Table 6.
Manuscripts comparing mortality rates in calves or general calf health, with and without a period of extended maternal contact1
| Study | Country | Breed2 | Contact type | Contact duration | Contact duration (controls) | Type of colostrum (control groups) | Amount of colostrum (control groups) | Calf age under study | n (calves) | No. of herds (no. of groups) | Conclusion | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Alvarez et al., 1980 | Mexico | HF, Brown Swiss, × Zebu | Restricted suckling | Calf present at milking, then restricted suckling | 0 d (immediate separation “at birth”) | Not specified, then milk by bucket | Not specified | 0–24 mo | 464 | 1 (2) | Mortality was 6% in restricted suckling group and 56% in artificially reared animals | +3 |
| Kovalcik et al., 1980 | Not specified | Blackspotted | Free Contact | 48-h observation | ≤1 h | Not specified | Not specified | 48 h | 6 | 1 (2) | Dam-reared calves urinated and defecated earlier and more frequently | +3 |
| Metz and Metz, 1986 | Poland | HF | Free contact | 24-h observation | 0 d (immediate separation) | Not specified | 2 L | 0–1 d | 67 | 1 (2) | Dam-reared calves urinated and defecated earlier, beneficial for first colostrum intake | + |
| Waltner- Toews et al., 1986 | Canada | HF | (Multi-herd study based upon questionnaires, farm visits, and record keeping) | 0–28 d | 1,800 | 35 | Calves that suckled naturally had lower odds of treatment for disease versus bucket-fed calves | + | ||||
| Quigley et al., 1995 | Not specified | Jersey | Free contact | 3 d | 0 d (immediate separation) | Fresh colostrum from dam | 1 L after birth, 1 L at 12 h | 0–32 d | 101 | 1 (2 relevant) | Mortality rates lower for suckling group | +3 |
| Boonbrahm et al., 2004a | Thailand | HF4 | Restricted suckling | 3 d full, 15 min (2×/d) for 80 d (postmilking) | 3 d full | Dam's colostrum | N/A5 | 4–84 d | 40 | 1 (2) | Increased mortality in separated calves vs. those with restricted suckling opportunity | +3 |
| Hartman et al., 1974 | United States | HF | (Multi-herd study with questionnaires on calf housing provided to producers) | N/A | 0–90 d | Not specified | 247 | Housing calves separately from cows had no effect on mortality rates | =3 | |||
| Curtis et al., 1988 | United States | HF | (Multi-herd study with standardized check-off forms provided to producers regarding health and mortality in addition to questions pertaining to calf management) | N/A | 0–90 d | 1,171 | 26 | Mortality not significantly different among calves receiving colostrum by suckling vs. other methods | = | |||
| Perez et al., 1990 | The Netherlands | HF, Dutch Friesian, Meuse-Rhine-Issel and cross breeds | (Multi-herd study comparing mortality in dairy calves under different managerial systems) | Varied | 0–28 d | 1,037 | 63 | Mortality not significantly different in calves that received colostrum by suckling versus by hand | = | |||
| Little et al., 1991 | Ethiopia | Friesian × Boran | Restricted suckling | 24 h free contact, then restricted suckling 2×/d before milking | 24 h | All of the dam's colostrum | 0–94 d | 13 | 1 (2) | No mortalities occurred, thus no difference between bucket reared and restricted suckling group | =3 | |
| Wells et al., 1996 | United States | HF4 | Free contact | 24 h | 12 h | Varied | Varied | 0–21 d | 9,484 | 906 | Increased mortality rate in calves separated at 24 vs. 12 h | − |
| Jenny et al., 1981 | United States | Varied | (Multi-herd study with survey forms on management practices and mortality data mailed to producers) | N/A | 0–6 mo | Not specified | 140 | Lower mortality in herds where calves were separated early | −3 | |||
| Gulliksen et al., 2009b | Norway | Norwegian Red4 | (Multi-herd study with questionnaires on calf housing provided to producers) | Varied | 0–7 d | 5,382 | 125 | Suckling calves tended to have increased risk of mortality compared with hand-fed calves | −6 | |||
Listed for each study are country, breed of cattle, type of cow-calf contact allowed, duration of this contact, how colostrum was fed to calves in the control condition (i.e., in which calves were not allowed to suckle), the amount of colostrum provided in this condition, the age range of calves under study, the total number of calves followed, the number of herds (and groups within a herd), and the authors' conclusion and direction of effect (with + signifying a beneficial effect of suckling or cow-calf contact, − signifying a negative effect, and = representing no difference. Studies are ordered chronologically within effect direction).
HF signifies that breed was reported as Holstein, Friesian, or Holstein-Friesian.
No statistical test performed.
Predominantly.
N/A = not applicable.
No significant difference, P = 0.07.