’un échographe portable muni d’une sonde linéaire de 7,5 Mhz. Les clichés les plus représentatifs des cornes utérines, du cervix et des organites ovariens ont été enregistrés et analysés. La courbe de résorption utérine a montré une phase de régression rapide entre J7 et J16 suivi d’une phase lente entre J17 et J45.Ledélai moyen pour l’involution utérine a été 26,6 ± 2,11jours. La reprise de l’activité ovarienne a été observée dans un délai de 68,5 ± 6,11 jours. Ce délai varie en fonction de la parité (p = 0,04).Mots clés : Involution utérine, activité ovarienne, postpartum, zébu. English Title: Dynamics of uterine involution and follicular growth during anoestrus postpartum in African zebu Peulh The prospects for rebreeding after calving were strongly influenced by postpartum anestrus duration which depends on the time of complete uterine involution and ovarian activity resumption. The aim of this study was to assess the characteristics of postpartum anestrus, in particular complete uterine involution and resumption of ovarian activity in the Peuhl zebu. It carried out on ten females (n = 10) which mean age and weight were extended between [4 - 13] years and [190 - 250] kg respectively. They were examined from Day 7 to Day 100 after calving by using a portable ultrasound scanner equipped with a 7.5 Mhz linear probe. The most representative images of uterine horns, cervix and ovarian structures have been frozen, recorded and exported for analyzing. The uterine resorption curve showed a rapid regression phase between Day 7 to 16 followed by a slow phase between D17 and D45. The mean time for uterine involution was 26.6 ± 2.11 days. Resumption of ovarian activity was observed within 68.5 ± 6.11 days. This time varies with parity (p = 0.04). Keywords: Uterine involution, ovarian activity, postpartum, Zebu cows

Milk production of crossbred holstein × zebu on different pasture-management strategies

The objective of this study was to evaluate nutrient intake and digestibility, yield and components of milk from Holstein × Zebu cows on Tanzania grass pastures using a fixed-rest period or 95% light interception. The treatments consisted of evaluations of two Tanzania-grass pasture-management strategies: LI95 - when the pasture reached 95% light interception (LI), with 3 paddock-occupation days; and FR - the pasture was managed with a 30-days defoliation interval (DI) and 3 paddock-occupation days. Ten recently calved cows per treatment in year 1 and eight cows per treatment in year 2 were used, i.e. five cows per replicate in year 2 and four cows per replicate in year 2. Intake and digestibility of pasture nutrients, milk yield and milk composition were evaluated. The management strategies imposed on the Tanzania-grass pasture did not affect nutrient intake or digestibility. Milk yield and milk components were not affected by the management strategies, but milk yield per area unit was affected by the use of 95% light interception. The management strategy applying 95% light interception implies greater efficiency in the use of area, which translates to a higher milk yield per unit area, and thus it can be recommended to increase milk yield per area.